数控加工技术概述外文翻译@中英文翻译@外文文献翻译

1 原文： The digital control process technology is summarized 1. digital control programming reaches such development The digital control programming is the segment that be able to obviously bring into play the beneficial result in at the moment CAD/CAPP/CAMs system the most most , such is living to achieve to design the process automation and raise process accuracy and processes the quality and cuts down the product development cycle and so on the respect is brining into play the significant action . Being living possess the greats quantity applications such as aviation industry and auto industry and so on territorys . Since giving birth to the intense demand of practice , wide-ranging research has wholly been carried on to the digital control programming technique in the home and abroad , and acquires the plentiful and substantial fruit . The next reaches such to the digital control programming and develops to act as some to introduce . 1.1 basic concept of digital control programming The digital control programming is through the spare parts drawings up the full process that obtains the digital control processing program . Its main mission is that the sword spot ( Cutterlocationpoint abbreviate CLs spot ) in the sword is processed away in the calculation . The point of intersection that sword the spot was oridinarily get to the cutting tool axial line against the cutting tool face still will be give out the sword shaft vector in much processs 1.2 digital control programming technique development survey MIT designed one kind of special language that is used in the inflexible spare parts digital control processing program establishments to the program problem in order to resolve in the digital control process , and 2 is called APT ( AutomaticallyProgrammedTool ) in the 50s . Well-developed editions such as after APT time and again develops , takeed shape such as APTII and APTIII ( the stereoscopic cutting action is employd ) and APT ( the algorithm improves , add much coordinates surface processes the programming meritorous service capacity ) and APTAC ( Advancedcontouring ) ( add cuts the database administration system ) and APT/SS ( SculpturedSurface ) ( add engraves the camber processes the programming meritorous service capacity ) and so on . Adoping APT language drawing up digital control order to have easy the refineing of order , and gos away the strongs point such as sword control is agile and so on , and causes the digital control process the programming , and moves upward up yet possess much not suitable points to geometry element .APT through assemble language grade to the machine tool order : Adoping language definition spare parts geometry form shape , and is difficult to depict complex geometry form shape , and lack audio-visual quality of geometry ； The certification measure that the figure audio-visual that is short of to spare parts form shape and the cutting tool movement locus displays and the cutting tool locus ； Being difficult to effectively join with CADs data bank and CAPPs system ； Not to act as easily up the high automation , the integrationization In view of the APTs language defect , in 1978 , France attained the system that the large rope airplane corporation starts development gathers assemble three dimensions design , analysis and NCs process integration , and is called in the interest of CATIA . Having ariseed alikely the systems such as EUCLID and NPU/GNCP and so on soon afterwards very quickly , the geometry molds 3 wholly valid settlements of these systems and the spare parts geometry form shape display is designed mutually and mends generates the cutting tool locus , and the problems such as the imitation to go away the sword process displays and certification and so on promoteed CAD and CAM developing to the integration orientation . The approximately idea that system ( CIMS ) and parallel project ( CE ) was manufacture in the calculating machine integration take shape up the 80s gradually on the base that the CAD/CAMs integration being living is approximately attend school . At the moment , and the necessaries that CE developed in order to adapt to CIMS , the digital control programming system to integrationization and intelligentization the development . Being living the integration respect , with the development accords with the STEP ( StandardfortheExchangeofProductModelData ) criterion parameterization feature moldmaking and systematically gives priority to , having carried on the highly effective work of greats quantity at the moment is the home and abroad development heatpoint Being living the intelligentization respect , the work has start only a short while ago , and still awaits that we leave hard 2、 NCs cutting tool locus generates the method study developing actuality Digital control programming core work is generateing the cutting tool locus , afterwards by such scattered one-tenth sword spot , places that the handle comes into being the digital control processing program afterwards viaing . The next cutting tool locus comes into being the means and actes as some and introduce 2.1 baseding on a little and string , surface and part of the body NCs sword track formation means CADs technique moves through the two dimension mapping , and 4 udergo the three dimensions wires frame and camber and the solid modelling generation , now the parameterization feature reacing is always moldded . Is living two dimension mapping together with three dimensions wires frame phase , in case the opening processes , the rough sketch is processed the digital control process is main with spot and string act as drive target , the plane area process and so on . This kind of level that personnel staff was requireed manipulating in the process is taller , complex mutually . Being living camber and the solid modelling generation , entity process had ariseed to based on . The entity process target is an entity ( oridinarily blendes for CSG and BREP express ) , its ( moreover , intersects , falls short of to operate ) but get yield through some fundamental parts of the body habitually after the set operation . The entity is processed not merely usable rough machining and semi precision work to the spare parts , and the great area cuts Yu Liang , and the effectiveness is processed in the raise , but also usable research together with development to digital control baseding on the feature programming system , is the feature process base Entity process oridinarily possess entity rough sketch process and the entity area and processes two kinds . The entity process realization means slices law ( SLICE ) in the interest of the straturm , in immediate future slices by the process entity in the way of one series of level , afterwards to obtains the intersection comes into being the isometry string dos worthwhile the sword the going away locus . The original slave system needs the angle depart , the digital control process that the ACISs geometry moldmaking being living achieved this 5 kind to based on a little on the terrace and the string and surface and entity Feature NCs sword track formation means 2.2 baseding on The parameterization feature molds to possess the specified development particular period , yet baseds on that feature cutting tool locus formation means research starts only a short while ago . The feature processes to cause digital control programming personnel staff to be out to let drop the step geometry message to those ( in case : Spot , string , surface and entity ) manipulate , but transforing to carry on the digital control programming in the interest of directly to accords with the feature that engineers and technicians are used to , and liftd the programming effectiveness enormously W.R.Mail and A.J.Mcleod are living in their research to give out one to based on feature NCs code generating sub system , and this systematic work rule is : Spare parts every one process wholly may be regarded as to adjust to make up the total that the spare parts form shape feature group processed . In immediate future the queen completees spare parts process is not processed that to the feature adjusting entirely form the shape in that way either form shape feature component . But each form shape feature either form shape feature series NCs code may generate voluntarily . The system opened up at the moment merely is applicable to 2.5Ds spare parts process The LeeandChang opened up one kind of raised liberal camber feature cutting tool locus of means autogeneration in the way of fictitious border system . This systematic work rule is : Being living to inlay inner place the raised liberal camber into one the minimal long and square , so raised liberal camber feature is transformd into the hollow feature . 6 Minimal the long and square incorporation against the end product pattern constituteed to be called one kind of indirect produce pattern on the fictitious pattern . That the cutting tool locus formation means separates into completees three paces : ( 1 ) and the cutting action polyhedron feature ； ( 2 ) and cuts the liberal camber feature ； ( 3 ) and the cutting action intersects the feature JongYunJung researcies baseds on the non- cutting action cutting tool locus formation problem of feature . The article process baseding on the feature locus separates into rough sketch process and processes two types with the inside area , and the definition this two types of process cutting action orientations , attains the aim that the entirety optimizes the cutting tool locus by means of decreasing the cutting action cutting tool locus . Type who talked about these fundamental features gos away sword way and cutting tool selection and process order and so on to main being aimed at of article some kinds of fundamental features ( hollow inner place Kong and step , trough ) , and averting repeatedly going away the sword by means of IP ( InterProgramming ) technique , with the non- cutting action cutting tool locus of optimization . Besides JongYunJong still is living , and his doctor in 1991 researcied tabrication feature extraction and baseds on feature cutting tool and the cutting tool way in the dissertation The feature process base is an entity process , and surely of course also may think the entity process being more high-quality . Yet feature process distinct entity process , and entity process possess it oneself the limitations . Feature process chiefly possess below difference against entity process : 7 Through approximately attends school says that the feature is the meritorous service capacity key element to make up the spare parts , and the operation that accords with engineers and technicians is used to , by engineers and technicians are know intimately ； The entity is the geometry target on low straturm , and is a geometric object that obtains after a series of Booleans calculation , and does not have whatever meritorous service capacity semantic information ； It frequently is adjusting the once only process of entire spare parts ( entity ) that the entity is processed . Yet in reality the spare parts is not very much probably merely once processed through in the way of the sword , frequently will go through a series of workmans of rough machining and semi precision work and precision work and so on stage , the place of spare parts difference oridinarily will be employd the difference cutting tool and process ； Now and then not only the spare parts will be employd up turning , but also employ up mill . Hence entity process is chiefly used spare parts rough machining and semi precision work . But but the feature on processing through essentially resolved the above-mentioned issue ； Feature process havees even more intellect . May regulate some kinds of settled admittedly process meanss as to the specially designated feature , particularly those have been living , and STEPs criterion the person who regulates the feature still more is such in this way . In case we wholly draw up the specially designated process means to all standards feature , it is you can imagine that spare parts that in that 8 way sufficiently succeed through the standard feature to those are processed such convenient quality . In case CAPP systematically be able to supply the relevant technology feature , NCPs system may decrease inputing mutually , and havees even more intellect enormously in that way . But these entity process can not achieved Feature process is favour of achieving through comprehensive integration of CAD , CAPP , NCP and CNCs system , and achieves the two-way going from place to place of message , in the interest of CIMS and even parallel project ( CE ) are settleed the well base ； It be helpless that but the entity is processed to these NCs sword track formation means 2.3 being on active service in several main CAD/CAMs systems is analysed Active duty CAM constitutes reaching the main meritorous service capacity That at the moment comparatively more mature CAMs system is main with two kinds of shapes achieves CAD/CAMs system integration : Integration CAD/CAMs system ( in case : UGII , Euclid and Pro/ENGINEERs and so on ) and independent relatively CAMs system ( in case : Mastercam and Surfcams and so on ) . Unitary less than the former data format is directly gaind the produce geometric model through CADs system , but the latter is main gains the produce geometric model by means of the neutral papers through else CADs systems . However , no matter is what the CAMs system growed the shape , wholly consising of five modules , in immediate future mutually technology parameter input module and cutting tool locus formation module and cutting tool locus compiler module and three dimensions process that dynamic imitation module and afterwards places the processing module . Next merely some famous CAD/CAMs system NCs process meanss are holied discussions . 9 UGIIs process means is analysed Oridinarily think that UGII is the best in trade circle , and havees representativeness digital control software most . That such havees the distinguishing feature most is the cutting tool locus formation means that such meritorous service capacity is powerful . Consists of turning , milling and string cuts and so on the consummate process means . In it milling chiefly possess the below meritorous service capacity : And PointtoPoint: Completeing the different openings processes And PanarMill: Plane is milled . Consising of that the one-way walkes surely , the two-way row are slice , and the hoop is slice along with rough sketch process to await And FixedContour: Admittedly much projectionss are areed processed stably . Dominateeing on being living on the single camber either much camber the removing of cutting tool in the way of the projection means , and that the control cutting tool is removed may be the cutting tool locus that has generateed , a series of either suite string And VariableContour: Variable projection is processed And Parameterline: Await that the parameter string is processed . The successive process of single camber either much camber may be adjust And ZigZagSurface: Cutting out process And RoughtoDepth: Rough machining . The depth is reachd assigning in the rough machining by Mao Pi And CavityMill: The many stages depth mould cavity processes . Rough machining that particularly is applicable to the male contact with the hollow standard 10 And SequentialSurface: The camber occuies simultaneously the workman . In accordance the spare parts and guides that and the thinking of check adjust the removing suppling the largesttest degree control of cutting tool EDSUnigraphics still consists of greats quantity else the respects meritorous service capacitys , and did not enumerate one by one here STRATAs process means is analysed STRATA is a digital control programming system development environment , and it is establishing ACISs geometry model building terrace on It supplys two kinds of programming development environments in the interest of consumer , in immediate future NCs command language interface and the NCs operation C+ storehouse . It may back three to mill , and turning and string cut NC and process , and may back wire frame , camber and the entity geometry model building . Such NCs cutting tool locus formation means is baseding on the physical model . STRATA is baseded on , and what supplys the process means in entity NCs cutting tool locus formation type storehouse consists of : ProfileToolpath: Rough sketch process AreaClearToolpath: The area on plane processes SolidProfileToolpath: The entity rough sketch is processed SolidAreaClearToolpath: The area on entity plane processes SolidFaceToolPath: The entity face processes SolidSliceToolPath: The entity severs process on plane LanguagebasedToolpath: Baseding on , language cutting tool locus generates Else CAD/CAM software , in case Euclid the person who awaits the NCs meritorous service capacity is each has his strong point , yet such 11 fundamental substance is almost alike , the not natural difference . 2.4 main problem of systematic sword track formation means of active duty CAM In accordance tradition CAD/CAMs system and CNCs system work means , CAMs system is with directly either the indirect means gains the produce geometry data model through CADs system ( by means of neutral papers ) . CAMs system is with spot , string , surface in the three dimensions geometrics model and either the entity is the drive target , the cutting tool locus is processed in the formation , and afterwards the shape with the cutting tool locating file viaes the handle is placed , with the NCs code shape supplys to CNCs machine tool , the some respects problems under being living in entire CAD/CAM and the CNCs system operation process to be : CAM systematically can only gain produce low tier of geometry message through CADs system , and can not seize voluntarily meritorous service capacity and the semantic information of produce geometry shape information and produce higher level . Hence manufacturing engineering master that entire CAMs process have to be living is very experience haves a hand in secondly , and completees mutually by means of the figure . In case : Manufacturing engineering master . The entire system automation degree is leted drop Being living in the CAMs system generation cutting tool locus , equal also merely embodying low straturm geometry message ( right line and arc geometry locating information ) , along with the a little process control information ( as moving forward ) to rate , main shaft rotation speed and trading sword and so on . Hence , can not obtain the process technology parameter that haves something to do with against generateing the cutting tool locus yet 12 The produce data between CAMs system every module are not unitied , and the independence is opposite to each other to every module . For instance the cutting tool locating file is merely keep the minutes the cutting tool locus and is not keep the minutes the relevant process technology parameter , the dynamic imitation of three dimensions merely keeps the minutes that the cutting tool locus interference against runs into , but keep the minutes interference and process target and correlation process technology parameter that runs into happen against such The CAM systematically is an independence system . Not thering is the unitary produce data model between CADs system together with the CAMs system , even if being the integrated CAD/CAMs system of integration in , one-way and unity is enjoyed also being only to message in all . CAM systematically can not sufficiently comprehend and complete message utilizing CADs system to have something to do with the produce , feature message that especially haves something to do with against process , equal CADs system can not gain the process data message that CAM systematically come into being yet . This is give parallel project implementation to bring the hardship 3、 digitals control techniques of simulation 3.1 calculating machine imitation approximately idea and application The angle through the project is see , and the imitation is the system by means of the test to the system model leave to research in the existing either design . Analysing the complex dynamic target , the imitation is one kind of valid means , may decrease the hazard , cuts down design and manufactures cycle , and practise thrift the investment . Calculating machine imitation is draing support from the calculating 13 machine , and utilizes the system model to adjust actually systematically testing the process which researcied . It is swiftly developed in the wake of the calculating machine technique development , and is living in the imitation to passess the more and more significant position . Three foundation maneuveies between the key element that the calculating machine imitation process may be notify by means of the picture 1 are depictd : The model building maneuver is by means of viewing either examination to the actual system , and is living to over look the less important element to reach on the base that examine the variable , and the means in the way of physics either mathematics is depictd , thereby obtains the similar pattern of actual system simplification . The meritorous service with the actual system of the pattern here be able to together with between the parameter ought to have similarity and homologous quality The imitation pattern is the mathematical model to the system ( simplifying the pattern ) carries on the specified algorithm handle , and causes such become the appropriate shape ( in case turns into iterative operation pattern by the numerical integration ) afterwards , yet becomes computation module computational mode that be able to be receiveed by the calculating machine . The imitation pattern is two simplification patterns to the actual system The imitation test is shall system imitation pattern be living the process rund in the calculating machine . The imitation is researching actual system one kind of technique by means of the test , may clarify systematically immanent structure variable and the ambient condition effect by means of the technique of simulation 14 Calculating machine technique of simulation main expressing of development tendency be living two respects : Application territory enlargement and imitation calculating machine intelligentization . The calculating machine technique of simulation not merely is living tradition project technique territory ( respects such as aviation , spaceflight and chemical industry and so on ) subsequent development , but also broadens up community economy and living beings and so on much non- project territorys , moreover , technique such as parallel processing , artificial intelligence , knowledge base and expert system and so on the development is affecing the imitation calculating machine development Digital control process imitation utilizes the calculating machine imitation practice process , being the forceful means to verify digital control processing program dependability and the calculation cutting action process , in order to decrease work attempies surely , and lifts production efficiency 3.2 digital control technique of simulation research present situation The APT process spare parts are completeed near the digital control order program control . In the interest of right quality to guarrantee the digital control order , guard against in process to intervene happenning , and is living in the actual manufacture , and constantly adopts attempting the anxious means to examine with what runs into . Yet this kind of means requiring a lot of labor expense is anticipateed , the cost expansively causes the manufacturing cost move upward , addd produce process time and production cycle . Adoping once more the locus to display the law afterwards , in immediate future in order to mark needle either pencil or writing brush replace the cutting tool , with colouring plank either paper replaces the work imitation cutting tool movement locus two dimension figure ( also 15 may display the two dimension semi process locus ) , possess the considerably great limitations . Three dimension and the many-dimensionss as to the work are processed , the cutting action locus that the inspection that the stuff that also possess use easily to cut replaces the work ( in case , paraffin wax , lumber , midified resin and plastic material and so on ) comes is processed . Yet APT and the process field is very important occupied in the attempt . For this reason , people are living always to research replace gradually attempting the anxious calculating machine emulation mode , and is living to attempt to slice that the respects such as environment modeling and imitation calculation and graphic display and so on acquire the significant progress , and develops to raise pattern accurateness and imitation calculation real timeization and improvement real feeling of graphic display and so on orientations at the moment Through attempies the pattern distinguishing feature sliceeing the environment seeing , NCs cutting action process imitation branch geometry imitation and mechanics imitation at the moment two respects . Geometry imitation is not consider that cutting action parameter and cutting force reach else the physics elements effects , the imitation cutting tool work geometric object movement , and with right quality of certification NCs order . The problem such as it may decrease either remove as a result of the machine tool injury that the program error causes and clamping apparatus damage either the cutting tool rolls over to snap and the spare parts are reported something as worthless and so on ； May decrease moreover through the product design up time manufacturing , and cut down the manufacturing cost . 16 Cutting action process mechanics imitation pertains to the physics imitation category , and its dynamic mechanics property by means of the imitation cutting action process is forecast that the cutting tool b reakage and cutting tool vibration and control cuts the parameter , thereby attains to optimize the cutting action process aim The geometry technique of simulation development is in the wake of geometry model building technique development but development , and consists of that quality graphic display and the ration is intervened verifying two respects . At the moment the means in common use possess the immediate solid modelling law , and the means of figure image space baseding on is requestted the intersection law with the scattered vector 3.3 immediate solid modelling law This kind of enveloping solid that the means is the work part of the body against the cutting tool movement takes shape is underway that the entity Boolean falls short of operating , and the work part of the body three dimensions patterns are continuously replaceed in the wake of the cutting action process Sungurtekin and Velcker opened up a miller simulation system . The three dimensions patterns that ought to systematically adopt CSGs law to keep the minutes Mao Pi utilize some fundamental primitives like cuboid , the cylindrical body and taper part of the body , and the set operation , particularly operating , the area by Mao Pi and a series of cutting tool scannings is keep the minutes , afterwards usies the set difference and operates through Mao Pizhongs order take-offing the scanning area . Traverse when the so-called area by has sweep is cutting the cutting tool to move along some locuss area . Per length of Mao Pixings shape that NCs code afterwards 17 display the alternation being living scanning Kawashima the person who awaits the joint tree law is expressed Mao Pi and the cutting action area in the way of the joint tree ( Graftree ) , in immediate future and Man Liangs kind connection except for empties the border connection is also as the leaf nodes of eight forks trees ( Octtree ) . The border connection embodys the half-space , and the CSGs operation that the connection substance utilized these half-spaces on to express . The half-space figure that the joint tree subdivided step permitted through the border connection is resolved . The cutting action imitation gradually utilizes Mao Pi and cutting action area to fall short of to operate achieving . The depth buffer algorithm was adoptd in the display of Mao Pi , by Mao Pi divides achieves the looking upon of Mao Pi in the interest of the polygon In the way of the real time baseding on solid modelling means successive renewal of realization Mao Pi may looking upon , very much elder when cosing , the observation means is propose then some are baseded on 3.4 means of figure image space baseding on This kind of blanking algorithm that the means was employd figure image space is achieved the entity Boolean calculation . The VanHook adopts scattered law of the image space dynamic figure imitation achieved process . He employs analogous figure blanking Zbuffers idea , scattered along the view orientation by Mao Pi and cutting tool , is living every one Mao Pi and the cutting tool expresss being called Dexels composition in the interest of the cuboid along Zs shaft on the screen pixels . 18 The cutting tool cuts that the process of Mao Pi simplifies to the dimension Boolean calculation along the view orientation , and catchs sight of that figure 3 cutting action process turns into two the Dexels composition comparing : CASE1: Merely Mao Pi displays Mao Pi , Break CASE2: Mao Pi displays cutting tool , Break after being living the cutting tool completely CASE3: The cutting tool cuts the ministry before Mao Pi , and replaces the Dexels composition of Mao Pi , and displays cutting tool , Break CASE4: The cutting tool internal cutting Mao Pi leaves out the Dexels composition of Mao Pi , and displays cutting tool , Break CASE5: The cutting tool internal cutting Mao Pi establishs fresh Mao Pis Dexels composition , and displays Mao Pi , Break CASE6: The cutting tool cuts the Mao Pi rear , and replaces the Dexels composition of Mao Pi , and displays Mao Pi , Break CASE7: The cutting tool displays Mao Pi , Break after being living Mao Pi completely CASE8: The merely cutting tool displays cutting tool , Break This kind of means is shutd entity Boolean calculation and the graphic display process into to a man , and causes the imitation graphic display possess the very good real time Hsu and Yang propose one kind of valid three real-time emulation means milling . They employ Zmap as the base data composition , and keeing the minutes two dimension grid every one diamond part Mao Pis altitude , in immediate future the Z direction is worth . This kind of data structure merely is applicable to the sword shaft Z direction three milling imitation . 19 Mill the operation to be worth by means of the depth that revises cutting tool each a few of movement , and replaces Zmaps value easily , and to replace the work graphic display to every one 3.5 the scattered vector is requestted the intersection law Since the fact that the now available solid modelling technique does not relate to that the official business fall short of and the camber bias is expressed , the Boolean calculation in pixel element room is not at all exact , and causes imitation certification possess the very great limitations . For this reason Chappel propose one kind to based on the camber technique to touch the vector ( Pointvector ) law . This kind of means is scattered by the camber according to the specified accuracy , and scatteredly in the way of these comes to express that camber . With every one scattered law swear is the vector orientation that was touch , the external looks that prolongs against the work is intersected . By means of the imitation cutting tool cutting action process , calculation every scattered along the law swear up the cutting tool away from S In case Sg and Sm is separately in the interest of the inside and outward deviation of camber process , in case Sgs Ss s SMs directions process is in inner place the error range , S sm piece slices by mistake . That means is divided into being cut the requestting intersecting ( Intersection ) three processs of camber scattered ( Discretization ) and examination some fixed position location ( Location ) and scattered some vector together with work entity . Adopt image mapping means to display processing the error figure ； The spare parts face process errors may accurately be depictd out . The total is baseded on in the solid modelling means geometric 20 model to show against actual process one another unanimously , and to cause between imitation ultimate killing together with design produce exact comparatively becomes the probability ； Tall yet the technique of solid modelling is requireed , the calculation is measured greatly , and the pragmatic environment of calculating machine that is living at the moment gets off and harder usies to real time examination and dynamic simulation . Figure image space baseding on means velocity is much fast , and can achieve the real-time emulation , yet thanks to the fact that the initial data wholly transforms to the pixel element value , does not easily carry on the exact examination . The surface treatment that the scattered vector requests the intersection law to based on the spare parts , be able to accurately depict the spare parts the process error , is chiefly used the camber process error examination 21 译文： 数控加工技术概述 1、数控编程及其发展 数控编程是目前 CAD/CAPP/CAM系统中最能明显发挥效益的环节之一，其在实现设计加工自动化、提高加工精度和加工质量、缩短产品研制周期等方面发挥着重要作用。在诸如航空工业、汽车工业等领域有着大量的应用。由于生产实际的强 烈需求，国内外都对数控编程技术进行了广泛的研究，并取得了丰硕成果。下面就对数控编程及其发展作一些介绍。 1.1、 数控编程的基本概念 数控编程是从零件图纸到获得数控加工程序的全过程。它的主要任务是计算加工走刀中的刀位点（ cutterlocationpoint简称 CL点）。 刀位点一般取为刀具轴线与刀具表面的交点，多轴加工中还要给出刀轴矢量 1.2、 数控编程技术的发展概况 为了解决数控加工中的程序编制问题， 50 年代， MIT 设计了一种专门用于机械零件数控加工程序编制的语言，称为 APT（ AutomaticallyProgrammedTool）。其后，APT 几经发展，形成了诸如 APTII、 APTIII（立体切削用）、 APT（算法改进，增加多坐标曲面加工编程功能）、 APTAC（ Advancedcontouring） (增加切削数据库管理系统 )和 APT/SS（ SculpturedSurface） (增加雕塑曲面加工编程功能 )等先进版。 采用 APT 语言编制数控程序具有程序简炼，走刀控制灵活等优点，使数控加工编程从面向机床指令的“汇编语言”级，上升到面向几何元素 .APT 仍有许多不便之处：采用语言定义零件几何形状，难以描述复杂的 几何形状，缺乏几何直观性； 缺少对零件形状、刀具运动轨迹的直观图形显示和刀具轨迹的验证手段；难以和 CAD 数据库和 CAPP 系统有效连接；不容易作到高度的自动化，集成化，针对APT 语言的缺点， 1978 年，法国达索飞机公司开始开发集三维设计、分析、 NC 加工一体化的系统，称为为 CATIA。 随后很快出现了象 EUCLID， UGII， INTERGRAPH， Pro/Engineering， MasterCAM 22 及 NPU/GNCP等系统，这些系统都有效的解决了几何造型、零件几何形状的显示，交互设计、修改及刀具轨迹生成，走刀过 程的仿真显示、验证等问题，推动了 CAD和 CAM向一体化方向发展。到了 80年代，在 CAD/CAM一体化概念的基础上，逐步形成了计算机集成制造系统（ CIMS）及并行工程（ CE）的概念。目前，为了适应CIMS及 CE发展的需要，数控编程系统正向集成化和智能化夫发展。 在集成化方面，以开发符合 STEP（ StandardfortheExchangeofProductModelData）标准的参数化特征造型系统为主，目前已进行了大量卓有成效的工作，是国内外开发的热点；在智能化方面，工作刚刚开始，还有待我们去努力。 2、 NC刀具轨迹生成方法研究发展现状 数控编程的核心工作是生成刀具轨迹，然后将其离散成刀位点，经后置处理产生数控加工程序。 下面就刀具轨迹产生方法作一些介绍 2.1、基于点、线、面和体的 NC刀轨生成方法 CAD 技术从二维绘图起步，经历了三维线框、曲面和实体造型发展阶段，一直到现在的参数化特征造型。在二维绘图与三维线框阶段，数控加工主要以点、线为驱动对象，如孔加工，轮廓加工，平面区域加工等。这种加工要求操作人员的水平较高，交互复杂。 在曲面和实体造型发展阶段，出现了基于实体的加工。 实体加工的加工对象是一个实体（ 一般为 CSG和 BREP混合表示的），它由一些基本体素经集合运算（并、交、差运算）而得。 实体加工不仅可用于零件的粗加工和半精加工，大面积切削掉余量，提高加工效率，而且可用于基于特征的数控编程系统的研究与开发，是特征加工的基础。实体加工一般有实体轮廓加工和实体区域加工两种。实体加工的实现方法为层切法（ SLICE），即用一组水平面去切被加工实体，然后对得到的交线产生等距线作为走刀轨迹。 本文从系统需要角度出发，在 ACIS 几何造型平台上实现了这种基于点、线、面和实体的数控加工 2.2、基于特征的 NC刀轨生成方法 23 参数化特征造型已有了一定的发展时期，但基于特征的刀具轨迹生成方法的研究才刚刚开始。特征加工使数控编程人员不在对那些低层次的几何信息（如：点、线、面、实体）进行操作，而转变为直接对符合工程技术人员习惯的特征进行数控编程，大大提高了编程效率 W.R.Mail和 A.J.Mcleod在他们的研究中给出了一个基于特征的 NC代码生成子系统，这个系统的工作原理是：零件的每个加工过程都可以看成对组成该零件的形状特征组进行加工的总和。 那么对整个形状特征或形状特征组分别加工后即完成了零件的加工。而每一形状特征或形状特征组的 NC代码可自动生成。目前开发的系统只适用于 2.5D零件的加工。 LeeandChang开发了一种用虚拟边界的方法自动产生凸自由曲面特征刀具轨迹的系统。这个系统的工作原理是：在凸自由曲面内嵌入一个最小的长方块，这样凸自由曲面特征就被转换成一个凹特征。 最小的长方块与最终产品模型的合并就构成了被称为虚拟模型的一种间接产品模型。 刀具轨迹的生成方法分成三步完成：（ 1）、切削多面体特征； （ 2）、切削自由曲面特征； （ 3）、切削相交特征 JongYunJung研究了基于特征的非切削刀具轨迹生成问题。文章把基于特征的加工轨迹分成轮廓加工和内区域加工两类，并定义了这两类加工的切削方向，通过减少切削刀具轨迹达到整体优化刀具轨迹的目的。文章主要针对几种基本特征（孔、内凹、台阶、槽），讨论了这些基本特征的典型走刀路径、刀具选择和加工顺序等，并通过 IP（ InterProgramming）技术避免重复走刀，以优化非切削刀具轨迹。 另外， JongYunJong还在他 1991年的博士论文中研究了制造特征提取和基于特征的刀具及刀具路径特征加工的基础是实体加工，当然也可认为是更高级的实体加工。但特征加工不同于实体加工，实体加工有它自身的局限 性。特征加工与实体加工主要有以下几点不同： 从概念上讲，特征是组成零件的功能要素，符合工程技术人员的操作习惯，为工程技术人员所熟知；实体是低层的几何对象，是经过一系列布尔运算而得到的一个几何体，不带有任何功能语义信息；实体加工往往是对整个零件（实体）的一次 24 性加工。但实际上一个零件不太可能仅用一把刀一次加工完，往往要经过粗加工、半精加工、精加工等一系列工步，零件不同的部位一般要用不同的刀具进行加工；有时一个零件既要用到车削，也要用到铣削。因此实体加工主要用于零件的粗加工及半精加工。而特征加工则从本质上解决了上 述问题； 特征加工具有更多的智能。对于特定的特征可规定某几种固定的加工方法，特别是那些已在 STEP标准规定的特征更是如此。如果我们对所有的标准特征都制定了特定的加工方法，那么对那些由标准特征够成的零件的加工其方便性就可想而知了。倘若 CAPP系统能提供相应的工艺特征，那么 NCP系统就可以大大减少交互输入，具有更多的智能。而这些实体加工是无法实现的特征加工有利于实现从 CAD、 CAPP、NCP及 CNC 系统的全面集成，实现信息的双向流动，为 CIMS乃至并行工程（ CE）奠定良好的基础； 而实体加工对这些是无能为力的 2.3、现役几个主要 CAD/CAM 系统中的 NC刀轨生成方法分析 现役 CAM的构成及主要功能。目前比较成熟的 CAM系统主要以两种形式实现CAD/CAM系统集成：一体化的 CAD/CAM系统（如： UGII、 Euclid、 Pro/ENGINEER等）和相对独立的 CAM 系统（如： Mastercam、 Surfcam等）。前者以内部统一的数据格式直接从 CAD 系统获取产品几何模型，而后者主要通过中性文件从其它 CAD系统获取产品几何模型。然而，无论是哪种形式的 CAM系统，都由五个模块组成，即交互工艺参数输入模块、刀具轨迹生成 模块、刀具轨迹编辑模块、三维加工动态仿真模块和后置处理模块。下面仅就一些著名的 CAD/CAM 系统的 NC 加工方法进行讨论。 UGII加工方法分析 一般认为 UGII是业界中最好，最具代表性的数控软件。 其最具特点的是其功能强大的刀具轨迹生成方法。 包括车削、铣削、线切割等完善的加工方法。 其中铣削主要有以下功能： 、 PointtoPoint：完成各种孔加工 、 PanarMill：平面铣削。 包括单向行切，双向行切，环切以及轮廓加工等 25 、 FixedContour：固定多轴投影加工。 用投影方法控制刀具在单张曲面上 或多张曲面上的移动，控制刀具移动的可以是已生成的刀具轨迹，一系列点或一组曲线 、 VariableContour：可变轴投影加工 、 Parameterline：等参数线加工。 可对单张曲面或多张曲面连续加工 、 ZigZagSurface：裁剪面加工 、 RoughtoDepth：粗加工。 将毛坯粗加工到指定深度 、 CavityMill：多级深度型腔加工。 特别适用于凸模和凹模的粗加工 、 SequentialSurface：曲面交加工。 按照零件面、导动面和检查面的思路对刀具的移动提供最大程度的控制 EDSUnigraphics还包括大量的其它方面的功能，这里就不一一列举了 STRATA加工方法分析 STRATA是一个数控编程系统开发环境，它是建立在 ACIS几何建模平台上的 它为用户提供两种编程开发环境，即 NC 命令语言接口和 NC 操作 C+类库。它可支持三轴铣削，车削和线切割 NC加工，并可支持线框、曲面和实体几何建模。其 NC刀具轨迹生成方法是基于实体模型。 STRATA基于实体的 NC刀具轨迹生成类库提供的加工方