机械工程外文翻译_缸体机械加工工艺设计

附录附录1英文原文Basic Machining Operations and Cutting TechnologyBasic Machining OperationsMachine tools have evolved from the early foot-powered lathes of the Egyptians and John Wilkinson's boring mill. They are designed to provide rigid support for both the work piece and the cutting tool and can precisely control their relative positions and the velocity of the tool with respect to the work piece. Basically, in metal cutting, a sharpened wedge-shaped tool removes a rather narrow strip of metal from the surface of a ductile work piece in the form of a severely deformed chip. The chip is a waste product that is considerably shorter than the work piece from which it came but with a corresponding increase in thickness of the uncut chip. The geometrical shape of work piece depends on the shape of the tool and its path during the machining operation.Most machining operations produce parts of differing geometry. If a rough cylindrical work piece revolves about a central axis and the tool penetrates beneath its surface and travels parallel to the center of rotation, a surface of revolution is produced, and the operation is called turning. If a hollow tube is machined on the inside in a similar manner, the operation is called boring. Producing an external conical surface uniformly varying diameter is called taper turning, if the tool point travels in a path of varying radius, a contoured surface like that of a bowling pin can be produced; or, if the piece is short enough and the support is sufficiently rigid, a contoured surface could be produced by feeding a shaped tool normal to the axis of rotation. Short tapered or cylindrical surfaces could also be contour formed.Flat or plane surfaces are frequently required. They can be generated by radial turning or facing, in which the tool point moves normal to the axis of rotation. In other cases, it is more convenient to hold the work piece steady and reciprocate the tool across it in a series of straight-line cuts with a crosswise feed increment before each cutting stroke. This operation is called planning and is carried out on a shaper. For larger pieces it is easier to keep the tool stationary and draw the work piece under it as in planning. The tool is fed at each reciprocation. Contoured surfaces can be produced by using shaped tools.Multiple-edged tools can also be used. Drilling uses a twin-edged fluted tool for holes with depths up to 5 to 10 times the drill diameter. Whether thedrill turns or the work piece rotates, relative motion between the cutting edge and the work piece is the important factor. In milling operations a rotary cutter with a number of cutting edges engages the work piece. Which moves slowly with respect to the cutter. Plane or contoured surfaces may be produced, depending on the geometry of the cutter and the type of feed. Horizontal or vertical axes of rotation may be used, and the feed of the work piece may be in any of the three coordinate directions.Basic Machine ToolsMachine tools are used to produce a part of a specified geometrical shape and precise I size by removing metal from a ductile material in the form of chips. The latter are a waste product and vary from long continuous ribbons of a ductile material such as steel, which are undesirable from a disposal point of view, to easily handled well-broken chips resulting from cast iron. Machine tools perform five basic metal-removal processes: I turning, planning, drilling, milling, and grinding. All other metal-removal processes are modifications of these five basic processes. For example, boring is internal turning; reaming, tapping, and counter boring modify drilled holes and are related to drilling; bobbing and gear cutting are fundamentally milling operations; hack sawing and broaching are a form of planning and honing; lapping, super finishing. Polishing and buffing are variants of grinding or abrasive removal operations. Therefore, there are only four types of basic machine tools, which use cutting tools of specific controllable geometry: 1. lathes, 2. planers, 3. drilling machines, and 4. milling machines. The grinding process forms chips, but the geometry of the abrasive grain is uncontrollable.The amount and rate of material removed by the various machining processes may be I large, as in heavy turning operations, or extremely small, as in lapping or super finishing operations where only the high spots of a surface are removed.A machine tool performs three major functions: 1. it rigidly supports the work piece or its holder and the cutting tool; 2. it provides relative motion between the work piece and the cutting tool; 3. it provides a range of feeds and speeds usually ranging from 4 to 32 choices in each case.Speed and Feeds in MachiningSpeeds, feeds, and depth of cut are the three major variables for economical machining. Other variables are the work and tool materials, coolant and geometry of the cutting tool. The rate of metal removal and power required for machining depend upon these variables.The depth of cut, feed, and cutting speed are machine settings that must be established in any metal-cutting operation. They all affect the forces, the power, and the rate of metal removal. They can be defined by comparing them to the needle and record of a phonograph. The cutting speed (V) is represented by the velocity of- the record surface relative to the needle in the tone arm at any instant. Feed is represented by the advance of the needle radially inward perrevolution, or is the difference in position between two adjacent grooves. The depth of cut is the penetration of the needle into the record or the depth of the grooves.Turning on Lathe CentersThe basic operations performed on an engine lathe are illustrated. Those operations performed on external surfaces with a single point cutting tool are called turning. Except for drilling, reaming, and lapping, the operations on internal surfaces are also performed by a single point cutting tool.All machining operations, including turning and boring, can be classified as roughing, finishing, or semi-finishing. The objective of a roughing operation is to remove the bulk of the material as rapidly and as efficiently as possible, while leaving a small amount of material on the work-piece for the finishing operation. Finishing operations are performed to obtain the final size, shape, and surface finish on the work piece. Sometimes a semi-finishing operation will precede the finishing operation to leave a small predetermined and uniform amount of stock on the work-piece to be removed by the finishing operation.Generally, longer work pieces are turned while supported on one or two lathe centers. Cone shaped holes, called center holes, which fit the lathe centers are drilled in the ends of the work piece-usually along the axis of the cylindrical part. The end of the work piece adjacent to the tail stock is always supported by a tail stock center, while the end near the head stock may be supported by a head stock center or held in a chuck. The head stock end of the work piece may be held in a four-jaw chuck, or in a type chuck. This method holds the work piece firmly and transfers the power to the work piece smoothly; the additional support to the work piece provided by the chuck lessens the tendency for chatter to occur when cutting. Precise results can be obtained with this method if care is taken to hold the work piece accurately in the chuck.Very precise results can be obtained by supporting the work piece between two centers. A lathe dog is clamped to the work piece; together they are driven by a driver plate mounted on the spindle nose. One end of the Work piece is mecained;then the work piece can be turned around in the lathe to machine the other end. The center holes in the work piece serve as precise locating surfaces as well as bearing surfaces to carry the weight of the work piece ?and to resist the cutting forces. After the work piece has been removed from the lathe for any reason, the center holes will accurately align the work piece back in the lathe or in another lathe, or in a cylindrical grinding machine. The work piece must never be held at the head stock end by both a chuck and a lathe center. While at first thought this seems like a quick method of aligning the work piece in the chuck, this must not be done because it is not possible to press evenly with the jaws against the work piece while it is also supported by the center. The alignment provided by the center will not be maintained and the pressure of the jaws may damage the center hole, the lathe center, andperhaps even the lathe spindle. Compensating or floating jaw chucks used almost exclusively on high production work provide an exception to the statements made above. These chucks are really work drivers and cannot be used for the same purpose as ordinary three or four-jaw chucks.While very large diameter work pieces are sometimes mounted on two centers, they are preferably held at the headstock end by faceplate jaws to obtain the smooth power transmission; moreover, large lathe dogs that are adequate to transmit the power not generally available, although they can be made as a special. Faceplate jaws are like chuck jaws except that they are mounted on a faceplate, which has less overhang from the spindle bearings than a large chuck would have.Introduction of MachiningMachining as a shape-producing method is the most universally used and the most important of all manufacturing processes. Machining is a shape-producing process in which a power-driven device causes material to be removed in chip form. Most machining is done with equipment that supports both the work piece and cutting tool although in some cases portable equipment is used with unsupported work piece.Low setup cost for small Quantities. Machining has two applications in manufacturing. For casting, forging, and press working, each specific shape to be produced, even one part, nearly always has a high tooling cost. The shapes that may he produced by welding depend to a large degree on the shapes of raw material that are available. By making use of generally high cost equipment but without special tooling, it is possible, by machining; to start with nearly any form of raw material, so tong as the exterior dimensions are great enough, and produce any desired shape from any material. Therefore .machining is usually the preferred method for producing one or a few parts, even when the design of the part would logically lead to casting, forging or press working if a high quantity were to be produced.Close accuracies, good finishes. The second application for machining is based on the high accuracies and surface finishes possible. Many of the parts machined in low quantities would be produced with lower but acceptable tolerances if produced in high quantities by some other process. On the other hand, many parts are given their general shapes by some high quantity deformation process and machined only on selected surfaces where high accuracies are needed. Internal threads, for example, are seldom produced by any means other than machining and small holes in press worked parts may be machined following the press working operations.Primary Cutting ParametersThe basic tool-work relationship in cutting is adequately described by means of four factors: tool geometry, cutting speed, feed, and depth of cut.The cutting tool must be made of an appropriate material; it must be strong, tough, hard, and wear resistant. The tool s geometry characterized by planes and angles, must be correct for each cutting operation. Cutting speed is the rate at which the work surface passes by the cutting edge. It may be expressed in feet per minute.For efficient machining the cutting speed must be of a magnitude appropriate to the particular work-tool combination. In general, the harder the work material, the slower the speed.Feed is the rate at which the cutting tool advances into the work piece. "Where the work piece or the tool rotates, feed is measured in inches per revolution. When the tool or the work reciprocates, feed is measured in inches per stroke, Generally, feed varies inversely with cutting speed for otherwise similar conditions.The depth of cut, measured inches is the distance the tool is set into the work. It is the width of the chip in turning or the thickness of the chip in a rectilinear cut. In roughing operations, the depth of cut can be larger than for finishing operations.The Effect of Changes in Cutting Parameters on Cutting TemperaturesIn metal cutting operations heat is generated in the primary and secondary deformation zones and these results in a complex temperature distribution throughout the tool, work piece and chip. A typical set of isotherms is shown in figure where it can be seen that, as could be expected, there is a very large temperature gradient throughout the width of the chip as the work piece material is sheared in primary deformation and there is a further large temperature in the chip adjacent to the face as the chip is sheared in secondary deformation. This leads to a maximum cutting temperature a short distance up the face from the cutting edge and a small distance into the chip.Since virtually all the work done in metal cutting is converted into heat, it could be expected that factors which increase the power consumed per unit volume of metal removed will increase the cutting temperature. Thus an increase in the rake angle, all other parameters remaining constant, will reduce the power per unit volume of metal removed and the cutting temperatures will reduce. When considering increase in unreformed chip thickness and cutting speed the situation is more complex. An increase in undeformed chip thickness tends to be a scale effect where the amounts of heat which pass to the work piece, the tool and chip remain in fixed proportions and the changes in cutting temperature tend to be small. Increase in cutting speed; however, reduce the amount of heat which passes into the work piece and this increase the temperature rise of the chip m primary deformation. Further, the secondary deformation zone tends to be smaller and this has the effect of increasing the temperatures in this zone. Other changes in cutting parameters have virtually no effect on the power consumed per unit volume of metal removed and consequently have virtually no effect on the cutting temperatures. Since ithas been shown that even small changes in cutting temperature have a significant effect on tool wear rate it is appropriate to indicate how cutting temperatures can be assessed from cutting data.The most direct and accurate method for measuring temperatures in high -speed-steel cutting tools is that of Wright &. Trent which also yields detailed information on temperature distributions in high-speed-steel cutting tools. The technique is based on the metallographic examination of sectioned high-speed-steel tools which relates microstructure changes to thermal history.Trent has described measurements of cutting temperatures and temperature ?distributions for high-speed-steel tools when machining a wide range of work piece materials. This technique has been further developed by using scanning electron ?microscopy to study fine-scale microstructure changes arising from over tempering of the tempered martens tic matrix of various high-speed-steels. This technique has also been used to study temperature distributions in both high-speed -steel single point turning tools and twist drills.Wears of Cutting ToolDiscounting brittle fracture and edge chipping, which have already been dealt with, tool wear is basically of three types. Flank wear, crater wear, and notch wear. Flank wear occurs on both the major and the minor cutting edges. On the major cutting edge, which is responsible for bulk metal removal, these results in increased cutting forces and higher temperatures which if left unchecked can lead to vibration of the tool and work piece and a condition where efficient cutting can no longer take place. On the minor cutting edge, which determines work piece size and surface finish, flank wear can result in an oversized product which has poor surface finish. Under most practical cutting conditions, the tool will fail due to major flank wear before the minor flank wear is sufficiently large to result in the manufacture of an unacceptable component.Because of the stress distribution on the tool face, the frictional stress in the region of sliding contact between the chip and the face is at a maximum at the start of the sliding contact region and is zero at the end. Thus abrasive wear takes place in this region with more wear taking place adjacent to the seizure region than adjacent to the point at which the chip loses contact with the face. This result in localized pitting of the tool face some distance up the face which is usually referred to as catering and which normally has a section in the form of a circular arc. In many respects and for practical cutting conditions, crater wear is a less severe form of wear than flank wear and consequently flank wear is a more common tool failure criterion. However, since various authors have shown that the temperature on the face increases more rapidly with increasing cutting speed than the temperature on the flank, and since the rate of wear of any type is significantly affected by changes in temperature, crater wear usually occurs at high cutting speeds.At the end of the major flank wear land where the tool is in contact with the uncut work piece surface it is common for the flank wear to be more pronounced than along the rest of the wear land. This is because of localised effects such as a hardened layer on the uncut surface caused by work hardening introduced by a previous cut, an oxide scale, and localised high temperatures resulting from the edge effect. This localised wear is usually referred to as notch wear and occasionally is very severe. Although the presence of the notch will not significantly affect the cutting properties of the tool, the notch is often relatively deep and if cutting were to continue there would be a good chance that the tool would fracture.If any form of progressive wear allowed to continue, dramatically and the tool would fail catastrophically, i. e. the tool would be no longer capable of cutting and, at best, the work piece would be scrapped whilst, at worst, damage could be caused to the machine tool. For carbide cutting tools and for all types of wear, the tool is said to have reached the end of its useful life long before the onset of catastrophic failure. For high-speed-steel cutting tools, however, where the wear tends to be non-uniform it has been found that the most meaningful and reproducible results can be obtained when the wear is allowed to continue to the onset of catastrophic failure even though, of course, in practice a cutting time far less than that to failure would be used. The onset of catastrophic failure is characterized by one of several phenomena, the most common being a sudden increase in cutting force, the presence of burnished rings on the work piece, and a significant increase in the noise level.Mechanism of Surface Finish ProductionThere are basically five mechanisms which contribute to the production of a surface which have been machined. These are(l) The basic geometry of the cutting process. In, for example, single point turning the tool will advance a constant distance axially per revolution of the workpiecc and the resultant surface will have on it, when viewed perpendicularly to the direction of tool feed motion, a series of cusps which will have a basic form which replicates the shape of the tool in cut.(2) The efficiency of the cutting operation. It has already been mentioned that cutting with unstable built-up-edges will produce a surface which contains hard built-up-edge fragments which will result in a degradation of the surface finish. It can also be demonstrated that cutting under adverse conditions such as apply when using large feeds small rake angles and low cutting speeds, besides producing conditions which lead to unstable built-up-edge production, the cutting process itself can become unstable and instead of continuous shear occurring in the shear zone, tearing takes place, discontinuous chips of uneven thickness are produced, and the resultant surface is poor. This situation is particularly noticeable when machining very ductile materials such as copper and aluminum.(3) The stability of the machine tool. Under some combinations of cutting conditions; work piece size, method of clamping ,and cutting tool rigidity relative to the machine tool structure, instability can be set up in the tool which causes it to vibrate. Under some conditions this vibration will reach and maintain steady amplitude whilst under other conditions the vibration will built up and unless cutting is stopped considerable damage to both the cutting tool and work piece may occur. This phenomenon is known as chatter and in axial turning is characterized by long pitch helical bands on the work piece surface and short pitch undulations on the transient machined surface.(4)The effectiveness of removing swarf. In discontinuous chip production machining, such as milling or turning of brittle materials, it is expected that the chip (swarf) will leave the cutting zone either under gravity or with the assistance of a jet of cutting fluid and that they will not influence the cut surface in any way. However, when continuous chip production is evident, unless steps are taken to control the swarf it is likely that it will impinge on the cut surface and mark it. Inevitably, this marking besides looking.(5)The effective clearance angle on the cutting tool. For certain geometries of minor cutting edge relief and clearance angles it is possible to cut on the major cutting edge and burnish on the minor cutting edge. This can produce a good surface finish but, of course, it is strictly a combination of metal cutting and metal forming and is not to be recommended as a practical cutting method. However, due to cutting tool wear, these conditions occasionally arise and lead to a marked change in the surface characteristics.Limits and TolerancesMachine parts are manufactured so they are interchangeable. In other words, each part of a machine or mechanism is made to a certain size and shape so will fit into any other machine or mechanism of the same type. To make the part interchangeable, each individual part must be made to a size that will fit the mating part in the correct way. It is not only impossible, but also impractical to make many parts to an exact size. This is because machines are not perfect, and the tools become worn. A slight variation from the exact size is always allowed. The amount of this variation depends on the kind of part being manufactured. For examples part might be made 6 in. long with a variation allowed of (three-thousandths) in. above and below this size. Therefore, the part could be to in. and still be the correct size. These are known as the limits. The difference between upper and lower limits is called the tolerance.A tolerance is the total permissible variation in the size of a part.The basic size is that size from which limits of size arc derived by the application of allowances and tolerances.Sometimes the limit is allowed in only one direction. This is known as unilateral tolerance.Unilateral tolerancing is a system of dimensioning where the tolerance (that is variation) is shown in only one direction from the nominal size. Unilateral tolerancing allow the changing of tolerance on a hole or shaft without seriously affecting the fit.When the tolerance is in both directions from the basic size it is known as a bilateral tolerance (plus and minus).Bilateral tolerancing is a system of dimensioning where the tolerance (that is variation) is split and is shown on either side of the nominal size. Limit dimensioning is a system of dimensioning where only the maximum and minimum dimensions arc shown. Thus, the tolerance is the difference between these two dimensions.Surface Finishing and Dimensional ControlProducts that have been completed to their proper shape and size frequently require some type of surface finishing to enable them to satisfactorily fulfill their function. In some cases, it is necessary to improve the physical properties of the surface material for resistance to penetration or abrasion. In many manufacturing processes, the product surface is left with dirt .chips, grease, or other harmful material upon it. Assemblies that are made of different materials, or from the same materials processed in different manners, may require some special surface treatment to provide uniformity of appearance.Surface finishing may sometimes become an intermediate step processing. For instance, cleaning and polishing are usually essential before any kind of plating process. Some of the cleaning procedures are also used for improving surface smoothness on mating parts and for removing burrs and sharp corners, which might be harmful in later use. Another important need for surface finishing is for corrosion protection in a variety ofenvironments. The type of protection procedure will depend largely upon the anticipated exposure, with due consideration to the material being protected and the economic factors involved.Satisfying the above objectives necessitates the use of main surface-finishing methods that involve chemical change of the surface mechanical work affecting surface properties, cleaning by a variety of methods, and the application of protective coatings, organic and metallic.In the early days of engineering, the mating of parts was achieved by machining one part as nearly as possible to the required size, machining the mating part nearly to size, and then completing its machining, continually offering the other part to it, until the desired relationship was obtained. If it was inconvenient to offer one part to the other part during machining, the final work was done at the bench by a fitter, who scraped the mating parts until the desired fit was obtained, the fitter therefore being a 'fitter' in the literal sense. It is obvious that the two parts would have to remain together, and m the event of one having to be replaced, the fitting would have to be done all over again. In these days, we expect to be able to purchase a replacement fora broken part, and for it to function correctly without the need for scraping and other fitting operations.When one part can be used 'off the shelf' to replace another of the same dimension and material specification, the parts are said to be interchangeable. A system of interchangeability usually lowers the production costs as there is no need for an expensive, 'fiddling' operation, and it benefits the customer in the event of the need to replace worn parts.Automatic Fixture DesignTraditional synchronous grippers for assembly equipment move parts to the gripper centre-line, assuring that the parts will be in a known position after they arc picked from a conveyor or nest. However, in some applications, forcing the part to the centre-line may damage cither the part or equipment. When the part is delicate and a small collision can result in scrap, when its location is fixed by a machine spindle or mould, or when tolerances are tight, it is preferable to make a gripper comply with the position of the part, rather than the other way around. For these tasks, Zaytran Inc. Of Elyria, Ohio, has created the GPN series of non- synchronous, compliant grippers. Because the force and synchronizations systems of the grippers are independent, the synchronization system can be replaced by a precision slide system without affecting gripper force. Gripper sizes range from 51b gripping force and in. stroke to 40Glb gripping force and 6in stroke. GrippersProduction is characterized by batch-size becoming smaller and smaller and greater variety of products. Assembly, being the last production step, is particularly vulnerable to changes in schedules, batch-sizes, and product design. This situation is forcing many companies to put more effort into extensive rationalization and automation of assembly that ?was ?previouslyextensive rationalization and automation of assembly that was previously the case. Although the development of flexible fixtures fell quickly behind the development of flexible handling systems such as industrial robots, there are, nonetheless promising attempts to increase the flexibility of fixtures. The fact that fixtures are the essential product - specific investment of a production system intensifies the economic necessity to make the fixture system more flexible.Fixtures can be divided according to their flexibility into special fixtures, group fixtures, modular fixtures and highly flexible fixtures. Flexible fixtures are characterized by their high adaptability to different work pieces, and by low change-over time and expenditure.There are several steps required to generate a fixture, in which a work piece is fixed for a production task. The first step is to define the necessary position of the work piece in the fixture, based on the unmachined or base pan, and the working features. Following this, a combination of stability planes must be selected. These stability planes constitute the fixture configuration in which the work piece is fixed in the defined position, all the forces or torques are compensated,。

Mechanical engineering1.The porfile of mechanical engineeringEngingeering is a branch of mechanical engineerig,itstudies mechanical and power generation especially power and movement.2.The history of mechanical engineering18th century later periods,the steam engine invention hasprovided a main power fountainhead for the industrialrevolution,enormously impelled each kind of mechznicalbiting.Thus,an important branch of a newEngineering –separated from the civil engineering tools andmachines on the branch-developed together with Birmingham andthe establishment of the Associantion of Mechanical Engineersin 1847 had been officially recognized.The mechanicalengineering already mainly used in by trial and error methodmechanic application technological development into professional engineer the scientific method of which in theresearch,the design and the realm of production used .From themost broad perspective,thedemend continuously to enhance theefficiencey of mechanical engineers improve the quality of work,and asked him to accept the history of the high degreeof education and training.Machine operation to stress not only economic but also infrastructure costs to an absolute minimun.3.The field of mechanical engineeringThe commodity machinery development in the develop country,in the high level material life very great degree is decided each kind of which can realize in the mechanical engineering.Mechanical engineers unceasingly will invent the machine next life to produce the commodity,unceasingly will develop the accuracy and the complexity more and more high machine tools produces the machine.The main clues of the mechanical development is:In order to enhance the excellent in quality and reasonable in price produce to increase the precision as well as to reduce the production cost.This three requirements promoted the complex control system development.The most successful machine manufacture is its machine and the control system close fusion,whether such control system is essentially mechanical or electronic.The modernized car engin production transmission line(conveyer belt)is a series of complex productions craft mechanization very good example.The people are in the process of development in order to enable further automation of the production machinery ,the use of a computer to store and handle largevolumes of data,the data is a multifunctional machine tools necessary for the production of spare parts.One of the objectives is to fully automated production workshop,threerotation,but only one officer per day to operate.The development of production for mechanical machinery must have adequate power supply.Steam engine first provided the heat to generate power using practical methods in the old human,wind and hydropower,an increase of engin .New mechanical engineering industry is one of the challenges faced by the initial increase thermal effciency and power,which is as big steam turbine and the development of joint steam boilers basically achieved.20th century,turbine generators to provide impetus has been sustained and rapid growth,while thermal efficiency is steady growth,and large power plants per kW capital consumption is also declining.Finally,mechanical engineers have nuclear energy.This requires the application of nuclear energy particularly high reliability and security, which requires solving many new rge power plants and the nuclear power plant control systems have become highly complex electroonics,fluid,electricity,water and mechanical parts networks All in all areas related to the mechanical engineers.Small internal combustion engine,both to the type(petrol and diesel machines)or rotary-type(gas turbines and Mong Kerr machine),as well as their broad application in the field of transport should also due to mechanical enginerrs.Throughout the transport,both in the air and space,or in the terrestrial and marine,mechanial engineers created a variety of equipment and power devices to their increasing cooperation with electrical engineers,especially in the development of appropration control systems.Mechanical engineers in the development of military weapons technology and civil war ,needs a similar,though its purpose is to enhance rather than destroy their productivity.However.War needs a lot of resources to make the area of techonlogy,many have a far-reaching development in peacetime efficiency.Jet aircraft and nuclear reactors are well known examples.The Biological engineering,mechanical engineering biotechnology is a relatively new and different areas,it provides for the replacement of the machine or increase the body functions as well as for medical equipment.Artficial limbs have been developed and have such a strong movement and touch response function of the human body.In the development of artificial organ transplant is rapid,complex cardiac machines and similar equipment to enable increasingly complexsurgery,and injuries and ill patients life functions can be sustained.Someenviromental control mechanical engineers through the initial efforts to drainage or irrigation pumping to the land and to mine and ventilation to control the human environment.Modern refrigeration and air-conditioning plant commonaly used reverse heat engine,where the heat from the engine from cold places to more external heat.Many mechanical engineering products,as well as other leading technology development city have side effects on the environment,producingnoise,water and air pollution caused,destroyed land and landscape.Improve productivity and diver too fast in the commodity,that the renewable natural forces keep pace.For mechanical engineers and others,environmental control is rapidly developing area,which includes a possible development and production of small quantities of pollutants machine sequnce,and the development of new equipment and teachnology has been to reduce and eliminate pollution.4.The role of mechanical engineeringThere are four generic mechanical engineers in common to the above all domains function.The 1st function is the understanding and the research mechanical sciencefoundation.It includes the power and movement of the relationship dynamics For example,in the vibration and movement of the relationship;Automaticcontrol;Study of the various forms of heart,energy,power relations between the thermodynamic;Fluidflows; Heat transfer; Lubricant;And material properties.The 2nd function will be conducts the research,thedesing and the development,this function in turn attempts to carry on the essential change to satisfy current and the future needs.This not only calls for a clear understanding of mechanical science,and have to break down into basic elements of a complex system capacity.But also the need for synthetic and innovative inventions.The 3rd function is produces the product and the power,includeplan,operation and maintenance.Its goal lies in the maintenance either enhances the enterprise or the organization longer-tern and survivabilaty prestige at the same time,produces the greatest value by the least investments and the consumption.The 4th function is mechanical engineer’s coordinated function,including the management,theconsultation,as well as carries on the market marking in certain situation.In all these function,one kind unceasingly to use thescience for a long time the method,but is not traditional or the intuition method tendency,this is a mechanical engineering skill aspect which unceasingly grows.These new rationalization means typical names include:The operations research,the engineering economics,the logical law problem analysis(is called PABLA) However,creativity is not rationalization.As in other areas,in mechanicalengineering, to take unexpected and important way to bring about a new capacity,still has a personal,markedcharacteristice.5.The design of mechanical engineeringThe design of mechanical is the design has the mechanical property the thing or the system,suchas:the instrument and the measuring appliance in very many situations,the machine design must use the knowledge of discipline the and so on mathematics,materials science and mechanics.Mechanical engineering desginincludeing all mechanical desgin,but it was a study,because it also includes all the branches of mechsnicalengineering,such as thermodynamics all hydrodynamics in the basic disciplines needed,in the mechanical engineering design of the initial stude or mechanical design.Designstages.The entire desgin process from start to finish,in the process,a demand that is designed forit and decided to do the start.After a lot of repetition,the final meet this demand by the end of the design procees and the plan.Designconsiderations.Sometimes in a system is to decide which parts needs intensity parts of geometric shapes and size an important factor in this context that we must consider that the intensity is an important factor in the design.When we use expression design considerations,we design parts that may affect the entire system design features.In the circumstances specified in the design,usually for a series of such functions must be taken into account.Howeever,to correct purposes,we should recognize that,in many cases the design of important design considerations are not calculated or test can determine the components or systems.Especiallystudents,wheen in need to make important decisions in the design and conduct of any operation that can not be the case,they are often confused.These are not special,they occur every day,imagine,forexample,a medical laboratory in the mechanical design,from marketing perspective,people have high expectations from the strength and relevance of impression.Thick,and heavy parts installed together:to produce a solid impression machines.And sometimes machinery and spare parts from the design style is the point and not theother point of view.Our purpose is to make those you do not be misled to believe that every design decision will need reasonable mathematical methods.Manufacturing refers to the raw meterials into finished products in the enterprise.Create three distinct phases.Theyare:input,processingexprot.The first phase includes the production of all products in line with market needs essential.First there must be the demand for the product,the necessary materials,while also needs such as energy,time,human knowledge and technology resourcess . Finall,the need for funds to obtain all the other resources. Lose one stage after the second phase of the resources of the processes to be distributed.Processing of raw materials into finished products of these processes.To complete the design,based on the design,and then develop plans.Plan implemented through various production processes.Management of resources and processes to ensure efficiency and productivity.Forexample,we must carefully manage resources to ensure proper use of funds.Finally,people are talking about the product market was cast.Stage is the final stage of exporting finished or stage.Once finished just purchased,it must be delivered to the users.According to productperformance,installation and may have to conduct further debugging in addition,someproducts,especially those very complex products User training is necessary.6.The processes of materials and maunfacturingHere said engineering materials into two main categories:metals and non-ferrous,high-performance alloys and power metals.Non-metallic futher divided into plastice,syntheticrubber,composite materials and ceramics.It said the production proccess is divided into several major process,includingshape,forging,casting/founding,heattreatment,fixed/connections ,measurement/ quality control and materalcutting.These processes can be further divide into each other’s craft.Various stages of the development of the manufacturing industry Over the years,the manufacturing process has four distinct stages of development, despite the overlap.These stages are:The first phase is artisanal,the second Phase is mechanization.The third phase is automation the forth Phase is integrated.When mankind initial processing of raw materials into finished products will be,they use manual processes.Each with their hands and what are the tools manusllyproduced.This is totally integrated production take shape.A person needsindentification,collectionmaterials,the design of a product to meet that demand,the production of such products and use it.From beginning to end,everything is focused on doing the work of the human ter in the industrial revolution introduced mechanized production process,people began to use machines to complete the work accomplished previously manual. This led to the specialization.Specialization in turn reduce the manufacture of integrated factors.In this stage of development,manufacturing workers can see their production as a whole represent a specific piece of the part of the production process.Onecan not say that their work is how to cope with the entire production process,or how they were loaded onto a production of parts finished.Development of manufacting processes is the next phase of the selection process automation.This is a computer-controlled machinery and processes.At this stage,automation island began to emerge in the workshop lane.Each island represents a clear production process or a group of processes.Although these automated isolated island within the island did raise the productivity of indivdualprocesses,but the overall productivity are often not change.This is because the island is not caught in other automated production process middle,but not synchronous withthem .The ultimate result is the efficient working fast parked through automated processes,but is part of the stagnation in wages down,causingbottlenecks.To better understand this problem,you can imagine the traffic in the peak driving a red light from the red Service Department to the next scene. Occasionally you will find a lot less cars,more than being slow-moving vehicles,but the results can be found by the next red light Brance.In short you real effect was to accelerate the speed of a red Department obstruction offset.If you and other drivers can change your speed and red light simultaneously.Will advance faster.Then,all cars will be consistent,sommthoperation,the final everyone forward faster.In the workshop where the demand for stable synchronization of streamlined production,and promoted integration of manufacturing development.This is a still evolving technology.Fully integrated in the circumstances,is a computer-controllrd machinery and processing.integrated is completed through computer.For example in the preceding paragraph simulation problems,the computer will allow all road vehicles compatible with the change in red.So that everyone can steady traffic.Scientific analysis of movement,timing and mechanics ofthe disciplines is that it is composed of two pater:statics and dynamics.Statics analyzed static system that is in the system,the time is not taken into account,research and analysis over time and dynamics of the system change.Dynameics from the two componets.Euler in 1775 will be the first time two different branches: Rigid body movement studies can conveniently divided into two parts:geometric and mechanics.The first part is without taking into account the reasons for the downward movement study rigid body from a designated location to another point of the movement,and must use the formula to reflect the actual,the formula would determine the rigid body every point position. Therefore,this study only on the geometry and,morespecifically,on the entities from excision.Obviously,the first part of the school and was part of a mechanical separation from the principles of dynamics to study movement,which is more than the two parts together into a lot easier.Dynamics of the two parts are subsequently divided into two separate disciplines,kinematic and dynamics,a study of movement and the movement strength.Therefore,the primary issue is the design of mechanical systems understand its kinematic.Kinematic studies movement,rather than a study ofits impact.In a more precise kinematic studies position,displacement,rotation, speed,velocity and acceleration of disciplines,foresample,or planets orbiting research campaing is a paradigm.In the above quotation content should be pay attention that the content of the Euler dynamics into kinematic and rigid body dynamics is based on the assumption that they are based on research.In this very important basis to allow for the treatment of two separate disciplines.For soft body,soft body shape and even their own soft objects in the campaign depends on the role of power in their possession.In such cases,should also study the power and movement,and therefore to a large extent the analysis of the increased complexity.Fortunately, despite the real machine parts may be involved are more or less the design of machines,usually with heavy material designed to bend down to the lowest parts.Therefore,when the kinematic analysis of the performance of machines,it is often assumed that bend is negligible,spare parts are hard,but when the load is known,in the end analysis engine,re-engineering parts to confirm this assnmption.机械工程1.机械工程简介机械工程是工程学的一个分支，它研究机械和动力的产，尤其是力和动力。

变速箱壳体机械加工工艺设计外文文献翻译、中英文翻译、外文翻译This article discusses the design of a gearbox shell machining process。

The process includes rough machining。

semi-finishing。

and finishing ns。

The article also covers the n of cutting tools。

cutting parameters。

and cutting fluids。

The goal of the process design is to achieve high n and efficiency XXX.nThe gearbox shell XXX power from the engine to the wheels。

The shell must be machined to high n to XXX n。

In this article。

we will discuss the design of a machining process for the gearbox shell.Rough MachiningXXX of the material from the gearbox shell。

This n is XXX。

care must be XXX to the workpiece。

The use of cutting fluids is also important to ce heat n and XXX.Semi-FinishingThe semi-XXX shape and size。

This n is XXX n and surface quality。

The use of cutting fluids is also important to ce heat n and XXX finish.FinishingXXX finishing n is the final step in the machining process。

外文原文：Machining TurningThe engine lathe, one of the oldest metal removal machines, has a number of useful and highly desirable attributes. Today these lathes are used primarily in small shops where smaller quantities rather than large production runs are encountered.The engine lathe has been replaced in today’s production shops by a wide variety of automatic lathes such as automatic tracer lathes, turret lathes, and automatic screw machines. All the advantages of single-point tooling for maximum metal removal, and the use of form tools for finished on a par with the fastest processing equipment on the scene today.Tolerances for the engine lathe depend primarily on the skill of the operator. The design engineer must be careful in using tolerances of an experimental part that has been produced on the engine lathe by a skilled operator. In redesigning an experimental part for production, economical tolerances should be used.Turret LathesProduction machining equipment must be evaluated now, more than ever before, in terms of ability to repeat accurately and rapidly. Applying this criterion for establishing the production qualification of a specific method, the turret lathe merits a high rating.In designing for low quantities such as 100 or 200 parts, it is most economical to use the turret lathe. In achieving the optimum tolerances possible on the turret lathe, the designer should strive for a minimum of operations.Automatic Screw MachinesGenerally, automatic screw machines fall into several categories; single-spindle automatics, multiple-spindle rapid, automatic chucking machines. Originally designed for rapid, automatic production of screws and similar threaded parts, the narrow field, and today plays a vital role in the mass production of a variety of precision parts. Quantities play an important part in the economy of the parts machined on the automatic screw machine. The cost of the parts machined can be reduced if the minimum economical lot size is calculated and the proper machine is selected for these quantities.Automatic Tracer LathesSince surface roughness depends greatly upon material turned, tooling, and feeds and speeds employed, minimum tolerances that can be held on automatic tracer lathes are not necessarily the most economical tolerances.In some cases, tolerances of ±0.05mm are held in continuous production using but one cut. Groove width can be held to ±0.0125mm on some parts. Bores and single-point finishes can be held to ±0.0125mm. On high-production runs where maximum output is desirable, a minimum tolerance of ±0.125mm is economical on both diameter and length of turn.MillingWith the exceptions of turning and drilling, milling is undoubtedly the most widely used method of removing metal. Well suited and readily adapted to the economical production of any quantity of parts, the almost unlimited versatility of milling process merits the attention and consideration of designers seriously with the manufacture of their product.As in any other process, parts that have to be milled should be designed with economical tolerances that can be achieved in production mill. If the part is designed with tolerances finer than necessary, additional operations will have to be added to achieve these tolerances-and this will increase the cost of the part.GrindingGrinding is one of the most widely used methods of finishing parts to extremely close tolerances and fine surface finishes. Currently, there are grinders for almost every type of grinding machine required. Where processing costs are excessive, parts redesigned to worthwhile. For example, wherever possible the production economy of centerless grinding should be taken advantage of by proper design consideration.Although grinding is usually considered a finishing operation, it is often employed as a complete machining process on work which can be ground down from rough condition without being turned or otherwise machined. Thus many types of forgings and other parts are finished completely with the grinding wheel at appreciable savings of time and expense.Classes of grinding machines include the following: cylindrical grinders, centerless grinders, internal grinders, surface grinders, and tool expense.The cylindrical and centerless grinders or taper work; thus splines, shafts, and similar parts are ground on cylindrical machines either of the common-center type orthe centerless machine.Thread grinders are used for grinding precision threads for thread gages, and threads on precision parts where the concentricity between the diameter of the shaft and pitch diameter of thread must be held to close tolerances.The internal grinders are used for grinding of precision holes, cylinder bores, and similar operations where bores of all kinds are to be finished.The surface grinders are for finishing all kinds of flat work, or work with plain surfaces which may be operated upon either by the edge of a wheel or by the face of a grinding wheel. These machines may have reciprocating or rotating tables.译文：机械加工金属切削机床中最早的一种是普通车床，当今仍有许多有用的特性。

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。

附录Process PlanningThe product design is the plan for the product and its components and subassemblies.To convert the product design into a physical entity ,a manufacturing plan is needed .The activity of developing such a plan is called process planning .It is the link between product design and manufacturing .Process planning involves determining the sequence of processing and assembly steps that must be accomplished to make the product .In the present chapter ,we examine processing planning and several related topics.At the outset ,we should distinguish between process planning and production planning ,which is covered in the following chapter. Process planning is concerned with the engineering and technological issues of how to make the products and its parts. What types of equipment and tooling are required to fabricate the parts and assemble the product ? Production planning is concerned with the logistics of making the product .After process planning is concerned with ordering the materials and obtaining the resources required to make the product in sufficient quantities to satisfy demand for it.Process PlanningProcess planning involves determining the most appropriate manufacturing and assembly processes and the sequence in which they should be accomplished to produce a given part or product according to specifications set forth in the product design documentation.The scope and variety of processes that can be planned are generally limited by the available processing equipment and technological capabilities of the company of plant .Parts that cannot be made internally must be purchased from outside vendors. It should be mentioned that the choice of processes is also limited by the details of the product design.This is apoint we will return to later.Process planning is usually accomplished by manufacturing engineers .(Other titles include in industrial engineer.) The process planner must be familiar with the particular manufacturing processes available in the factory and be able to interpret engineering drawings .Based on the planner’s knowledge,skill,and experience ,the processing steps are developed in the most logical sequence to make each part .Following is a list of the many decisions and details usually include within the scope of process planning :.Interpretation of design drawings.The part of product design must be analyzed (materials,dimensions,tolerances ,surface finished,etc.) at the start of the process planning procedure..Process and sequence.The process planner must select which processes are required and their sequence.A brief description of processing steps must be prepared..Equipment selection . In general , process planners must develop plans that utilize existing equipment in the plant .Otherwise ,the component must be purchased ,or an investment must be made in new equipment ..Tools ,dies,molds,fixtures,and gages.The process must decide what tooling is required for each processing step.The actual design and fabrication of these tools is usually delegated to a tool design department and tool room ,or an outside vendor specializing in that type of tool is contacted.Methods analysis .Workplace layout ,small tools ,hoists for lifting heavy parts ,even in some cases hand and body motions must be specified for manual operations .The industrial engineering department is usually responsible for this area..Work standards.Work measurement techniques are used to set time standards for each operation ..Cutting tools and cutting conditions.These must be specified for machiningoperations ,often with reference to standard handbook recommendations.Process Planning for partsFor individual parts,the processing sequence is documented on a form called a route sheet .(Not all companies use the name route sheet ;another name is “operation sheet .”)Just as engineering drawings are used to specify the product design ,route sheets are used to specify the process plan .They are counterparts,one for product design ,the other for manufacturing .A typical route sheet ,illustrated in Fig.21.1,includes the following information: (1) all operations to be performed on the work part ,listed in the order in which they should be performed ; (2) a brief description of each operation indicating the processing to be accomplished,with references to dimensions and tolerances on the part drawing; (3) the specific machines on which the work to be done; and (4) special tooling such as dies molds ,cutting tools,jigs or fixtures ,and gages.Some companies also include setup times ,cycle time standards,and other data.It is called a route sheet because the processing sequence defines the route that the part must follow in the factory .Some of the guidelines in preparing a route sheet are listed in Table 21-1.Decisions on process to be used to fabricate a given part are based largely on the starting material for the part .This starting material is selected by the product designer.Once the material has been specified ,the range of the possible processing operation is reduced considerably .The product designer’s decisions on starting material are based primarily on functional requirements ,although economics and manufacturability a role in the selection.A typical processing sequence to fabricate an individual part consists of : (1) a basic process,(2)secondary processes ,(3) operations to enhance physical properties,and (4)finishing operations.The sequence is shown in Fig.21.2. A basic process determines the starting geometry of the workpart.Metal casting ,plastic molding ,and roling of sheet metal are examples of basic processes.The starting geometry must often be refined by secondaryprocesses,operations that transform the starting geometry (or close to final geometry ).The secondary geometry processes that might be used are closely correlated to the basic process that provides the starting geometry.When sand casting is the basic processes,machining operations are generally the second processes .When a rolling mill produces sheet metal,stamping operations such as punching and bending are the secondary processes.When plastic injection molding is the basic process ,secondary operations are often unnecessary,because most of the geometric features that would otherwise require machining can be created by the molding operation.Plastic molding and other operation that require no subsequent secondary processing are called net shape processes.Operations that require some but not much secondary processing (usually machining ) are referred to as near net shape processes.Some impression die forgings are in this category .These parts can often be shaped in the forging operation(basic processes)so that minimal machining (secondary processing )is required .Once the geometry has been established ,the next step for some parts is to improve their mechanical and physical properties .Operations to enhance properties do not alter the geometry of the part;instead,they alter physical properties .Heat treating operations on metal parts are the most common examples .Similar heating treatments are performed on glass to produce tempered glass.For most manufactured parts ,these property-enhancing operations are not required in the processing sequence ,as indicated by the alternative arrow path in Fig.21.2.Finally finish operations usually provide a coat on the work parts (or assembly )surface. Examples inclued electroplating ,thin film deposition techniques ,and painting.The purpose of the coating is to enhance appearance ,change color ,or protect the surface from corrosion,abrasion ,and so forth .Finishing operations are not required on many parts ;for example, plastic molding rarely require finishing .When finishing is required ,it is usuallythe final step in the processing sequence .Table 21-2 presents some typical processing sequences for common materials used in manufacturing .In most cases,parts and materials arriving at the factory have complete their basic process.Thus ,the first operation in the process plan follows the basic process that has provided the starting geometry of the part ..For example ,machined parts begain as bar stock or castings or forgings,which are purchased from outide vendors.The process plan begains with the machining operations in the company’s own plant .Stempings begin as sheet metal coils or strips that are bought from the rolling mill.These raw materials are supplied outside sources so that the secondary processes,property-enhancing operations ,and finishing operatios can be performed in the company’s own factory.In addition to the route sheet ,a more detailed description of eac operation is usually prepared. This is filed in the particular production department office where the operation is performed.It lists specific details of the operation ,such as cutting conditionsand toolings(if the operation is machining )and other instructions that may be useful to the amchine operator.The desciptions often include sketches of the machine setup.Processing Planning for AssembliesThe type of assembly method used for a given product depends on factors such as : (1) the anticipated production quantities ;(2) complexity of the assembled product ,for example ,the number of distinct components ;and (3)assembly processes used ,for example ,mechanical assembly versus welding .For a product that is to be made in relatively small quantities ,assembly is usually performed on manual assembly lines .For simple products of a dozen or so components,to be made in large quantities ,automated assembly systems are appropriate .In any case ,there is a precedence order in which the work must be accomplished .The precedence requirements are sometimes portrayed graphically on a precedence diagram.Process planning for assembly involves development of assembly instructions,but in more detail .For low production quantities,the entire assembly is completed at a single station .For high production on an assembly line ,process planning consists of allocating work elements to the individual stations of the line, a procedure called line balancing.The assembly line routes the work unit to individual stations in the proper order as determined by the line balance solution.As in process planning for individual components ,any tools and fixtures required to accomplish an assembly task must be determined ,designed,and built;and the workstation arrangement must belaid out.工艺规程制订产品设计是用于产品,及它的部件装配的计划. 为了把产品设计转换成一个实际物体 ,这需要一个制造计划。

机械设计外文文献翻译、中英文翻译unavailable。

The first step in the design process is to define the problem and XXX are defined。

the designer can begin toXXX evaluated。

and the best one is XXX。

XXX.Mechanical DesignA XXX machines include engines。

turbines。

vehicles。

hoists。

printing presses。

washing machines。

and XXX and methods of design that apply to XXXXXX。

cams。

valves。

vessels。

and mixers.Design ProcessThe design process begins with a real need。

Existing apparatus may require XXX。

efficiency。

weight。

speed。

or cost。

while new apparatus may be XXX。

To start。

the designer must define the problem and XXX。

ideas and concepts are generated。

evaluated。

and refined until the best one is XXX。

XXX.XXX。

assembly。

XXX.During the preliminary design stage。

it is important to allow design XXX if some ideas may seem impractical。

they can be corrected early on in the design process。

机械加工介绍（中英文对照）1 LathesLathes are machine tools designed primarily to do turning, facing and boring, Very little turning is done on other types of machine tools, and none can do it with equal facility. Because lathes also can do drilling and reaming, their versatility permits several operations to be done with a single setup of the work piece. Consequently, more lathes of various types are used in manufacturing than any other machine tool.The essential components of a lathe are the bed, headstock assembly, tailstock assembly, and the leads crew and feed rod.The bed is the backbone of a lathe. It usually is made of well normalized or aged gray or nodular cast iron and provides s heavy, rigid frame on which all the other basic components are mounted. Two sets of parallel, longitudinal ways, inner and outer, are contained on the bed, usually on the upper side. Some makers use an inverted V-shape for all four ways, whereas others utilize one inverted V and one flat way in one or both sets, They are precision-machined to assure accuracy of alignment. On most modern lathes the way are surface-hardened to resist wear and abrasion, but precaution should be taken in operating a lathe to assure that the ways are not damaged. Any inaccuracy in them usually means that the accuracy of the entire lathe is destroyed.The headstock is mounted in a foxed position on the inner ways, usually at the left end of the bed. It provides a powered means of rotating the word at various speeds . Essentially, it consists of a hollow spindle, mounted in accurate bearings, and a set of transmission gears-similar to a truck transmission—through which the spindle can be rotated at a number of speeds. Most lathes provide from 8 to 18 speeds, usually in a geometric ratio, and on modern lathes all the speeds can be obtained merely by moving from two to four levers. An increasing trend is to provide a continuously variable speed range through electrical or mechanical drives.Because the accuracy of a lathe is greatly dependent on the spindle, it is of heavy construction and mounted in heavy bearings, usually preloaded tapered roller or ball types. The spindle has a hole extending through its length, through which long bar stock can be fed. The size ofmaximum size of bar stock that can be machined when the material must be fed through spindle.The tailsticd assembly consists, essentially, of three parts. A lower casting fits on the inner ways of the bed and can slide longitudinally thereon, with a means for clamping the entire assembly in any desired location, An upper casting fits on the lower one and can be moved transversely upon it, on some type of keyed ways, to permit aligning the assembly is the tailstock quill. This is a hollow steel cylinder, usually about 51 to 76mm(2to 3 inches) in diameter, that can be moved several inches longitudinally in and out of the upper casting by means of a hand wheel and screw.The size of a lathe is designated by two dismensions. The first is known as the swing. This is the maximum diameter of work that can be rotated on a lathe. It is approximately twice the distance between the line connecting the lathe centers and the nearest point on the ways, The second size dimension is the maximum distance between centers. The swing thus indicates the maximum work piece diameter that can be turned in the lathe, while the distance between centers indicates the maximum length of work piece that can be mounted between centers.Engine lathes are the type most frequently used in manufacturing. They are heavy-duty machine tools with all the components described previously and have power drive for all tool movements except on the compound rest. They commonly range in size from 305 to 610 mm(12 to 24 inches)swing and from 610 to 1219 mm(24 to 48 inches) center distances, but swings up to 1270 mm(50 inches) and center distances up to 3658mm(12 feet) are not uncommon. Most have chip pans and a built-in coolant circulating system. Smaller engine lathes-with swings usually not over 330 mm (13 inches ) –also are available in bench type, designed for the bed to be mounted on a bench on a bench or cabinet.Although engine lathes are versatile and very useful, because of the time required for changing and setting tools and for making measurements on the work piece, thy are not suitable for quantity production. Often the actual chip-production tine is less than 30% of the total cycle time. In addition, a skilled machinist is required for all the operations, and such persons are costly and often in short supply. However, much of theoperator’s t ime is consumed by simple, repetitious adjustments and in watching chips being made. Consequently, to reduce or eliminate the amount of skilled labor that is required, turret lathes, screw machines, and other types of semiautomatic and automatic lathes have been highly developed and are widely used in manufacturing.2 Numerical ControlOne of the most fundamental concepts in the area of advanced manufacturing technologies is numerical control (NC). Prior to the advent of NC, all machine tools ere manually operated and controlled. Among the many limitations associated with manual control machine tools, perhaps none is more prominent than the limitation of operator skills. With manual control, the quality of the product is directly related to and limited to the skills of the operator. Numerical control represents the first major step away from human control of machine tools.Numerical control means the control of machine tools and other manufacturing systems through the use of prerecorded, written symbolic instructions. Rather than operating a machine tool, an NC technician writes a program that issues operational instructions to the machine tool. For a machine tool to be numerically controlled, it must be interfaced with a device for accepting and decoding the programmed instructions, known as a reader.Numerical control was developed to overcome the limitation of human operators, and it has done so. Numerical control machines are more accurate than manually operated machines, they can produce parts more uniformly, they are faster, and the long-run tooling costs are lower. The development of NC led to the development of several other innovations in manufacturing technology:Electrical discharge machining,Laser cutting,Electron beam welding.Numerical control has also made machine tools more versatile than their manually operated predecessors. An NC machine tool can automatically produce a wide of parts, each involving an assortment of widely varied and complex machining processes. Numerical control has allowed manufacturers to undertake the production of products that wouldnot have been feasible from an economic perspective using manually controlled machine tolls and processes.Like so many advanced technologies, NC was born in the laboratories of the Massachusetts Institute of Technology. The concept of NC was developed in the early 1950s with funding provided by the U.S. Air Force. In its earliest stages, NC machines were able to made straight cuts efficiently and effectively.However, curved paths were a problem because the machine tool had to be programmed to undertake a series of horizontal and vertical steps to produce a curve. The shorter the straight lines making up the steps, the smoother is the curve, Each line segment in the steps had to be calculated.This problem led to the development in 1959 of the Automatically Programmed Tools (APT) language. This is a special programming language for NC that uses statements similar to English language to define the part geometry, describe the cutting tool configuration, and specify the necessary motions. The development of the APT language was a major step forward in the fur ther development from those used today. The machines had hardwired logic circuits. The instructional programs were written on punched paper, which was later to be replaced by magnetic plastic tape.A tape reader was used to interpret the instructions written on the tape for the machine. Together, all of this represented a giant step forward in the control of machine tools. However, there were a number of problems with NC at this point in its development.A major problem was the fragility of the punched paper tape medium. It was common for the paper tape containing the programmed instructions to break or tear during a machining process. This problem was exacerbated by the fact that each successive time a part was produced on a machine tool, the paper tape carrying the programmed instructions had to be rerun through the reader. If it was necessary to produce 100 copies of a given part, it was also necessary to run the paper tape through the reader 100 separate tines. Fragile paper tapes simply could not withstand the rigors of a shop floor environment and this kind of repeated use.This led to the development of a special magnetic plastic tape. Whereas the paper carried the programmed instructions as a series of holes punched in the tape, the plastic tape carried the instructions as a seriesof magnetic dots. The plastic tape was much stronger than the paper tape, which solved the problem of frequent tearing and breakage. However, it still left two other problems.The most important of these was that it was difficult or impossible to change the instructions entered on the tape. To made even the most minor adjustments in a program of instructions, it was necessary to interrupt machining operations and make a new tape. It was also still necessary to run the tape through the reader as many times as there were parts to be produced. Fortunately, computer technology became a reality and soon solved the problems of NC associated with punched paper and plastic tape.The development of a concept known as direct numerical control (DNC) solved the paper and plastic tape problems associated with numerical control by simply eliminating tape as the medium for carrying the programmed instructions. In direct numerical control, machine tools are tied, via a data transmission link, to a host computer. Programs for operating the machine tools are stored in the host computer and fed to the machine tool an needed via the data transmission linkage. Direct numerical control represented a major step forward over punched tape and plastic tape. However, it is subject to the same limitations as all technologies that depend on a host computer. When the host computer goes down, the machine tools also experience downtime. This problem led to the development of computer numerical control.3 TurningThe engine lathe, one of the oldest metal removal machines, has a number of useful and highly desirable attributes. Today these lathes are used primarily in small shops where smaller quantities rather than large production runs are encountered.The engine lathe has been replaced in today’s production shops by a wide variety of automatic lathes such as automatic of single-point tooling for maximum metal removal, and the use of form tools for finish on a par with the fastest processing equipment on the scene today.Tolerances for the engine lathe depend primarily on the skill of the operator. The design engineer must be careful in using tolerances of an experimental part that has been produced on the engine lathe by a skilledoperator. In redesigning an experimental part for production, economical tolerances should be used.Turret Lathes Production machining equipment must be evaluated now, more than ever before, this criterion for establishing the production qualification of a specific method, the turret lathe merits a high rating.In designing for low quantities such as 100 or 200 parts, it is most economical to use the turret lathe. In achieving the optimum tolerances possible on the turrets lathe, the designer should strive for a minimum of operations.Automatic Screw Machines Generally, automatic screw machines fall into several categories; single-spindle automatics, multiple-spindle automatics and automatic chucking machines. Originally designed for rapid, automatic production of screws and similar threaded parts, the automatic screw machine has long since exceeded the confines of this narrow field, and today plays a vital role in the mass production of a variety of precision parts. Quantities play an important part in the economy of the parts machined on the automatic screw machine. Quantities less than on the automatic screw machine. The cost of the parts machined can be reduced if the minimum economical lot size is calculated and the proper machine is selected for these quantities.Automatic Tracer Lathes Since surface roughness depends greatly on material turned, tooling , and feeds and speeds employed, minimum tolerances that can be held on automatic tracer lathes are not necessarily the most economical tolerances.In some cases, tolerances of 0.05mm are held in continuous production using but one cut . groove width can be held to 0.125mm on some parts. Bores and single-point finishes can be held to 0.0125mm. Onhigh-production runs where maximum output is desirable, a minimum tolerance of 0.125mm is economical on both diameter and length of turn2 Simple Machines and ToolsA What Do the Simple Machines Mean?Simple machines are devices which allow energy to be transferred from one place to another. With the help of machines our lives are made much easier.To many people the word "machine" means things like a tractor, an electric drill, a bulldozer, a sewing machine or a bicycle. These are machines, but they are really very complicated ones, such as ones made up of many simple machines. There are only a few kinds of simple machines. They are the lever, the wheel and axle, the inclined plane, gears, pulleys and hydraulics.Simple machines can do the following:They allow energy to be transferred from the place where it is available to the place where it is used.They can change the size and direction of force. Certain types of machines allow us to apply a very large force to something by using a small force. This is called a force advantage.They can change the distance and speed with which something is moving. This is called giving a distance or speed advantage.A typical example of simple machines is the lever, which has found extremely wide use in our production practice. Some other simple machines can be seen like a seesaw, an axe, a wheelbarrow, a pair of scissors and a hammer. These are examples of levers. By using these, tasks which would be difficult for you to do can be done more easily.A lever is a rigid bar. The crowbar in Figure 1 is an example of a simple lever. All levers have the following parts:1. The fulcrum is the fixed point around which the lever can turn.2. The effort force is the force applied to the lever. It is sometimes called the input force or simply the effort.3. The effort arm is the distance between the fulcrum and the point where the effort force is applied.4. The load force is the force moving the load. It is the output force of the lever and is sometimes simply called the load.5. The load arm is the distance from the fulcrum to the position of the load.A wheelbarrow allows us to lift a heavy load by using a fairly small force. The wheelbarrow can be draw as a rigid bar as is shown in figure 2. the wheel axle acts as the fulcrum. It can easily be seen that the effort arm is longer than the load arm. This gives a force advantage because the load force is greater than the effort force that is applied. However, the effort force has to be moved much further than the load.Fig.1 A crow-bar Fig.2 A wheelbarrowIf the fulcrum is placed so that the load arm is longer than the effort arm, a large force is needed to move a small load, but it moves the load a long way. This gives a speed advantage. This idea can be seen in the fishing rod. The large effort force applied by the fisherman moves only a small load, the fish. However itdoes allow the fisherman to drag the fish in quickly.Often simple machines are made of double levers. Scissors, pliers, nutcrackers and tinsnips are all double levers.double levers 双重杠杆effort arm 力臂effort force 作用力force advantage 力增益in a more convenient way 以某种较为方便的方式inclined plane 斜面load arm 重力臂load force 荷载力（重力）rigid bar 刚性杆speed advantage 速度增益input force 输入力文中为作用力output force 输出力文中为载荷力或阻力B Tools and MachinesEach department in manufacturing uses tools to do its job. In general, tools and machines process (change) materials or information. Production department workers use tools to change materials into finished products. The finance department uses calculators and computers to keep track of the company's finances. Marketing workers send product information to consumers through advertisements made with video and audio recording machines. Workers in manufacturing must know how to use the tools of their trade.Defining tools and machinesTools extend human abilities in doing the work of processing (changing) materials or information. So, strictly speaking, machines are also tools. Tools extend human abilities by increasing the power, speed, efficiency, accuracy, and productivity of work. We cannot drive nails in boards withour bare hands, but we can drive nails with a tool – the hammer. We can do math problems in our head, but an electronic calculator is faster and more accurate. Both the hammer and the calculator are tools that extend our abilities.Generally, tools can be described as hand tools, power hand tools, or machines. A hand tool is the simplest form. The user holds it in the hand and moves it to perform work. It is powered only by the user. Hand saws, screwdrivers, and hand planes are examples of hand tools. Power hand tools are improved hand tools. The user holds one in the hand and moves it to perform work, but the processing power comes from an external source, such as an electric motor. Power circular saws, electric screwdrivers, and power planes are some power hand tools. Machines stay still during processing and use an externally powered tool that is fastened to the machine to do the actual processing. Table saws, drill presses, and planers are all machines.Another category of manufacturing tools is equipment. Equipment covers devices that cannot be defined as machine, power hand tools, or hand tools. Equipment stays still on a structure during processing and uses human or thermal (heat) power too process materials. Examples include the human-powered squaring shears for shearing metal and ovens, and furnaces used to melt materials.All tools, machines, and equipment extend human abilities by increasing the power, speed, efficiency, accuracy, and productivity of processing materials or information.The six basic machinesWe base the principles that describe how tools work on the basic machines – wheelsevers, pulleys, inclined planes, wedges, and screws, (see the fig.). The purpose of these basic machines is to gain a mechanical advantage in doing work. A mechanical advantage is an increase in a force. Mechanical advantage of force is abbreviated MAF. A simple example is driving nails in wood. Without a hammer, you would not be able to drive the nails. By placing the hammer in your hand, you create a lever that gives you a mechanical advantage of force over the nail. The nail itself uses wedge action to cut into the wood.For anther example, look at the frill press, often found in labs. The drill bit uses a wedge for its cutting action. Inclined planes hold the drill bit in the chuck. Screw threads hold the drill press together. Pulleys transfer power from the motor to the drill bit. The handle on the drill press acts as a lever attached to a wheel and axle. Every time one of the six basic machines is used in a tool or machine, mechanical advantage is realized. Identify the six basic machines in other tools and machines in your lab.drill bit 钻头drill press 钻床electric screwdriver 电动螺丝刀finance department 财务部marketing worker 销售人员power circular saw 电动圆盘锯power hand tool 电动工具power plane 电刨mechanical advantage 机械增益中文译文1.车床车床主要是为了进行车外圆、车端面和镗孔等项工作而设计的机床。

TOOL WEAR MECHANISMS ON THE FLANK SURFACE OF CUTTINGINSERTSFOR HIGH SPEED WET MACHINING5.1 IntroductionAlmost every type of machining such as turning, milling, drilling, grinding..., uses a cutting fluid to assist in the cost effective production of pa rts as set up standard required by the producer [1]. Using coolant with some cutting tools material causes severe failure due to the lack of their resistance to thermal shock (like AL2O3 ceramics), used to turn steel. Other cutting tools materials like cubic boron nitride (CBN) can be used without coolant, due to the type of their function. The aim of using CBN is to raise the temperature of the workpice to high so it locally softens and can be easily machined.The reasons behind using cutting fluids can be summarized as follows.® Extending the cutting tool life achieved by reducing heat generated and as a result less wear rate is achieved. It will also eliminate the heat from theshear zone and the formed chips.® Cooling the work piece of high quality materia l under operation plays an important role since thermal distortion of the surface and subsurfacedamage is a result of excessive heat that must be eliminated or largelyreduced to produce a high quality product.Reducing cutting forces by its lubricating e ffect at the contact interface region and washing and cleaning the cutting region during machining from small chips. The two main reasons for using cutting fluids are cooling and lubrication.Cutting Fluid as a Coolant:The fluid characteristics and condition of use determine the coolant action of the cutting fluid, which improves the heat transfer at the shear zone between the cutting edge, work piece, and cutting fluid. The properties of the coolant in this case must include a high heat capacity to carry away heat and good thermal conductivity to absorb the heat from the cutting region. The water-based coolant emulsion with its excellent high heat capacity is able to reduce tool wear [44]. Cutting Fluid as a Lubricant:The purpose is to reduce friction bet ween the cutting edge, rake face and the work piece material or reducing the cutting forces (tangential component). As the friction drops the heat generated isdropped. As a result, the cutting tool wear rate is reduced and the surface finish is improved.Cutting Fluid PropertiesFree of perceivable odorPreserve clarity throughout lifeKind and unirritated to skin and eyes.Corrosion protection to the machine parts and work piece.Cost effective in terms off tool life, safety, dilution ratio, and fluid lif e.[1]5.1.1 Cutting Fluid TypesThere are two major categories of cutting fluidsNeat Cutting OilsNeat cutting oils are poor in their coolant characteristics but have an excellent lubricity. They are applied by flooding the work area by a pump and re-circulated through a filter, tank and nozzles. This type is not diluted by water, and may contain lubricity and extreme-pressure additives to enhance their cutting performance properties. The usage of this type has been declining for their poor cooling ability, causing fire risk, proven to cause health and safety risk to the operator [1].® Water Based or Water Soluble Cutting FluidsThis group is subdivided into three categories:1.Emulsion ` mineral soluble' white-milky color as a result of emulsion of oil inwater. Contain from 40%-80% mineral oil and an emulsifying agent beside corrosion inhibitors, beside biocide to inhibit the bacteria growth.2.Micro emulsion `semi-synthetic' invented in 1980's, has less oil concentrationand/or higher emulsifier ratio 10%-40% oil. Due to the high levels ofemulsifier the oil droplet size in the fluid are smaller which make the fluid more translucent and easy to see the work piece during operation. Otherimportant benefit is in its ability to emulsify any leakage of oil from themachine parts in the cutting fluid, a corrosion inhibitors, and bacteria control.3.Mineral oil free `synthetic' is a mix of chemicals, water, bacteria control,corrosion inhibitors, and dyes. Does not contain any mineral oils, andprovides good visibility.23 to the work piece. bare in mind that the lack of mineral oil in this type of cuttingfluid needs to take more attention to machine parts lubrication since it should not leave an oily film on the machine parts, and might cause seals degradation due the lack of protection.5.1.2 Cutting Fluid SelectionMany factors influence the selection of cutting fluid; mainly work piece material, type of machining operation, machine tool parts, paints, and seals. Table 5-1 prepared at the machine tool industry res earch association [2] provides suggestions on the type of fluid to be used.5.1.3 Coolant ManagementTo achieve a high level of cutting fluids performance and costeffectiveness, a coolant recycling system should be installed in the factory. This system will reduce the amount of new purchased coolant concentrate and coolant disposable, which will reduce manufacturing cost. It either done by the company itself or be rented out, depends on the budget and management policy of the company [1].Table 5-1 Guide to the selection of cutting fluids for general workshop applications.Machining operation Workpiece materialFree machining and low - carbon Medium- Carbon steels High Carbon and alloy steels Stainlessand heattreated GrindingClear type soluble oil, semi synthetic or chemical Turning General purpose, soluble oil, semi synthetic or synthetic fluid Extreme-pressuresoluble oil,semi-synthetic orsyntheticfluid Milling General purpose, soluble oil, semi synthetic or synthetic Extreme- pressure soluble oil, semi- synthetic or synthetic Extreme-pressuresoluble oil,semi-synthetic orsyntheticfluid(neat cutting oilsmay beDrillingExtreme- pressure soluble oil, semi- synthetic or GearShapping Extreme-pressure soluble oil, Neat-cutting oils preferable HobbingExtreme-pressure soluble oil, semi-synthetic or synthetic fluid (neat cutting oils may be Neat-cutti ng oils BratchingExtreme-pressure soluble oil, semi-synthetic or synthetic fluid (neat Tapping Extreme-pressure soluble oil, semi-synthetic or Neat-cuttingpreferableNote: some entreis deliberately extend over two or more columns, indicating awide range of possible applications. Other entries are confined to aspecific class of work material.Adopt ed f rom Edw ard and Wri ght [2]5.2 Wear Mechanisms Under Wet High Speed M achiningIt is a common belief that coolant usage in metal cutting reduces cuttingtemperature and extends tools life. However, this researchshowed that this is not necessarily true to be generalized overcutting inserts materials. Similar research was ca rried out ondifferent cutting inserts materials and cutting conditionssupporting our results. Gu et al [36] have recorded adifference in tool wear mechanisms between dry and wetcutting of C5 milling inserts. Tonshoff et al [44] alsoexhibited different wear mechanisms on AL 2O 3/TiC inserts inmachining ASTM 5115, when using coolants emulsionscompared to dry cutting. In addition, Avila and Abrao [20]experienced difference in wear mechanisms activated at theflank side, when using different coolants in t estingAL 2O 3lTiC tools in machining AISI4340 steel. The wearmechanisms and the behavior of the cutting inserts studied inthis research under wet high speed-machining (WHSM)condition is not fully understood. Therefore, it was theattempt of this research to focus on the contributions incoating development and coating techniques of newlydeveloped materials in order to upgrade their performance attough machining conditions. This valuable research providesinsight into production timesavings and increase inprofitability. Cost reductions are essential in the competitiveglobal economy; thus protecting local markets and consistingin the search of new ones.5.3 Experimental Observations on Wear Mechanisms of Un-CoatedCemented Carbide Cutting Inserts in High Speed WetMachiningIn this section, the observed wear mechanisms are presented of uncoated cemented carbide tool (KC313) in machining ASTM 4140 steel under wet condition. The overall performance of cemented carbide under using emulsion coolant has been improved in terms of extending tool life and reducing machining cost. Different types of wear mechanisms were activated at flank side of cutting inserts as a result of using coolant emulsion during machining processes. This was due to the effect of coolant in reducing the average temperature of the cutting tool edge and shear zone during machining. As a result abrasive wear was reduced leading longer tool life. The materials of cutting tools behave differently to coolant because of their varied resistance to thermal shock. The following observations recorded the behavior of cemented carbide during high speed machining under wet cutting.Figure5-1 shows the flank side of cutting inserts used at a cutting speed of 180m/min. The SEM images were recorded after 7 minutes of machining. It shows micro-abrasion wear, which identified by the narrow grooves along the flank side in the direction of metal flow, supported with similar observations documented by Barnes and Pashby [41] in testing through-coolant-drilling inserts of aluminum/SiC metal matrix composite. Since the cutting edge is the weakest part of the cutting insert geometry, edge fracture started first due to the early non-smooth engagement between the tool and the work piece material. Also, this is due to stress concentrations that might lead to a cohesive failure on the transient filleted flank cutting wedge region [51, 52]. The same image of micro-adhesion wear can be seen at the side and tool indicated by the half cone27 shape on the side of cutting tool. To investigate further, a zoom in view was taken atthe flank side with a magnification of 1000 times and presented in Figure 5-2A. It shows clear micro-abrasion wear aligned in the direction of metal flow, where the cobalt binder was worn first in a hi gher wear rate than WC grains which protruded as big spherical droplets. Figure 5-2B provides a zoom-in view that was taken at another location for the same flank side. Thermal pitting revealed by black spots in different depths and micro-cracks, propagated in multi directions as a result of using coolant. Therefore, theii~ial pitting, micro-adhesion and low levels of micro-abrasion activated under wet cutting; while high levels of micro-abrasion wear is activated under dry cutting (as presented in the prev ious Chapter).Figure 5-3A was taken for a cutting insert machined at 150mlmin. It shows a typical micro-adhesion wear, where quantities of chip metal were adhered at the flank side temporarily. Kopac [53] exhibited similar finding when testing HSS-TiN drill inserts in drilling SAE1045 steel. This adhered metal would later be plucked away taking grains of WC and binder from cutting inserts material and the process continues. In order to explore other types of wear that might exist, a zoom-in view with magnification of 750 times was taken as shown in Figure5-3B. Figure 5-3B show two forms of wears; firstly, micro-thermal cracks indicated by perpendicular cracks located at the right side of the picture, and supported with similar findings of Deamley and Trent [27]. Secondly, micro-abrasion wear at the left side of the image where the WC grains are to be plucked away after the cobalt binder was severely destroyed by micro-abrasion. Cobalt binders are small grains and WC is the big size grains. The severe distort ion of the binder along with the WC grains might be due to the activation of micro-adhesion and micro-abrasionFigure 5-1 SEM image of (KC313) showing micro abrasion and micro-adhesion (wet).SEM micrographs of (KC313) at 180m/min showing micro-abrasion where cobalt binder was worn first leaving protruded WC spherical droplets (wet).(a)SEM micrographs of (KC313) at 180m/min showing thermal pitting (wet).Figure 5-2 Magnified views of (KC313) under wet cutting: (a) SEM micrographs of (KC313) at 180mlmin showing micro-abrasion where cobalt binderwas worn first leaving protruded WC spherical droplets (wet ), (b) SEMmicrographs of (KC313) at 180.m/min showing thermal pitting (wet ).SEM image showing micro-adhesion wear mechanism under 150m/min (wet).(a)SEM image showing micro-thermal cracks, and micro-abrasion.Figure 5-3 Magnified views of (KC313) at 150m/min (wet): (a) SEM image showing micro-adhesion wear mechanism under 150m/min (wet), (b) SEM image showing micro-fatigue cracks, and micro-abrasion (wet).Wear at the time of cutting conditions of speed and coolant introduction. Therefore, micro-fatigue, micro-abrasion, and micro-adhesion wear mechanisms are activated under wet condition, while high levels of micro-abrasion were observed under dry one.Next, Figure 5-4A was taken at the next lower speed (120m/min). It shows build up edge (BUE) that has sustained its existence throughout the life of the cutting tool, similar to Huang [13], Gu et al [36] and Venkatsh et al [55]. This BUE has protected the tool edge and extended its life. Under dry cutting BUE has appeared at lower speeds (90 and 60 m/min), but when introducing coolant BUE started to develop at higher speeds, This is due to the drop in shear zone temperature that affected the chip metal fl ow over the cutting tool edge, by reducing the ductility to a level higher than the one existing at dry condition cutting. As a result, chip metal starts accumulating easier at the interface between metal chip flow, cutting tool edge and crater surface to form a BUE. In addition to BUE formation, micro-abrasion wear was activated at this speed indicated by narrow grooves.To explore the possibility of other wear mechanisms a zoom-in view with a magnification of 3500 times was taken and shown in Figure 5-4B. Micro- fatigue is evident by propagated cracks in the image similar to Deamley and Trent [27] finding. Furthermore, Figure 5-4B shows indications of micro-abrasion wear, revealed by the abrasion of cobalt binder and the remains of big protruded WC grains. However, the micro-abrasion appeared at this speed of 120m/min is less severe than the same type of micro-wear observed at 150m/min speed, supported with Barnes [41] similar findings. Therefore, micro-abrasion, BUE and micro-fatigue were activated under wet condition while, adhesion, high levels micro-abrasion, and no BUE were under dry cutting.SEM i m a g e o f(KC313) showing build up e d g e under 120m/min (wet).(a)SEM i m a g e o f(KC3 13) showing micro-fatigue, and micro-abrasion (wet). Figure 5-4 SEM images of (KC313) at 120m/min (wet), (a) SEM image of (KC313). showing build up edge, (b) SEM image of(K C313) showing micro-fatigue and micro-abrasion33 Figure 5-5 is for a cutting tool machined at 90m/min, that presents a goodcapture of one stage of tool life after the BUE has been plucked away. The bottom part of the flank side shows massive metal adhesion from the work piece material. The upper part of the figure at the edge shows edge fracture. To stand over the reason of edge fracture, the zoom-in view with magnification of 2000 times is presented in Figure 5-6A. The micro-fatigue crack image can be seen as well as micro-attrition revealed by numerous holes, and supported with Lim et al [31] observations on HSS-TiN inserts. As a result of BUE fracture from the cutting tool edge, small quantities from the cutting tool material is plucked away leaving behind numerous holes. Figure 5-6B is another zoom-in view of the upper part of flank side with a magnification of 1000 times and shows micro-abrasion wear indicated by the narrow grooves. Furthermore, the exact type of micro-wear mechanism appeared at the flank side under 60 m/min. Therefore, in comparison with dry cutting at the cutting speed of 90 m/min and 60 m/min, less micro-abrasion, bigger BUE formation, and higher micro-attrition rate were activated.Figure 5-5 SEM image showing tool edge after buildup edge was plucked away.SEM image showing micro-fatigue crack, and micro-attrition.(a)SEM image showing micro-abrasion.Figure 5-6 SEM images of (KC313) at 90m/min:(a) SEM image showing micro-fatigue crack, and micro-attrition, (b) SEM image showingmicro-abrasion.5.4 Experimental Observations on Wear Mechanisms of Coated CementedCarbide with TiN-TiCN-TiN Coating in High Speed WetMachiningInvestigating the wear mechanisms of sandwich coating under wet cutting is presented in this section starting from early stages of wear. Figure 5-7 shows early tool wear starting at the cutting edge when cutting at 410m/min. Edge fracture can be seen, it has started at cutting edge due to non-smooth contact between tool, work piece, micro-abrasion and stress concentrations. To investigate further the other possible reasons behind edge fracture that leads to coating spalling, a zoom-in view with magnification of 2000 ti mes was taken and presented at Figure 5-8A. Coating fracture can be seen where fragments of TiN (upper coating) had been plucked away by metal chips. This took place as result of micro-abrasion that led to coating spalling. On the other hand, the edge is t he weakest part of the cutting insert geometry and works as a stress concentrator might lead to a cohesive failure on the transient filleted flank cutting wedge region [51, 52].Both abrasion wear and stress concentration factor leave a non-uniform edge configuration at the micro scale after machining starts. Later small metal fragments started to adhere at the developed gaps to be later plucked away by the continuous chip movement as shown in Figure 5-8A. Another view of edge fracture was taken of the same cutting tool with a magnification of 2000 times as shown in Figure 5-8B. It presents fracture and crack at the honed tool edge. A schematic figure indicated by Figure 5-9, presented the progressive coated cutting inserts failure starting at the insert edge. It was also noticed during the inserts test that failure takes place first at the inserts edge then progressed toward the flank side. Consequently, a study on optimizing the cutting edgeFigure 5-7 SEM image of (KC732) at 410m/min showing edge fractur e and micro-abrasion (wet).SEM image showing edge fracture.(a)SEM image showing fracture and crack at the honed insert edge.Figure 5-8 SEM of (KC732) at 410m/min and early wear stage (wet): (a) SEM image showing edge fracture, (b) SEM image showing fr acture and crack atthe honed insert edge.radius to improve coating adhesion, and its wear resistance, might be also a topic for future work.Figure 5-1.0A was taken after tool failure at a speed of 410m/min. It shows completely exposed substrate and severe sliding wear at the flank side. The coating exists at the crater surface and faces less wear than the flank side. Therefore it works as an upper protector for the cutting edge and most of the wear will take place at the flank side as sliding wear. Figu re 5-10B is a zoom-in view with magnification of 3500 times, and shows coating remaining at the flank side. Nonetheless, micro-abrasion and a slight tensile fracture in the direction of metalchip flow. Ezugwa et al [28] and Kato [32] have exhibited simila r finding. However, the tensile fracture in this case is less in severity than what had been observed at dry cutting. This is due to the contribution of coolant in dropping the cutting temperature, which has reduced the plastic deformation at high temperature as a result. Hence, in comparison with the dry cutting at the same speed, tensile fracture was available with less severity and micro-abrasion/sliding. However, in dry cutting high levels of micro-abrasion, high levels of tensile fracture and sliding wear occurred.Figure 5-11 was taken at early stages of wear at a speed of 360m/min. It shows sliding wear, coating spalling and a crack starting to develop between TiN and TiCN coating at honed tool edge. Figure5-12A shows nice presentation of what had been described earlier regarding the development of small fragments on the tool edge. The adhered metal fragments work along with micro-abrasion wear to cause coating spalling.SEM image showing sliding wear.(a)SEM image showing micro-abrasion and tensile fracture.Figure 5-10 SEM images of (KC732) at 410m/min after failure (wet): (a) SEM image showing sliding wear, (b) SEM image showing micro-abrasionand tensile fracture.Figure 5-11 SEM image at early stage of wear of 360m/min (wet) showing coating and spalling developing crack between TiN and TiCN layers.The size of the metal chip adhered at the edge is almost 15g. Since it is unstable it will be later plucked away taking some fragments of coatings with it and the process continues. Another zoom in view with a magnification of 5000 times for the same insert is shown in Figure 5-12B indicating a newly developed crack between the coating layers.Figure 5-13A is taken of the same insert after failure when machining at 360m/min and wet condition. Coating spalling, and sliding wear can be seen and indicated by narrow grooves. In addition, initial development of notch wear can be seen at the maximum depth of cut.Further investigation is carried out by taking a zoom in view with a magnification of 2000 times as shown in Figure 5-13B. A clear micro-abrasion wear and micro-fatigue cracks were developed as shown, which extended deeply through out the entire three coating layers deep until the substrate. Therefore, in comparison with dry cutting, micro-fatigue crack, less tensile fracture, less micro-abrasion wear were activated at wet cutting. While micro- fatigue crack, high levels of micro-abrasion, and high levels of tensile fracture are distinguish the type of wear under dry condition at the same cutting spee d.Next, Figure 5-14A is taken for cutting tools machined at 310m/min. The results are similar to the previous inserts machined at 360m/min, where adhesion of metal fragments occurred at the tool edge, sliding wear and coating spalling. In addition, the black spot appeared at the top of the figure on the crater surface is a void resulting from imperfections in the coating process. At this condition, the crater surface will be worn faster than the flank surface.SEM image showing adhered metal fragments at tool edge.(a)SEM image showing developed crack between coating layers.Figure 5-12 SEM image of (KC732) at early wear 360m/min (wet): (a) SEM image showing adhered metal fragments at tool edge, (b) SEM image showingdeveloped crack between coating layers.(a)SEM image showing coating spalling and sliding wear after tool failure(b)SEM image showing micro-abrasion, and micro-fatigue cracks developedbetween coating layersFigure 5-13 SEM image of KC732 after failure machined at 360m/min(b)(wet): (a) SEM image showing coating spalling and sliding wear after toolfailure, (b) SEM image showing micro-abrasion, and micro-fatiguecracks developed between coating layers.翻译：在高速潮湿机械加工条件下后刀面表层磨损机理5.1 介绍几乎每类型用机器制造譬如转动, 碾碎, 钻井, 研..., 使用切口流体协助零件的有效的生产当设定标准由生产商[ 1 ] 需要。

机械加工外文翻译、中英文翻译、机械类外文文献翻译The engine lathe is an old but still useful metal removal machine with many desirable attributes。

While it is no longer commonlyXXX。

In today's n shops。

it has largely been XXX。

turret lathes。

and automatic XXX of single-point tooling for maximum metal removal。

and the use of form tools for finished products that are on par with the fastest processing XXX.When it XXX for the engine lathe。

it largely depends on the skill of the operator。

Design XXX part for n。

it is XXX.XXX cutting tools。

XXX ns。

as the machine can perform these ns in one setup。

They are also capable of producing parts with high n and accuracy。

XXX industries.Now more than ever。

n machining XXX of a specific method。

the XXX.When designing for low quantities。

such as 100 or 200 parts。

it is most cost-effective to use a XXX。

designers should aim to minimize the number of ns required.Another n for n XXX。