机械毕业设计英文外文翻译330模具高速铣削加工技术
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毕业设计(论文)外文资料翻译学院(系):机械工程系专业:机械工程及自动化姓名:学号:外文出处:High-speed machining and demandFor the development附件:1.外文资料翻译译文;2.外文原文附件1:外文资料翻译高速切削加工的发展及需求高速切削加工是当代先进制造技术的重要组成部分,拥有高效率、高精度及高表面质量等特征。
本文介绍此技术的定义、发展现状、适用领域以及中国的需求情况。
高速切削加工是面向21世纪的一项高新技术,它以高效率、高精度和高表面质量为基本特征,在汽车工业、航空航天、模具制造和仪器仪表等行业中获得了愈来愈广泛的应用,并已取得了重大的技术经济效益,是当代先进制造技术的重要组成部分。
高速切削是实现高效率制造的核心技术,工序的集约化和设备的通用化使之具有很高的生产效率。
可以说,高速切削加工是一种不增加设备数量而大幅度提高加工效率所必不可少的技术。
高速切削加工的优点主要在于:提高生产效率、提高加工精度及降低切削阻力。
有关高速切削加工的含义,目前尚无统一的认识,通常有如下几种观点:切削速度很高,通常认为其速度超过普通切削的5-10倍;机床主轴转速很高,一般将主轴转速在10000-20000r/min以上定为高速切削;进给速度很高,通常达15-50m/min,最高可达90m/min;对于不同的切削材料和所釆用的刀具材料,高速切削的含义也不尽相同;切削过程中,刀刃的通过频率(Tooth Passing Frequency)接近于“机床-刀具-工件”系统的主导自然频率(Dominant Natural Frequency)时,可认为是高速切削。
可见高速切削加工是一个综合的概念。
1992年,德国Darmstadt工业大学的H. Schulz教授在CIRP上提出了高速切削加工的概念及其涵盖的范围,如图1所示。
认为对于不同的切削对象,图中所示的过渡区(Transition)即为通常所谓的高速切削範围,这也是当时金属切削工艺相关的技术人员所期待或者可望实现的切削速度。
毕业论文中英文资料外文翻译文献附录附录1:英文原文Selection of optimum tool geometry and cutting conditionsusing a surface roughness prediction model for end milling Abstract Influence of tool geometry on the quality of surface produced is well known and hence any attempt to assess the performance of end milling should include the tool geometry. In the present work, experimental studies have been conducted to see the effect of tool geometry (radial rake angle and nose radius) and cutting conditions (cutting speed and feed rate) on the machining performance during end milling of medium carbon steel. The first and second order mathematical models, in terms of machining parameters, were developed for surface roughness prediction using response surface methodology (RSM) on the basis of experimental results. The model selected for optimization has been validated with the Chi square test. The significance of these parameters on surface roughness has been established with analysis of variance. An attempt has also been made to optimize the surface roughness prediction model using genetic algorithms (GA). The GA program gives minimum values of surface roughness and their respective optimal conditions.1 IntroductionEnd milling is one of the most commonly used metal removal operations in industry because of its ability to remove material faster giving reasonably good surface quality. It is used in a variety of manufacturing industries including aerospace and automotive sectors, where quality is an important factor in the production of slots, pockets, precision moulds and dies. Greater attention is given to dimensional accuracy and surface roughness of products by the industry these days. Moreover, surface finish influences mechanical properties such as fatigue behaviour, wear, corrosion, lubrication and electrical conductivity. Thus, measuring and characterizing surface finish can be considered for predicting machining performance.Surface finish resulting from turning operations has traditionally received considerable research attention, where as that of machining processes using multipoint cutters, requires attention by researchers. As these processes involve large number of parameters, it would bedifficult to correlate surface finish with other parameters just by conducting experiments. Modelling helps to understand this kind of process better. Though some amount of work has been carried out to develop surface finish prediction models in the past, the effect of tool geometry has received little attention. However, the radial rake angle has a major affect on the power consumption apart from tangential and radial forces. It also influences chip curling and modifies chip flow direction. In addition to this, researchers [1] have also observed that the nose radius plays a significant role in affecting the surface finish. Therefore the development of a good model should involve the radial rake angle and nose radius along with other relevant factors.Establishment of efficient machining parameters has been a problem that has confronted manufacturing industries for nearly a century, and is still the subject of many studies. Obtaining optimum machining parameters is of great concern in manufacturing industries, where the economy of machining operation plays a key role in the competitive market. In material removal processes, an improper selection of cutting conditions cause surfaces with high roughness and dimensional errors, and it is even possible that dynamic phenomena due to auto excited vibrations may set in [2]. In view of the significant role that the milling operation plays in today’s manufacturing world, there is a need to optimize the machining parameters for this operation. So, an effort has been made in this paper to see the influence of tool geometry(radial rake angle and nose radius) and cutting conditions(cutting speed and feed rate) on the surface finish produced during end milling of medium carbon steel. The experimental results of this work will be used to relate cutting speed, feed rate, radial rake angle and nose radius with the machining response i.e. surface roughness by modelling. The mathematical models thus developed are further utilized to find the optimum process parameters using genetic algorithms.2 ReviewProcess modelling and optimization are two important issues in manufacturing. The manufacturing processes are characterized by a multiplicity of dynamically interacting process variables. Surface finish has been an important factor of machining in predicting performance of any machining operation. In order to develop and optimize a surface roughness model, it is essential to understand the current status of work in this area.Davis et al. [3] have investigated the cutting performance of five end mills having various helix angles. Cutting tests were performed on aluminium alloy L 65 for three milling processes (face, slot and side), in which cutting force, surface roughness and concavity of a machined plane surface were measured. The central composite design was used to decide on the number of experiments to be conducted. The cutting performance of the end mills was assessed usingvariance analysis. The affects of spindle speed, depth of cut and feed rate on the cutting force and surface roughness were studied. The investigation showed that end mills with left hand helix angles are generally less cost effective than those with right hand helix angles. There is no significant difference between up milling and down milling with regard tothe cutting force, although the difference between them regarding the surface roughness was large. Bayoumi et al.[4] have studied the affect of the tool rotation angle, feed rate and cutting speed on the mechanistic process parameters (pressure, friction parameter) for end milling operation with three commercially available workpiece materials, 11 L 17 free machining steel, 62- 35-3 free machining brass and 2024 aluminium using a single fluted HSS milling cutter. It has been found that pressure and friction act on the chip – tool interface decrease with the increase of feed rate and with the decrease of the flow angle, while the cutting speed has a negligible effect on some of the material dependent parameters. Process parameters are summarized into empirical equations as functions of feed rate and tool rotation angle for each work material. However, researchers have not taken into account the effects of cutting conditions and tool geometry simultaneously; besides these studies have not considered the optimization of the cutting process.As end milling is a process which involves a large number f parameters, combined influence of the significant parameters an only be obtained by modelling. Mansour and Abdallaet al. [5] have developed a surface roughness model for the end milling of EN32M (a semi-free cutting carbon case hardening steel with improved merchantability). The mathematical model has been developed in terms of cutting speed, feed rate and axial depth of cut. The affect of these parameters on the surface roughness has been carried out using response surface methodology (RSM). A first order equation covering the speed range of 30–35 m/min and a second order equation covering the speed range of 24–38 m/min were developed under dry machining conditions. Alauddin et al. [6] developed a surface roughness model using RSM for the end milling of 190 BHN steel. First and second order models were constructed along with contour graphs for the selection of the proper combination of cutting speed and feed to increase the metal removal rate without sacrificing surface quality. Hasmi et al. [7] also used the RSM model for assessing the influence of the workpiece material on the surface roughness of the machined surfaces. The model was developed for milling operation by conducting experiments on steel specimens. The expression shows, the relationship between the surface roughness and the various parameters; namely, the cutting speed, feed and depth of cut. The above models have not considered the affect of tool geometry on surface roughness.Since the turn of the century quite a large number of attempts have been made to find optimum values of machining parameters. Uses of many methods have been reported in the literature to solve optimization problems for machining parameters. Jain and Jain [8] have usedneural networks for modeling and optimizing the machining conditions. The results have been validated by comparing the optimized machining conditions obtained using genetic algorithms. Suresh et al. [9] have developed a surface roughness prediction model for turning mild steel using a response surface methodology to produce the factor affects of the individual process parameters. They have also optimized the turning process using the surface roughness prediction model as the objective function. Considering the above, an attempt has been made in this work to develop a surface roughness model with tool geometry and cutting conditions on the basis of experimental results and then optimize it for the selection of these parameters within the given constraints in the end milling operation.3 MethodologyIn this work, mathematical models have been developed using experimental results with the help of response surface methodolog y. The purpose of developing mathematical models relating the machining responses and their factors is to facilitate the optimization of the machining process. This mathematical model has been used as an objective function and the optimization was carried out with the help of genetic algorithms.3.1 Mathematical formulationResponse surface methodology(RSM) is a combination of mathematical and statistical techniques useful for modelling and analyzing the problems in which several independent variables influence a dependent variable or response. The mathematical models commonly used are represented by:where Y is the machining response, ϕ is the response function and S, f , α, r are milling variables and ∈is the error which is normally distributed about the observed response Y with zero mean.The relationship between surface roughness and other independent variables can be represented as follows,where C is a constant and a, b, c and d are exponents.To facilitate the determination of constants and exponents, this mathematical model will have to be linearized by performing a logarithmic transformation as follows:The constants and exponents C, a, b, c and d can be determined by the method of least squares. The first order linear model, developed from the above functional relationship using least squares method, can be represented as follows:where Y1 is the estimated response based on the first-order equation, Y is the measured surface roughness on a logarithmic scale, x0 = 1 (dummy variable), x1, x2, x3 and x4 are logarithmic transformations of cutting speed, feed rate, radial rake angle and nose radiusrespectively, ∈is the experimental error and b values are the estimates of corresponding parameters.The general second order polynomial response is as given below:where Y2 is the estimated response based on the second order equation. The parameters, i.e. b0, b1, b2, b3, b4, b12, b23, b14, etc. are to be estimated by the method of least squares. Validity of the selected model used for optimizing the process parameters has been tested with the help of statistical tests, such as F-test, chi square test, etc. [10].3.2 Optimization using genetic algorithmsMost of the researchers have used traditional optimization techniques for solving machining problems. The traditional methods of optimization and search do not fare well over a broad spectrum of problem domains. Traditional techniques are not efficient when the practical search space is too large. These algorithms are not robust. They are inclined to obtain a local optimal solution. Numerous constraints and number of passes make the machining optimization problem more complicated. So, it was decided to employ genetic algorithms as an optimization technique. GA come under the class of non-traditional search and optimization techniques. GA are different from traditional optimization techniques in the following ways:1.GA work with a coding of the parameter set, not the parameter themselves.2.GA search from a population of points and not a single point.3.GA use information of fitness function, not derivatives or other auxiliary knowledge.4.GA use probabilistic transition rules not deterministic rules.5.It is very likely that the expected GA solution will be the global solution.Genetic algorithms (GA) form a class of adaptive heuristics based on principles derived from the dynamics of natural population genetics. The searching process simulates the natural evaluation of biological creatures and turns out to be an intelligent exploitation of a random search. The mechanics of a GA is simple, involving copying of binary strings. Simplicity of operation and computational efficiency are the two main attractions of the genetic algorithmic approach. The computations are carried out in three stages to get a result in one generation or iteration. The three stages are reproduction, crossover and mutation.In order to use GA to solve any problem, the variable is typically encoded into a string (binary coding) or chromosome structure which represents a possible solution to the given problem. GA begin with a population of strings (individuals) created at random. The fitness of each individual string is evaluated with respect to the given objective function. Then this initial population is operated on by three main operators – reproduction cross over and mutation– to create, hopefully, a better population. Highly fit individuals or solutions are given theopportunity to reproduce by exchanging pieces of their genetic information, in the crossover procedure, with other highly fit individuals. This produces new “offspring” solutions, which share some characteristics taken from both the parents. Mutation is often applied after crossover by altering some genes (i.e. bits) in the offspring. The offspring can either replace the whole population (generational approach) or replace less fit individuals (steady state approach). This new population is further evaluated and tested for some termination criteria. The reproduction-cross over mutation- evaluation cycle is repeated until the termination criteria are met.4 Experimental detailsFor developing models on the basis of experimental data, careful planning of experimentation is essential. The factors considered for experimentation and analysis were cutting speed, feed rate, radial rake angle and nose radius.4.1 Experimental designThe design of experimentation has a major affect on the number of experiments needed. Therefore it is essential to have a well designed set of experiments. The range of values of each factor was set at three different levels, namely low, medium and high as shown in Table 1. Based on this, a total number of 81 experiments (full factorial design), each having a combination of different levels of factors, as shown in Table 2, were carried out.The variables were coded by taking into account the capacity and limiting cutting conditions of the milling machine. The coded values of variables, to be used in Eqs. 3 and 4, were obtained from the following transforming equations:where x1 is the coded value of cutting speed (S), x2 is the coded value of the feed rate ( f ), x3 is the coded value of radial rake angle(α) and x4 is the coded value of nose radius (r).4.2 ExperimentationA high precision ‘Rambaudi Rammatic 500’ CNC milling machine, with a vertical milling head, was used for experimentation. The control system is a CNC FIDIA-12 compact. The cutting tools, used for the experimentation, were solid coated carbide end mill cutters of different radial rake angles and nose radii (WIDIA: DIA20 X FL38 X OAL 102 MM). The tools are coated with TiAlN coating. The hardness, density and transverse rupture strength are 1570 HV 30, 14.5 gm/cm3 and 3800 N/mm2 respectively.AISI 1045 steel specimens of 100×75 mm and 20 mm thickness were used in the present study. All the specimens were annealed, by holding them at 850 ◦C for one hour and then cooling them in a furnace. The chemical analysis of specimens is presented in Table 3. Thehardness of the workpiece material is 170 BHN. All the experiments were carried out at a constant axial depth of cut of 20 mm and a radial depth of cut of 1 mm. The surface roughness (response) was measured with Talysurf-6 at a 0.8 mm cut-off value. An average of four measurements was used as a response value.5 Results and discussionThe influences of cutting speed, feed rate, radial rake angle and nose radius have been assessed by conducting experiments. The variation of machining response with respect to the variables was shown graphically in Fig. 1. It is seen from these figures that of the four dependent parameters, radial rake angle has definite influence on the roughness of the surface machined using an end mill cutter. It is felt that the prominent influence of radial rake angle on the surface generation could be due to the fact that any change in the radial rake angle changes the sharpness of the cutting edge on the periphery, i.e changes the contact length between the chip and workpiece surface. Also it is evident from the plots that as the radial rake angle changes from 4◦to 16◦, the surface roughness decreases and then increases. Therefore, it may be concluded here that the radial rake angle in the range of 4◦to 10◦would give a better surface finish. Figure 1 also shows that the surface roughness decreases first and then increases with the increase in the nose radius. This shows that there is a scope for finding the optimum value of the radial rake angle and nose radius for obtaining the best possible quality of the surface. It was also found that the surface roughness decreases with an increase in cutting speed and increases as feed rate increases. It could also be observed that the surface roughness was a minimum at the 250 m/min speed, 200 mm/min feed rate, 10◦radial rake angle and 0.8 mm nose radius. In order to understand the process better, the experimental results can be used to develop mathematical models using RSM. In this work, a commercially available mathematical software package (MATLAB) was used for the computation of the regression of constants and exponents.5.1 The roughness modelUsing experimental results, empirical equations have been obtained to estimate surface roughness with the significant parameters considered for the experimentation i.e. cutting speed, feed rate, radial rake angle and nose radius. The first order model obtained from the above functional relationship using the RSM method is as follows:The transformed equation of surface roughness prediction is as follows:Equation 10 is derived from Eq. 9 by substituting the coded values of x1, x2, x3 and x4 in termsof ln s, ln f , lnαand ln r. The analysis of the variance (ANOV A) and the F-ratio test have been performed to justify the accuracy of the fit for the mathematical model. Since the calculated values of the F-ratio are less than the standard values of the F-ratio for surface roughness as shown in Table 4, the model is adequate at 99% confidence level to represent the relationship between the machining response and the considered machining parameters of the end milling process.The multiple regression coefficient of the first order model was found to be 0.5839. This shows that the first order model can explain the variation in surface roughness to the extent of 58.39%. As the first order model has low predictability, the second order model has been developed to see whether it can represent better or not.The second order surface roughness model thus developed is as given below:where Y2 is the estimated response of the surface roughness on a logarithmic scale, x1, x2, x3 and x4 are the logarithmic transformation of speed, feed, radial rake angle and nose radius. The data of analysis of variance for the second order surface roughness model is shown in Table 5.Since F cal is greater than F0.01, there is a definite relationship between the response variable and independent variable at 99% confidence level. The multiple regression coefficient of the second order model was found to be 0.9596. On the basis of the multiple regression coefficient (R2), it can be concluded that the second order model was adequate to represent this process. Hence the second order model was considered as an objective function for optimization using genetic algorithms. This second order model was also validated using the chi square test. The calculated chi square value of the model was 0.1493 and them tabulated value at χ2 0.005 is 52.34, as shown in Table 6, which indicates that 99.5% of the variability in surface roughness was explained by this model.Using the second order model, the surface roughness of the components produced by end milling can be estimated with reasonable accuracy. This model would be optimized using genetic algorithms (GA).5.2 The optimization of end millingOptimization of machining parameters not only increases the utility for machining economics, but also the product quality toa great extent. In this context an effort has been made to estimate the optimum tool geometry and machining conditions to produce the best possible surface quality within the constraints.The constrained optimization problem is stated as follows: Minimize Ra using the model given here:where xil and xiu are the upper and lower bounds of process variables xi and x1, x2, x3, x4 are logarithmic transformation of cutting speed, feed, radial rake angle and nose radius.The GA code was developed using MATLAB. This approach makes a binary coding system to represent the variables cutting speed (S), feed rate ( f ), radial rake angle (α) and nose radius (r), i.e. each of these variables is represented by a ten bit binary equivalent, limiting the total string length to 40. It is known as a chromosome. The variables are represented as genes (substrings) in the chromosome. The randomly generated 20 such chromosomes (population size is 20), fulfilling the constraints on the variables, are taken in each generation. The first generation is called the initial population. Once the coding of the variables has been done, then the actual decoded values for the variables are estimated using the following formula: where xi is the actual decoded value of the cutting speed, feed rate, radial rake angle and nose radius, x(L) i is the lower limit and x(U) i is the upper limit and li is the substring length, which is equal to ten in this case.Using the present generation of 20 chromosomes, fitness values are calculated by the following transformation:where f(x) is the fitness function and Ra is the objective function.Out of these 20 fitness values, four are chosen using the roulette-wheel selection scheme. The chromosomes corresponding to these four fitness values are taken as parents. Then the crossover and mutation reproduction methods are applied to generate 20 new chromosomes for the next generation. This processof generating the new population from the old population is called one generation. Many such generations are run till the maximum number of generations is met or the average of four selected fitness values in each generation becomes steady. This ensures that the optimization of all the variables (cutting speed, feed rate, radial rake angle and nose radius) is carried out simultaneously. The final statistics are displayed at the end of all iterations. In order to optimize the present problem using GA, the following parameters have been selected to obtain the best possible solution with the least computational effort: Table 7 shows some of the minimum values of the surface roughness predicted by the GA program with respect to input machining ranges, and Table 8 shows the optimum machining conditions for the corresponding minimum values of the surface roughness shown in Table 7. The MRR given in Table 8 was calculated bywhere f is the table feed (mm/min), aa is the axial depth of cut (20 mm) and ar is the radial depth of cut (1 mm).It can be concluded from the optimization results of the GA program that it is possible toselect a combination of cutting speed, feed rate, radial rake angle and nose radius for achieving the best possible surface finish giving a reasonably good material removal rate. This GA program provides optimum machining conditions for the corresponding given minimum values of the surface roughness. The application of the genetic algorithmic approach to obtain optimal machining conditions will be quite useful at the computer aided process planning (CAPP) stage in the production of high quality goods with tight tolerances by a variety of machining operations, and in the adaptive control of automated machine tools. With the known boundaries of surface roughness and machining conditions, machining could be performed with a relatively high rate of success with the selected machining conditions.6 ConclusionsThe investigations of this study indicate that the parameters cutting speed, feed, radial rake angle and nose radius are the primary actors influencing the surface roughness of medium carbon steel uring end milling. The approach presented in this paper provides n impetus to develop analytical models, based on experimental results for obtaining a surface roughness model using the response surface methodology. By incorporating the cutter geometry in the model, the validity of the model has been enhanced. The optimization of this model using genetic algorithms has resulted in a fairly useful method of obtaining machining parameters in order to obtain the best possible surface quality.中文翻译选择最佳工具,几何形状和切削条件利用表面粗糙度预测模型端铣摘要:刀具几何形状对工件表面质量产生的影响是人所共知的,因此,任何成型面端铣设计应包括刀具的几何形状。
翻译部分英文部分ADV ANCED MACHINING PROCESSESAs the hardware of an advanced technology becomes more complex, new and visionary approaches to the processing of materials into useful products come into common use. This has been the trend in machining processes in recent years.. Advanced methods of machine control as well as completely different methods of shaping materials have permitted the mechanical designer to proceed in directions that would have been totally impossible only a few years ago.Parallel development in other technologies such as electronics and computers have made available to the machine tool designer methods and processes that can permit a machine tool to far exceed the capabilities of the most experienced machinist.In this section we will look at CNC machining using chip-making cutting tools. CNC controllers are used to drive and control a great variety of machines and mechanisms, Some examples would be routers in wood working; lasers, plasma-arc, flame cutting, and waterjets for cutting of steel plate; and controlling of robots in manufacturing and assembly. This section is only an overview and cannot take the place of a programming manual for a specific machine tool. Because of the tremendous growth in numbers and capability of comp uters ,changes in machine controls are rapidly and constantly taking place. The exciting part of this evolution in machine controls is that programming becomeseasier with each new advanced in this technology.Advantages of Numerical ControlA manually operated machine tool may have the same physical characteristics as a CNC machine, such as size and horsepower. The principles of metal removal are the same. The big gain comes from the computer controlling the machining axes movements. CNC-controlled machine tools can be as simple as a 2-axis drilling machining center (Figure O-1). With a dual spindle machining center, the low RPM, high horsepower spindle gives high metal removal rates. The high RPM spindle allows the efficient use of high cutting speed tools such as diamonds and small diameter cutters (Figure O-2). The cutting tools that remove materials are standard tools such as milling cutters, drills, boring tools, or lathe tools depending on the type of machine used. Cutting speeds and feeds need to be correct as in any other machining operation. The greatest advantage in CNC machining comes from the unerring and rapid positioning movements possible. A CNC machine does dot stop at the end of a cut to plan its next move; it does not get fatigued; it is capable of uninterrupted machining error free, hour after hour. A machine tool is productive only while it is making chips.Since the chip-making process is controlled by the proper feeds and speeds, time savings can be achieved by faster rapid feed rates. Rapid feeds have increased from 60 to 200 to 400 and are now often approaching 1000 inches per minute (IPM). These high feed rates can pose a safety hazard to anyone within the working envelope of the machine tool.Complex contoured shapes were extremely difficult to product prior to CNC machining .CNC has made the machining of these shapes economically feasible. Design changes on a part are relatively easy to make by changing the program that directs the machine tool.A CNC machine produces parts with high dimensional accuracy and close tolerances without taking extra time or special precautions, CNC machines generally need less complex work-holding fixtures, which saves time by getting the parts machined sooner. Once a program is ready and production parts, each part will take exactly the same amount of time as the previous one. This repeatability allows for a very precise control of production costs. Another advantage of CNC machining is the elimination of large inventories; parts can be machined as needs .In conventional production often a great number of parts must be made at the same time to be cost effective. With CNC even one piece can be machined economically .In many instances, a CNC machine can perform in one setup the same operations that would require several conventional machines.With modern CNC machine tools a trained machinist can program and product even a single part economically .CNC machine tools are used in small and large machining facilities and range in size from tabletop models to huge machining centers. In a facility with many CNC tools, programming is usually done by CNC programmers away from the CNC tools. The machine control unit (MCU) on the machine is then used mostly for small program changes or corrections. Manufacturing with CNC tools usually requires three categories of persons. The first is the programmer, who is responsible for developing machine-ready code. The next person involved is the setup person, who loads the raw stork into the MCU, checks that the co rrect tools are loaded, and makes the first part. The third person is the machine and unloads the finished parts. In a small company, one person is expected to perform all three of these tasks.CNC controls are generally divided into two basic categories. One uses a ward address format with coded inputs such as G and M codes. The other users a conversational input; conversational input is also called user-friendly or prompted input. Later in this section examples of each of these programming formats in machining applications will be describes.CAM and CNCCAM systems have changed the job of the CNC programmer from one manually producing CNC code to one maximizing the output of CNC machines. Since CNC machine tools are made by a great number of manufacturers, many different CNC control units are in use. Control units from different manufacturers use a variety of program formats and codes. Many CNC code words are identical for different controllers, but a great number vary from one to another.To produce an identical part on CNC machine tools with different controllers such as one by FANCU, OKUMA or DYNAPATH, would require completely different CNC codes. Each manufacturer is constantly improving and updating its CNC controllers. These improvements often include additional code words plus changes in how the existing code works.A CAM systems allows the CNC programmer to concentrate on the creation of an efficient machining process, rather then relearning changed code formats. A CNC programmer looks atthe print of a part and then plans the sequence of machining operations necessary to make it (Figure O-3). This plan includes everything, from the selection of possible CNC machine tools, to which tooling to use, to how the part is held while machining takes place. The CNC programmer has to have a thorough understanding of all the capacities and limitations of the CNC machine tools that a program is to be made for. Machine specifications such as horsepower, maximum spindle speeds, workpiece weight and size limitations, and tool changer capacity are just some of the considerations that affect programming.Another area of major importance to the programmer is the knowledge of machining processes. An example would be the selection of the surface finish requirement specified in the part print. The sequence of machining processes is critical to obtain acceptable results. Cutting tool limitations have to be considered and this requires knowledge of cutting tool materials, tool types, and application recommendations.A good programmer will spend a considerable amount of time in researching the rapidly growing volume of new and improved tools and tool materials. Often the tool that was on the cutting edge of technology just two years ago is now obsolete. Information on new tools can come from catalogs or tool manufacturers' tooling engineers. Help in tool selection or optimum tool working conditions can also be obtained from tool manufacturer software. Examples would be Kennametal's "TOOLPRO", software designed to help select the best tool grade, speed, and feed rates for different work materials in turning application. Another very important feature of "TOOLPRO" is the display of the horsepower requirement for each machining selection. This allow the programmer to select a combination of cutting speed, feed rate, and depth of cut that equals the machine's maximum horsepower for roughing cuts. For a finishing cut, the smallest diameter of the part being machined is selected and then the cutting speed varied until the RPM is equal to the maximum RPM of the machine. This helps in maximizing machining efficiency. Knowing the horsepower requirement for a cut is critical if more than one tool is cutting at the same time.Software for a machining center application would be Ingersoll Tool Company's "Actual Chip Thickness", a program used to calculate the chip thickness in relation to feed-per-tooth for a milling cutter, especially during a shallow finishing cut. Ingersoll's "Rigidity Analysis" software ealculates tool deflection for end mills as a function of tool stiffness and tool force.To this point we looked at some general qualifications that a programmer should possess. Now we examine how a CAM system works. Point Control Company's SmartCam system uses the following approach. First, the programmer makes a mental model of the part to be machined. This includes the kind of machining to be performed-turning or milling. Then the part print is studied to develop a machining sequence, roughing and finishing cuts, drilling, tapping, and boring operations. What work-holding device is to be used, a vise or fixture or clamps? After these considerations, computer input can be started. First comes the creation of a JOBPLAN. This JOBPLAN consists of entries such as inch or metric units, machine type, part ID, type of workpiece material, setup notes, and a description of the required tools.This line of information describes the tool by number, type, and size and includes theappropriate cutting speed and feed rate. After all the selected tools are entered, the file is saved.The second programming step is the making of the part. This represents a graphic modeling of the projected machining operation. After selecting a tool from the prepared JOBPLAN, parameters for the cutting operation are entered. For a drill, once the coordinate location of the hole and the depth are given, a circle appears on that spot. If the location is incorrect, the UNDO command erases this entry and allows you to give new values for this operation. When an end mill is being used, cutting movements (toolpath) are usually defined as lines and arcs. As a line is programmed, the toolpath is graphically displayed and errors can be corrected instantly.At any time during programming, the command SHOWPATH will show the actual toolpath for each of the programmed tools. The tools will be displayed in the sequence in which they will be used during actual machining. If the sequence of a tool movement needs to be changed, a few keystrokes will to that.Sometimes in CAM the programming sequence is different from the actual machining order. An example would be the machining of a pocket in a part. With CAM, the finished pocket outline is programmed first, then this outline is used to define the ro ughing cuts to machine the pocket. The roughing cuts are computer generated from inputs such as depth and width of cut and how much material to leave for the finish cut. Different roughing patterns can be tried out to allow the programmer to select the most efllcient one for the actual machining cuts. Since each tool is represented by a different color, it is easy to observe the toolpath made by each one.A CAM system lets the programmer view the graphics model from varying angles, such as a top, front, side, or isometric view. A toolpath that looks correct from a top view, may show from a front view that the depth of the cutting tool is incorrect. Changes can easily be made and seen immediately.When the toolpath and the sequence of operations are satisfactory, machine ready code has to be made. This is as easy as specifying the CNC machine that is to be used to machine the part. The code generator for that specific CNC machin e during processing accesses four different files. The JOBPLAN file for the tool information and the GRAPHICE file for the toolpath and cutting sequence. It also uses the MACHINE DEFINE file which defines the CNC code words for that specific machine. This file also supplies data for maximum feed rates, RPM, toolchange times, and so on. The fourth file taking part in the code generating process is the TEMPLATE file. This file acts like a ruler that produces the CNC code with all of its parts in the right place and sequence. When the code generation is complete, a projected machining time is displayed. This time is calculated from values such as feed rates and distances traveled, noncutting movements at maximum feed rates between points, tool change times, and so on. The projected machining time can be revised by changing tooling to allow for higher metal removal rates or creating a more efficient toolpath. This display of total time required can also be used to estimate production costs. If more then one CNC machine tool is available to machine this part, making code and comparing the machining time may show that one machine is more efficient than the others.CAD/CAMAnother method of creating toolpath is with the use of a Computer-aided Drafting (CAD) file. Most machine drawings are created using computers with the description and part geometry stored in the computer database. SmartCAM, though its CAM CONNECTION, will read a CAD file and transfer its geometry represents the part profile, holes, and so on. The programmer still needs to prepare a JOBPLAN with all the necessary tools, but instead of programming a profile line by line, now only a tool has to be assigned to an existing profile. Again, using the SHOWPA TH function will display the toolpath for each tool and their sequence. Constant research and developments in CAD/CAM interaction will change how they work with each other. Some CAD and CAM programs, if loaded on the same computer, make it possible to switch between the two with a few keystrokes, designing and programming at the same time.The work area around the machine needs to be kept clean and clear of obstructions to prevent slipping or tripping. Machine surfaces should not be used as worktables. Use proper lifting methods to handle heavy workpieces, fixtures, or heavy cutting tools. Make measurements only when the spindle has come to a complete standstill. Chips should never be handled with bare hands.Before starting the machine make sure that the work-holding device and the workpiece are securely fastened. When changing cutting tools, protect the workpiece being machined from damage, and protect your hands from sharp cutting edges. Use only sharp cutting tools. Check that cutting tools are installed correctly and securely.Do not operate any machine controls unless you understand their function and what the y will do.The Early Development Of Numerically Controlled Machine ToolsThe highly sophisticated CNC machine tools of today, in the vast and diverse range found throughout the field of manufacturing processing, started from very humble beginnings in a number of the major industrialized countries. Some of the earliest research and development work in this field was completed in USA and a mention will be made of the UK's contribution to this numerical control development.A major problem occurred just after the Second World War, in that progress in all areas of military and commercial development had been so rapid that the levels of automation and accuracy required by the modern industrialized world could not be attained from the lab our intensive machines in use at that time. The question was how to overcome the disadvantages of conventional plant and current manning levels. It is generally ackonwledged that the earliest work into numerical control was the study commissioned in 1947 by the US governme nt. The study's conclusion was that the metal cutting industry throughout the entire country could not copy with the demands of the American Air Force, let alone the rest of industry! As a direct result of the survey, the US Air Force contracted the Persons Corporation to see if they could develop a flexible, dynamic, manufacturing system which would maximize productivity. TheMassachusetts Institute of Technology (MIT) was sub-contracted into this research and development by the Parsons Corporation, during the period 1949-1951,and jointly they developed the first control system which could be adapted to a wide range of machine tools. The Cincinnati Machine Tool Company converted one of their standard 28 inch "Hydro-Tel" milling machines or a three-axis automatic milling made use of a servo-mechanism for the drive system on the axes. This machine made use of a servomechanism for the drive system on the axes, which controlled the table positioning, cross-slide and spindle head. The machine cab be classified as the first truly three axis continuous path machine tool and it was able to generate a required shape, or curve, by simultaneous slide way motions, if necessary.At about the same times as these American advances in machine tool control were taking Place, Alfred Herbert Limited in the United Kingdom had their first Mutinous path control system which became available in 1956.Over the next few years in both the USA and Europe, further development work occurred. These early numerical control developments were principally for the aerospace industry, where it was necessary to cut complex geometric shapes such as airframe components and turbine blades. In parallel with this development of sophisticated control systems for aerospace requirements, a point-to-point controller was developed for more general machining applications. These less sophisticated point-to-point machines were considerably cheaper than their more complex continuous path cousins and were used when only positional accuracy was necessary. As an example of point-to-point motion on a machine tool for drilling operations, the typical movement might be fast traverse of the work piece under the drill's position-after drilling the hole, anther rapid move takes place to the next hole's position-after retraction of the drill. Of course, the rapid motion of the slideways could be achieved by each axis in a sequential and independent manner, or simultaneously. If a separate control was utilisec for each axis, the former method of table travel was less esse ntial to avoid any backlash in the system to obtain the required degree of positional accuracy and so it was necessary that the approach direction to the next point was always the same.The earliest examples of these cheaper point-to-point machines usually did not use recalculating ball screws; this meant that the motions would be sluggish, and sliderways would inevitably suffer from backlash, but more will be said about this topic later in the chapter.The early NC machines were, in the main, based upon a modified milling machine with this concept of control being utilized on turning, punching, grinding and a whole host of other machine tools later. Towards the end of the 1950s,hydrostatic slideways were often incorporated for machine tools of highly precision, which to sonic extent overcame the section problem associated with conventional slideway response, whiles averaging-out slideway inaccuracy brought about a much increased preasion in the machine tool and improved their control characteristics allows "concept of the machining center" was the product of this early work, as it allowed the machine to manufacture a range of components using a wide variety of machining processes at a single set-up, without transfer of workpieces to other variety machine tools. A machining center differed conceptually in its design from that of a milling machine, In that thecutting tools could be changed automatically by the transfer machanism, or selector, from the magazine to spindle, or vice versa.In this ductively and the automatic tool changing feature enabled the machining center to productively and efficiently machine a range of components, by replacing old tools for new, or reselecting the next cutter whilst the current machining process is in cycle.In the mid 1960s,a UK company, Molins, introduced their unique "System 24" which was meant represent the ability of a system to machine for 24 hours per day. It could be thought of as a "machining complex" which allowed a series of NC single purpose machine tools to be linked by a computerized conveyor system. This conveyor allowed the work pieces to be palletized and then directed to as machine tool as necessary. This was an early, but admirable, attempt at a form of Flexible manufacturing System concept, but was unfortunately doomed to failure. Its principal weakness was that only a small proportion of component varieties could be machine at any instant and that even fewer work pieces required the same operations to be performed on them. These factors meant that the utilization level was low, coupled to the fact that the machine tools were expensive and allowed frequent production bottlenecks of work-in-progress to arise, which further slowed down the whole operation.The early to mid-1970s was a time of revolutionary in the area of machine tool controller development, when the term computerized numerical control (CNC) became a reality. This new breed of controllers gave a company the ability to change work piece geometries, together with programs, easily with the minimum of development and lead time, allowing it to be economically viable to machine small batches, or even one-off successfully. The dream of allowing a computerized numerical controller the flexibility and ease of program editing in a production environment became a reality when two ralated factors occurred.These were:the development of integrated circuits, which reduces electronics circuit size, giving better maintenance and allowing more standardization of desing; that general purpose computers were reduced in size coupled to the fact that their cost of production had fallen considerably.The multipie benefits of cheaper electorics with greater reliability have result in the CNC fitted to the machine tools today, with the power and sophistication progtessing considerably in the last few years, allowing an almost artificial intelligence(AI) to the latest systems. Over the years, the machine tools builders have produced a large diversity in the range of applications of CNC and just some of those development will be reviewed in V olume Ⅲ。
[铣削机械加工外文翻译、中英文翻译、机械类外文文献翻译]外文翻译本科毕业论文〔设计〕相关中英文翻译资料资料题目:铣削学生姓名:所在院系:机电学院所学专业:机电技术教育MILLING Milling is bsic mchining process in which the surfce is generted by the progressive formtion nd removl of chips of mteril from the workpiece s it is fed to rotting cutter in direction perpendiculr to the xis of the cutter. In some cses the workpiece is sttionry nd the cutter is fed to the work. In most instnces multiple-tooth cutter is used so tht the metl removl rte is high, nd frequently the desired surfce is obtined in single pss of the work. The tool used in milling is known s milling cutter. It usully consists of cylindricl body which rottes on its xis nd contins eqully spced peripherl teeth tht intermittently engge nd cut the workpiece. 1 In some cses the teeth extend prt wy cross one or both Ends of the cylinder. Becuse the milling principle provides rpid metl removl nd cn produce good surfce finish, it is prticulrly well-suited for mss-production work, nd excellent milling mchines hve been developed for this purpose. However, very ccurte nd verstile millingMchines of generl-purpose nture lso hve been developed tht re widely used in jobshop nd tool nd die work. shop tht is equipped with milling mchine nd n engine lthe cn mchine lmost ny type of product of suitble size. Types of Milling Opertions. Milling opertions cn be clssified into two brod ctegories, ech of which hs severl vritions: 1. In peripherl milling surfce is generted by teeth locted in the periphery of the cutter body; the surfce is prllel with the xis of rottion of the cutter. Both flt nd formed surfces cn be produced by this method. The cross section of the resulting surfce corresponds to the xil contour of the cutter. This procedure often is clled slb milling. 2. In fce milling the generted flt surfce is t right ngles to the cutter xis nd is the combined result of the ctions of the portions of the teeth locted on both the periphery nd the fce of the cutter. 2 The mjor portion of the cutting is done by the peripherl portions of the teeth with the fce portions providing finishing ction. The bsic concepts of peripherl nd fce milling re illustrted in Fig. 16-1. Peripherl milling opertions usully re performed on mchines hving horizontl spindles, wheres fce milling is done on both horizontl- nd verticl-spindle mchines.Surfce Genertion in Mimng. Surfces cn be generted in milling by two distinctly different methods depicted in Fig. 16-2. Note tht in up milling the cutter rottes ginsi the direction of feed the workpiece, wheres in down milling the rottion is in the sme direction s the feed. s shown in Fig. 16-2, the method of chip formtion is quite different in the two cses. In up milling the c hip is very thin t the beginning, where the tooth first contcts the work, nd increses in thickness, becoming mximum where the tooth leves the work. The cutter tends topush the work long nd lift it upwrd from Tool-work reltionshios in peripherl nd fce milling the tble. This ction tends to eliminte ny effect of looseness in the feed screw nd nut of the milling mchine tble nd results in smooth cut. However, the ction lso tends to loosen the work from the clmping device so tht greter clmping forcers must be employed. In ddition, the smoothness of the generted surfce depends gretly on the shrpness of the cutting edges. In down milling, mximum chip thickness cecum close to the point t which the tooth contcts the work. Becuse the reltive motion tends to pull the workpiece into the cutter, ll possibility of looseness in the tble feed screwmust be eliminted if down milling is to be used. It should never be ttempted on mchines tht re not designed for this type of milling. Insmush s the mteril yields in pproximtely tngentil direction t the end of the tooth enggement, there is much less tendency for the mchined surfce to show tooth mrks thn when up milling is used. nother considerble dvntge of down milling is tht the cutting force tends to hold the work ginst the mchine tble, permitting lower clmping force to be employed. 3 This is prticulrly dvntgeous when milling thin workpiece or when tking hevy cuts. Sometimes disdvntge of down milling is tht the cutter teeth strike ginst the surfce of the work t the beginning of ech chip. When the workpiece hs hrd surfce, such s cstings do, this my cuse the teeth to dull rpidly. Milling Cutters. Milling cutters cn be clssified severl wys. One method is to group them into two brod clsses, bsed on tooth relief, s follows: 1.Profile-cutters hve relief provided on ech tooth by grinding smll lnd bck of the cutting edge. The cutting edge my be stright or curved.2.In form or cm-reheved cutters the cross section of ech tooth is n eccentric curve behind the cutting edge, thus providing relief. ll sections of the eccentric relief, prllel withthe cutting edge, must hve the sme contour s the cutting edge. Cutters of this type re shrpened by grinding only the fce of the teeth, with the contour of the cutting edge thus remining unchnged. nother useful method of clssifiction is ccording to the method of mounting the cutter. rbor cutters re those tht hve center hole so they cn be mounted on n rbor. Shnk cutters hve either tpered or stright integrl shnk. Those with tpered shnks cn be mounted directly in the milling mchine spindle, wheres stright-shnk cutters re held in chuck. Fcing cutters usully re bolted to the end of stub rbor. The common types of milling cutters, clssified by this system re s follows: Types of Milling Cutters. Hin milling cutters re cylindricl or disk-shped, hving stright or helicl teeth on the periphery. They re used for milling flt surfces. This type of opertion is clled pli n or slb milling. Ech tooth in helicl cutter engges the work grdully, nd usully more thn one tooth cuts t given time. This reduces shock nd chttering tendencies nd promotes smoother surfce. Consequently, this type of cutter usully is preferred over one with stright teeth. Side milling cutters re similr to plin milling cutters except tht the teeth extend rdilly prt wy cross one or both ends ofthe cylinder towrd the :center. The teeth my be either stright or helicl. Frequently these cutters re reltively nrrow, being disklike in shpe. Two or more side milling cutters often re spced on n rbor to mke simultneous, prllel cuts, in n opertion clled strddle milling. Interlocking slotting cutters consist of two cutters similr to side mills, but mde to operte s unit for milling slots. The two cutters re djusted to the desired width by inserting shims between them. Stggered-tooth milling cutters re nrrow cylindricl cutters hving stggered teeth, nd with lternte teeth hving opposite helix ngles. They re ground to cut only on the periphery, but ech tooth lso hs chip clernce ground on the protruding side. These cutters hve free cutting ction tht mkes them prticnlrly effective in milling deep slots. Metl-slitting sws re thin, plin milling cutters, usully from 1/32 to 3/16 inch thick, which hve their sides slightly "dished" to provide clernce nd prevent binding. They usully hve more teeth per inch of dimeter thn ordinry plin milling cutters nd re used for milling deep, nrrow slots nd for cutting-off opertions. 铣削铣削是机械加工的一个基础方法。
毕业设计(论文)外文资料翻译学院:机械工程专业:机械设计制造及其自动化姓名:学号:3082108330外文出处:Lecture Notes in Computer science (用外文写)附件: 1.外文资料翻译译文;2.外文原文。
注:请将该封面与附件装订成册。
附件1:外文资料翻译译文高速加工和现代模具制造一、概述1 目前模具制造的发展现状和趋势模具作为重要的工艺装备,在消费品、电器电子、汽车、飞机制造等工业部门中,占有举足轻重的地位。
工业产品零件粗加工的75%,精加工的50%及塑料零件的90%将由模具完成。
目前中国模具市场需求已达500亿元之规模。
汽车模具、特别是覆盖件模具年增长速度将超过20%;建材模具也迅速发展,各种异型材模具、墙面和地面模具成为模具的新增长点,今后几年塑料门窗和塑料排水管增长将超过30%;家电模具年增长速度将超过10%;IT业年均增长速度超过20%,对模具的需求占模具市场的20%。
2004年中国机床工具工业产值将继续增长。
我国模具制造市场潜力巨大。
根据资料统计,近年来,我国模具的年总产值达到30亿美元,进口超过10亿美元,出口超过1亿美元。
增长从1995年的25%增加到2005年的50%。
国外专家预言:亚洲在全球模具制造中占据的份额,将从1995年的25%增加至2005年的50%。
中国模具工业发展迅速,形成了华东和华南两人基地,并且逐渐扩大到其他省份。
(山东,安徽,四川) 1996年~2002年,模具制造业产值年平均增长14%, 2003年增长25%。
2003年我国模具产值为450亿人民币总产量位居世界第3,出口模具3.368亿美元,比上年增长33.5%。
但是,我国技术含量低的模具已供过于求,精密、复杂的高档模具很大部分依靠进口。
每年进口模具超过10亿美元。
出口超过1亿美元,精密模具精度要求在2~3u m,大型模具需要满足8000kN合模力注塑机的要求;小型模具需满足直径1mm 塑料管的要求。
中英文对照外文翻译文献(文档含英文原文和中文翻译)英文:High-speed millingHigh-speed machining is an advanced manufacturing technology, different from the traditional processing methods. The spindle speed, cutting feed rate, cutting a small amount of units within the time of removal of material has increased three to six times. With high efficiency, high precision and high quality surface as the basic characteristics of the automobile industry, aerospace, mold manufacturing and instrumentation industry, such as access to a wide range of applications, has made significant economic benefits, is the contemporary importance of advanced manufacturing technology. For a long time, people die on the processing has been using a grinding or milling EDM (EDM) processing, grinding, polishing methods. Although the high hardness of the EDM machine parts, but the lower the productivity of its application is limited. With the development of high-speed processing technology, used to replace high-speed cutting, grinding and polishing process to die processing has become possible. To shorten the processing cycle, processing and reliable quality assurance, lower processing costs.1 One of the advantages of high-speed machiningHigh-speed machining as a die-efficient manufacturing, high-quality, low power consumption in an advanced manufacturing technology. In conventional machining in a series of problems has plagued by high-speed machining of the application have been resolved.1.1 Increase productivityHigh-speed cutting of the spindle speed, feed rate compared withtraditional machining, in the nature of the leap, the metal removal rate increased 30 percent to 40 percent, cutting force reducedby 30 percent, the cutting tool life increased by 70% . Hardened parts can be processed, a fixture in many parts to be completed rough, semi-finishing and fine, and all other processes, the complex can reach parts of the surface quality requirements, thus increasing the processing productivity and competitiveness of products in the market.1.2 Improve processing accuracy and surface qualityHigh-speed machines generally have high rigidity and precision, and other characteristics, processing, cutting the depth of small, fast and feed, cutting force low, the workpiece to reduce heat distortion, and high precision machining, surface roughness small. Milling will be no high-speed processing and milling marks the surface so that the parts greatly enhance the quality of the surface. Processing Aluminum when up Ra0.40.6um, pieces of steel processing at up to Ra0.2 ~ 0.4um.1.3 Cutting reduce the heatBecause the main axis milling machine high-speed rotation, cutting a shallow cutting, and feed very quickly, and the blade length of the workpiece contacts and contact time is very short, a decrease of blades and parts of the heat conduction. High-speed cutting by dry milling or oil cooked up absolute (mist) lubrication system, to avoid the traditional processing tool in contact with the workpiece and a lot of shortcomings to ensure that the tool is not high temperature under the conditions of work, extended tool life.1.4 This is conducive to processing thin-walled partsHigh-speed cutting of small cutting force, a higher degree of stability, Machinable with high-quality employees compared to the company may be very good, but other than the company's employees may Suanbu Le outstanding work performance. For our China practice, we use the models to determine the method of staff training needs are simple and effective. This study models can be an external object, it can also be a combination of internal and external. We must first clear strategy for the development of enterprises. Through the internal and external business environment and organizational resources, such as analysis, the future development of a clear business goals and operational priorities. According to the business development strategy can be compared to find the business models, through a comparative analysis of the finalization of business models. In determining business models, a, is the understanding of its development strategy, or its market share and market growth rate, or the staff of the situation, and so on, according to the companies to determine the actual situation. As enterprises in different period of development, its focus is different, which means that enterprises need to invest the manpower and financial resources the focus is different. So in a certain period of time, enterprises should accurately selected their business models compared with the departments and posts, so more practical significance, because the business models are not always good, but to compare some aspects did not have much practical significance, Furthermore This can more fully concentrate onthe business use of limited resources. Identify business models, and then take the enterprise of the corresponding departments and staff with the business models for comparison, the two can be found in the performance gap, a comparative analysis to find reasons, in accordance with this business reality, the final identification of training needs. The cost of training is needed, if not through an effective way to determine whether companies need to train and the training of the way, but blind to training, such training is difficult to achieve the desired results. A comparison only difference between this model is simple and practical training.1.5 Can be part of some alternative technology, such as EDM, grinding high intensity and high hardness processingHigh-speed cutting a major feature of high-speed cutting machine has the hardness of HRC60 parts. With the use of coated carbide cutter mold processing, directly to the installation of a hardened tool steel processing forming, effectively avoid the installation of several parts of the fixture error and improve the parts of the geometric location accuracy. In the mold of traditional processing, heat treatment hardening of the workpiece required EDM, high-speed machining replace the traditional method of cutting the processing, manufacturing process possible to omit die in EDM, simplifying the processing technology and investment costs .High-speed milling in the precincts of CNC machine tools, or for processing centre, also in the installation of high-speed spindle on the general machine tools. The latter not only has the processing capacity of general machine tools, but also for high-speed milling, a decrease of investment in equipment, machine tools increased flexibility. Cutting high-speed processing can improve the efficiency, quality improvement, streamline processes, investment and machine tool investment and maintenance costs rise, but comprehensive, can significantly increase economic efficiency.2 High-speed millingHigh-speed milling the main technical high-speed cutting technology is cutting the development direction of one of it with CNC technology, microelectronic technology, new materials and new technology, such as technology development to a higher level. High-speed machine tools and high-speed tool to achieve high-speed cutting is the prerequisite and basic conditions, in high-speed machining in the performance of high-speed machine tool material of choice and there are strict requirements.2.1 High-speed milling machine in order to achieve high-speed machiningGeneral use of highly flexible high-speed CNC machine tools, machining centers, and some use a dedicated high-speed milling, drilling. At the same time a high-speed machine tool spindle system and high-speed feeding system, high stiffness of the main characteristics of high-precision targeting and high-precision interpolation functions, especially high-precision arc interpolation function. High-speed machining systems of the machine a higher demand, mainly in the followingareas:General use of highly flexible high-speed CNC machine tools, machining centers, and some use a dedicated high-speed milling, drilling. At the same time a high-speed machine tool spindle system and high-speed feeding system, high stiffness of the main characteristics of high-precision targeting and high-precision interpolation functions, especially high-precision arc interpolation function. High-speed machining systems of the machine a higher demand, mainly in the following areas:High-speed milling machine must have a high-speed spindle, the spindle speed is generally 10000 ~ 100000 m / min, power greater than 15 kW. But also with rapid speed or in designated spots fast-stopping performance. The main axial space not more than 0 .0 0 0 2 m m. Often using high-speed spindle-hydrostatic bearings, air pressure-bearing, mixed ceramic bearings, magnetic bearing structure of the form. Spindle cooling general use within the water or air cooled.High-speed processing machine-driven system should be able to provide 40 ~ 60 m / min of the feed rate, with good acceleration characteristics, can provide 0.4 m/s2 to 10 m/s2 acceleration and deceleration. In order to obtain good processing quality, high-speed cutting machines must have a high enough stiffness. Machine bed material used gray iron, can also add a high-damping base of concrete, to prevent cutting tool chatter affect the quality of processing. A high-speed data transfer rate, can automatically increase slowdown. Processing technology to improve the processing and cutting tool life. At present high-speed machine tool manufacturers, usually in the general machine tools on low speed, the feed of the rough and then proceed to heat treatment, the last in the high-speed machine on the half-finished and finished, in improving the accuracy and efficiency at the same time, as far as possible to reduce processing Cost.2.2 High-speed machining toolHigh-speed machining tool is the most active one of the important factors, it has a direct impact on the efficiency of processing, manufacturing costs and product processing and accuracy. Tool in high-speed processing to bear high temperature, high pressure, friction, shock and vibration, such as loading, its hardness and wear-resistance, strength and toughness, heat resistance, technology and economic performance of the basic high-speed processing performance is the key One of the factors. High-speed cutting tool technology development speed, the more applications such as diamond (PCD), cubic boron nitride (CBN), ceramic knives, carbide coating, (C) titanium nitride Carbide TIC (N) And so on. CBN has high hardness, abrasion resistance and the extremely good thermal conductivity, and iron group elements between the great inertia, in 1300 ℃ would not have happened significant role in the chemical, also has a good stability. The experiments show that with CBN cutting toolHRC35 ~ 67 hardness of hardened steel can achieve very high speed. Ceramics have good wear resistance and thermal chemical stability, its hardness, toughness below the CBN, can be used for processing hardness of HRC <5 0 parts. Carbide Tool good wear resistance, but thehardness than the low-CBN and ceramics. Coating technology used knives, cutting tools can improve hardness and cutting the rate, for cutting HRC40 ~ 50 in hardness between the workpiece. Can be used to heat-resistant alloys, titanium alloys, hightemperature alloy, cast iron, Chungang, aluminum and composite materials of high-speed cutting Cut, the most widely used. Precision machining non-ferrous metals or non-metallic materials, or the choice of polycrystalline diamond Gang-coated tool.2.3 High-speed processing technologyHigh-speed cutting technology for high-speed machining is the key. Cutting Methods misconduct, will increase wear tool to less than high-speed processing purposes. Only high-speed machine tool and not a good guide technology, high-speed machining equipment can not fully play its role. In high-speed machining, should be chosen with milling, when the milling cutter involvement with the workpiece chip thickness as the greatest, and then gradually decreased. High-speed machining suitable for shallow depth of cut, cutting depth of not more than 0.2 mm, to avoid the location of deviation tool to ensure that the geometric precision machining parts. Ensure that the workpiece on the cutting constant load, to get good processing quality. Cutting a single high-speed milling path-cutting mode, try not to interrupt the process and cutting tool path, reducing the involvement tool to cut the number to be relatively stable cutting process. Tool to reduce the rapid change to, in other words when the NC machine tools must cease immediately, or Jiangsu, and then implement the next step. As the machine tool acceleration restrictions, easy to cause a waste of time, and exigency stop or radical move would damage the surface accuracy. In the mold of high-speed finishing, in each Cut, cut to the workpiece, the feed should try to change the direction of a curve or arc adapter, avoid a straight line adapter to maintain the smooth process of cutting.3 Die in high-speed milling processing ofMilling as a highly efficient high-speed cutting of the new method,inMould Manufacturing has been widely used. Forging links in the regular production model, with EDM cavity to be 12 ~ 15 h, electrodes produced 2 h. Milling after the switch to high-speed, high-speed milling cutter on the hardness of HRC 6 0 hardened tool steel processing. The forging die processing only 3 h20min, improve work efficiency four to five times the processing surface roughness of Ra0.5 ~ 0.6m, fully in line with quality requirements.High-speed cutting technology is cutting technology one of the major developments, mainly used in automobile industry and die industry, particularly in the processing complex surface, the workpiece itself or knives rigid requirements of the higher processing areas, is a range of advanced processing technology The integration, high efficiency and high quality for the people respected. It not only involves high-speed processing technology, but also including high-speed processing machine tools, numerical control system, high-speed cutting tools and CAD / CAMtechnology. Die-processing technology has been developed in the mold of the manufacturing sector in general, and in my application and the application of the standards have yet to be improved, because of its traditional processing with unparalleled advantages, the future will continue to be an inevitable development of processing technology Direction.4 Numerical control technology and equipping development trend and countermeasureEquip the engineering level, level of determining the whole national economy of the modernized degree and modernized degree of industry, numerical control technology is it develop new developing new high-tech industry and most advanced industry to equip (such as information technology and his industry, biotechnology and his industry, aviation, spaceflight, etc. national defense industry) last technology and getting more basic most equipment. Marx has ever said "the differences of different economic times, do not lie in what is produced, and lie in how to produce, produce with some means of labor ". Manufacturing technology and equipping the most basic means of production that are that the mankind produced the activity, and numerical control technology is nowadays advanced manufacturing technology and equips the most central technology. Nowadays the manufacturing industry all around the world adopts numerical control technology extensively, in order to improve manufacturing capacity and level, improve the adaptive capacity and competitive power to the changeable market of the trends. In addition every industrially developed country in the world also classifies the technology and numerical control equipment of numerical control as the strategic materials of the country, not merely take the great measure to develop one's own numerical control technology and industry, and implement blockading and restrictive policy to our country in view of " high-grade, precision and advanced key technology of numerical control " and equipping. In a word, develop the advanced manufacturing technology taking numerical control technology as the core and already become every world developed country and accelerate economic development in a more cost-effective manner, important way to improve the overall national strength and national position. Numerical control technology is the technology controlled to mechanical movement and working course with digital information, integrated products of electromechanics that the numerical control equipment is the new technology represented by numerical control technology forms to the manufacture industry of the tradition and infiltration of the new developing manufacturing industry, namely the so-called digitization is equipped, its technological range covers a lot of fields: (1)Mechanical manufacturing technology; (2)Information processing, processing, transmission technology; (3)Automatic control technology; (4)Servo drive technology;(5)Technology of the sensor; (6)Software engineering ,etc..Development trend of a numerical control technologyThe application of numerical control technology has not only brought the revolutionary change to manufacturing industry of the tradition, make the manufacturing industry become the industrialized symbol , and with the constant development of numerical control technology andenlargement of the application, the development of some important trades (IT , automobile , light industry , medical treatment ,etc. ) to the national economy and the people's livelihood of his plays a more and more important role, because the digitization that these trades needed to equip has already been the main trend of modern development. Numerical control technology in the world at present and equipping the development trend to see, there is the following several respect [1- ] in its main research focus.5 A high-speed, high finish machining technology and new trend equippedThe efficiency, quality are subjavanufacturing technology. High-speed, high finish machining technology can raise the efficiency greatly , improve the quality and grade of the products, shorten production cycle and improve the market competitive power. Japan carries the technological research association first to classify it as one of the 5 great modern manufacturing technologies for this, learn (CIRP) to confirm it as the centre in the 21st century and study one of the directions in international production engineering.In the field of car industry, produce one second when beat such as production of 300,000 / vehicle per year, and many variety process it is car that equip key problem that must be solved one of; In the fields of aviation and aerospace industry, spare parts of its processing are mostly the thin wall and thin muscle, rigidity is very bad, the material is aluminium or aluminium alloy, only in a situation that cut the speed and cut strength very small high, could process these muscles, walls. Adopt large-scale whole aluminium alloy method that blank " pay empty " make the wing recently, such large-scale parts as the fuselage ,etc. come to substitute a lot of parts to assemble through numerous rivet , screw and other connection way, make the intensity , rigidity and dependability of the component improved. All these, to processing and equipping the demand which has proposed high-speed, high precise and high flexibility.According to EMO2001 exhibition situation, high-speed machining center is it give speed can reach 80m/min is even high , air transport competent speed can up to 100m/min to be about to enter. A lot of automobile factories in the world at present, including Shanghai General Motors Corporation of our country, have already adopted and substituted and made the lathe up with the production line part that the high-speed machining center makes up. HyperMach lathe of U.S.A. CINCINNATI Company enters to nearly biggest 60m/min of speed, it is 100m/min to be fast, the acceleration reaches 2g, the rotational speed of the main shaft has already reached 60 000r/min. Processing a thin wall of plane parts, spend 30min only, and same part general at a high speed milling machine process and take 3h, the ordinary milling machine is being processed to need 8h; The speed and acceleration of main shaft of dual main shaft lathes of Germany DMG Company are up to 120000r/mm and 1g.In machining accuracy, the past 10 years, ordinary progression accuse of machining accuracy of lathe bring 5μm up to from 10μm already, accurate grades of machining center from 3~5μm, rise to 1~1.5μm, and ultrap recision machining accuracy is it enter nanometer grade to begin already(0.01μm).In dependability, MTBF value of the foreign numerical control device has already reached above 6 000h, MTBF value of the servo system reaches above 30000h, demonstrate very high dependability .In order to realize high-speed, high finish machining, if the part of function related to it is electric main shaft, straight line electrical machinery get fast development, the application is expanded further .5.2 Link and process and compound to process the fast development of the lathe in 5 axesAdopt 5 axles to link the processing of the three-dimensional curved surface part, can cut with the best geometry form of the cutter , not only highly polished, but also efficiency improves by a large margin . It is generally acknowledged, the efficiency of an 5 axle gear beds can equal 2 3 axle gear beds, is it wait for to use the cubic nitrogen boron the milling cutter of ultra hard material is milled and pared at a high speed while quenching the hard steel part, 5 axles link and process 3 constant axles to link and process and give play to higher benefit. Because such reasons as complicated that 5 axles link the numerical control system , host computer structure that but go over, it is several times higher that its price links the numerical control lathe than 3 axles , in addition the technological degree of difficulty of programming is relatively great, have restricted the development of 5 axle gear beds.At present because of electric appearance of main shaft, is it realize 5 axle complex main shaft hair structure processed to link greatly simplify to make, it makes degree of difficulty and reducing by a large margin of the cost, the price disparity of the numerical control system shrinks. So promoted 5 axle gear beds of head of complex main shaft and compound to process the development of the lathe (process the lathe including 5).At EMO2001 exhibition, new Japanese 5 of worker machine process lathe adopt complex main shaft hair, can realize the processing of 4 vertical planes and processing of the wanton angle, make 5 times process and 5 axles are processed and can be realized on the same lathe, can also realize the inclined plane and pour the processing of the hole of awls. Germany DMG Company exhibits the DMUVoution series machining center, but put and insert and put processing and 5 axles 5 times to link and process in once, can be controlled by CNC system or CAD/CAM is controlled directly or indirectly.5.3 Become the main trend of systematic development of contemporary numerical control intelligently, openly, networkedly.The numerical control equipment in the 21st century will be sure the intelligent system, the intelligent content includes all respects in the numerical control system: It is intelligent in order to pursue the efficiency of processing and process quality, control such as the self-adaptation of the processing course, the craft parameter is produced automatically; Join the convenient one in order to improve the performance of urging and use intelligently, if feedforward control , adaptiveoperation , electrical machinery of parameter , discern load select models , since exactly makes etc. automatically; The ones that simplified programming , simplified operating aspect are intelligent, for instance intelligent automatic programming , intelligent man-machine interface ,etc.; There are content of intelligence diagnose , intelligent monitoring , diagnosis convenient to be systematic and maintaining ,etc..Produce the existing problem for the industrialization of solving the traditional numerical control system sealing and numerical control application software. A lot of countries carry on research to the open numerical control system at present, such as NGC of U.S.A. (The Next Generation Work-Station/Machine Control), OSACA of European Community (Open System Architecture for Control within Automation Systems), OSEC (Open System Environment for Controller) of Japan, ONC (Open Numerical Control System) of China, etc.. The numerical control system melts to become the future way of the numerical control system open. The so-called open numerical control system is the development of the numerical control system can be on unified operation platform, face the lathe producer and end user, through changing, increasing or cutting out the structure target(numerical control function), form the serration, and can use users specially conveniently and the technical know-how is integrated in the control system, realize the open numerical control system of different variety , different grade fast, form leading brand products with distinct distinction. System structure norm of the open numerical control system at present, communication norm , disposing norm , operation platform , numerical control systematic function storehouse and numerical control systematic function software development ,etc. are the core of present research.The networked numerical control equipment is a new light spot of the fair of the internationally famous lathe in the past two years. Meeting production line , manufacture system , demand for the information integration of manufacturing company networkedly greatly of numerical control equipment, realize new manufacture mode such as quick make , fictitious enterprise , basic Entrance that the whole world make too. Some domestic and international famous numerical control lathes and systematic manufacturing companies of numerical control have all introduced relevant new concepts and protons of a machine in the past two years, if in EMO2001 exhibition, " Cyber Production Center " that the company exhibits of mountain rugged campstool gram in Japan (Mazak) (intellectual central production control unit, abbreviated as CPC); The lathe company of Japanese big Wei (Okuma ) exhibits " IT plaza " (the information technology square , is abbreviated as IT square ); Open Manufacturing Environment that the company exhibits of German Siemens (Siemens ) (open the manufacturing environment, abbreviated as OME),etc., have reflected numerical control machine tooling to the development trend of networked direction.5.4 Pay attention to the new technical standard, normal setting-up5.4.1 Design the norm of developing about the numerical control systemAs noted previously, there are better common ability, flexibility, adaptability, expanding in theopen numerical control system, such countries as U.S.A. ,European Community and Japan ,etc. implement the strategic development plan one after another , carry on the research and formulation of the systematic norm (OMAC , OSACA , OSEC ) of numerical control of the open system structure, 3 biggest economies in the world have carried on the formulation that nearly the same science planned and standardized in a short time, have indicated a new arrival of period of change of numerical control technology. Our country started the research and formulation of standardizing the frame of ONC numerical control system of China too in 2000.5.4.2 About the numerical control standardThe numerical control standard is a kind of trend of information-based development of manufacturing industry. Information exchange among 50 years after numerical control technology was born was all because of ISO6983 standard, namely adopt G, M code describes how processes, its essential characteristic faces the processing course, obviously, he can't meet high-speed development of modern numerical control technology's needs more and more already. For this reason, studying and making a kind of new CNC system standard ISO14649 (STEP-NC) in the world, its purpose is to offer a kind of neutral mechanism not depending on the concrete system, can describe the unified data model in cycle of whole life of the products, thus realize the whole manufacture process, standardization of and even each industrial field product information.The appearance of STEP-NC may be a revolution of the technological field of the numerical control, on the development and even the whole manufacturing industry of numerical control technology, will exert a far-reaching influence. First of all, STEP-NC puts forward a kind of brand-new manufacture idea, in the traditional manufacture idea, NC processes the procedures to all concentrate on individual computer. Under the new standard, NC procedure can be dispersed on Internet, this is exactly a direction of open , networked development of numerical control technology. Secondly, STEP-NC numerical control system can also reduce and process the drawing (about 75%), process the procedure to work out the time (about 35%) and process the time (about 50%) greatly.At present, American-European countries pay much attention to the research of STEP-NC, Europe initiates IMS plan (1999.1.1-2001.12.3) of STEP-NC. 20 CAD/CAM/CAPP/CNC users, manufacturers and academic organizations from Europe and Japan participated in this plan. STEP Tools Company of U.S.A. is a developer of the data interchange software of manufacturing industry in the global range, he has already developed the super model (Super Model ) which accuses of information exchange of machine tooling by counting, its goal is to describe all processing courses with the unified norm. Such new data interchange form has already been verified in allocating the SIEMENS, FIDIA and European OSACA-NC numerical control at present.6 pairs of basic estimations of technology and industry development of numerical control of our country。
附录附录1英文原文:High-speed cutting processing in mold manufactureapplicationA.J.G. Nuttall *, G. LodewijksAbstractThe current mold application is widespread, also had the very big development with it related die making technology. At present, used the high-speed cutting production mold already to become the die making the general trend. In some mold Manufacturer, the high speed engine bed big area substitution electrical discharge machine, the high-speed cutting production mold already gradually became the die making the general trend. It can improve mold's size, the shape and the surface roughness, reduces even omits the manual sharpening, thus reduces production cost and the reduction manufacturing cycle. This article through to the traditional mold processing craft and the high speed mold processing craft's contrast, elaborated the high-speed cutting processing superiority. In the article also briefly introduced the high-speed cutting processing in the processing craft aspect key technologies.Keywords High-speed cutting Grinding tool Grinding tool processing Process technology1 Introduction1.1 IntroductionAlong with the advance in technology and the industry swift development, the mold already became in the industrial production to use the extremely widespread main craft to equip now. The mold takes the important craft equipment, in Industry sectors and so on consumable, electric appliance electron, automobile, airplane manufacture holds the pivotal status. The manufactured products components rough machining 75%, the precision work 50% and the plastic parts 90% will complete by the mold. At present the Chinese mold market demand has reached 50,000,000,000 Yuan scales, our country die making market potential is huge. The mold is one kind of special-purpose tool, uses in forming () each metal or the nonmetallic material needs the components the shape product, this kind of special-purpose tool general designation mold. The mold is in the industrial production the most foundation equipment, is realizes the few cuttings and the non-cutting essential tool. The mold has widely used in the industrial production each domain, like the automobile, the motorcycle, the domestic electric appliances, the instrument, the measuring appliance, the electron and so on, in them 60%~80% components need the mold to carry on the manufacture; The highly effective production in enormous quantities's, bolt, nut and gasket standard letters and so on plastic also need the mold to produce; The engineering plastics, the powder metallurgy, the rubber, the alloy compression casting, the glass formation and so on need to use the mold to take shape.1.2 High-speed cutting process technologyAs the name suggests, the high-speed cutting, first is the high speed, namely must have the high spindle speed, for instance 12000r/min, 18000r/min, 30000r/min, 40000r/min, even also had a higher rotational speed still in the experiment; On the other hand, should also have the bigger to feed quantity, like 30000mm/min, 40000mm/min, even 60000mm/min; Has is after again the rapid traverse, trades fast the knife, the main axle trade the knife, from the static state arrives its needs rotational speed rise time and so on, only then achieved the above standards to be able to call it high speed.Next is must aim at the different processing object, the different degree of hardness, the different material quality, the different shape to choose the corresponding reasonable parameter, but cannot pursue constantly to be high speed and be high speed, regarding the die space processing, the shape is specially complex, but the cutting tool diameter is also small time, because cutting tool's path is not the simple translation, but is the curve, even has right angle corner time, technological parameter rational especially important, if because wants to maintain the identicalfeed rate carries on the orthogonal cutting, will not be able to do well will cause as a result of the engine bed moving part's huge inertia the cutting tool will make when the bend angle movement to break suddenly, but the variable motion can, becauseMovements and so on acceleration and deceleration create the thickness of cutting the instantaneous change, but causes the cutter change to enable the work piece surface to have cuts, from this causes the processing drop in quality, therefore, in view of the different processing object, needs the programmers to choose the reasonable cutting tool path, optimized cutting parameter; On the other hand, according to needs to choose the suitable cutting velocity, only then can display the high-speed cutting truly like the strong point.The high-speed cutting (HSC) is an advanced technique of manufacture which for the past ten years rapidly rises. Because the high-speed cutting technology has the cutting efficiency to be high, the processing quality high, can process the hard steel stock and the good efficiency directly, causes profession and so on aviation, mold, automobile, light industry and information production efficiencies and the manufacture quality obviously enhances, and causes the processing craft and the equipment corresponding renewal. Therefore is similar to the numerical control technology is the same, the high-speed cutting and the high speed processing have become in the 21st century a machine-building industry influence profound technological revolution. At present, adapts the HSC request high speed machining center and other high speed numerically-controlled machine tool has assumed the popularization tendency in the developed country, our country recently is also speeding up the development.The high-speed cutting processing is faces for the 21st century a high technology and new technology, it is one kind is different with the traditional processing processing way. Compares with it, the high-speed cutting processing main axle rotational speed high, cuts high for the speed, the cutting quantity is small, but in the unit time material excises the quantity to increase 3 ~ 6 times actually. It take the high efficiency, the high accuracy and the high surface quality as the basic characteristic, in profession and so on in automobile industry, aerospace, mold manufacture and instrument measuring appliance has obtained the increasingly widespread application, and has obtained the significant technology economic efficiency, is the contemporary advanced manufacture technology important constituent.When with traditional way processing mold, often uses the electric spark machining, but the electrode design and makes itself is the technological process which time-consuming takes the trouble. But after uses the high-speed cutting processing, because the narrow and small region processing realization and the high grade superficial result, let the electrode the utilization ratio reduce greatly. Moreover, makes the electrode with the high speed mill also to be possible to makethe production efficiency to enhance to a new scale.The major part mold may use the high-speed cutting technology to process, like the forging die, the compression casting mold, cast with the blow molding mold and so on. Hammers the cavity body shallowly, the cutting tool life is long; Compression casting mold size moderate, the productivity is high; Casts with the blow molding mold general size small, quite is economical.2 the high-speed cutting processing mold relative traditionprocesses the mold the superiority2.1 Enhances the productivityIn the high-speed cutting the main axle rotational speed and enters for the speed enhancement, may enhance material removing rate. At the same time, the high-speed cutting may process the hard components, a many Cmmponents attipe clamps may complete thick, half essence and the precision work and so on the complete working procedure, also may meet the components surface quality requirements directly to the complex profile processing, therefore, the high-speed cutting craft often may save the electric spark Machining, manually rub repairs and so on the working procedure, reduces the craft route, then enhances the processing productivity greatly.The high-speed cutting processing permission use big to feed rate, enhances 5~10 times compared to the convention machining, the unit interval/unit time material excision rate may enhance 3~6 times, the process period may reduce greatly. This may use in processing needs to excise the metal massively the components, specially has the very vital significance regarding the aviation industry.2.2 Improvement processing precishon and surface qualhtyThe high rpeed engine bed must have high performance and so on rigidity and high accuracy, at the same time because cutting force low, the work piece thermal deformation reduces, the cutting tool distorts slightly, the high-speed cutting processing precision Is very high. Depth of cut small, but enters for the speed quickly, the processing surface roughness is very small, cuts when the aluminum alloy may reach Ra0.4 ~ 0.6, when cutting steel stock may reach Ra0.2 ~ 0.4.Compares with the conventional cutting, when high-speed cutting processing the cutting force may reduce 30% at least, this may reduce the processing regarding the processing rigidity bad components to distort, causes some thin wall class fine work piece the machining into possible. Because revolves high speed time the cutting tool cuts the excitation frequency is far away from the craft system's forced oscillation, has guaranteed the good processing condition. Because the cutting force is too small, cut the hot influence to be small, causes the cutting tool, the work piece distortion to be small, maintained the size accuracy, moreover also caused the friction between the cutting tool work piece changes is small, the cutting destruction level thinned, the residual stress was small, has realized the high accuracy, the low roughness processing.2.3 The reduced cutting produces quantity of heatBecause the high-speed cutting processing is the shallow cutting, simultaneously the feed rateis very quick, the knife edge and the work piece contact length and the contact duration were short, reduced the knife edge and the work piece heat conduction, has avoided when the traditional processing met everywhere in the cutting tool and the work piece to have the big calorimetry shortcoming, guaranteed that the cutting tool worked under the temperature not high condition, lengthened cutting tool's service life. As shown in Figure 1, A is time the high-speed cutting processing heat conduction process, B is the traditional processing heat conduction process.Fig.1 high speed processing and traditional processing heat conductionThe high-speed cutting processing process is extremely rapid, 95% above cutting quantity of heat are extremely few, components not because the temperature rise will cause the warp or the inflation distortion. The high-speed cutting is suitable specially for the processing easy thermal deformation components. Is low regarding the processing melting point the metal which, easy to oxidize (for example magnesium), the high-speed cutting has certain significance.2.4 advantageoued in the processing thin wall componentsTime high-speed cutting's cutting force is small, has the high stability, but the high quality processes the thin wall components. Uses as shown in Figure 2 the lamination down milling the processing method, but high-speed cutting wall thickness 0.2mm, wall high 20mm thin wall components. This time, the knife edge and the work piece contact duration was short, has avoided the sidewall distortion.Figure.2 high-speed cutting thin wall components2.5 change the part substitutes certain crafts, like electric spark machining, abrasive machining and so onHigh strength and the high degree of hardness's processing is also a high-speed cutting major characteristic, at present, the high-speed cutting has been possible the work hardness to reach HRC60 the components, therefore, the high-speed cutting can process after the heat treatment hardens the work piece. In the tradition processes in mold's craft, before the precision work, hardens the work piece after the heat treatment to carry on the electric spark machining, may omit in the die making craft with the high-speed cutting processing substitution tradition cutting's processing method the electric spark machining, simplified the processing craft and the cost of investment.the mold's size, the shape and the surface roughness are very important, if after processing the mold cannot meet the requirements the quality precision, needs the massive handworks to rub repairs the work, the handwork rubs repairs can obtain the good surface quality, but it will affect mold's size and the shape precision. Therefore must omit as far as possible in the mold processing rubs manually repairs, improves the mold quality, reduces the production cost and the manufacturing cycle.Figure 3 is the traditional mold processing process: The semifinished materials -> rough machining -> semi-finishing -> heat treatment hardens -> the electric spark machining -> precision work -> to rub manually repairs. Figure 4 is the high speed mold processing process: Hardened semifinished materials -> rough machining -> semi-finishing -> precision work.Figure.3 the traditional mold processes processFigure 4 the high speed mold processes processin Figure 4, in the high speed mold machining process reduced two technological processes,probably reduces the process period 30%~50%. In the traditional processing craft's electric spark machining forms the hardened level easily in the melting processing surface layer, degree of hardness may reach 1000Hv, brings the difficulty for the following machining and the abrasive machining. The electric spark machining also easy to cause the surface layer fatigue cracking and cutting tool's breakage.2.6 Economic efficiency remarkable enhancementSynthesis above all sorts of merits, namely: The comprehensive efficiency will improve, the quality enhances, the working procedure simplifies, the engine bed investment and the cutting tool investment as well as the maintenance cost increase and so on, will use the high-speed cutting craft to cause the synthesis economic efficiency remarkable enhancement.3 high-speed cutting processing craft essential technologyThe high speed engine bed and the high speed cutter are the realization high-speed cutting premise and the basic condition, has the strict request in the high-speed cutting processing to the high speed engine bed performance and the cutting tool material choice.In order to realize the high-speed cutting processing, uses the high flexible high speed numerical control engine bed, the processing center generally, also some use special-purpose high speed mills, drilling machine. At the same time the engine bed has the high speed main axle to be systematic and the high rapid advance or progress gives the system, the high main axle rigidity characteristic, the high accuracy localization function and the high accuracy insert makes up the function, specially the circular arc high accuracy inserts makes up the function.The high-speed cutting cutting tool and ordinary processes the cutting tool the material to have is very greatly different. The main use cutting tool material has the hard alloy, the crystal combination diamond (PCD), the crystal combination cube boron nitride (PCBN) and the ceramics and so on.The high-speed cutting craft technology also is carries on the high-speed cutting processing the key. The cutting method chooses is improper, can make the cutting tool to intensify the attrition, cannot achieve the high speed processing completely the goal. The practice proved, if only then the high speed engine bed and the cutting tool but do not have the good craft technology to make the instruction, the expensive high-speed cutting processing equipment cannot fully play the role. The high-speed cutting processing craft essential technology mainly includes the cutting method and the cutting parameter choice optimization.a. Cutting way choiseIn the high-speed cutting processing, should select the down milling processing as far as possible, because in down milling time, the cutting tool just cut into the thickness of chip which the work piece produces to a big way, afterward reduces gradually. When up milling, the cutting tool just cut into the thickness of chip which the work piece produces to be smallest, afterward the accumulation, increased the cutting tool and the work piece friction like this gradually, has the big calorimetry on the knife edge, therefore produces in the up milling quantity of heat when down milling are more than, the radial force also greatly increases. Meanwhile in the down milling, the knife edge main compression stress, but when the up milling the knife edge tension stress, the stressful condition is bad, reduced cutting tool's service life, the down milling and the up milling the cutting tool cuts into the work piece the process, as shown in Figure 5.Figure.5 the cutting tool cuts into the work piece the process hintb. Maintains constant metal removing rateThe high-speed cutting processing is shallowly suitable for shallowly to cut the depth, the depth of cut should not surpass 0.2/ 0.2mm (ae/Ap), this is for avoids the cutting tool the position deviation, guarantees processes the mold the geometry precision. Maintains constant metal removing rate, guaranteed adds on the work piece the cutting load is constant, by obtains following several good processing effect: (1) may maintain constant cutting load; (2) may maintain the scrap size constant; (3) has the good hot shift; (4) the cutting tool and the work piece maintain at the cold condition; (5) does not need skilled to operate for the quantity and the main axle rotational speed;(6) may lengthen the cutting tool the life; (7) can guarantee the good processing quality and so on.c.choice of the Feeds wayRegarding has opens the mouth die space the region, feeds as far as possible from material outside, by real-time analysis material cutting condition. But regarding does not have the die space enclosed area, selects the screw feed method, cuts into the local region.d. As far as possible reduced cutting tool's commutation rapidlyReduces the cutting tool as far as possible the rapidly commutation, because the zigzag pattern mainly applies in the traditional processing, mainly chooses the return route or the sole way cutting in the high-speed cutting processing. This is because in commutation time the NC engine bed must stop (urgently changing down) immediately then the again execution next step of operation. As a result of engine bed acceleration limitation, but is easy to create the time the waste, stops anxiously or whips then can destroy the surface roughness, also has the possibility because has cut but produces the broach or in the outside undercut. Chooses the sole way cutting pattern to carry on the down milling, does not sever the cutting process and the cutting tool way as far as possible, reduces the cutting tool to cut into as far as possible cuts the number of times, by obtains the relatively stable cutting process.For example, in the cutting mold corner processing, the traditional processing method is usesthe translation (G1), when the cutting tool cuts to the fillet place, the velocity of movement reduces speed, at the same time when enters for the commutation the cutting tool movement is not continuously, can have the massive friction and the quantity of heat in the intermittent process, if processes the aluminum alloy or other light metal alloys, produces the quantity of heat will damage the work piece surface quality.If uses the high-speed cutting processing the method, the use is smaller than the cutting mold corner radius cutting tool, the use high speed engine bed high accuracy circular arc inserts makes up the function (G2, G3) processes the mold corner, the high speed engine bed circular arc inserts makes up the movement is the continuous process, cannot have the cutting tool intermittent motion, thus reduced the cutting tool and the mold contact length and the time, avoids having the massive heat.e In Z direction cutting continual planeThe traditional processing die space's method uses the profile milling, this processing way increased the cutting tool to cut into, to cut the work piece the number of times, has affected the work piece surface quality, has limited the engine bed and the cutting tool formidable function display. In the high-speed cutting processing, often uses the Z direction cutting continual plane. Uses step pitch which is smaller than the convention, thus reduces each tooth cutting elimination quantity, the improvement processing surface's quality, reduced the process period.4 High-speed cutting process technology in die makingapplicationThe high-speed cutting process technology has a series of characteristics and the production benefit aspect's great potential, already becomes country competition research and so on Germany, US and Japan important areas of technology. Now, US, Germany, Japan, France, Switzerland, Italy produce the different specification's each kind of commercialization high speed engine bed already entered the market, applies in the airplane, the automobile and the die making.Along with the high-speed cutting process technology introduction mold industry, has had the very tremendous influence to the traditional mold processing craft, changed the mold processing technical process. Because the mold profile is the very complex free surface generally, and degree of hardness is very high, uses conventional the machining method to satisfy the precision and the shape request with difficulty. The conventional processing method is after the annealing carries on the milling processing, then carries on the heat treatment, the grinding or the electric spark machining, finally the manual polish, polishing, cause the processing cycle to be very long like this. Specially the manual process period, must account for the entire processing cycle to be very big a part. HSC may achieve the accuracy requirement which the mold processes, reduced has even cancelled the manual processing, because and new cutting tool material (for example PCD, PCBN, cermet and so on) the appearance, HSC may the work hardness achieve HRC60, even degree of hardness higher work piece material, after might process hard mold, substitution electric spark machining and abrasive machining.The high speed milling processing has the highly effective high accuracy in the die making as well as may process the high hard material the merit, already obtained the widespread application in the industrially advanced country. The high-speed cutting process technology introduction mold industry, mainly applies in the following several aspects:1) hard mold die space direct processing. After using the high-speed cutting to be possible to process the hard material the characteristic direct processing hard mold die space, improved the quality which and the efficiency the mold processes, may substitute for the electric spark machining.(2) EDM (electric spark) electrode processing. Applied the high-speed cutting technology processing electrode to raise the electric spark machining efficiency to play the very major role. The high-speed cutting electrode improved electrode's surface quality and the precision, reduced the following working process.3) fast sample workpiece manufacture. Uses the high-speed cutting processing efficiencyhigh characteristic, may use in processing the plastic and the aluminum alloy model. After the CAD design produces the 3D full-scale mockup fast, is higher than the fast prototype manufacture efficiency, the quality is good.(4) mold's fast repair. The mold often needs to repair in the use process, lengthens the service life, in the past was mainly completes depending on the electrical finishing, now uses the high speed processing to be possible to complete this work quickly, moreover might use the original NC procedure, did not need to establish.5 ConclusionThe high-speed cutting processing uses the high cutting velocity and the feed rate, the small radial direction and the axial depth of cut, the cutting force is small, the processing surface roughness is very small, cutting tool life enhancement; With the high-speed cutting processing way substitution tradition processing way processing mold, might omit the electric spark machining and rub manually repairs, raised the productivity which the mold processed, reduced the production cost, reduced the processing cycle; When research high-speed cutting processing, must unify closely with the high-speed cutting processing technology, realizes the high efficiency, the high accuracy truly and the redundant reliable goal.The high-speed cutting process technology is the advanced technique of manufacture, has the broad application prospect. Replaces EDM with the high-speed cutting processing (or majority of replaces) speeds up the mold development speed, realizes the craft update major step. The promoted application high-speed cutting process technology applies in the mold manufacturing industry, not only may enhance the machine-finishing large scale the efficiency, the quality, reduces the cost, moreover may lead a series of high technology and new technology industry the development. Therefore, current strengthens the high-speed cutting technology the basic research, establishes the high-speed cutting database, the high-speed cutting safety work standard, enhances the engine bed and tool profession development innovation ability, speeds up the high-speed cutting cutting tool system, the high-speed cutting engine bed system's research development and the industrial production, already was the urgent matter.References[1] A.C. Low, J.W. Kyle, Grinding tool technology recent development, The Mechanical Engineers Association, London, 1986. High-speed cutting and grinding tool manufacture[2] K.L. Johnson, High-speed cutting and grinding tool manufacture, Cambridge University Press, Cambridge, 1985.[3] W.DMay, E.L. Morris, D. Atack, new using of Cutting technology, Applied Physics 30 (1959) 1713–1724.[4] S.C. Hunter, Grinding tool manufacture, Applied Mechanics 28 (1961) 611–617.[5] G. Lodewijks, Dynamics of Belt Systems, Thesis, Delft University of Technology, Delft, 1995.[6] A.N. Gent, High-speed cutting outline, Carl Hanser Verslag, 2001.中文翻译高速切削加工在模具制造中的新应用A.J.G. Nuttall *, G. Lodewijks摘要当前模具应用广泛,与之相关的模具制造技术也有了很大的发展。
本科毕业设计(论文)外文资料翻译外文翻译英文原文High-speed machining and demand for the development of High-speed machining is contemporary advanced manufacturing technology an important component of the high-efficiency, High-precision and high surface quality, and other features. This article presents the technical definition of the current state of development of China's application fields and the demand situation.High-speed machining is oriented to the 21st century a new high-tech, high-efficiency, High-precision and high surface quality as a basic feature, in the automobile industry, aerospace, Die Manufacturing and instrumentation industries gained increasingly widespread application, and has made significant technical and economic benefits. contemporary advanced manufacturing technology an important component part.HSC is to achieve high efficiency of the core technology manufacturers, intensive processes and equipment packaged so that it has a high production efficiency. It can be said that the high-speed machining is an increase in the quantity of equipment significantly improve processing efficiency essential to the technology. High-speed machining is the major advantages : improve production efficiency, improve accuracy and reduce the processing of cutting resistance.The high-speed machining of meaning, at present there is no uniform understanding, there are generally several points as follows : high cutting speed. usually faster than that of their normal cutting 5 -10 times; machine tool spindle speed high, generally spindle speed in -20000r/min above 10,000 for high-speed cutting; Feed at high velocity, usually 15 -50m/min up to 90m/min; For different cutting materials and the wiring used the tool material, high-speed cutting the meaning is not necessarily the same; Cutting process, bladed through frequency (Tooth Passing Frequency) closer to the "machine-tool - Workpiece "system the dominant natural frequency (Dominant Natural Frequency), can be considered to be high-speed cutting. Visibility high-speed machining is a comprehensive concept.1992. Germany, the Darmstadt University of Technology, Professor H. Schulz in the 52th on the increase of high-speed cutting for the concept and the scope, as shown in Figure 1. Think different cutting targets, shown in the figure of the transition area (Transition), to be what is commonly called the high-speed cutting, This is also the timeof metal cutting process related to the technical staff are looking forward to, or is expected to achieve the cutting speed.High-speed machining of machine tools, knives and cutting process, and other aspects specific requirements. Several were from the following aspects : high-speed machining technology development status and trends.At this stage, in order to achieve high-speed machining, general wiring with high flexibility of high-speed CNC machine tools, machining centers, By using a dedicated high-speed milling, drilling. These equipment in common is : We must also have high-speed and high-speed spindle system feeding system, Cutting can be achieved in high-speed process. High-speed cutting with the traditional cutting the biggest difference is that "Machine-tool-workpiece" the dynamic characteristics of cutting performance is stronger influence. In the system, the machine spindle stiffness, grip or form, a long knife set, spindle Broach, torque tool set, Performance high-speed impact are important factors.In the high-speed cutting, material removal rate (Metal Removal Rate, MRR), unit time that the material was removed volume, usually based on the "machine-tool-workpiece" whether Processing System "chatter." Therefore, in order to satisfy the high-speed machining needs, we must first improve the static and dynamic stiffness of machine spindle is particularly the stiffness characteristics. HSC reason at this stage to be successful, a very crucial factor is the dynamic characteristics of the master and processing capability.In order to better describe the machine spindle stiffness characteristics of the project presented new dimensionless parameter - DN value, used for the evaluation of the machine tool spindle structure on the high-speed machining of adaptability. DN value of the so-called "axis diameter per minute speed with the product." The newly developed spindle machining center DN values have been great over one million. To reduce the weight bearing, but also with an array of steel products than to the much more light ceramic ball bearings; Bearing Lubrication most impressive manner mixed with oil lubrication methods. In the field of high-speed machining. have air bearings and the development of magnetic bearings and magnetic bearings and air bearings combined constitute the magnetic gas / air mixing spindle.Feed the machine sector, high-speed machining used in the feed drive is usually larger lead, multiple high-speed ball screw and ball array of small-diameter silicon nitride (Si3N4) ceramic ball, to reduce its centrifugal and gyroscopic torque; By usinghollow-cooling technology to reduce operating at high speed ball screw as temperature generated by the friction between the lead screw and thermal deformation.In recent years, the use of linear motor-driven high-speed system of up to'' Such feed system has removed the motor from workstations to Slide in the middle of all mechanical transmission links, Implementation of Machine Tool Feed System of zero transmission. Because no linear motor rotating components, from the role of centrifugal force, can greatly increase the feed rate. Linear Motor Another major advantage of the trip is unrestricted. The linear motor is a very time for a continuous machine shop in possession of the bed. Resurfacing of the very meeting where a very early stage movement can go, but the whole system of up to the stiffness without any influence. By using high-speed screw, or linear motor can greatly enhance machine system of up to the rapid response. The maximum acceleration linear motors up to 2-10G (G for the acceleration of gravity), the largest feed rate of up to 60 -200m/min or higher.2002 world-renowned Shanghai Pudong maglev train project of maglev track steel processing, Using the Shenyang Machine Tool Group Holdings Limited McNair friendship company production plants into extra-long high-speed system for large-scale processing centers achieve . The machine feeding system for the linear guide and rack gear drive, the largest table feed rate of 60 m / min, Quick trip of 100 m / min, 2 g acceleration, maximum speed spindle 20000 r / min, the main motor power 80 kW. X-axis distance of up to 30 m, 25 m cutting long maglev track steel error is less than 0.15 mm. Maglev trains for the smooth completion of the project provided a strong guarantee for technologyIn addition, the campaign machine performance will also directly affect the processing efficiency and accuracy of processing. Mold and the free surface of high-speed machining, the main wiring with small cut deep into methods for processing. Machine requirements in the feed rate conditions, should have high-precision positioning functions and high-precision interpolation function, especially high-precision arc interpolation. Arc processing is to adopt legislation or thread milling cutter mold or machining parts, the essential processing methods.Cutting Tools Tool Material developmenthigh-speed cutting and technological development of the history, tool material is continuous progress of history. The representation of high-speed cutting tool material is cubic boron nitride (CBN). Face Milling Cutter use of CBN, its cutting speed can be as high as 5000 m / min, mainly for the gray cast iron machining. Polycrystalline diamond(PCD) has been described as a tool of the 21st century tool, It is particularly applicable to the cutting aluminum alloy containing silica material, which is light weight metal materials, high strength, widely used in the automobile, motorcycle engine, electronic devices shell, the base, and so on. At present, the use of polycrystalline diamond cutter Face Milling alloy, 5000m/min the cutting speed has reached a practical level. In addition ceramic tool also applies to gray iron of high-speed machining;Tool Coating : CBN and diamond cutter, despite good high-speed performance, but the cost is relatively high. Using the coating technology to make cutting tool is the low price, with excellent mechanical properties, which can effectively reduce the cost. Now high-speed processing of milling cutter, with most of the wiring between the Ti-A1-N composite technology for the way of multi-processing, If present in the non-ferrous metal or alloy material dry cutting, DLC (Diamond Like Carbon) coating on the cutter was of great concern. It is expected that the market outlook is very significant;Tool clamping system : Tool clamping system to support high-speed cutting is an important technology, Currently the most widely used is a two-faced tool clamping system. Has been formally invested as a commodity market at the same clamping tool system are : HSK, KM, Bigplus. NC5, AHO systems.In the high-speed machining, tool and fixture rotary performance of the balance not only affects the precision machining and tool life. it will also affect the life of machine tools. So, the choice of tool system, it should be a balanced selection of good products.Process ParametersCutting speed of high-speed processing of conventional shear velocity of about 10 times. For every tooth cutter feed rate remained basically unchanged, to guarantee parts machining precision, surface quality and durability of the tool, Feed volume will also be a corresponding increase about 10 times, reaching 60 m / min, Some even as high as 120 m / min. Therefore, high-speed machining is usually preclude the use of high-speed, feed and depth of cut small cutting parameters. Due to the high-speed machining cutting cushion tend to be small, the formation of very thin chip light, Cutting put the heat away quickly; If the wiring using a new thermal stability better tool materials and coatings, Using the dry cutting process for high-speed machining is the ideal technology program.High-speed machining field of applicationFlexible efficient production lineTo adapt to the needs of new models, auto body panel molds and resin-prevention block the forming die. must shorten the production cycle and reduce the cost ofproduction and, therefore, we must make great efforts to promote the production of high-speed die in the process. SAIC affiliated with the company that : Compared to the past, finishing, further precision; the same time, the surface roughness must be met, the bending of precision, this should be subject to appropriate intensive manual processing. Due to the extremely high cutting speed, and the last finishing processes, the processing cycle should be greatly reduced.To play for machining centers and boring and milling machining center category represented by the high-speed machining technology and automatic tool change function of distinctions Potential to improve processing efficiency, the processing of complex parts used to be concentrated as much as possible the wiring process, that is a fixture in achieving multiple processes centralized processing and dilute the traditional cars, milling, boring, Thread processing different cutting the limits of technology, equipment and give full play to the high-speed cutting tool function, NC is currently raising machine efficiency and speed up product development in an effective way. Therefore, the proposed multi-purpose tool of the new requirements call for a tool to complete different parts of the machining processes, ATC reduce the number of ATC to save time, to reduce the quantity and tool inventory, and management to reduce production costs. More commonly used in a multifunctional Tool, milling, boring and milling, drilling milling, drilling-milling thread-range tool. At the same time, mass production line, against the use of technology requires the development of special tools, tool or a smart composite tool, improve processing efficiency and accuracy and reduced investment. In the high-speed cutting conditions, and some special tools can be part of the processing time to the original 1 / 10 below, results are quite remarkable.HSC has a lot of advantages such as : a large number of materials required resection of the workpiece with ultrafine, thin structure of the workpiece, Traditionally, the need to spend very long hours for processing mobile workpiece and the design of rapid change, short product life cycle of the workpiece, able to demonstrate high-speed cutting brought advantages.中文译文高速切削加工的发展及需求高速切削加工是当代先进制造技术的重要组成部分,拥有高效率、高精度及高表面质量等特征。
High-speed milling——高速铣削(机械工程毕业设计英文文献及翻译)High-speed milling——高速铣削High-speed machining is an advanced manufacturing technology,different from the traditional processing methods. The spindle speed, cutting feed rate, cutting a small amount of units within the time of removal of material has increased three to six times. With high efficiency, high precision and high quality surface as the basic characteristics of the automobile industry, aerospace, moldmanufacturing and instrumentation industry, such as access to a widerange of applications, has made significant economic benefits, is the contemporary importance of advanced manufacturing technology. For a long time, people die on the processing has been using a grinding or milling EDM (EDM) processing, grinding, polishing methods. Although the high hardness of the EDM machine parts, but the lower the productivity of its application is limited. With the development of high-speed processing technology, used to replace high-speed cutting, grinding and polishing process to die processing has become possible. To shorten the processing cycle, processing and reliable quality assurance, lower processing costs.1 One of the advantages of high-speed machiningHigh-speed machining as a die-efficient manufacturing, high-quality, low power consumption in an advanced manufacturing technology. Inconventional machining in a series of problems has plagued by high-speed machining of the application have been resolved.1.1 Increase productivityHigh-speed cutting of the spindle speed, feed rate compared withtraditional machining, in the nature of the leap, the metal removal rate increased 30 percent to 40 percent, cutting force reduced by 30 percent, the cutting tool life increased by 70% . Hardened parts can be processed, a fixture in many parts to be completed rough, semi-finishing and fine, and all other processes, the complex can reach parts of the surface quality requirements, thus increasing the processingproductivity and competitiveness of products in the market.1.2 Improve processing accuracy and surface qualityHigh-speed machines generally have high rigidity and precision, and other characteristics, processing, cutting the depth of small, fast and feed, cutting force low,the workpiece to reduce heat distortion, and high precision machining, surface roughness small. Milling will be no high-speed processing and milling marks the surface so that the parts greatly enhance the quality of the surface. Processing Aluminum when upRa0.40.6um, pieces of steel processing at up to Ra0.2 ~ 0.4um. 1.3 Cutting reduce the heatBecause the main axis milling machine high-speed rotation, cutting a shallow cutting, and feed very quickly, and the blade length of the workpiece contacts and contact time is very short, a decrease of bladesand parts of the heat conduction. High-speed cutting by dry milling or oil cooked up absolute (mist) lubrication system, to avoid thetraditional processing tool in contact with the workpiece and a lot of shortcomings to ensurethat the tool is not high temperature under the conditions of work, extended tool life.1.4 This is conducive to processing thin-walled partsHigh-speed cutting of small cutting force, a higher degree of stability, Machinable with high-quality employees compared to the company may be very good, but other than the company's employees may Suanbu Le outstanding work performance. For our China practice, we use the models to determine the method of staff training needs are simple and effective. This study models can be an external object, it can also be a combination of internal and external. We must first clear strategy for the development of enterprises. Through the internal and external business environment and organizational resources, such as analysis, the future development of a clear business goals and operational priorities. According to the business development strategy can be compared to find the business models, through a comparative analysis of the finalization of business models. In determining business models, a, is the understanding of its development strategy, or its market share and market growth rate, or the staff of the situation, and so on, according to the companies to determine the actual situation. As enterprises in different period of development, its focus is different, which meansthat enterprises need to invest the manpower and financial resources thefocus is different. So in a certain period of time, enterprises should accurately selected their business models compared with the departments and posts, so more practical significance, because the business models are not always good, but to compare some aspects did not have much practical significance, Furthermore Thiscan more fully concentrate on the business use of limited resources. Identify business models, and then take the enterprise of the corresponding departments and staff with the business models for comparison, the two can be found in the performance gap, a comparative analysis to find reasons, in accordance with this business reality, the final identification of training needs. The cost of training is needed, if not through an effective way to determine whether companies need to train and the training of the way, but blind to training, such training is difficult to achieve the desired results. A comparison only difference between this model is simple and practical training. 1.5 Can be part of some alternative technology, such as EDM, grinding high intensity and high hardness processingHigh-speed cutting a major feature of high-speed cutting machine has the hardness of HRC60 parts. With the use of coated carbide cutter mold processing, directly to the installation of a hardened tool steel processing forming, effectively avoid the installation of several parts of the fixture error and improve the parts of the geometric location accuracy. In the mold of traditional processing, heat treatment hardening of the workpiece required EDM, high-speed machining replacethe traditional method of cutting the processing, manufacturing process possible to omit die in EDM, simplifying the processing technology and investment costs .High-speed milling in the precincts of CNC machine tools, or for processing centre, also in the installation of high-speed spindle on the general machine tools. The latter not only has the processing capacity of general machine tools, but also for high-speed milling, a decrease of investment in equipment, machine tools increased flexibility. Cutting high-speed processing can improve the efficiency, quality improvement, streamline processes, investment and machine tool investment and maintenance costs rise, but comprehensive, can significantly increase economic efficiency.2 High-speed millingHigh-speed milling the main technical high-speed cutting technology is cutting the development direction of one of it with CNC technology, microelectronic technology, new materials and new technology, such as technology development to a higher level. High-speed machine tools and high-speed tool to achieve high-speed cutting is the prerequisite and basic conditions, in high-speed machining in the performance of high-speed machine tool material of choice and there are strict requirements. 2.1 High-speed milling machine in order to achieve high-speed machining General use of highly flexible high-speed CNC machine tools, machining centers, and some use a dedicated high-speed milling, drilling. At the same time a high-speed ma chine tool spindle system andhigh-speed feeding system, high stiffness of the main characteristics of high-precision targeting and high-precision interpolation functions, especially high-precision arc interpolation function. High-speed machining systems of the machine a higher demand, mainly in thefollowing areas:General use of highly flexible high-speed CNC machine tools, machining centers, and some use a dedicated high-speed milling, drilling. At the same time a high-speed machine tool spindle system and high-speed feeding system, high stiffness of the main characteristics of high-precision targeting and high-precision interpolation functions,especially high-precision arc interpolation function. High-speed machining systems of the machine a higher demand, mainly in thefollowing areas: High-speed milling machine must have a high-speed spindle, the spindle speed is generally 10000 ~ 100000 m / min, power greater than 15 kW. But also with rapid speed or in designated spotsfast-stopping performance. The main axial space not more than 0 .0 0 0 2 m m. Often using high-speed spindle-hydrostatic bearings, air pressure-bearing, mixed ceramic bearings, magnetic bearing structure of the form. Spindle cooling general use within the water or air cooled.High-speed processing machine-driven system should be able toprovide 40 ~ 60 m / min of the feed rate, with good acceleration characteristics, can provide 0.4 m/s2 to 10 m/s2 acceleration and deceleration. In order to obtain goodprocessing quality, high-speed cutting machines must have a high enough stiffness. Machine bed materialused gray iron, can also add a high-damping base of concrete, to prevent cutting tool chatter affect the quality of processing. A high-speed data transfer rate, can automatically increase slowdown. Processing technology to improve the processing and cutting tool life. At present high-speed machine tool manufacturers, usually in the general machine tools on low speed, the feed of the rough and then proceed to heat treatment, the last in the high-speed machine on the half-finished and finished, in improving the accuracy and efficiency at the same time, as far as possible to reduce processing Cost.2.2 High-speed machining toolHigh-speed machining tool is the most active one of the important factors, it has a direct impact on the efficiency of processing, manufacturing costs and product processing and accuracy. Tool in high-speed processing to bear high temperature, highpressure, friction, shock and vibration, such as loading, its hardness and wear-resistance, strength and toughness, heat resistance, technology and economic performance of the basic high-speed processing performance is the key One of the factors. High-speed cutting tool technology development speed, the more applications such as diamond (PCD), cubic boron nitride (CBN), ceramic knives, carbide coating, (C) titanium nitride Carbide TIC (N) And so on. CBN has high hardness, abrasion resistance and the extremely good thermal conductivity, andiron group elements between the great inertia, in 1300 ? would not have happened significant role in thechemical, also has a good stability. The experiments show that with CBN cutting tool HRC35 ~ 67 hardness of hardened steel can achieve very high speed. Ceramics have good wear resistance and thermal chemical stability, its hardness, toughness below the CBN, can be used for processing hardness of HRC <5 0 parts. Carbide Tool good wear resistance, but the hardness than the low-CBN and ceramics. Coating technology used knives, cutting tools can improve hardness and cutting the rate, for cutting HRC40 ~ 50 in hardness between the workpiece. Can be used toheat-resistant alloys, titanium alloys, hightemperature alloy, cast iron, Chungang, aluminum and composite materials of high-speed cutting Cut,the most widely used. Precision machining non-ferrous metals or non-metallic materials, or the choice of polycrystalline diamond Gang-coated tool.2.3 High-speed processing technologyHigh-speed cutting technology for high-speed machining is the key. Cutting Methods misconduct, will increase wear tool to less than high-speed processing purposes. Only high-speed machine tool and not a good guide technology, high-speed machining equipment can not fully play its role. In high-speed machining, should be chosen with milling, when the milling cutter involvement with the workpiece chip thickness as the greatest, and then gradually decreased. High-speedmachining suitable for shallowdepth of cut, cutting depth of not more than 0.2 mm, to avoid the location of deviation tool to ensure that the geometric precisionmachining parts. Ensure that the workpiece on the cutting constant load, to get good processing quality. Cutting a single high-speed millingpath-cutting mode, try not to interrupt the process and cutting tool path, reducing the involvement tool to cut the number to be relatively stable cutting process. Tool to reduce therapid change to, in other words when the NC machine tools must cease immediately, or Jiangsu, and then implement the next step. As the machine tool acceleration restrictions, easy to cause a waste of time, and exigency stop or radical move would damage the surface accuracy. In the mold of high-speed finishing, in each Cut, cut to the workpiece, the feed should try to change the direction of a curve or arc adapter, avoida straight line adapter to maintain the smooth process of cutting.3 Die in high-speed milling processing ofMilling as a highly efficient high-speed cutting of the newmethod,in Mould Manufacturing has been widely used. Forging links in the regular production model, with EDM cavity to be 12 ~ 15 h, electrodes produced 2 h. Milling after the switch to high-speed, high-speed milling cutter on the hardness of HRC 6 0 hardened tool steel processing. The forging die processing only 3 h20min, improve work efficiency four to five times the processing surface roughness of Ra0.5 ~ 0.6m, fully in line with quality requirements.High-speed cutting technology is cutting technology one of the major developments, mainly used in automobile industry and die industry, particularly in the processing complex surface, the workpiece itself orknives rigid requirements of the higher processing areas, is a range of advanced processing technology The integration, high efficiency and high quality for the people respected. It not only involves high-speed processing technology, but also including high-speed processing machine tools, numerical control system, high-speed cutting tools and CAD / CAM technology. Die-processing technology has been developed in the mold of the manufacturing sector in general, and in my application and the application of the standards have yet to be improved, because of its traditional processing with unparalleled advantages, the future will continue to be an inevitable development of processing technologyDirection.高速铣削高速切削加工是一种先进制造技术,不同于传统加工方式。
外文翻译---模具高速铣削加工技术外文资料翻译Mold high speed milling processing technologyThe abstract Introduced the high speed milling in the mold processing application as well as the influence, and brief introduction high speed milling engine bed structure, control system and cutting tool. Has carried on the simple analysis to the high speed processing craft.Key word high speed milling; mold processingFirst, forewordIn the modern mold production, along with to models artistic and the function must obtain more and more high, models the internal structure to design more and more complex, the mold contour design day by day is also complex, the free curved surface accounts for the proportion to increase unceasingly, the corresponding mold structure also designs more and more complex. These all set a higher request to the mold processing technology, not only should guarantee the high manufacture precision and the surface quality, moreover must pursue the processing surface artistic. Along with is unceasingly thorough to the high speed processing engineering research, is processing the engine bed, the numerical control system, the cutting tool system, CAD/ especiallyCorrelation technology and so on CAM software develops unceasingly under the impetus, high speed processes the technology more and more many to apply in the mold cavity processing and the manufacture.The numerical control high-speed cutting processing took in the mold manufacture a most important advanced manufacturetechnology, is the collection is highly effective, high quality, the low consumption in a body advanced manufacture technology. Is opposite in the traditional machining, its cutting speed, entered to the speed had the very big enhancement, moreover cut the mechanism not to be same. The high-speed cutting caused the machining to have the leap, its specific power metal excision rate enhanced 30%~40%, the cutting force reduced 30%, the cutting tool working durability enhanced 70%, remained hotly large scale reduces in the workpiece cutting, the low step shudder vanished nearly. Along with the cutting speed enhancement, unit time semifinished materials material removing rate increased, the cutting time reduced, the processing efficiency enhanced, thus reduced the product manufacture cycle, enhanced the product market competitive power. At the same time, the high speed processing small amount entered quickly causes the cutting force to reduce, the scrap high speed discharged reduced the work piece cutting force and the thermal load distorts, enhances the rigidity to be bad and the thin wall components machining possibility. Because cutting force reducing, the rotational speed enhancement causes the cutting system the operating frequency to be far away the engine bed the low step natural frequency, but the work piece surface roughness is most sensitive to the low step frequency, from this reduced the surface roughness. In mold high hard steel stock (HRC45~HRC65) in the processing process, uses the high-speed cutting to be possible to substitute for the working procedure which the electrical finishing and rubs truncates polishes, thus has avoided the electrode manufacture and the time-consuming electrical finishing, large scale reduced fitter'spolishing with to throw the light quantity. Thin wall mold work piece more and more needs which regarding some markets in, the high speed milling also may smoothly complete, moreover in the high speed milling CNC processing center, a mold attire clamps may complete the multiplex step of processing.The high speed processing technology has had the huge influence to the mold processing craft, changed the traditional mold processing to use "the annealing→milling processing→heat treatment→to rub truncates" or"the electric spark machining→manually polishes, polishes" and so on the complex long technical process, even might use the high-speed cutting processing substitution original complete working procedure. The high speed processing technology besides may apply in the hard mold cavity direct processing (in particular half precision work and precision work), in EDM aspect and so on electrode processing, fast type manufacture also obtained the widespread application. The mass productions practice indicated that, the application high-speed cutting technology may save in the mold following processing 80% handwork to grind the time approximately, saves the processing cost expense nearly 30%, the mold face work precision may reach 1 m, the cutting tool cutting efficiency may enhance one time.Second, high speed milling processing engine bedThe high-speed cutting technology is one of machining technology main development directions, it along with foundation technology the and so on CNC technology, microelectronic technology, new material and new structure development but steps a higher stair. Because the mold processes particular as well as high speed processing technology own characteristic, (processed engine bed, numerical controlsystem, cutting tool to the mold high speed processing related technology and the craft system and so on) proposed processeda higher request compared to the traditional mold.1. High stable engine bed strut partThe high-speed cutting engine bed lathe bed and so on supports the part to be supposed to have very well moves, the static rigidity, hot rigidity and best damping characteristic. The majority of engine beds all use high grade, the high rigidity and Gao Kangzhang the gray iron took the strut part material, some engine bed companies also increase the high damping characteristic in the foundation polymer concrete, by increases its vibration-proof and the thermostability, this not only may guarantee the engine bed precision is stable, also may prevent when cutting the cutting tool inspires trembles. Uses the enclosed lathe bed design, the overall casting lathe bed, the symmetrical lathe bed structure and has the densely covered stiffener and so on also enhances the engine bed stable important measure. Some engine bed companies' research and development departments in design process, but also uses the modality analysis and the finite element structure computation and so on, optimized the structure, stably causes the engine bed strut part to be reliable.2. Engine bed main axleThe high speed engine bed main axle performance is the realization high-speed cutting processing important condition. The high-speed cutting engine bed main axle rotational speed scope is 10000~100000m/Min, the main axle power is bigger than 15kW. Is not bigger than 0.005mm through the main axle compressed air of or axial play between the cooling system control hilt and the main axle. Also requests the main axle to havethe fast vertical speed, to assign the performance which the position is fast stops (namely to have extremely high angle addition and subtraction speed), therefore the high speed main axle often uses the liquid static pressure bearing type, the air static pressure bearing type, the thermo-compression nitriding silicon (Si3N4) the ceramic bearing magnetism aerosol bearing type isostructuralism form. Lubricates uses technology and so on oil gas lubrication, splash lubrication. The main axle cools uses the main axle interior water cooling generally or air cooled.3. The engine bed actuates the systemIn order to satisfy the mold high speed processing the need, high speed processesthe engine bed the actuation system to be supposed to have the following characteristic:(1) high entering for speed.The research indicated that, regarding the minor diameter cutting tool, enhances the rotational speed and each tooth enters for the quantity is advantageous in reduces the cutting tool attrition. At present commonly used entering for the speed range is 20~30m/Min, like uses leads greatly the ball bearing guide screw transmission, enters may reach 60m/ for the speedMin; Uses the straight line electrical machinery thenmay enable to achieve 120m/ to the speedMin.(2) high acceleration.Has the good acceleration characteristic to the three dimensional complex curved surface silhouette high speed processing request actuation system, the request provides the driver which the high rapid advance or progress gives (to enter speed approximately 40m/ quicklyMin, the 3D outline processingspeed is 10m/Min), can provide 0.4m/S2 to 10m/The s2 acceleration and reduces the speed.The engine bed manufacturer mostly uses the entire closed loop position servo-control slightly to lead, the great size, the high grade ball bearing guide screw or leads greatly many guide screws. Along with the electrical machinery technology development, the advanced straight line electric motor already was published, and the success applied in the CNC engine bed. The advanced straight line direct motor drive enable the CNC engine bed no longer to have the mass inertia, in advance, question and so on lag and vibration, sped up the servo speed of response, increased the servo-control precision and the engine bed processing precision.4. Numerical control systemThe advanced numerical control system is guaranteed the mold complex curved surface high speed processing quality and the efficiency key aspect, the mold high-speed cutting processing to the numerical control system basic request is:A. High speed numerical control return route (Digital control loop), including:32 or above 64 bit parallel processors and 1.5Gb hard disk; Extremely short straight line electrical machinery sampling time.B. Speed and acceleration feed-forward control (Feed forward control); Digitalactuation system crawling control (Jerk control).C. Advanced inserts makes up the method (to insert based on the NURBS transect makes up), by obtains the good surface quality, the precise size and the high geometry precision.D. Pretreatment (Look-ahead) function. The request has the large capacity cushion register, may read in advance and inspectsmany segments (for example the DMG engine bed to be possible to reach 500 segments, the Simens system may reach a 1000~2000 segment), in order to when is processed the superficial shape (curvature) changes may promptly adopt changes for measure and so on speed by avoids cutting and so on.E. The error compensatory function, including because the straight line electrical machinery, the main axle and so on gives off heat the hot error which causes to compensate, the quadrantal error compensates, the measurement system error compensates and so on the function. In addition, the mold high-speed cutting processing very is also high to the data transmission speed request.F. The traditional data connection, like the RS232 serial mouth transmission speed is 19.2kb, but many advanced processings centers have used the ether local area network (Ethernet) to carry on the data transmission, the speed may reach 200kb.5. Cooling lubricationThe high speed processing uses the belt coating the hard alloy tools, in high speed, the high temperature situation does not need the cutting compound, the cutting efficiency to be higher. This is because: The milling main axle high speed revolves, the cutting compound if achieved the cutting area, first must overcome the enormous centrifugal force; Even if it overcame the centrifugal force to enter the cutting area, also was possible as a result of the cutting area high temperature but to evaporate immediately, the cooling effect very small did not even have; At the same time the cutting compound can cause the cutting tool edge of a sword the temperature intense change, is easy to causethe crack the production, therefore must pick the oil used/Gas cooling lubrication dry type cutting way. This way may use the compressed gas rapidly the cutting which the cutting area produces, thus the massive cuttings hotly will carry off, at the same time might forms extremely thin microscopic protective film after the atomization lubricating oil in the cutting tool edge of a sword and the work piece surface, but effectively will lengthen the cutting tool life and enhances the components the surface quality.Third, high-speed cutting processing cutting toolThe cutting tool is in the high-speed cutting processing one of most active important factors, it is affecting the processing efficiency, the production cost and the product processing precision directly. The cutting tool must withstand load and so on high temperature, high pressure, friction, impact and vibration in the high speed processing process, the high-speed cutting cutting tool should have the good machine capability and the thermostability, namely has the good anti- impact, the wearability and resists heat the weary characteristic. The high-speed cutting processing cutting tool technological development speed is very quick, application many like diamonds (PCD), cubic boron nitride (CBN), ceramic cutting tool, coating hard alloy, (carbon) titanium nitrides hard alloy TIC (N) and so on.In the processing cast iron and in the alloy steel cutting tool, the hard alloy is the most commonly used cutting tool material. Hard alloy tools resistance to wear good, but the solidity ratio cube boron nitride and the ceramics are low. In order to enhance degree of hardness and the superficially attractive fineness, uses the cutting tool coating technology, the coating material for thetitanium nitrides (TiN), the aluminium nitride titanium (TiALN) and so on. The coating technology causes the coating by the sole coating development for multilayered, the many kinds of coating material coating, has become one of enhancement high-speed cutting ability essential technical. The diameter in the 10~40mm scope, also has the carbon titanium nitrides coating the hard alloy bit to be able to process the Luo river degree of hardness to be smaller than 42 materials, but the titanium nitrides aluminum coating cutting tool can process the Luo river degree of hardness is 42 even higher materials. When high-speed cutting steel products, the cutting tool material should select the hot rigidity and the fatigue strength high P kind of hard alloy, the coating hard alloy, the cubic boron nitride (CBN) and the CBN compound cutting tool material (WBN) and so on. The cutting cast iron, should select the fine grain K kind of hard alloy to carry on the rough machining, selects the compound nitrided silicon ceramics or the crystal combination cube boron nitride (PCNB) the compound cutting tool carries on the precision work. When precise processing non-ferrous metal or nonmetallic material, should select crystal combination diamond PCD or the CVD diamond coating cutting tool. When choice cutting parameter, in view of the circular shear blade and a ball milling cutter, should pay attention to the effective diameter the concept. The high speed milling cutting tool should press the balance design manufacture. The cutting tool front anglemust be smaller than the conventional cutting tool front angle, the clearance angle is slightly big. The host vice- cutting edge attachment point should the cavetto or the lead angle, increases the vertex angle, prevents the knife point place hot attrition. Should enlarge nearby the knife point the cutting edgelength and the cutting tool material volume, enhances the cutting tool rigidity. Is safe in the guarantee and satisfies the processing request under the condition, the cutting tool hangs extends as far as possible short, cutter body central toughness is friends with. The hilt must be sturdier than the cutting tool diameter, connects the handle to assume but actually the pyramidal, by increases its rigidity. As far as possible central the refrigerant hole in the cutting tool and the cutting tool system. A ball end mill must consider effectively cuts the length, the cutting edge must be as far as possible short, two spiral grooves balls end mill usually uses in the thick mill complex curved surface, four spiral grooves balls end mill usually uses in the fine mill complex curved surface.Fourth, mold high speed processing craftThe high speed processing including take removes the remainder as the goal rough machining, the residual rough machining, as well as take gains the high grade processing surface and the slight structure as the goal half precision work, the precision work and the mirror surface processing and so on.1. Rough machiningThe mold rough machining essential target is pursues in the unit time material removing rate, and is half precision work preparation work piece geometry outline. In the high speed processing rough machining should adopt the craft plan is the high cutting speed, Gao Jin giving rate and the small cutting specifications combination. The contour processing way is one processing way which the multitudinous CAM software uses generally. Using is spiral contour and so on the Z axis contour two ways which are many, also is in processes the region only time to feed, in does not lift the knife in the situation to producecontinuously the smooth cutting tool way, enters, draws back the knife way to use the circular arc to cut into, to cut. The spiral contour way characteristic is, has not waited the high level between the knife road migration, may avoid frequently lifting the knife, feeding to the components surface quality influence and mechanical device nonessential consuming. To is steep and the flat site processes separately, the computation suits contour and suits the use similar 3D bias the region, and may use the spiral way, in very little lifts the cutting tool way which the knife in the situation produces optimizes, obtains the better surface quality. In the high speed processing, certainly must adopt the circular arc to cut into, to cut the connection way, as well as the circular arc transition, avoids changing the cutting tool to enter suddenly for the direction, the prohibition use direct under knife connection way, avoids burying the cutting tool the work piece. When processes the mold cavity, should avoid the cutting tool vertical insertion work piece under, but should use inclines the knife way (commonly used angle of bank for 20°~30°), best uses the screw type under knife by to reduce the cutting tool load. When processes the mold core, should under the knife then level cut into the work piece as far as possible first from the work piece. The cutting tool cuts into, cuts when the work piece should use as far as possible inclines the type (or round arc-type) cuts into, cuts, vertically avoids cutting into, cutting. Uses climbs up the type cutting to be possible to reduce the cutting heat, reduces the cutting tool stress and the work hardening degree, improves the processing quality.2. Half precision workThe mold half precision work essential target is causes the work piece outline shape smoothly, surface finish remainder even,this especially is important regarding the tool steel mold, because it will affect time the precision work cutting tool layer of cutting area change and cutting tool load change, thus influence cutting process stability and precision work surface quality.The rough machining is based on the volume model, the precision work then is based on the face mold. Before develops CAD/The CAM system to the components geometry description is not continual, after because has not described in front of the rough machining, the precision work processes the model the average information, therefore the rough machining surface surplus processing remainder distribution and the great surplus processing remainder is unknown. Therefore should fifty-fifty the precision work strategy carry on the optimization after to guarantee half precision work the work piece surface has the even surplus processing remainder. The optimized process includes: After the rough machining the outline computation, the great surplus processing remainder computation, the biggest permission processing remainder determination, is bigger than the biggest permission processing remainder the profile district (for example transition radius and so on scoop channel, corner is smaller than rough machining cutting tool radius region) as well as when half precision work the knife heart path computation to the surplus processing remainderand so on.The existing mold high speed processes CAD/The CAM software has the surplus processing remainder analysis function mostly, and can act according to the surplus processing remainder the size and the distribution situation uses the reasonable half precision work strategy. After like the MasterCAM software provided has tied the shape milling (Pencil milling) andthe surplus milling (Rest milling) and so on the method eliminates the rough machining the surplus processing remainder big quoin by to guarantee the following working procedure even processing remainder.3. Precision workThe mold high speed precision work strategy is decided by the cutting tool and the work piece contact point, but the cutting tool and the work piece contact point but changes along with the processing surface curved surface slope and the cutting tool effective radius change. Regarding by the complex curved surface processing which many curved surface combination but becomes, should carry on the continuous treating as far as possible in a working procedure, but is not carries on the processing separately to each curved surface, by reduces lifts the knife, under the knife number of times. However, because processes the superficial slope change, if only defines the processing the side to eat the knife quantity (Step over), possibly creates on the slope different surface the actual step of distance non-uniformity, thus influence processing quality.In the ordinary circumstances, the precision work curved surface radius of curvature should be bigger than the cutting tool radius 1.5 times, by evades the no admittance to the direction suddenly transformation. In the mold high speed precision work, when each time cuts into, cuts the work piece, enters for the direction change should as far as possible use the circular arc or the curve switches over, avoids using the straight line to switch over, by maintains the cutting process the stability.Fifth, concluding remarkThe high-speed cutting technology is one of machining technology main development directions, at present mainlyapplies in the automobile industry and the mold profession, in the processing complex curved surface domain, work piece itself or the cutting tool system rigidity request high processing domain and so on, is the many kinds of advanced processings technology integration in particular, its is highlyeffective high grade, esteems for the people. It not only involves to the high speed processing craft, moreover also includes high speed processes the engine bed, the numerical control is systematic, the high-speed cutting cutting tool and CAD/CAM technology and so on. The mold high speed processing technology generally has applied at present in the developed country mold manufacturing industry, but still waited for in our country's application scope and the application level the enhancement, because it had the tradition to process the incomparable superiority, still will be the next processing technology inevitable development direction.模具高速铣削加工技术摘要介绍了高速铣削在模具加工中的应用以及影响,并简要的介绍了高速铣削机床的结构、控制系统和刀具。
附件:模具高速铣削加工技术摘要介绍了高速铣削在模具加工中的应用以及影响,并简要的介绍了高速铣削机床的结构、控制系统和刀具。
对高速加工的工艺进行了简单的分析。
关键词高速铣削;模具加工一、前言在现代模具生产中,随着对塑件的美观度及功能要求得越来越高,塑件内部结构设计得越来越复杂,模具的外形设计也日趋复杂,自由曲面所占比例不断增加,相应的模具结构也设计得越来越复杂。
这些都对模具加工技术提出了更高要求,不仅应保证高的制造精度和表面质量,而且要追求加工表面的美观。
随着对高速加工技术研究的不断深入,尤其在加工机床、数控系统、刀具系统、CAD/CAM软件等相关技术不断发展的推动下,高速加工技术已越来越多地应用于模具型腔的加工与制造中。
数控高速切削加工作为模具制造中最为重要的一项先进制造技术,是集高效、优质、低耗于一身的先进制造技术。
相对于传统的切削加工,其切削速度、进给速度有了很大的提高,而且切削机理也不相同。
高速切削使切削加工发生了本质性的飞跃,其单位功率的金属切除率提高了30%~40%,切削力降低了30%,刀具的切削寿命提高了70%,留于工件的切削热大幅度降低,低阶切削振动几乎消失。
随着切削速度的提高,单位时间毛坯材料的去除率增加了,切削时间减少了,加工效率提高了,从而缩短了产品的制造周期,提高了产品的市场竞争力。
同时,高速加工的小量快进使切削力减少了,切屑的高速排出减少了工件的切削力和热应力变形,提高了刚性差和薄壁零件切削加工的可能性。
由于切削力的降低,转速的提高使切削系统的工作频率远离机床的低阶固有频率,而工件的表面粗糙度对低阶频率最为敏感,由此降低了表面粗糙度。
在模具的高淬硬钢件(HRC45~HRC65)的加工过程中,采用高速切削可以取代电加工和磨削抛光的工序,从而避免了电极的制造和费时的电加工,大幅度减少了钳工的打磨与抛光量。
对于一些市场上越来越需要的薄壁模具工件,高速铣削也可顺利完成,而且在高速铣削CNC加工中心上,模具一次装夹可完成多工步加工。
高速加工技术对模具加工工艺产生了巨大影响,改变了传统模具加工采用的“退火→铣削加工→热处理→磨削”或“电火花加工→手工打磨、抛光”等复杂冗长的工艺流程,甚至可用高速切削加工替代原来的全部工序。
高速加工技术除可应用于淬硬模具型腔的直接加工(尤其是半精加工和精加工)外,在EDM电极加工、快速样件制造等方面也得到了广泛应用。
大量生产实践表明,应用高速切削技术可节省模具后续加工中约80%的手工研磨时间,节约加工成本费用近30%,模具表面加工精度可达1 m,刀具切削效率可提高1倍。
二、高速铣削加工机床高速切削技术是切削加工技术的主要发展方向之一,它随着CNC技术、微电子技术、新材料和新结构等基础技术的发展而迈上更高的台阶。
由于模具加工的特殊性以及高速加工技术的自身特点,对模具高速加工的相关技术及工艺系统(加工机床、数控系统、刀具等)提出了比传统模具加工更高的要求。
1.高稳定性的机床支撑部件高速切削机床的床身等支撑部件应具有很好的动、静刚度,热刚度和最佳的阻尼特性。
大部分机床都采用高质量、高刚性和高抗张性的灰铸铁作为支撑部件材料,有的机床公司还在底座中添加高阻尼特性的聚合物混凝土,以增加其抗振性和热稳定性,这不但可保证机床精度稳定,也可防止切削时刀具振颤。
采用封闭式床身设计,整体铸造床身,对称床身结构并配有密布的加强筋等也是提高机床稳定性的重要措施。
一些机床公司的研发部门在设计过程中,还采用模态分析和有限元结构计算等,优化了结构,使机床支撑部件更加稳定可靠。
2.机床主轴高速机床的主轴性能是实现高速切削加工的重要条件。
高速切削机床主轴的转速范围为10000~100000m/min,主轴功率大于15kW。
通过主轴压缩空气或冷却系统控制刀柄和主轴间的轴向间隙不大于0.005mm。
还要求主轴具有快速升速、在指定位置快速准停的性能(即具有极高的角加减速度),因此高速主轴常采用液体静压轴承式、空气静压轴承式、热压氮化硅(Si3N4)陶瓷轴承磁悬浮轴承式等结构形式。
润滑多采用油气润滑、喷射润滑等技术。
主轴冷却一般采用主轴内部水冷或气冷。
3.机床驱动系统为满足模具高速加工的需要,高速加工机床的驱动系统应具有下列特性:(1)高的进给速度。
研究表明,对于小直径刀具,提高转速和每齿进给量有利于降低刀具磨损。
目前常用的进给速度范围为20~30m/min,如采用大导程滚珠丝杠传动,进给速度可达60m/min;采用直线电机则可使进给速度达到120m/min。
(2)高的加速度。
对三维复杂曲面廓形的高速加工要求驱动系统具有良好的加速度特性,要求提供高速进给的驱动器(快进速度约40m/min,3D轮廓加工速度为10m/min),能够提供0.4m/s2到10m/s2的加速度和减速度。
机床制造商大多采用全闭环位置伺服控制的小导程、大尺寸、高质量的滚珠丝杠或大导程多头丝杠。
随着电机技术的发展,先进的直线电动机已经问世,并成功应用于CNC机床。
先进的直线电动机驱动使CNC机床不再有质量惯性、超前、滞后和振动等问题,加快了伺服响应速度,提高了伺服控制精度和机床加工精度。
4.数控系统先进的数控系统是保证模具复杂曲面高速加工质量和效率的关键因素,模具高速切削加工对数控系统的基本要求为:a. 高速的数字控制回路(Digital control loop),包括:32位或64位并行处理器及1.5Gb以上的硬盘;极短的直线电机采样时间。
b. 速度和加速度的前馈控制(Feed forward control);数字驱动系统的爬行控制(Jerk control)。
c. 先进的插补方法( 基于NURBS的样条插补),以获得良好的表面质量、精确的尺寸和高的几何精度。
d. 预处理(Look-ahead)功能。
要求具有大容量缓冲寄存器,可预先阅读和检查多个程序段(如DMG机床可多达500个程序段,Simens系统可达1000~2000个程序段),以便在被加工表面形状(曲率)发生变化时可及时采取改变进给速度等措施以避免过切等。
e. 误差补偿功能,包括因直线电机、主轴等发热导致的热误差补偿、象限误差补偿、测量系统误差补偿等功能。
此外,模具高速切削加工对数据传输速度的要求也很高。
f. 传统的数据接口,如RS232串行口的传输速度为19.2kb,而许多先进的加工中心均已采用以太局域网(Ethernet)进行数据传输,速度可达200kb。
5.冷却润滑高速加工采用带涂层的硬质合金刀具,在高速、高温的情况下不用切削液,切削效率更高。
这是因为:铣削主轴高速旋转,切削液若要达到切削区,首先要克服极大的离心力;即使它克服了离心力进入切削区,也可能由于切削区的高温而立即蒸发,冷却效果很小甚至没有;同时切削液会使刀具刃部的温度激烈变化,容易导致裂纹的产生,所以要采用油/气冷却润滑的干式切削方式。
这种方式可以用高压气体迅速吹走切削区产生的切削,从而将大量的切削热带走,同时经雾化的润滑油可以在刀具刃部和工件表面形成一层极薄的微观保护膜,可有效地延长刀具寿命并提高零件的表面质量。
三、高速切削加工的刀具刀具是高速切削加工中最活跃重要的因素之一,它直接影响着加工效率、制造成本和产品的加工精度。
刀具在高速加工过程中要承受高温、高压、摩擦、冲击和振动等载荷,高速切削刀具应具有良好的机械性能和热稳定性,即具有良好的抗冲击、耐磨损和抗热疲劳的特性。
高速切削加工的刀具技术发展速度很快,应用较多的如金刚石(PCD)、立方氮化硼(CBN)、陶瓷刀具、涂层硬质合金、(碳)氮化钛硬质合金TIC(N)等。
在加工铸铁和合金钢的切削刀具中,硬质合金是最常用的刀具材料。
硬质合金刀具耐磨性好,但硬度比立方氮化硼和陶瓷低。
为提高硬度和表面光洁度,采用刀具涂层技术,涂层材料为氮化钛(TiN)、氮化铝钛(TiALN)等。
涂层技术使涂层由单一涂层发展为多层、多种涂层材料的涂层,已成为提高高速切削能力的关键技术之一。
直径在10~40mm范围内,且有碳氮化钛涂层的硬质合金刀片能够加工洛氏硬度小于42的材料,而氮化钛铝涂层的刀具能够加工洛氏硬度为42甚至更高的材料。
高速切削钢材时,刀具材料应选用热硬性和疲劳强度高的P类硬质合金、涂层硬质合金、立方氮化硼(CBN)与CBN复合刀具材料(WBN)等。
切削铸铁,应选用细晶粒的K类硬质合金进行粗加工,选用复合氮化硅陶瓷或聚晶立方氮化硼(PCNB)复合刀具进行精加工。
精密加工有色金属或非金属材料时,应选用聚晶金刚石PCD或CVD金刚石涂层刀具。
选择切削参数时,针对圆刀片和球头铣刀,应注意有效直径的概念。
高速铣削刀具应按动平衡设计制造。
刀具的前角比常规刀具的前角要小,后角略大。
主副切削刃连接处应修圆或导角,来增大刀尖角,防止刀尖处热磨损。
应加大刀尖附近的切削刃长度和刀具材料体积,提高刀具刚性。
在保证安全和满足加工要求的条件下,刀具悬伸尽可能短,刀体中央韧性要好。
刀柄要比刀具直径粗壮,连接柄呈倒锥状,以增加其刚性。
尽量在刀具及刀具系统中央留有冷却液孔。
球头立铣刀要考虑有效切削长度,刃口要尽量短,两螺旋槽球头立铣刀通常用于粗铣复杂曲面,四螺旋槽球头立铣刀通常用于精铣复杂曲面。
四、模具高速加工工艺高速加工包括以去除余量为目的的粗加工、残留粗加工,以及以获取高质量的加工表面及细微结构为目的的半精加工、精加工和镜面加工等。
1.粗加工模具粗加工的主要目标是追求单位时间内的材料去除率,并为半精加工准备工件的几何轮廓。
高速加工中的粗加工所应采取的工艺方案是高切削速度、高进给率和小切削用量的组合。
等高加工方式是众多CAM软件普遍采用的一种加工方式。
应用较多的是螺旋等高和等Z轴等高两种方式,也就是在加工区域仅一次进刀,在不抬刀的情况下生成连续光滑的刀具路径,进、退刀方式采用圆弧切入、切出。
螺旋等高方式的特点是,没有等高层之间的刀路移动,可避免频繁抬刀、进刀对零件表面质量的影响及机械设备不必要的耗损。
对陡峭和平坦区域分别处理,计算适合等高及适合使用类似3D偏置的区域,并且可以使用螺旋方式,在很少抬刀的情况下生成优化的刀具路径,获得更好的表面质量。
在高速加工中,一定要采取圆弧切入、切出连接方式,以及拐角处圆弧过渡,避免突然改变刀具进给方向,禁止使用直接下刀的连接方式,避免将刀具埋入工件。
加工模具型腔时,应避免刀具垂直插入工件,而应采用倾斜下刀方式(常用倾斜角为20°~30°),最好采用螺旋式下刀以降低刀具载荷。
加工模具型芯时,应尽量先从工件外部下刀然后水平切入工件。
刀具切入、切出工件时应尽可能采用倾斜式(或圆弧式)切入、切出,避免垂直切入、切出。
采用攀爬式切削可降低切削热,减小刀具受力和加工硬化程度,提高加工质量。