缸体机械加工工艺设计.doc

_CylinderblockmachiningprocessdesignEnginepartsengineblockisamorecomplexstructureofsparepartsbox,itshighprecision,complexprocess,andtheprocessingqualitywillaffecttheoverallperformanceengine,soithasbecometheenginemanufacturersfocuspartsone.1.TechnicalCharacteristicsoftheenginecylinderblockCylindercastforawholestructure,anditsupperpart4cylindermountinghole;cylinderstandardcylinderisdividedintoupperandlowerdivisionsintotwoparts;cylindertotherearofthefront-sidearrangementofthepreviousthreecoaxialmountingholeofthecamshaftandtheidleraxlehole.Cylinderprocessfeaturesare:thestructureofcomplexshape;processingplane,morethanholes;unevenwallthicknessandstiffnessislow;processingofhighprecisiontypicalofbox-typeprocessingpart.Themainprocessingofthesurfaceofcylinderblocktopsurface,themainbearingside,cylinderbore,themainandcamshaftbearingboreholesandsoon,theywilldirectlyaffectthemachiningaccuracyoftheengineassemblyprecisionandperformance,mainlyrelyonprecisionequipment,industrialfixturesreliabilityandprocessingtechnologytoensurethereasonableness.2.EngineblockprocessdesignprinciplesandthebasisforDesignTechnologyprogramshouldbetoensureproductqualityatthesametime,givefullconsiderationtotheproductioncycle,costandenvironmentalprotection;basedontheenterprisesabilitytoactivelyadoptadvancedprocesstechnologyandequipment,andconstantlyenhancetheirleveloftechnology.Engineblockmachiningprocessdesignshouldfollowthefollowingbasicprinciples:(1)Theselectionofprocessingequipment,theprincipleofselectionadoptedtheprincipleofselectionadoptedtheprincipleofcombiningrigid-flexible,processingeachhorizontalmachiningcenterislocatedmainlysmalloperationswithverticalmachiningcenter,thekeyprocessacrankhole,cylinderhole,balancershaftholeHigh-speedprocessingofhigh-precisionhorizontalmachiningcenter,anupperandlowernon-criticalprocessesbeforeandafterthefour-dimensionalhigh-efficiencyroughmillingandhaveacertainadjustmentrangeofspecialmachineprocessing;(2)focusonakeyprocessinprincipleprocessthebodycylinderbore,crankshafthole,BalanceShaftholesurfacefinishingandthecombinationofprecisionmillingcylinderhead,usingaprocessfocusedonasetupprogramtocompleteallprocessingelementsinordertoensureproductaccuracyThekeyqualityprocessestomeetthecylindercapacityandtherelevanttechnicalrequirements;Accordingtothetechnologicalcharacteristicsofautomobileenginecylinderblockandtheproductionmandate,theengineblockmachiningautomaticproductionlineiscomposedofhorizontalmachiningcenterCWK500andCWK500Dmachiningcenters,specialmilling/boringmachine,verticalmachiningcentersmatec-30Landotherappliances.(1)topandbottom,andtilecoveredonlythecombinationofapertureroughmillingmachinededicatedtothismachinetodouble-sidedhorizontalmillingmachine,usingmovingtabledrivenparts,machinetoolsimportedSiemensS7-200PLCsystemcontrol,machinecontrolcabinetsetupanindependent,cuttingautomatetheprocessiscompletedandtwokindsofautomaticandadjustthestate;(2)high-speedhorizontalmachiningcentermachiningcentercanberealizedCWK500themaximumflowofwetprocessing,butbecauseofequipment,automaticBTAtreatmentsystemthroughthebuilt-intrayunderthewide-typechipconveyorandthecompletionofthemachiningcentercanbedryprocessing;machinetoolspindlespeed6000r/min,rapidfeedingspeed38m/min;(3)Thecombinationoffrontandrearfaceroughmillingmachinetoolusinghydraulictransmission;controlsystemimportedSiemensS7-200PLCsystemcontrol,machinetoolshaveacertainflexibility;(4)ThespecialmachineTXK1500thismachineverticalmachiningcenterbythemodificationofshape,withverticalmachiningcenterfeaturesandperformance,thismachinehashighstrength,highwear-resistant,highstability,highaccuracy,high-profileetc.;(5)high-speedverticalmachiningcentermatec-30Lofthemachiningcenterspindlehighspeed9000r/min.ControlsystemusesSiemensSINUMERIK840Dcontrolsystem;(6)high-speedhorizontalmachiningcenterspindleCWK500Dhighestspeed15000r/min.3.EngineblockmachiningprocessdesignthemaincontentEngineblockcomplexstructure,highprecision,argesize,isthin-walledparts,thereareanumberofhighprecisionplaneandholes.Engineblockmachiningprocesscharacteristics;mainlyflatandtheholeprocessing,processingofflatgenerallyuseplaning,millingmethodssuchasprocessing,processingofholeusedmainlyboring,processingandmulti-purposedrillingholes.Asthecylindercomplexstructure.sohowtoensurethatthemutualpositionofthesurfaceprocessingprecisionisanimportantissue.3.1TheselectionofblankEngineblockonthematerialsusedaregenerallygraycastironHT150,HT200,HT250,thereisalsocastaluminumorsteelplate,thisengineblockusinghigh-strengthalloycastiron.Cylinderintheprocessingpriortoagingtreatmentinordertoeliminatestressandimprovetheroughcastingmechanicalproperties.Improvetheroughaccuracy,reductionofmachiningallowance,istoimprovetheautomatedproductionlinesystemproductivityandprocessingqualityoftheimportantmeasures.Astheforeignbox-typepartsofroughqualityandhighprecision,anditsproduction-linesystemhasbeenimplementeddirectlyontheblankline,notonlyeliminatingtheneedforblankcheckdevicealsosavestheroughqualityproblemsduetowasteofmachiningtime,increaseoverallefficiency.Therefore,therefinementofroughistoimprovetheproductivityofthemostpromisingwayout.Fortheengineblockproductionline,canberoughinpartson-linepre-millingsixface,removingmostofthemargin,tofacilitatedirecton-lineparts.3.2MachiningprocessselectionandprocessingofthebenchmarkChoosetherightprocessingtechnologybaseisdirectlyrelatedtotheprocessingqualitycanensuretheparts.Generallyspeaking,processbenchmarkingcanbedividedintocoarseandfinereferencebase.(1)Thebaselinefortheon-linethickrough,whichisparticularlyimportantthechoiceofbenchmarkcrude,ifcrudebenchmarkchoiceunreasonable,willtheunevendistributionofmachiningallowance,processingandsurfaceoffsets,resultinginwaste.Inthecylinderproductionline,wehaveadoptedforthecoarsesideofthebase;(2)Refinedthebaseofthisboxfortheengineblockparts,thegeneraluseofsidetwosalesforafullrangeofuniformbenchmarks,Forthelongerautomatedproductionpositioning,therefore,willbedividedinto2-3segmentpinholesused.Inthecylinderpinholeoftheprocess,wehaveadoptedtotheside,bottomandthespindleholepositioning,intheprocessingcenterontheprocess.3.3MachiningProcessingStagesandprocessesofthearrangementsOftenapartofmanyapparentneedforprocessing,ofcourse,thesurfacemachiningaccuracyaredifferent.Processingofhighprecisionsurface,oftenafterrepeatedprocessing;Asfortheprocessingofthesurfaceoflowprecision,onlyneedtogothroughoneortwoonthelist.Thus,whenthedevelopmentprocessinordertoseizetheprocessinghighprecisionsurface,thisconflict,thereasonablearrangementprocessesandrationaldivisionstageofprocessing.Arrangetheorderoftheprincipleofprocessis:afterthefirstcoarserefined,thefirstsurfaceafterthehole,thefirstbenchmarkother.Intheengineblockmachining,thesameshouldfollowthisprinciple.(1)roughingstageengineblockmachiningprocess,thearrangementsforroughingprocess,tofullycarryoutroughrough,trimmostofthemargininordertoensureproductionefficiency;(2)semi-finishingphaseoftheengineblockmachining,inordertoensuretheaccuracyofthemiddleofsomeimportantsurfaceprocessing,andarrangesomesemi-finishingoperations,willberequiredaccuracyandsurfaceroughnessofthesurfaceofthemiddleofsomeprocessingtocomplete,whiledemandingthesurfaceofsemi-finished,toprepareforfuturefinishing;(3)Thefinishingstageofrequiringhighaccuracyandsurfaceroughnessofthesurfaceprocessing;(4)secondaryprocessing,suchassmallsurfacescrewholes,youcanfinishofthemajorsurfaceaftertheonehand,whentheworkpiecedeformationprocesslittleimpactatthesametimealsoreducedtherejectionrate;Inaddition,ifthemainsurfaceofawaste,thesesmallthesurfacewillnothavetobeprocessed,thusavoidingawasteofman-hours.However,iftheprocessingisveryeasyforasmallsurfacebumpsthemainsurface,itshouldbeplacedonasmallsurfacefinishpriortothemainsurfacefinishing;(5)shouldmakeproperarrangementsforsecondaryprocessessuchasproductinspectionprocess,inpartroughingstage,thekeyprocessbeforeandafterprocessing,sparepartsalltheprocessinghasbeencompleted,shouldbeappropriatearrangements.Stageofprocessingdivision,hasthefollowingadvantages:First,itcantakemeasurestoeliminatetheroughworkpieceafterthestress,toensureaccuracy;second,finishingontheback,andwillnotdamageduringtransportthesurfaceoftheworkpiecehasbeenprocessed;again,firstroughingthesurfacedefectscanbedetectedearlyandpromptlydealwithrough,donotwasteworkinghours.Butmostsmallparts,donotsubverythin.3.4cylindersurfaceofthemainprocessingandsecondaryprocessesCylindersurfaceandsupportthemainprocessingoperationsare:(1)planeprocessingatpresent,themillingofengineblocksistheprimarymeansofplanarprocessing,domesticmillingfeedrateisgenerally300-400mm/min,andforeign2000-4000mm/minmillingfeedratecomparedtofarcry,tobeonincreasing,therefore,improvethemillingfeedrate,reduceoverheadtimeistoimprovetheproductivityofthemajormeansoffinishinganumberofplaneengineblockwhenthemillingfeedratetoreach2399mm/min,greatlyimprovedefficiency;Topsurfaceofthecylindermillingisakeyprocessintheprocess,theflatnessrequirementsfor0.02/145mm,thesurfaceroughnessofRa1.6um.Processinginthecylinder,theuseofsideandspindlebearingborepositioning,top,bottomandmiddlevagayonlyaperturewhileprocessingusedintheprocessinglineoutsideoftheknifedevicecanbettermeettheengineblockmachiningaccuracy;(2)Generalholesmachiningholesingeneralarestillusingthetraditionalprocessingofdrilling,expansion,boring,reaming,tappingandothercraftapproach.Issuesinthedesignprocessofspecificprograms,useofcoatedcuttingtools,cuttingtoolsandotheradvancedtoolswithinthecooling,andusingalargeflowofcoolingsystems,greatlyimprovingthecuttingspeed,improvedproductivity;(3)deepholeprocessingofthetraditionalprocessingmethodisusedtogradetwistdrillfeed,lowefficiencyoftheirproduction,processingandqualityispoor.Thedeepholeintheengineblockprocessing,theuseofgundrillingprocess;(4)Thethree-axismachiningholesforthecylinder-axismachiningholesholesofhighprecision,longworkinghoursoftherestrictiveprocess.Thus,workarrangements,processingmethods,toolsandsoonshouldbespecialattention.Allcoverpre-processing,thatis,semi-circularholeandthecylinderblockmainbearingcapoftheshortageofprocessing,itsmainpurposeistoremoveblankmargin,releasestress,toprepareforthepost-orderprocessing;incrankshaftmachiningprocessingcenterhole,usingdouble-sidedBoring,boringthefirstholesinthecrankshaftholeatoneendto1/2length,andthenturn180degreesworkbench,formtheotherendandthenboreanother1/2length.(5)Thecylinderboremachiningcylinderholecylindermachiningprocessingisakeyprocessintheone,undernormalcircumstances,themachiningprocessasaroughboring,semi-fineboring,precisionboringandhoning.Cylinderborewallfortheearlydetectionofcastingdefects,eliminatestress,shouldbethickcylinderboringholesinadvance;duetothestructuralcharacteristicsofthedifferentcylinderbore,mustbeinhoningprocesstoimprovethecylinderboresurfacequality.Inthehigh-volumeproduction,thecylinderborehoninggenerallyusethemulti-axisgrindingmachineorhoningAutomaticLine.Hereweusehoningautomaticlines,fromthecoarse-heng.Fine-hengandtestingequipment,composedofthree;(6)Cleaningcleaningisdividedintowetcleaninganddrycleaning.Machiningcylinderautomaticproductionlineusingalargeflowofwetcleaning;(7)Detectpointsoutsidethelinedetectionandlinedetectionoftwokinds.Qualityinspectionintheengineblock,accordingtotheactualsituationwithlinesoutsidethedetection,themainuseofcoordinatemeasuringmachineintegratedmeasurementsofthecylinder,each200samples1-5pieces,eachclassrandomone.4.SummaryThroughtheengineblockofthestructureandprocesscharacteristicsoftheanalysis,discussestheengineblockmachiningprocessdesignprinciplesandbasisofthechoiceofcuttingparameters,andU-turnathighspeedmillingandboring,forexample,design,analysisoftheenginecylinderbodyofhigh-speedmillingandturnoverboringprocess,andintheprocessingneedtopayattentionto. 缸体机械加工工艺设计发动机缸体是发动机零件中结构较为复杂的箱体零件，其精度要求高，加工工艺复杂，并且加工加工质量的好坏直接影响发动机整个机构的性能，因此，它成为各个发动机生产厂家所关注的重点零件之一。1.发动机缸体的工艺特点缸体为一整体铸造结构，其上部有4个缸套安装孔；缸体的水平隔板将缸体分成上下两部分；缸体的前端面从到后排列有三个同轴线的凸轮轴安装孔和惰轮轴孔。缸体的工艺特点是：结构、形状复杂；加工的平面和孔比较多；壁厚不均，刚度低；加工精度要求高，属于典型的箱体类加工零件。缸体的主要加工表面有顶面、主轴承侧面、缸孔、主轴承孔及凸轮轴孔等，它们的加工精度将直接影响发动机的装配精度和工作性能，主要依靠设备进度、工夹具的可靠性和加工工艺的合理性来保证。2.发动机缸体工艺方案设计原则和依据设计工艺方案应在保证产品质量的同时，充分考虑生产周期、成本和环境保护；根据本企业能力，积极采用国内外先进的工艺技术和装备，不断提高企业工艺水平。发动机缸体机械加工工艺设计应遵循以下基本原则：（1）加工设备选型原则加工设备选型采用刚柔结合的原则，加工设备以卧式加工中心为主，少量采用立式加工中心，关键工序曲轴孔、缸孔、平衡轴孔加工采用高精度高速卧式加工中心，非关键工序上下前后四个平面的粗铣采用高效并有一定调整范围的专用机床加工；（2）集中工序原则关键工序曲轴孔、缸孔、平衡轴孔的精加工缸盖结合面的精铣，采用在集中在一道工序一次装夹完成全部加工内容方案，以确保产品精度满足缸体关键品质的工艺性能和有关技术要求。根据汽车发动机缸体的工艺特点和生产任务要求，发动机缸体机械加工自动生产线由卧式加工中心CWK500和CWK500D加工中心、专用铣/镗床、立式加工中心matec-30L等设备组成。（1）顶底面及瓦盖止口面粗铣组合机床本机床为双面卧式专用铣床，采用移动工作台带动工件，机床采用进口西门子S7-200PLC系统控制，机床设独立电控柜，切削过程自动化完成，有自动和调整两种状态；（2）高速卧式加工中心CWK500该加工中心可实现最大流量的湿加工，但由于设备自动排屑处理系统是通过位于托盘下的内置宽式排屑器而完成，该加工中心可以进行干加工；机床主轴转速6000r/min，快速进给速度38m/min；（3）前后端面粗铣组合机床机床采用液压传动；控制系统采用进口西门子S7-200PLC系统控制，机床具有一定的柔性；（4）采用机床TXK1500本机床有立式加工中心改造而成形，具备立式加工中心的特点及性能，该机床具有高精度、高强度、高耐磨度、高稳定性、高配置等优点；（5）高速立式加工中心matec-30L该加工中心主轴最高转速9000r/min。控制系统采用西门子公司SINUMERIK840D控制系统（6）高速卧式加工中心CWK500D主轴最高转速15000r/min。3.发动机缸体机械加工工艺设计的主要内容发动机缸体结构复杂，精度要求高，尺寸较大，是薄壁零件，有若干精度要求较高的平面和孔。发动机缸体机械加工的工艺特点是：主要是平面和孔的加工，加工平面一般采用刨、铣削等方法加工，加工孔主要采用镗削，加工小孔多用钻削。由于缸体结构复杂，因此如何保证各表面的相互位置精度是加工中的一个重要问题。3.1毛坯的选择发动机缸体采用的材料一般是灰铸铁HT150、HT200、HT250，也有采用铸铝或者钢板的，此发动机缸体采用高强度合金铸铁。缸体在加工前进行时效处理，以消除铸件内应力和改善毛坯的力学性能。提高毛坯精度，减少加工余量，是提高自动生产线系统生产率及加工质量的重要措施。由于国外箱体类零件毛坯质量和精度较高，其生产线系统已实现了毛坯直接上线，既省去了毛坯检查装置，也节省了由于毛坯质量问题而浪费的加工工时，提高了综合效益。因此，精化毛坯是提高生产率最有潜力的出路。对于发动机缸体生产线，可在零件上线前粗铣六个面，去除大部分余量，便于零件直接上线。3.2机械加工工艺基准的选择和加工选择合理的加工工艺基准，直接关系到能否保证零件的加工质量。一般来说，工艺基准可分为粗基准和精基准。（1）粗基准对于上线的毛坯，其粗基准的选择尤为重要，如果粗基准选择不合理，会使加工余量分布不均匀，加工面偏移，造成废品。在缸体生产线中，我们采用侧面作为粗基准；（2）粗基准对于发动机缸体这种箱体零件来说，一般采用“一面两销”为全线的统一基准。对于较长的自动自动生产线系统，由于定位销孔在使用过程中的磨损造成定位不准确，因此，将定位销孔分为2-3段使用。在缸体定位销孔的加工中，我们采用了以侧面、底面和主轴孔定位，在加工中心上加工。3.3机械加工加工阶段的划分和工序的安排一个零件往往有许多表面需要加工，当然表面的加工精度是不同的。加工精度较高的表面，往往要经过多次加工；而对于加工精度低的表面，只要经过一两次就行了。因此，拟定工艺顺序时，要抓住“加工精度高的表面”这个矛盾，合理安排工序和合理划分加工阶段。安排工艺顺序的原则是：先粗后精，先面后孔，先基准后其他。在发动机缸体的机械加工中同样应遵循这一原则。（1）粗加工阶段在发动机缸体的机械加工过程中，安排粗加工工序，对毛坯全面进行粗加工，切去大部分余量，以保证生产效率；（2）半精加工阶