Jigs-and-Fixture解析.ppt

机械工程英语 MechanicalEngineeringEnglish DefinitionofaDrillJig Introduction NewTermsandTerminologies Contents TypicalJigsandFixtures 1 2 3 4 NewWordsandTerminologies Jig 钻模Fixture 夹具Workpiece 工件Cuttingtool 刀具 切削工具 切削刀具Clamp vt 夹住 加紧 n 夹具Casting n 铸造 铸件Forging n 锻造 锻件Rib n 加强肋Core n 型芯Drill n 钻头 钻机Reamer n 铰刀 NewWordsandTerminologies Cutter n 铣刀Bolt n 螺栓Nut n 螺母Clearance n 间隙Observance n 遵守Encroach 侵犯 侵占Perpendicular 垂直的Tap 攻螺纹Bushing n 套管 衬管 Hardened steel 淬火钢Flange n 法兰 凸缘Milling n 铣削planing n 刨Shaping n 成形Turning n 车削 车削加工Tenon n 突隼 NewWordsandTerminologies Introduction Ithasalreadybeenstatedthattheworkpiecemustbelocatedrelativetothecuttingtool andbesecuredinthatposition Aftertheworkpiecehasbeenmarkedout itisstillnecessarytopositionitwithrespecttothemachinemovements andtoclampitinthatpositionbeforemachiningisstarted 已经说明了工件必须相对于切削刀具定位并确保到位 工件划线后 仍有必要将其相对于切削运动定位 并在机加工开始前把它装夹到位 工件 划线 机械工程英语 Whenseveralidenticalworkpiecesaretobeproducedtheneedtomarkouteachpartiseliminatedbytheuseofjigsandfixtures butifacastingorforgingisinvolved atrialworkpieceismarkedout toensurethattheworkpiececanbeproducedfromit andtoensurethatribs cores etc havenotbecomemisplaced 当要加工若干同样的工件时 使用钻模和夹具可以不必在每个工件上划线 但对铸件或锻件而言 还需取一试验工件划线以保证照此加工不会将加强肋 型芯等放错位置 钻模 夹具 铸件 锻件 加强肋 型芯 机械工程英语 Jigsandfixturesarealikeinthattheybothincorporatedevicestoensurethattheworkpieceiscorrectlylocatedandclamped buttheydifferinthatjigsincorporatemeansoftoolguidingduringtheactualcuttingoperation andfixturesdonot Inpractice theonlycuttingtoolsthatcanbeguidedwhileactuallycuttingaredrills reamers andsimilarcutters andsojigsareassociatedwithdrillingoperations andfixtureswithallotheroperations Fixturesmayincorporatemeansofsettingthecuttingtoolsrelativetothelocationsystem 钻模和夹具的相似点是它们都把保证工件正确定位和夹紧的装置相结合 它们的不同在于钻模在实际切削作业中还能与刀具导向方法相结合 它们的不同在于钻模在实际切削作业中还能与刀具导向方法相结合 而夹具则不能 实际上 在真实切削中能被导向的切削刀具只有钻头 铰刀和类似的刀具 因此钻模用于钻削作业 而夹具用于其余作业 夹具可以与切削刀具相对定位系统装夹的方法结合在一起 夹紧 切削操作 钻头 铰刀 刀具 机械工程英语 Theadvantagesofjigsandfixturescanbesummarizedasfollows 1 Markingoutandothermeasuringandsettingoutmethodsareeliminated 2 Unskilledworkersmayproceedconfidentlyandquicklyinknowledgethattheworkpiececanbepositionedcorrectly andthetoolsguidedorset 钻模和夹具的优点可归纳如下 1 可以省去划线和其它测量及放样程序 2 在知道工件能正确定位 刀具能恰当导向或装夹的情况下 不熟练的工人也能自信而快速地操作 布置 安装 机械工程英语 3 theassemblyofpartsisfacilitated sinceallcomponentswillbeidenticalwithinsmalllimits and trying andfilingofworkiseliminated 4 Thepartswillbeinterchangeable andiftheproductsoldoverawidearea theproblemofsparepartswillbesimplified 3 由于所有零件在较小极限范围内是相同的 可以省掉工件的 试装 和锉削 所以零件装配很方便 4 零件具有互换性 这样如果产品在较大范围内销售的话 备件问题将简单化 锉削 机械工程英语 Boltholesoftenhave1 5mmoreven3 0mmclearanceforthebolt andthereadermaydoubtthenecessityofmakingprecisionjigsforsuchwork Itmustberememberedthatthejigs oncemade willbeusedonmanycomponents andtheextracostofanaccuratelymadejigisspreadoveralargeoutput Furthermore itissurprisinghowsmallerrorsaccumulateinamechanismduringitsassembly Whenaclearanceisspecified itisbettertoensureitsobservance ratherthantoallowcarelessmarkingoutandmachiningtoencroachuponit 螺栓孔常给螺栓留出1 5毫米或甚至3 0毫米的间隙 读者可能会怀疑为这样的工作制造精密钻模的必要性 但要记住 这种钻模一旦造好 可用于许多零部件 精确制造钻模的额外成本可分摊在大量产品上 此外 这样做在装配机械装置时其累积误差之小也是令人惊讶的 在确定一个间隙时 最好能保证它的习惯要求 而不是随便划线和机加工使其超出正常的界限 螺栓 间隙 遵守 侵犯 侵占 机械工程英语 1 Thelocationofworkpiece Fig 13 1representsabodythatiscompletelyfreeinspace Inthisconditionithassixdegreesoffreedom ConsiderthesefreedomswithrespecttothethreemutuallyperpendicularaxesXX YY andZZ Thebodycanmovealonganyoftheseaxes itthereforehasthreefreedomsoftranslation Itcanalsorotateaboutanyofthethreeaxes itthereforehasthreefreedomsofrotation Thetotalnumberoffreedomsissix 自由度 垂直的 axis 机械工程英语 Whenworkislocated asmanyofthesefreedomsaspossiblemustbeeliminated toensurethattheoperationisperformedwiththerequiredaccuracy Accuracyisensuredbymachiningsuitablelocationfeaturesasearlyaspossible andusingthemforalllocation unlessotherconsiderationsmeanthatotherlocationfeaturesmustbeused Ifitisnecessary thenewlocationfeaturesmustbemachinedasaresultoflocationfromtheformerlocationfeatures 机械工程英语 1 工件的定位 图13 1表示一个在空间完全自由的物体 在这种情况下它具有六个自由度 相对于三根互相垂直的坐标轴XX YY和ZZ来考虑这些自由度 此物体能沿三根坐标轴的任意一根移动 这样就具有三个平移自由度 它也能围绕三根坐标轴的任意一根回转 这样它又具有三个旋转自由度 总的自由度数目是六个 当工件被定位时 必须尽可能多地消除这些自由度 以保证作业按要求精度进行 除非有必要采用另外定位要素的其它考虑 精度可通过尽可能早地加工合适的定位要素并采用它们进行所有定位来保证 如果必要的话 新的定位要素必须作为先前的定位要素的定位结果来加工 机械工程英语 2 Theclampingoftheworkpiece Theclampingsystemmustbesuchthattheworkpieceisheldagainstthecuttingforces andtheclampingforcesmustnotbesogreatastocausetheworkpiecetobecomedistortedordamaged Theworkpiecemustbesupportedbeneaththepointofclamping toensurethattheforcesaretakenbythemainframeofthejigorfixture andontothemachinetableandbed Whenjigsandfixturesaredesigned theclampingsystemisdesignedtoensurethatthecorrectclampingforceisapplied andthattheclampscanbeoperatedquicklybutwithsafety 切削力 装夹力 机械工程英语 2 工件的装夹 装夹系统必须使工件对着切削力夹持 而且装夹力又不能大得引起工件变形或损坏 工件必须在装夹点下被支撑 以保证这些力由钻模或夹具的主框架来承受并传递给机床工作台和床身 在设计钻模和夹具时 要同时设计装夹系统来保证提供恰当的装夹力 并使装夹操作快速而安全 DefinitionofaDrillJig Adrilljigisadeviceforensuringthataholetobedrilled tapped orreamedinaworkpiecewillbemachinedintheproperplace Basicallyitconsistsofaclampingdevicetoholdthepartinpositionunderhardened steelbushingsthroughwhichthedrillpassesduringthedrillingoperation Thedrillisguidedbythebushings Iftheworkpieceisofsimpleconstruction thejigmaybeclampedontheworkpiece Inmostcases however theworkpieceisheldbythejig andthejigisarrangedsothattheworkpiececanbequicklyinsertedandasquicklyremovedafterthemachiningoperationisperformed 钻 攻螺纹 铰 淬火钢 套管 衬管 DefinitionofaDrillJig 钻模是一种确保在工件正确位置进行钻孔 攻丝或铰孔加工的装置 它基本上由在淬硬钢衬套下将零件夹持到位的夹持装置组成 钻孔作业中钻头穿过这些衬套 通过它们来导向 如果工件结构比较简单 钻模可夹持在工件上 然而大多数情况下 工件由钻模来夹持 并且把钻模设计成能将工件迅速装入而在加工后同样能很快取出 机械工程英语 Jigsmakeitpossibletodrill ream andtapholesatmuchgreaterspeedsandwithgreateraccuracythanwhentheholesareproducedbyconventionalhandmethods Anotheradvantageisthatskilledworkersarenotrequiredwhenjigsareused Responsibilityfortheaccuracyofholelocationistakenfromtheoperatorandgiventothejig 相对于用常规的手工方法加工孔 钻模使得钻孔 铰孔和攻丝速度快很多而且精度更高成为可能 另一个优点是采用钻模时不需要熟练工人 保证孔定位精度的责任从操作者身上转移到了钻模上 机械工程英语 Thetermjigshouldbeusedonlyfordevicesemployedwhiledrilling reaming ortappingholes Itisnotfastenedtothemachineonwhichitisusedandmaybemovedaroundonthetableofthedrillingmachinetobringeachbushingdirectlyunderthedrill Jigsphysicallylimitandcontrolthepathofthecuttingtool 钻模这个术语只用在服务于钻孔 铰孔或攻丝的装置上 它不固定在使用它的钻床上 它能在钻床工作台上到处移动以使每个衬套都直接位于钻头下 钻模有形地限制和控制钻削刀具的路径 机械工程英语 Iftheoperationincludesmachiningoperationslikemilling planing shaping turning etc thetermfixtureshouldbeused Afixtureholdstheworkduringmachiningoperationsbutdoesnotcontainspecialarrangementsforguidingthecuttingtool asdrilljigsdo 如果作业还包括其它象铣削 刨削 成型 车削等机加工 则应采用夹具这一术语 夹具在机加工作业时夹持工件 但它不象钻模那样包含引导切削刀具的特殊布置 TypicalJigsandFixtures Typicaldrilljig Figure13 2illustratesadrillingjigfordrillingfourholesintheflangeofaworkpiecethathasbeencompletedexceptforthefourholes Theworkpiecehasanaccuratelymachinedbore andislocatedfromtheboreandtheendface fromacylindricalpost Thereisnoneedtocontroltherotationalpositionabouttheaxisofthebore becauseuptothetimewhentheholesaredrilled itissymmetricalaboutthataxis Thefourbushesusedtocontrolthedrillareheldinthedrillplate which withthehandnut isusedtoclamptheworkpieceagainstthebaseofthefixture TypicalJigsandFixtures 典型的钻模 图13 2所示为一个能在某工件的法兰上钻四个孔的钻模 该工件除了这四个孔外已全部完成 此工件有一精确机加工的大孔 因此通过一圆柱体采用该孔和工件端面定位 由于直至钻这些小孔时 工件都对称于大孔轴线 所以没必要控制围绕大孔轴线回转的位置 四个控制钻头的衬套装在钻板里 连同手拧螺母一起用于靠着夹具基座夹持工件 TypicalJigsandFixtures Typicalmillingfixture Figure13 3illustratesasimplemillingfixtureformillingtheslotintheotherwisecompletedworkpieceshown Theworkpieceislocatedfromtwoofthefourholesinitsbase andfromtheundersideofthebase Theworkpieceisclampedinposition andcutterislocatedagainstthesettingblock whichprovidessettingorcutterpositionanddepthofcut Thefixturemustbepositionedrelativetothemachinetable thisisdonebyengaging