机械制造工艺学双语课件.pdf

《机械制造工艺学双语课件.pdf》由会员分享，可在线阅读，更多相关《机械制造工艺学双语课件.pdf（9页珍藏版）》请在淘文阁 - 分享文档赚钱的网站上搜索。

1、制造技术基础复习基本概念、基本原理英语表达参考Review the Basic Concepts and Principles ofReview the Basic Concepts and Principles of Fundamentals of Manufacturing TechnologyFundamentals of Manufacturing Technologyinin EnglishEnglishCHAPTER ONEDESIGN FOR MECHANICAL PROCESS PLANNINGDESIGN FOR MECHANICAL PROCESS PLANNINGSect

2、ion 1Basic conceptsProduction procedure of mechanical productsProcess procedure of machiningElements of Process procedure of machining1 sequence 工序；2 installation 安装；3 station 工位；4 step 工步；5 pass 走刀SequenceSequence:process procedure that consists of several sequencesduring which workersduring which

3、workersoperate on the works continuously in the same place;operate on the works continuously in the same place;(操作者、加工地、工作对象人为划分，相对可变)Installation:in a sequence if the work is required to put into position and clamp severaltimes,the,the partpart ofof sequencesequence donedone inin oneone positioning

4、positioning andand clampingclamping is is calledcalled ananinstallation;installation;(确定）StationStation:In an installation,by using the indexing or moving device the work is changed itsposition relatively to the cutting tool.All the tasks done for the work in one machiningAll the tasks done for the

5、work in one machiningposition in an installation is termed as the station;position in an installation is termed as the station;(确定）StepStep：InIn oneone stationstation if if thethe surfacesurface cut,cut,cuttingcutting tool,tool,velocity,velocity,andand feedfeed remainremainunchanged,these working co

6、ntents are thought of as the step.unchanged,these working contents are thought of as the step.(加工表面、刀具、切削速度、进给量任一改变均为另一工步）Pass:When the surface of the work is cut for any one time,such task carried out isPass:When the surface of the work is cut for any one time,such task carried out isnamed as the p

7、assnamed as the pass(刀具在加工表面的每一次切削）Processing systemProcessing system:a system that contains the work to be machined,fixture that holds the work in theproper position,cutting tool that machines the work directly,and machine tool that givesthe power and provide the movements to acplish the processing

8、.In recent years thegauging and measuring is added to the system.Relationship between the batch and the pattern of productionN=Qn(1%)N-program of production,Q-annual turnout of the productn-number of the ponents a year,nb=NAF-share rate,-wasterate,F-annualworkingdays,A-number of days for inventory,-

9、number of ponents in a lotA Program of productionIn a period of planning,the turnout of product and schedule to be fulfilled is called program.(计划期的产量加进度=生产纲领）The turnout in one year planning is named the annualThe turnout in one year planning is named the annualprogramprogram.B Batch of productionA

10、t a time,the number of identical products to be put into production or to be producedis termed asbatch of production.(一次投入生产的同一产品的数量=生产批量）1/9Process planning for machining operationsProcess planning for machining operations:stipulated document for technological process(机械加工工艺规程：以工艺文件形式规定的机械加工工艺过程)Pa

11、tterns of the process planning for machiningGenerally speaking,the process planning for machining appears in the form of sheet or card withthe same basic content in three patterns:Pattern A:sheetsheet ofof processprocess proceduresprocedures(工艺过程卡),a very simple and concise document,usually for sing

12、le/small batch productionPattern B:sheet of process operationsheet of process operation(机械加工工艺卡),often for batch productionPattern C:sheetsheet ofof processprocess sequencesequence(机械加工工序卡),with detailed and plete contents,frequently for massive productionSection 2Location and Datum of the work in m

13、achiningInstallation and clamping(装夹）:concerning about the ways in which the work is installed andclamped in the fixture or on the machine tool,including two aspects,locating(locating(定位定位)andclamping(clamping(夹紧夹紧).Locating:the procedure during which the work gains its proper position in the fixtur

14、ethe work gains its proper position in the fixture or onthe machine tool.Clamping:when the workpiece has gained its correct position in the fixture,it will be subject tothe external forces while being machined.So,toto holdhold oror keepkeep thethe workpieceworkpiece inin thethe correctcorrectpositio

15、n is definitely required,which is called clamping.position is definitely required,which is called clamping.Six-Point Locating Principles：A cuboid is in cartesian coordinate with six degrees of freedomThe six degrees of freedom are three linear movements along the three coordinate axes,X,Y,and Zrespe

16、ctively,and three rotations around these coordinate axesX,Y,and ZIn theory,the locating point is the geometric point;inreality,it is something different with itsthree dimensions.The following are monly used in workshops.Button locator(支撑钉);Plug(档销);Supporting plate（支撑板）;Pin/pin locator（长销）Button;Cut

17、 pin/rhombus pin（削边销/菱形销）;Mandrel（心轴）;V block（形块）Short V block（短形块）;Positioning sleeve（定位套）;Fixed/floating conic pin（固定/浮动锥销）;Center(顶尖（固定/浮动）)plete positioningplete positioning:locating with constraint for all six degrees of freedom.Inplete positioningInplete positioning:locating with constraint fo

18、r less than six degrees of freedom.Under/over-positioningUnder/over-positioning:the number of constraints of degree of freedom is less than that required.Under-positioning ought to be avoided and,Under-positioning ought to be avoided and,Over-positioningOver-positioning:thethe samesame degreedegree

19、ofof freedomfreedom is is constrainedconstrained byby twotwo oror eveneven moremoreconstrainingconstraining points,points,suchsuch situationsituation is is calledcalled overover positioning,positioning,whichwhich willwill bebe allowedallowedoccasionally.occasionally.Datum(Datum(基准基准)is the point,lin

20、e or surface based on which the geometric relation-ships amonggeometricelements of the object to be worked at are determined.The concept is so importantthat is may be used for any aspect of production,from design,through manufacturing includingsequences of operation,to the gauging and assemblyTechno

21、logical/process datumsSequential datum:Sequential datum:on the sequential drawing,datum that is used in this sequence to determinethe size,form,and position of the work after being machined is named Sequential datum.TheThethree aspects are supposed to be taken into consideration:three aspects are su

22、pposed to be taken into consideration:the priority of sequential datum ispaid to the design datum,that is use the design datum as sequential datum,the selected datum isfavorable for the location and the gauging of the work,and if the above requirements are hardly2/9met,the datum used to guarantee th

23、e technical conditions.Datum may be classified into two categories,Datum may be classified into two categories,Design datum and Technological datum,according to their functions.Design datum and Technological datum,according to their functions.I I designdesign datum:datum:inin designdesign ofof ponen

24、ts,ponents,thethe originorigin fromfrom whichwhich,according,according toto thethe assemblyassemblyrelationshiprelationship ofof thethe ponentponent andand thethe relativerelative relationshiprelationship ofof thethe structuralstructural elementselements ofof thetheponentponent itself,itself,thethe

25、dimensioningdimensioning is is done.done.TheseThese originaloriginal positionspositions areare calledcalled designdesigndatums.(datums.(设计图纸上零件标注的起始位置设计图纸上零件标注的起始位置)II technological datum:datum used in the process operations is termed technological datum,II technological datum:datum used in the proc

26、ess operations is termed technological datum,which can be even classified as:which can be even classified as:Locating datum:datum used for the workpiece to gain its proper position in machining,itLocating datum:datum used for the workpiece to gain its proper position in machining,itdirectly influenc

27、es the effectiveness of machining.Locating datum coversdirectly influences the effectiveness of machining.Locating datum coversRough datum andFinishing datum.a)Rough datum/Finishing datum:un-machined locating datum,in other word,any locatingdatum used in the first sequence of operation in the manufa

28、cturing process planning is the roughdatum;finishing datum:machined locating datum.b)additional/auxiliary datum:the specially designed datum in the workpiece because of therequirement of the mechanical process operations.Gauging datum:during and after machining,datum used for measuring and checking

29、theGauging datum:during and after machining,datum used for measuring and checking theform,position,and error of size,of the workpiece.form,position,and error of size,of the workpiece.Assembling datum:in assembling datum adopted to determine the relative positions of theAssembling datum:in assembling

30、 datum adopted to determine the relative positions of thework or the ponent in the product.work or the ponent in the product.Section 3Design of the routes of machining processesroutes of machining processes（工艺路线的制定）（工艺路线的制定）Consideration must be taken with the locating datumlocating datum of the wor

31、kpiece(定位基准）,the processthe processmethodsmethods（加工方法）,the order of the processesthe order of the processes（加工顺序）,heat treatment（热处理）,testing（检验），and the related operations（其他工序）.A selection of locating datums(定位基准的选择)B selection of economic accuracy and process methods of machining（机加的经济精度与方法）C ma

32、chining routes for the typical surfaces（典型表面的加工路线外圆、孔和平面）D order of sequences（工序顺序安排）Selecting rules of rough machining datumSelecting rules of rough machining datum:Iguarantee the proper relative positions.IIguarantee reasonable allocation of the allowance forthe surface being machined.III facilita

33、te the locating and clamping of the workpiece.For this reason,the selected surfaces asthe datums must be to some extent smooth,enough-sized,flasher-free,without otherdefectssuch as reservoir and riser or the like.IV the rough locating datum used only for one time(without repetition)Selecting rules o

34、f finishing machining datum:Selecting rules of finishing machining datum:Ioverlapping principle(基准重合）-datum used as the same as design datumII unifying principle（基准统一）-use the same datum as early and as frequently as possibleIII inter-reference principle（互为基准）-especially used for the high accuracy o

35、f relativepositions of the surfacesIV self-reference principle（自为基准)-for sequence of small roughness,small and evenallowanceVclamping-facilitating/convenient principle（便于装夹）-for proper and secure(reliable)locating,simple structure of the clamping device with easy operationEconomic accuracy in machin

36、ing(Economic accuracy in machining(经济加工精度经济加工精度)Under the mon machining conditions,that is,with facilities and tooling in standard quality,Under the mon machining conditions,that is,with facilities and tooling in standard quality,3/9the operators with typical skills,and in rated time,the machining i

37、s done with the relevantthe operators with typical skills,and in rated time,the machining is done with the relevantaccuracy and roughness imparted to the ponent.Such accuracy and roughness is called theaccuracy and roughness imparted to the ponent.Such accuracy and roughness is called theeconomic ac

38、curacy in machiningeconomic accuracy in machiningOrder of sequences（工序顺序安排）a datum first then others;b flat first then others,generally;c the main surfaces first;d rough machining first,followed by finishing machiningCentralized,decentralizes sequences and theCentralized,decentralizes sequences and

39、theMachining stagesMachining stagesI rough machiningIIsemi-finishing machiningIII finishing machiningIV precision,ultra-precision,and smooth machiningSection 4 Determination of machining allowance,dimensions between sequences,and tolerancemachining allowancemachining allowance:the difference between

40、 the size of the blank and that of the ponent designon drawingthe total allowancethe total allowance is equal to the sum of material thickness to be removed for every step in theprocess operation.Sequential allowanceSequential allowance:the thickness of metal removal of the cut layer in every sequen

41、ceThe relationship between the total allowance and Sequential allowance will be expressed inThe relationship between the total allowance and Sequential allowance will be expressed interms ofterms ofnZo=Z1+Z2+Zo=Z1+Z2+Zn=+Zn=i=1ZiCHAPTER TWO DESIGN PRINCIPLES OF MACHINE TOOL JIGS AND DESIGN PRINCIPLE

42、S OF MACHINE TOOL JIGS ANDFIXTURESFIXTURESSection 1introduction to the machine tool jigs and fixturesFunction,constituents,and classificationFunction,constituents,and classification（夹具的功用，组成和分类）（夹具的功用，组成和分类）Function:Function:the machine tool jig or fixture is a device used in machine tool by which t

43、heworkpiece obtains and keeps the proper position relative to the machine tool before and duringthe workpiece being machined.Constituents of the fixtureConstituents of the fixture:Six elements or units of a jig or fixtureIlocating elements:for locating the work,such as button locator,base(body),and

44、rhombus.IItool guide:for guiding the tool or adjusting relative position of the tool to the fixture,suchas,tool setting block.III clamping device:for holding the work firmly,such as the bolt,screw,and the heel.IV connecting elements:for determining the position of the fixture on the machine tool and

45、connecting the fixture with the machine tool,such as the locating key,and the base.Vbody:for connecting all the elements and devices as a whole,and through the body thefixture being fixed to the machine tool,such as the base.VI additions:for other purposes,like indexing,safeguarding,error-avoiding a

46、nd the like,such asthe stop pin.Classification of the fixture:Classification of the fixture:AccordingAccording toto thethe rangerange ofof usageusage,fixtures can generally be classified into six categories:all-purpose,special,all-purpose adjustable and group,posite,transferring fixtures.InIn accord

47、anceaccordance withwith thethe machinemachine tooltool onon whichwhich thethe fixturefixture is is utilized,utilized,fixtures can also beclassified into lathe,milling machine,drill,borer,grinder,automatic machine tool,and NCmachine tool,fixtures.BasedBased onon thethe powerpower whichwhich drivesdri

48、ves thethe clampingclamping devicesdevices toto holdhold thethe workwork firmlyfirmly inin place,place,fixtures can even be classified into manual,pneumonic,hydraulic,electric-magnetic,andvacuum,fixtures4/9Section 2Workpiece-location in the fixtureWorkpiece-location in the fixture*the analysis and c

49、alculation of locating error*the analysis and calculation of locating errormonly used methods of locating and the locating elements（the surfaces of the workpiece)A locating by flat/plane/surface（平面定位）Fixed/adjustable/self-adapted/auxiliary support(固定/可调/自位/辅助支承)Section 3Workpiece-clamping in the fix

50、tureRequirements of the clamping forcesRequirements of the clamping forcesDetermination of the clamping forcesDetermination of the clamping forcesmonly used clamping mechanismsmonly used clamping mechanismsRequirements of the clamping forcesIsustain,during the whole period of clamping,the proper pos