机械制造技术基础课件-chapter3-section8-2012 (2)

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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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