COMPUTER-AIDED CNC PROGRAMMING
FOR THE MACHINING OF NON-TYPICAL PARTS
Grzegorz Nikiel
Grzegorz NIKIEL, Ph.D., Eng., University of Bielsko-Bia?a, Department of
Manufacturing Technology and Automation, 43-309 Bielsko-Bia?a, ul. Willowa 2,
gnikiel@ath.bielsko.pl
1. Introduction
Many manufacturing firms, especially medium and small, has to solve problem of production development and search of new customers. In many cases this leads to the assortment enlarging of already manufactured products. Often this is joined with implementation of the new manufacturing processes. In conditions of market competition it demands high flexibility which is often got in way replacing of conventional manufacturing resources by the modern CNC tool machines [1]. This is essentials condition for more efficient development, higher quality and faster adoption to new requirements [2]. For maintenance of the low costs of manufacturing for production of small and medium batches very often the Group Technology is applied [3]. With help of grouping of the manufactured components into families more efficient the machines, devices, workers are used. In the processes planning one from most important tasks is the CNC machine tool programming [4, 5]. Very often the CAD/CAM systems are used from reason their possibility of flexible programming. In the case of typical components such approach the positive results gives, though it demands an efficient co-operations between constructors and technologist.
Sometimes from different reasons it is impossible, especially when the Group Technology is applied. Usually the part programs for machining of single components are created, but the modern CNC controllers offer some methods of programming, which to machining of some similar components can be used. Such methods are:
1.Cycles [6]. The cycles are design for machining of typical surfaces (the holes, threads, slots etc.). Usually a parametric description of machined surfaces is applied which enable the easy and fast changes of their geometry. Unfortunately they be
characterized by small flexibility and small influence onto strategy of machining, dependent only from the parameters of cycle. In the modern controllers it permit onto a Workshop Oriented Programming (WOP), i.e. programming directly by the operators, often aided by a dialog programming (sometimes a conversational programming called). Therefore this is relative simple programming method, very often used in industrial practice.
2.Parametric programming [5, 6]. A typical part program is executed from beginning to end in one run. In parametric programming the execution of part program can run into different way (e.g. by conditional instruction IF.. THEN.. use). In addition, a multiple repetition of the part program fragment is accessible (REPEAT loop, WHILE loop etc.). Furthermore, the arithmetical functions and other advanced functions are possible. The axis positions, feed and speed functions, etc. can be specified by a parametric expressions (by R-parameters use). Into this way it was been possible to create own machining cycles also. This approach demands high skills of programming and is very labour-consuming also. Exact verification of the program is necessary, in this its immunity in the dangerous situations (e.g. joined with application of incorrect value of the input parameters). Therefore in view of above mentioned defects it is infrequently used in industrial practice.
3. Programming based on the freely defined contours.The task depends on defining of machined contour and its automatic conversion to the CNC codes. If the automatic cutter radius compensation (the G41 and G42 functions) is not used then additionally a equidistant has to be generated. This sub-task is easy to realization if mentioned contour is represented in a CAD system – with help of the Offset function. Second sub-task often is realized in way of export of graphic form of the tool path to the typical formats of data exchange (DXF, HPGL etc.). In next step by the suitable postprocessors use (for example the solution given in [7]) conversion of tool path onto the CNC codes is performed. From practical regards this approach in generality for the simple operations is applied, e.g. a laser cutting, a water jet cutting etc. A solution integrating both sub-tasks in one
application program are applied also – the AutoCUT is the best example [8]. In practice this solution is not applied too often although it possesses many advantages.
In the conditions of small batch production a process planning to the CNC programming is often restricted [9]. In this situation large meaning has integration of the CAD/CAM systems with omission of CAPP stage. The Features idea is then a effective method of data exchange [10, 11, 12]. When the Group Technology is used, after supplement by appropriate data bases and knowledge bases, it can be best solution for production of typical elements [13, 14]. In case of non-typical parts such approach generally is ineffective. Mainly in view of the widely applied methods of Features recognizing which limit number of the Feature types [10, 12]. Maybe in future a solution will bring integration of CAD/CAM/CNC systems based on the STEP-NC standards (ISO 14649, ISO 10303:238) [15, 16] which will replace traditionally applied CNC programming with G-codes onto thing of the neutral format of data exchange.
2. Analysis of the examples
Presented below examples of the group CNC machining are a fragment of production program from the small firm. Generally this components have non-typical shapes, they are manufactured from hard materials (e.g. austenitic stainless steel), usually needed the special jigs and fixtures, in the conditions of small batch production. The planning processes in this case demand a participation of technologists with large experience. A specific character of accessible tool machines for defining of the method of CNC programming should to consider also. After execution of detailed analysis onto subject of the discussed methods the following conclusions were formulated:
?The machined shapes exclude applying of the standard cycles. Most of the programs is design for the complicated profiles machining. From here description of these profiles is largest problem. Moreover, machining of the components is
performed on the different tool machines, equipped in different controller.
?For most of machined components the exact drawing documentation is not made. In a production order the general drawings are included, often described by parametric dimensions. Then current values of this parameters are given also.
?Short series and large variety of the components demands fast modifying of current production program. Fast CNC programming and the programs implementation is necessary, best directly at tool machine (WOP).
?Often the operators of tool machines possess large knowledge and experience in the area of manufacturing technology, sufficient for preparation of simple program (in range of the technology). Fast preparation of the tool path is limitation only.
General conclusion is such, that in presented case use of the universal CAD/CAM systems for CNC programming is very difficult. Moreover, it joins with high costs of shopping and trainings for the workers. Low flexibility of this method is expected also, especially time of programming can be a great problem. In this situation a parametric programming as the best solution was
considered. But, as it was shew on the examples, the parametric programming can be realized in different way.
2.1. Example I – the grooved rollers finish machining
Finish machining of the grooved rollers family was subject of research (Fig. 1). Basic changing dimensions for rollers were external diameter d, working profile length L and profile angle α. The profile of co-operate roller is moved by half pitch. Finish machining is performed by turning with use of tool with the V type rhombic insert (nose angle equal 35°), where the nose radius rε is equal 0,4 mm (Fig. 1). The tool reference point is located in the insert nose center. For each pair of rollers their profile is designed in a CAD environment according to the dimensions of rolling elements. A fast method of tool path generation was the main subject of performed research. First of all generating of the tool path (only finishing, without rough machining which is programmed in a manual mode) and forming it in accordance with requirements of appropriate language. As has been mentioned above the use of parametric program was considered. With help of the advanced programming
methods (e.g. transformations of co-ordinate system, sub-programs etc.) it was been possible to achievement the aim of this study. However, number of the machined rollers is very small (some per year). Therefore another approach was accepted. Because for each roller a exact CAD model is prepared (2D model), it was used to CNC programming. For achievement of this aim the following activities was considered:
?For each used CNC controller the framework of part program is created, including program header, technological functions, tool functions and program end (without tool path).
?In a CAD environment the model co-ordinate system is assigned to the workpiece co-ordinate system.
?In the semi-automatic mode from the model of working surface a tool path is extracted with use the Offset function.
?Manually the run-in path and the run-out path is added. For different elements of tool path (with working interpolation or with rapid interpolation) different
attributes of line were applied.
?The designed tool path is converted to a numerical form in semi-automatic mode by special program (written in LISP language) and inserted to the part program (created previously). User has to show only first element of the tool path, further analysis is worked out on basis of the drawing data base (Fig. 2).
?Finally the part program is verified, the cutting parameters values are corrected and a graphical simulation of machining is executed (Fig. 3). Total time of program planning (without preparing of CAD model) then about some minutes. An universal postprocessor was not applied (e.g. [7]) because format of the CNC program can be easily adapt to requirements of controller. Furthermore time of designing became significantly shortened.
2.2. Example II – the multi-edge rings profile machining
The multi-edge rings profile machining was subject of the research (Fig. 4). On the face three zones of grooves are machined. Number of grooves (n1, n2, n3) results from companies' recommendations. In every zone the constant value of pitch S is kept. The grooves dimensions (S, F, G) and the chamfer dimension w are changing and they have to be contain in the recommended limits. Their values are calculated for the constant diameters D1 and D2 (given in a production order). Just after complete determining of grooves geometrical form the machining operation can be designed. The rings are machined by tool with square insert (S type) – Fig. 4. The tool reference point is located in the insert nose center. In order to clearly determine of the remaining ring dimensions the following dependences were accepted (according to the recommendations):
and the geometrical dependences are described as follows (Fig. 4):
what causes that the S, w and F dimensions in given ranges have to be changed until total number of grooves will not be a natural number. The above task as a optimization problem has treated where three decision values are given (S, w and F) and the constrains is given according to equation (1). The criterion function is calculated according to equation (2). The problem of optimization has solved by the Hooke-Jeves method use [17].
When ring geometry is finally determined then calculations of tool path elements is very simple – tool is moved along equidistant. Therefore was assumed that this two tasks will be solved by means of one program (Fig. 5), a similar approach was showed in [18]. After introduction of value of well-known dimensions (e.g. from production order) the value of remaining dimensions are automatically calculated. If user accepts this values then the part program is generated automatically (in non-parametric form). In opposite case user can improve values of dimensions and their correctness is checked by program. After execution of simulation (Fig. 6) the part program can be transmitted to CNC controller.
2.3. Example III – the eccentric seal rings machining
The eccentric seal rings machining was subject of the research. The external surface of ring which have shape of cone, is machined in analyzed operation. (Fig.
7). A machining datum is located on the internal cylindrical surface (with diameter D) and on the face surface. The groove with diameter dr is made as option. Steel cylindrical ring is a semi-product (from acid-resistant steel or from stainless steel). Described operation comprise two stages: the roughing machining (removal of considerable allowance on part of ring) and finish machining (for obtainment of the exact shape). The shape accuracy has larger importance than the surface roughness (the exploational requirements) [19]. The operation is executed by use of typical tool with rhombic insert (C type). In the part program a linear position of tool (linear co-ordinates Z and X) and an angular position of spindle (angular co-ordinate C) have to be joint. Initially a 3D parametric model making was analyzed (e.g. in AutoDesk
Inventor environment) and use it for generating of the part program (e.g. in EdgeCAM environment [20, 21]). Finally another approach was accepted – a parametric program was used for rings machining. This decision is justified by following premises:
?larger influence onto machining strategy, especially due to the machined materials;
?possibility of program set-up directly at the machine tool, even by machine operators;
?easy and fast changes of part program execution;
?considerably smaller size of program;
?high cost of the CAM systems.
Nevertheless this solution own one important disadvantage – the group program has to work in accordance to very complicated algorithm. Especially, where calculations of co-ordinate points on the cone have to be carried out. Moreover, cutter radius compensation is performed (automatic cutter radius compensation is impossible). In this situation efficiency of a CNC controller can to make significant limitation. It was checked that time of calculation at full implementation of mentioned algorithm on the CNC controller is too long in relation to required speed of machining. Simplifying of the program was indispensable for correct realization of this operation.
The final form of proposed CNC program is showed in Fig. 8. The main program (PIERSCIEN.MPF) is fixed for the rings family, where the machining in a parametric form is described. A subprogram (DANE.SPF) is a data set (in the R-parameters form) which dimensions of the concrete ring define (from a design documentation). Moreover, mentioned subprogram contains the technological parameters (a speed, a feed, etc.) and co-ordinates of the selected points on the machined surface. These points are required to calculation other remaining coordinates in the part program. Mentioned coordinates are determined by use of an additional program, working in the external computer [19]. To tasks of this program should help user at data introducing (Fig. 9), the necessary calculations and the subprogram saving in accordance with requirements of given CNC controller. In next step the part program simulation can be performed (Fig. 10). In last step the part program is sent to a CNC controller.
In proposed form the main program contains about 190 blocks, the subprogram –about 150 blocks. If it was accepted first from considered solutions then part program is considerably longer. Presented part program generates about 80÷100 thousands of the tool movements.
3. A CNC programming in off-line mode
A CNC programming directly on the machine tools (in on-line mode) is very difficult, even sometime impossible. Advanced methods of parametric programming (calculation on the parameters, the structural functions, the jumps etc.) demand exact verification of the algorithm. Exclude this functions usually such part programs use simple methods for the co-ordinates giving. A graphical simulation of parametric programs was not been possible to execute in wide applied popular CAM systems (from reason of the rules of their work). Moreover, often in industrial practice fast conversion a NC program to other language is required. From this in practice sometimes one should to create specialized software [22].
Therefore the original system for NC programs analysis and simulation was realized [23] – Fig. 3, Fig. 6, Fig. 10. Acceleration and facilitation of programming in off-line mode,especially for parametric programs is main purpose. Discussed system contains typical modules – specialized editor, graphical simulation module, offset registers, parameters table, programs database, serial transmission module, etc. As base language was accepted Sinumerik 840D/810D (Siemens) because largest set of functions it contains. Onto its basis was created original, internal programming language (where work philosophy is based on the APT system idea). Therefore the work of this system runes in accordance with presented architecture – Fig. 11.
A preprocessor translates the part program written in language of concrete controller (Siemens, Fanuc, Heidenhain) onto its internal language. Simultaneously syntactic correctness of the part program is checked. In this form the CNC program is analyzed and executed through processor and in analogical form is remembered. In next step this program can be simulated or translated by postprocessor onto CNC program for other controllers. If necessary is including a new language then should to make only new postprocessor or preprocessor, without necessity of changes in the processor. Common procedures for analyses and simulation, included in the processor, simplify adaptation of the system to new tasks.
4. Conclusion
In all presented above examples the typical CNC programming methods use was analyzed. Both cycles as programming with help of the Computer Aided Manufacturing systems (CAM) based on parametric solid models were ineffective. For all analyzed surfaces their geometry is significantly different from geometry of the standard cycles. If CAM software is used then has to be prepared exact model of the machined part (by CAD software). In conditions of small batch production no always this is possible. Use of described methods of programming can be often one
real solution.
Presented approach possesses many advantages. Firstly, significantly reduce the part programming time (to some minutes). The CNC programs can be generated by operators directly at tool machine. Possession of the exact drawings of machined parts is not required (with except of first presented example). Correctness of the generated programs is very high, applying of additional verification (e.g. graphical simulation) usually does not join from modification (except changes of machining parameter values). Significantly is decreased time and cost of the programs start. More expensive CAM software are not necessary. This approach could reduce the number of program changeovers and decrease programs length. The disadvantages of presented approach are naturally also. Firstly, is necessary additional time onto analysis of problem, solution proposing and often additional software preparing. Formulating of the complex geometric
dependences for a tool path calculation demands large knowledge from area of mathematics and geometry. Moreover, a user should to know to write this formulas in the form of computer programs. Such approach does not have to generate additional costs onto shopping of the commercial programming systems because are accessible their free non-commercial versions (e.g. used by author Borland Turbo Delphi, AutoLISP or Visual Basic for Application available as the programming interfaces for AutoCAD, Inventor, etc.).
In opinion of author in situation of process planning for the parts about non-typical shapes, especially when Group Technology is used, applying of non-typical methods of CNC programming is required also. Then use of unconventional tools of computer aid is necessary. Described in this paper solutions are the best example of this approach.
References
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计算机辅助数控编程应用于非典型零件的加工
（Grzegorz Nikiel博士，波兰别尔斯克-比亚瓦，制造技术与自动化学院）
1.简介
许多制造公司，尤其是中，小型要解决生产发展和新客户的搜索问题。在许多情况下，这导致了生产的产品品种已扩大。通常这是加入了新的制造工艺的实施。在市场竞争条件下的高灵活性的要求往往是在传统的制造资源取代了现代数控工具机的方式得到了。这是更有效的发展要领，质量更高，更快的速度为新的要求条件。对于生产成本低的中小批量生产，往往成组技术维护应用。随着所制造的部件组合成的家庭更有效地帮助机器，设备，工人使用。在规划的过程中最重要的任务之一是数控机床的编程。很多时候的CAD / CAM系统所使用的原因，他们的灵活编程的可能性。在典型情况下，这种做法元件积极成果提供，但它要求建设者和技术人员之间有效的合作行动。
有时从不同的原因，是不可能的，尤其是在成组技术被应用。通常为单一成分加工的零件程序的创建，但现代CNC控制器提供了一些编程方法，这在一些类似部件的加工可以使用。这种方法是：
1.周期。设计的周期是典型的表面加工（孔，螺纹，槽等）。通常是加工表面参数描述适用于几何形状，使他们容易和快速变化。不幸的是他们的特点和灵活性，小到小的加工策略的影响，只能从周期的参数而定。在现代控制它允许一个研讨会上面向编程（WOP），即通过编程往往一个对话框编程（有时称为会话编程）资助的经营者，直接。因此，这是相对简单的编程方法，往往应用于工业实践。
2.参数化编程。一个典型的一部分，执行程序从开始到结束一分。参数规划的一部分，程序的执行可能遇到不同的方式（例如，如果..然后..使用条件指令）。此外，对部分程序段多重复访问（重复循环，而循环等）。此外，算术功能和其他先进的功能是可能的。轴的位置，饲料和速度的功能等，可以指定一个参数表达式（由R -参数的使用）。一直到这一点，有人可能创造自己的加工周期也途径。这种方法需要高技能的编程劳动，是非常耗时也。该方案的精确验证是必要的，这在危险情况下的豁免权（例如，对输入参数的应用程序加入了不正确的值）。
因此，在上述缺陷的看法是很少用于工业实践。
3.规划自由定义轮廓的基础。这个任务依赖于加工轮廓及其自动转换到数控代码定义。如果自动刀具半径补偿（即G41和G42的功能的）不使用，则有另外一个等距离的产生。此子任务是很容易实现的，如果提到轮廓CAD系统中的代表 - 与OFFSET函数的帮助。第二个子任务往往体现在对工具的路径图形形式的出口方式向数据交换（DXF文件，HPGL格式等）的典型格式。在合适的后处理器的使用（例如[7]中给出的解决方案）数控刀具上的代码路径转换下一步就是执行。从实际方面的一般性的简单的操作，这种方法被应用，例如：激光切割，水射流切割等一个解决方案，集成两个分在一个应用程序任务也适用 - 在AutoCUT就是最好的例子。这个解决方案是在实践中往往没有应用，虽然它具有许多优点。在小批量生产的条件下工艺设计到数控编程通常限制[9]。在这种情况下有较大意义的CAD / CAM与遗漏的CAPP系统集成的阶段。想法是那么的特点的数据交换的有效方法。当使用成组技术后，通过适当的数据库和知识库的补充，它可以最佳解决方案的典型元素的生产。在非典型零件通常情况下这种做法是无效的。主要是在识别特征的看法，普遍采用的方法的特征类型限制数。也许在未来的解决方案将带来的CAD / CAM /数控的STEP - NC的标准为基础的系统集成（异14649，国际标准化组织10303:238）将取代传统的东西运用到数控G代码编程中立的数据交换格式。
2.分析的例子
下面的例子集团主办的数控加工的生产计划由小企业的片段。一般来说，这部分有不典型形状，它们是从硬质材料（如奥氏体不锈钢），通常需要在小批量生产的条件的特殊夹具及固定装置，制造。规划进程在这种情况下需要一个大的经验与技术专家的参与。可访问工具机的数控编程的方法确定具体的角色应该也考虑。经过详细分析了执行上讨论了以下结论制定方法问题：
?形状的加工周期排除标准的应用。这些项目大部分是加工复杂的轮廓设计。在这里，从这些配置文件描述的最大问题。此外，组件的加工上执行不同的工具，不同的控制器配备机。
?机械零部件图纸文件的确切不进行。在生产订单的总图都包括在内，往往尺寸
外文出处： 《Exploiting Software How to Break Code》By Greg Hoglund, Gary McGraw Publisher : Addison Wesley Pub Date : February 17, 2004 ISBN : 0-201-78695-8 译文标题： JDBC接口技术 译文： JDBC是一种可用于执行SQL语句的JavaAPI（ApplicationProgrammingInterface应用程序设计接口）。它由一些Java语言编写的类和界面组成。JDBC为数据库应用开发人员、数据库前台工具开发人员提供了一种标准的应用程序设计接口，使开发人员可以用纯Java语言编写完整的数据库应用程序。 一、ODBC到JDBC的发展历程 说到JDBC，很容易让人联想到另一个十分熟悉的字眼“ODBC”。它们之间有没有联系呢？如果有，那么它们之间又是怎样的关系呢？ ODBC是OpenDatabaseConnectivity的英文简写。它是一种用来在相关或不相关的数据库管理系统（DBMS）中存取数据的，用C语言实现的，标准应用程序数据接口。通过ODBCAPI，应用程序可以存取保存在多种不同数据库管理系统（DBMS）中的数据，而不论每个DBMS使用了何种数据存储格式和编程接口。 1．ODBC的结构模型 ODBC的结构包括四个主要部分：应用程序接口、驱动器管理器、数据库驱动器和数据源。应用程序接口：屏蔽不同的ODBC数据库驱动器之间函数调用的差别，为用户提供统一的SQL编程接口。 驱动器管理器：为应用程序装载数据库驱动器。 数据库驱动器：实现ODBC的函数调用，提供对特定数据源的SQL请求。如果需要，数据库驱动器将修改应用程序的请求，使得请求符合相关的DBMS所支持的文法。 数据源：由用户想要存取的数据以及与它相关的操作系统、DBMS和用于访问DBMS的网络平台组成。 虽然ODBC驱动器管理器的主要目的是加载数据库驱动器，以便ODBC函数调用，但是数据库驱动器本身也执行ODBC函数调用，并与数据库相互配合。因此当应用系统发出调用与数据源进行连接时，数据库驱动器能管理通信协议。当建立起与数据源的连接时，数据库驱动器便能处理应用系统向DBMS发出的请求，对分析或发自数据源的设计进行必要的翻译，并将结果返回给应用系统。 2．JDBC的诞生 自从Java语言于1995年5月正式公布以来，Java风靡全球。出现大量的用java语言编写的程序，其中也包括数据库应用程序。由于没有一个Java语言的API，编程人员不得不在Java程序中加入C语言的ODBC函数调用。这就使很多Java的优秀特性无法充分发挥，比如平台无关性、面向对象特性等。随着越来越多的编程人员对Java语言的日益喜爱，越来越多的公司在Java程序开发上投入的精力日益增加，对java语言接口的访问数据库的API 的要求越来越强烈。也由于ODBC的有其不足之处，比如它并不容易使用，没有面向对象的特性等等，SUN公司决定开发一Java语言为接口的数据库应用程序开发接口。在JDK1．x 版本中，JDBC只是一个可选部件，到了JDK1．1公布时，SQL类包（也就是JDBCAPI）
前言 在目前激烈的市场竞争中，产品投入市场的迟早往往是成败的关键。模具是高质量、高效率的产品生产工具，模具开发周期占整个产品开发周期的主要部分。因此客户对模具开发周期要求越来越短，不少客户把模具的交货期放在第一位置，然后才是质量和价格。因此，如何在保证质量、控制成本的前提下加工模具是值得认真考虑的问题。模具加工工艺是一项先进的制造工艺，已成为重要发展方向，在航空航天、汽车、机械等各行业得到越来越广泛的应用。模具加工技术，可以提高制造业的综合效益和竞争力。研究和建立模具工艺数据库，为生产企业提供迫切需要的高速切削加工数据，对推广高速切削加工技术具有非常重要的意义。本文的主要目标就是构建一个冲压模具工艺过程，将模具制造企业在实际生产中结合刀具、工件、机床与企业自身的实际情况积累得高速切削加工实例、工艺参数和经验等数据有选择地存储到高速切削数据库中，不但可以节省大量的人力、物力、财力，而且可以指导高速加工生产实践，达到提高加工效率，降低刀具费用，获得更高的经济效益。 1.冲压的概念、特点及应用 冲压是利用安装在冲压设备（主要是压力机）上的模具对材料施加压力，使其产生分离或塑性变形，从而获得所需零件（俗称冲压或冲压件）的一种压力加工方法。冲压通常是在常温下对材料进行冷变形加工，且主要采用板料来加工成所需零件，所以也叫冷冲压或板料冲压。冲压是材料压力加工或塑性加工的主要方法之一，隶属于材料成型工程术。 冲压所使用的模具称为冲压模具，简称冲模。冲模是将材料（金属或非金属）批量加工成所需冲件的专用工具。冲模在冲压中至关重要，没有符合要求的冲模，批量冲压生产就难以进行；没有先进的冲模，先进的冲压工艺就无法实现。冲压工艺与模具、冲压设备和冲压材料构成冲压加工的三要素，只有它们相互结合才能得出冲压件。 与机械加工及塑性加工的其它方法相比，冲压加工无论在技术方面还是经济方面都具有许多独特的优点，主要表现如下； (1) 冲压加工的生产效率高，且操作方便，易于实现机械化与自动化。这是
附录 科技译文： Numerical Control Numerical Control(NC) is a method of controlling the movements of machineComponents by directly inserting coded instructions in the form of numerical data(numbers and data ) into the system.The system automatically interprets these data and converts to output signals. These signals ,in turn control various machine components ,such as turning spindles on and off ,changing tools,moving the work piece or the tools along specific paths,and turning cutting fluits on and off. In order to appreciate the importer of numerical control of machines ,let’s briefly review how a process such as machining has been carried out traditionally .After studying the working drawing of a part, the operator sets up the appropriate process parameters(such as cutting speed ,feed,depth of cut,cutting fluid ,and so on),determines the sequence of operations to be performed,clamps the work piece in a workholding device such as chuck or collet ,and proceeds to make the part .Depending on part shape and the dimensional accuracy specified ,this approach usually requires skilled
附录一英文科技文献翻译 英文原文： Experimental investigation of laser surface textured parallel thrust bearings Performance enhancements by laser surface texturing (LST) of parallel-thrust bearings is experimentally investigated. Test results are compared with a theoretical model and good correlation is found over the relevant operating conditions. A compari- son of the performance of unidirectional and bi-directional partial-LST bearings with that of a baseline, untextured bearing is presented showing the bene?ts of LST in terms of increased clearance and reduced friction. KEY WORDS: ?uid ?lm bearings, slider bearings, surface texturing 1. Introduction The classical theory of hydrodynamic lubrication yields linear (Couette) velocity distribution with zero pressure gradients between smooth parallel surfaces under steady-state sliding. This results in an unstable hydrodynamic ?lm that would collapse under any external force acting normal to the surfaces. However, experience shows that stable lubricating ?lms can develop between parallel sliding surfaces, generally because of some mechanism that relaxes one or more of the assumptions of the classical theory. A stable ?uid ?lm with su?cient load-carrying capacity in parallel sliding surfaces can be obtained, for example, with macro or micro surface structure of di?erent types. These include waviness [1] and protruding microasperities [2–4]. A good literature review on the subject can be found in Ref. [5]. More recently, laser surface texturing (LST) [6–8], as well as inlet roughening by longitudinal or transverse grooves [9] were suggested to provide load capacity in parallel sliding. The inlet roughness concept of Tonder [9] is based on ??e?ective clearance‘‘ reduction in the sliding direction and in this respect it is identical to the par- tial-LST concept described in ref. [10] for generating hydrostatic e?ect in high-pressure mechanical seals. Very recently Wang et al. [11] demonstrated experimentally a doubling of the load-carrying capacity for the surface- texture design by reactive ion etching of SiC
毕业设计（论文）外文文献翻译 文献、资料中文题目：软件开发概念和设计方法文献、资料英文题目： 文献、资料来源： 文献、资料发表（出版）日期： 院（部）： 专业： 班级： 姓名： 学号： 指导教师： 翻译日期： 2017.02.14
外文资料原文 Software Development Concepts and Design Methodologies During the 1960s, ma inframes and higher level programming languages were applied to man y problems including human resource s yste ms,reservation s yste ms, and manufacturing s yste ms. Computers and software were seen as the cure all for man y bu siness issues were some times applied blindly. S yste ms sometimes failed to solve the problem for which the y were designed for man y reasons including: ?Inability to sufficiently understand complex problems ?Not sufficiently taking into account end-u ser needs, the organizational environ ment, and performance tradeoffs ?Inability to accurately estimate development time and operational costs ?Lack of framework for consistent and regular customer communications At this time, the concept of structured programming, top-down design, stepwise refinement，and modularity e merged. Structured programming is still the most dominant approach to software engineering and is still evo lving. These failures led to the concept of "software engineering" based upon the idea that an engineering-like discipl ine could be applied to software design and develop ment. Software design is a process where the software designer applies techniques and principles to produce a conceptual model that de scribes and defines a solution to a problem. In the beginning, this des ign process has not been well structured and the model does not alwa ys accurately represent the problem of software development. However,design methodologies have been evolving to accommo date changes in technolog y coupled with our increased understanding of development processes. Whereas early desig n methods addressed specific aspects of the
机械设计理论 机械设计是一门通过设计新产品或者改进老产品来满足人类需求的应用技术科学。它涉及工程技术的各个领域，主要研究产品的尺寸、形状和详细结构的基本构思，还要研究产品在制造、销售和使用等方面的问题。 进行各种机械设计工作的人员通常被称为设计人员或者机械设计工程师。机械设计是一项创造性的工作。设计工程师不仅在工作上要有创造性，还必须在机械制图、运动学、工程材料、材料力学和机械制造工艺学等方面具有深厚的基础知识。如前所诉，机械设计的目的是生产能够满足人类需求的产品。发明、发现和科技知识本身并不一定能给人类带来好处，只有当它们被应用在产品上才能产生效益。因而，应该认识到在一个特定的产品进行设计之前，必须先确定人们是否需要这种产品。 应当把机械设计看成是机械设计人员运用创造性的才能进行产品设计、系统分析和制定产品的制造工艺学的一个良机。掌握工程基础知识要比熟记一些数据和公式更为重要。仅仅使用数据和公式是不足以在一个好的设计中做出所需的全部决定的。另一方面，应该认真精确的进行所有运算。例如，即使将一个小数点的位置放错，也会使正确的设计变成错误的。 一个好的设计人员应该勇于提出新的想法，而且愿意承担一定的风险，当新的方法不适用时，就使用原来的方法。因此，设计人员必须要有耐心，因为所花费的时间和努力并不能保证带来成功。一个全新的设计，要求屏弃许多陈旧的，为人们所熟知的方法。由于许多人墨守成规，这样做并不是一件容易的事。一位机械设计师应该不断地探索改进现有的产品的方法，在此过程中应该认真选择原有的、经过验证的设计原理，将其与未经过验证的新观念结合起来。 新设计本身会有许多缺陷和未能预料的问题发生，只有当这些缺陷和问题被解决之后，才能体现出新产品的优越性。因此，一个性能优越的产品诞生的同时，也伴随着较高的风险。应该强调的是，如果设计本身不要求采用全新的方法，就没有必要仅仅为了变革的目的而采用新方法。 在设计的初始阶段，应该允许设计人员充分发挥创造性，不受各种约束。即使产生了许多不切实际的想法，也会在设计的早期，即绘制图纸之前被改正掉。只有这样，才不致于堵塞创新的思路。通常，要提出几套设计方案，然后加以比较。很有可能在最后选定的方案中，采用了某些未被接受的方案中的一些想法。
附录 INTEGRATION OF MACHINERY （From ELECTRICAL AND MACHINERY INDUSTRY）ABSTRACT Machinery was the modern science and technology development inevitable result, this article has summarized the integration of machinery technology basic outline and the development background .Summarized the domestic and foreign integration of machinery technology present situation, has analyzed the integration of machinery technology trend of development. Key word：integration of machinery ，technology，present situation ，product t，echnique of manufacture ，trend of development 0. Introduction modern science and technology unceasing development, impelled different discipline intersecting enormously with the seepage, has caused the project domain technological revolution and the transformation .In mechanical engineering domain, because the microelectronic technology and the computer technology rapid development and forms to the mechanical industry seepage the integration of machinery, caused the mechanical industry the technical structure, the product organization, the function and the constitution, the production method and the management system has had the huge change, caused the industrial production to enter into “the integration of machinery” by “the machinery electrification” for the characteristic development phase. 1. Integration of machinery outline integration of machinery is refers in the organization new owner function, the power function, in the information processing function and the control function introduces the electronic technology, unifies the system the mechanism and the computerization design and the software which constitutes always to call. The integration of machinery development also has become one to have until now own system new discipline, not only develops along with the science and technology, but also entrusts with the new content .But its basic characteristic may summarize is: The integration of machinery is embarks from the system viewpoint, synthesis community technologies and so on utilization mechanical technology, microelectronic technology, automatic control technology,
本科毕业论文(设计) 外文翻译 学院：机电工程学院 专业：机械工程及自动化 姓名：高峰 指导教师：李延胜 2011年05 月10日 教育部办公厅 Failure Analysis，Dimensional Determination And
Analysis，Applications Of Cams INTRODUCTION It is absolutely essential that a design engineer know how and why parts fail so that reliable machines that require minimum maintenance can be designed．Sometimes a failure can be serious，such as when a tire blows out on an automobile traveling at high speed．On the other hand，a failure may be no more than a nuisance．An example is the loosening of the radiator hose in an automobile cooling system．The consequence of this latter failure is usually the loss of some radiator coolant，a condition that is readily detected and corrected．The type of load a part absorbs is just as significant as the magnitude．Generally speaking，dynamic loads with direction reversals cause greater difficulty than static loads，and therefore，fatigue strength must be considered．Another concern is whether the material is ductile or brittle．For example，brittle materials are considered to be unacceptable where fatigue is involved． Many people mistakingly interpret the word failure to mean the actual breakage of a part．However，a design engineer must consider a broader understanding of what appreciable deformation occurs．A ductile material，however will deform a large amount prior to rupture．Excessive deformation，without fracture，may cause a machine to fail because the deformed part interferes with a moving second part．Therefore，a part fails(even if it has not physically broken)whenever it no longer fulfills its required function．Sometimes failure may be due to abnormal friction or vibration between two mating parts．Failure also may be due to a phenomenon called creep，which is the plastic flow of a material under load at elevated temperatures．In addition，the actual shape of a part may be responsible for failure．For example，stress concentrations due to sudden changes in contour must be taken into account．Evaluation of stress considerations is especially important when there are dynamic loads with direction reversals and the material is not very ductile． In general，the design engineer must consider all possible modes of failure，which include the following． ——Stress ——Deformation ——Wear ——Corrosion ——Vibration ——Environmental damage ——Loosening of fastening devices
外文翻译 专业机械设计制造及其自动化学生姓名刘链柱 班级机制111 学号1110101102 指导教师葛友华
外文资料名称： Design and performance evaluation of vacuum cleaners using cyclone technology 外文资料出处：Korean J. Chem. Eng., 23(6), (用外文写) 925-930 (2006) 附件： 1.外文资料翻译译文 2.外文原文
应用旋风技术真空吸尘器的设计和性能介绍 吉尔泰金，洪城铱昌，宰瑾李， 刘链柱译 摘要：旋风型分离器技术用于真空吸尘器 - 轴向进流旋风和切向进气道流旋风有效地收集粉尘和降低压力降已被实验研究。优化设计等因素作为集尘效率，压降，并切成尺寸被粒度对应于分级收集的50％的效率进行了研究。颗粒切成大小降低入口面积，体直径，减小涡取景器直径的旋风。切向入口的双流量气旋具有良好的性能考虑的350毫米汞柱的低压降和为1.5μm的质量中位直径在1米3的流量的截止尺寸。一使用切向入口的双流量旋风吸尘器示出了势是一种有效的方法，用于收集在家庭中产生的粉尘。 摘要及关键词：吸尘器; 粉尘; 旋风分离器 引言 我们这个时代的很大一部分都花在了房子，工作场所，或其他建筑，因此，室内空间应该是既舒适情绪和卫生。但室内空气中含有超过室外空气因气密性的二次污染物，毒物，食品气味。这是通过使用产生在建筑中的新材料和设备。真空吸尘器为代表的家电去除有害物质从地板到地毯所用的商用真空吸尘器房子由纸过滤，预过滤器和排气过滤器通过洁净的空气排放到大气中。虽然真空吸尘器是方便在使用中，吸入压力下降说唱空转成比例地清洗的时间，以及纸过滤器也应定期更换，由于压力下降，气味和细菌通过纸过滤器内的残留粉尘。 图1示出了大气气溶胶的粒度分布通常是双峰形，在粗颗粒（>2.0微米）模式为主要的外部来源，如风吹尘，海盐喷雾，火山，从工厂直接排放和车辆废气排放，以及那些在细颗粒模式包括燃烧或光化学反应。表1显示模式，典型的大气航空的直径和质量浓度溶胶被许多研究者测量。精细模式在0.18?0.36 在5.7到25微米尺寸范围微米尺寸范围。质量浓度为2?205微克，可直接在大气气溶胶和 3.85至36.3μg/m3柴油气溶胶。
I / 11 本科毕业设计外文翻译 <2018届） 论文题目基于WEB 的J2EE 的信息系统的方法研究 作者姓名[单击此处输入姓名] 指导教师[单击此处输入姓名] 学科(专业 > 所在学院计算机科学与技术学院 提交日期[时间 ]
基于WEB的J2EE的信息系统的方法研究 摘要：本文介绍基于工程的Java开发框架背后的概念，并介绍它如何用于IT 工程开发。因为有许多相同设计和开发工作在不同的方式下重复，而且并不总是符合最佳实践，所以许多开发框架建立了。我们已经定义了共同关注的问题和应用模式，代表有效解决办法的工具。开发框架提供：<1）从用户界面到数据集成的应用程序开发堆栈；<2）一个架构，基本环境及他们的相关技术，这些技术用来使用其他一些框架。架构定义了一个开发方法，其目的是协助客户开发工程。 关键词：J2EE 框架WEB开发 一、引言 软件工具包用来进行复杂的空间动态系统的非线性分析越来越多地使用基于Web的网络平台，以实现他们的用户界面，科学分析，分布仿真结果和科学家之间的信息交流。对于许多应用系统基于Web访问的非线性分析模拟软件成为一个重要组成部分。网络硬件和软件方面的密集技术变革[1]提供了比过去更多的自由选择机会[2]。因此，WEB平台的合理选择和发展对整个地区的非线性分析及其众多的应用程序具有越来越重要的意义。现阶段的WEB发展的特点是出现了大量的开源框架。框架将Web开发提到一个更高的水平，使基本功能的重复使用成为可能和从而提高了开发的生产力。 在某些情况下，开源框架没有提供常见问题的一个解决方案。出于这个原因，开发在开源框架的基础上建立自己的工程发展框架。本文旨在描述是一个基于Java的框架，该框架利用了开源框架并有助于开发基于Web的应用。通过分析现有的开源框架，本文提出了新的架构，基本环境及他们用来提高和利用其他一些框架的相关技术。架构定义了自己开发方法，其目的是协助客户开发和事例工程。 应用程序设计应该关注在工程中的重复利用。即使有独特的功能要求，也
机械类外文翻译 塑料注塑模具浇口优化 摘要:用单注塑模具浇口位置的优化方法，本文论述。该闸门优化设计的目的是最大限度地减少注塑件翘曲变形，翘曲，是因为对大多数注塑成型质量问题的关键，而这是受了很大的部分浇口位置。特征翘曲定义为最大位移的功能表面到表面的特征描述零件翘曲预测长度比。结合的优化与数值模拟技术，以找出最佳浇口位置，其中模拟armealing算法用于搜索最优。最后，通过实例讨论的文件，它可以得出结论，该方法是有效的。 注塑模具、浇口位臵、优化、特征翘曲变形关键词: 简介 塑料注射成型是一种广泛使用的，但非常复杂的生产的塑料产品，尤其是具有高生产的要求，严密性，以及大量的各种复杂形状的有效方法。质量ofinjection 成型零件是塑料材料，零件几何形状，模具结构和工艺条件的函数。注塑模具的一个最重要的部分主要是以下三个组件集:蛀牙，盖茨和亚军，和冷却系统。拉米夫定、Seow(2000)、金和拉米夫定(2002) 通过改变部分的尼斯达到平衡的腔壁厚度。在平衡型腔充填过程提供了一种均匀分布压力和透射电镜,可以极大地减少高温的翘曲变形的部分～但仅仅是腔平衡的一个重要影响因素的一部分。cially Espe,部分有其功能上的要求,其厚度通常不应该变化。 pointview注塑模具设计的重点是一门的大小和位臵,以及流道系统的大小和布局。大门的大小和转轮布局通常被认定为常量。相对而言,浇口位臵与水口大小布局也更加灵活,可以根据不同的零件的质量。 李和吉姆(姚开屏,1996a)称利用优化流道和尺寸来平衡多流道系统为multiple 注射系统。转轮平衡被形容为入口压力的差异为一多型腔模具用相同的蛀牙,也存
沈阳工业大学工程学院 毕业设计（论文）外文翻译 毕业设计（论文）题目：工具盒盖注塑模具设计 外文题目：Friction , Lubrication of Bearing 译文题目：轴承的摩擦与润滑 系（部）：机械系 专业班级：机械设计制造及其自动化0801 学生姓名：王宝帅 指导教师：魏晓波 2010年10 月15 日
外文文献原文： Friction , Lubrication of Bearing In many of the problem thus far , the student has been asked to disregard or neglect friction . Actually , friction is present to some degree whenever two parts are in contact and move on each other. The term friction refers to the resistance of two or more parts to movement. Friction is harmful or valuable depending upon where it occurs. friction is necessary for fastening devices such as screws and rivets which depend upon friction to hold the fastener and the parts together. Belt drivers, brakes, and tires are additional applications where friction is necessary. The friction of moving parts in a machine is harmful because it reduces the mechanical advantage of the device. The heat produced by friction is lost energy because no work takes place. Also , greater power is required to overcome the increased friction. Heat is destructive in that it causes expansion. Expansion may cause a bearing or sliding surface to fit tighter. If a great enough pressure builds up because made from low temperature materials may melt. There are three types of friction which must be overcome in moving parts: (1)starting, (2)sliding, and(3)rolling. Starting friction is the friction between two solids that tend to resist movement. When two parts are at a state of rest, the surface irregularities of both parts tend to interlock and form a wedging action. To produce motion in these parts, the wedge-shaped peaks and valleys of the stationary surfaces must be made to slide out and over each other. The rougher the two surfaces, the greater is starting friction resulting from their movement . Since there is usually no fixed pattern between the peaks and valleys of two mating parts, the irregularities do not interlock once the parts are in motion but slide over each other. The friction of the two surfaces is known as sliding friction. As shown in figure ,starting friction is always greater than sliding friction . Rolling friction occurs when roller devces are subjected to tremendous stress which cause the parts to change shape or deform. Under these conditions, the material in front of a roller tends to pile up and forces the object to roll slightly uphill. This changing of shape , known as deformation, causes a movement of molecules. As a result ,heat is produced from the added energy required to keep the parts turning and overcome friction. The friction caused by the wedging action of surface irregularities can be overcome
毕业设计（论文） 外文翻译 题目西安市水源工程中的 水电站设计 专业水利水电工程 班级 学生 指导教师 2016年
研究钢弧形闸门的动态稳定性 牛志国 河海大学水利水电工程学院，中国南京，邮编210098 nzg_197901@https://www.doczj.com/doc/e010980937.html,，niuzhiguo@https://www.doczj.com/doc/e010980937.html, 李同春 河海大学水利水电工程学院，中国南京，邮编210098 ltchhu@https://www.doczj.com/doc/e010980937.html, 摘要 由于钢弧形闸门的结构特征和弹力，调查对参数共振的弧形闸门的臂一直是研究领域的热点话题弧形弧形闸门的动力稳定性。在这个论文中，简化空间框架作为分析模型，根据弹性体薄壁结构的扰动方程和梁单元模型和薄壁结构的梁单元模型，动态不稳定区域的弧形闸门可以通过有限元的方法，应用有限元的方法计算动态不稳定性的主要区域的弧形弧形闸门工作。此外，结合物理和数值模型，对识别新方法的参数共振钢弧形闸门提出了调查，本文不仅是重要的改进弧形闸门的参数振动的计算方法，但也为进一步研究弧形弧形闸门结构的动态稳定性打下了坚实的基础。 简介 低举升力，没有门槽，好流型，和操作方便等优点，使钢弧形闸门已经广泛应用于水工建筑物。弧形闸门的结构特点是液压完全作用于弧形闸门，通过门叶和主大梁，所以弧形闸门臂是主要的组件确保弧形闸门安全操作。如果周期性轴向载荷作用于手臂，手臂的不稳定是在一定条件下可能发生。调查指出:在弧形闸门的20次事故中，除了极特殊的破坏情况下，弧形闸门的破坏的原因是弧形闸门臂的不稳定;此外，明显的动态作用下发生破坏。例如:张山闸，位于中国的江苏省，包括36个弧形闸门。当一个弧形闸门打开放水时，门被破坏了，而其他弧形闸门则关闭，受到静态静水压力仍然是一样的，很明显，一个动态的加载是造成的弧形闸门破坏一个主要因素。因此弧形闸门臂的动态不稳定是造成弧形闸门(特别是低水头的弧形闸门)破坏的主要原是毫无疑问。