机械制造技术基础课件-chapter3-section8-2012 (2)

2021/6/13SCUT13.8ThefunctionanddesignmethodofprocessplanningfileThetermprocessroute(工艺规程)referstotheprocessplanningfileinwhichtheprocessandoperationmethodarespecified.Inanotherword,thesequenceofeachoperation,thepartdimensions,toleranceandtechnicalrequirement,technicalequipmentandmeasures,cuttingparameters,standardproductiontime,andlevelsofoperators’skillareallincludedintheprocessplanningfile.2021/6/13SCUT23.8.1Theformatofaprocesssheet工艺过程卡Theformatofapartprocesssheetmadebydifferentcompaniesisquitedifferent.In1982,thepre-mechanicalindustryministry(原机械工业部）issuedtheministrystandardtoregulatetheformatofapartprocesssheet(referredtoJB/Z1187.3-82).Nevertheless,operationsheetsarelargelyidenticalbutwithminordifferences.Usuallythefollowingitemsshouldbeincludedinaprocesssheet.Nameofpartandtype；NameandNo.ofpart；Rawmaterial；Nameofoperation；Nameofplant.2021/6/13SCUT3Insingleorsmallbatchtypeproduction,onlyageneralandsimpleprocessplanningsheetisprepared,shownasthefollowingsample,wheretheproductnameandtype,partnameanddrawingNo.,thekindsandmaterialoftheroughcast,operationNo.nameandcontent,theworkshopforeachoperation,equipmentsandtimeschedulingareallincluded.3.8.1Theformatofaprocesssheet工艺过程卡2021/6/13SCUT4processplanningsheet3.8.1Theformatofaprocesssheet工艺过程卡2021/6/13SCUT5InBatchtypeproduction,usuallyadetailedoperationalsheetisplanned,showasthesamplegivenbelow,inwhichnotonlythecontentofaprocesssheetmustbeincluded,butalsothedetaileddescriptionoftheoperationalstepandposition,theoperationaldimensionsandspecificationsareincluded.Anoperationaldraftshouldbegivenforsomemainoperations,inwhichthedesireddimensionsachievedinthatoperation,thetolerance,theroughnessandthesetupmustbemarked.Insingleorsmallbatchtypeproduction,someimportantpartsalsoaskforanoperationalsheet.3.8.1Theformatofaprocesssheet工艺过程卡2021/6/13SCUT6operationalsheet3.8.1Theformatofaprocesssheet工艺过程卡2021/6/13SCUT7Partoperationaldraft3.8.1Theformatofaprocesssheet工艺过程卡2021/6/13SCUT8Beforeproductsaremanufactured,technicalandproductionpreparationcanbemadeaccordingtothedemandsofprocessplanningsheet.Accordingtotheprocessplanningsheet,thekinds,typeandnumberofmachinetools,theproductionareaneeded,theplanarrangementofequipment,thenumber,typeandclassofoperatorsrequiredcanallbedecided.Then,theplanningoffactorypreparation,enlargingorrebuildingwillbedecidedaccordingly.3.8.1Theformatofaprocesssheet工艺过程卡2021/6/13SCUT9ThefunctionsofprocessplanningsheetThefunctionsoftheprocessplanningsheetareasfollows：(1)Themaintechniqueforgivingregulationstoguidetheproduction.(2)Thebasisoforganizationandmanagement.(3)Themaininformationtoguidethebuilding,enlargingorrebuildingofamechanicalfactory.3.8.1Theformatofaprocesssheet工艺过程卡•Howtodesignthemachiningprocessofaworkpiece?2021/6/13SCUT102021/6/13SCUT113.8.2Theanalysisoftheprocessingperformance(加工性分析）1.Inspectthedesigndrawing：checkifthedimensionsarecompleteandstructuralexpressionisclear.2.Analyzeifthespecificationsarereasonable,including:（1）Thedimensionalaccuracy；（2）Thegeometricalshapeaccuracy；（3）Thepositionalaccuracybetweenthemainmachinedsurfaces（4）Requirementofthesurfacequality；（5）Requirementoftheheattreatment.Step1•3、CheckifthematerialisproperlychosenUsetheusuallyusedmaterialasfaraspossibleifitmeetstherequirement,suchas45steel3.8.2Theanalysisoftheprocessingperformance(加工性分析）Thedeterminationofrawmaterialisrelatedwiththepartgeometricalshape,dimensions,mechanicalperformanceofmaterialandproductiontype,currentproductionconditionsoftheworkshop.Castingincludescaststeel,castiron,castalloyetc.Theshapeofthecastscanvaryfromcomplicationtosimplicity,anddimensionscanbeverylarge.Forginghasbettermechanicalperformancethancastings,however.manyintricateandcoredshapespossibleincastingcannotbeforged.ProfiledbarTheshapeofcrosssectioncanberound,rectangularorotherdifferentshapes.Barsareoftenmachinedintoshafts,dishesorroundshellswithenginelathe,turretlathe,orautomaticorsemiautomaticlathe,andthedimensionscanvaryfromsmalltomediumsize.butitsthicknessislimitedwithinarange.Weldingforcomplicatedandlargepartscanbeweldedfromprofiledbarorforgedparts，buttheweldedpartperformsbadlyinsomerespects.Engineeringplasticusedwidelyinmechanicalmanufacturinginrecentyears.Itsshapecanvaryfromsimpletocomplicated,andthedimensionaccuracyishigh,butmechanicalperformanceisweak.3.8.2Theanalysisoftheprocessingperformance•4、AnalysisoftheprocessingcapabilityrelatedwiththepartstructureTheconceptofpartstructuralprocessingcapability:thefeasibilityandeconomicalperformancewhenmanufacturingapart(1)Whenplanningthepartmachiningprocessroutine,theanalysisofthecuttingperformanceismainlyconcerned.(2)Thelocalstructuralrequirementwhenmachiningapart（局部结构的加工工艺性）(3)Theoverallstructuralrequirementwhenmachiningapart（整体结构加工工艺性）3.8.2TheanalysisoftheprocessingperformanceExamplesaboutthelocalstructuralrequirement(1)Convenientfortheapproachingandrecedingofthecuttingtool(2)Makesurethecuttingtoolcanworknormally(3)Makesurethemachiningisefficient(4)Avoidingdeepholemachining(5)Useexternalconnectioninplaceofinternalconnection(6)Onesetuptomachi