机械制造技术基础课件-新第1章课件（1）

SchoolofMechanicalandAutomotiveEngineeringSouthChinaUniversityofTechnologyChapter1FundamentalsofMachiningSchoolofMechanicalandAutomotiveEngineeringSouthChinaUniversityofTechnologySchoolofMechanicalandAutomotiveEngineeringSouthChinaUniversityofTechnology0.1Theimportanceofcuttingtool•Saying:sharptoolsmakegoodwork•俗语：工欲善其事，必先利其器•Saying:Grindingachopperwillnotdelaytheworkofcuttingfirewood•俗语：磨刀不误砍柴工0.IntroductionSchoolofMechanicalandAutomotiveEngineeringSouthChinaUniversityofTechnologyCuttingtoolisthedirectworkingcomponentsforproductioninmachines,soitdeterminesthemachiningprecisionandefficiency.Itsconsumptionmarketoccupiesmorethan50%thatofmachine.Theimprovementoftoolqualitywillbringsahugeindirecteconomicbenefit,about3billiondollars.0.1Theimportanceofcuttingtool0.IntroductionSchoolofMechanicalandAutomotiveEngineeringSouthChinaUniversityofTechnology俗语“车工一把刀”揭示了车刀对于一名车工的重要性，它直接影响着车削加工的质量和车削加工的效率。Agoodmechanicworksshouldbeabletogrindandselectcuttingtool.0.1Theimportanceofcuttingtool0.IntroductionSchoolofMechanicalandAutomotiveEngineeringSouthChinaUniversityofTechnology0.IntroductionBasicrequirement:Conceptsanddefinitionofcuttingtoolgeometry(刀具几何角度定义）andreferencesystem（参考系）,usuallyusedcuttingtoolmaterial（常用刀具材料）Teachingmethod:2-Dand3-Dfiguretoshowthedefinitionusinglathecuttingtool.MainCluesofthedevelopmentofcuttingtoolmaterial.SchoolofMechanicalandAutomotiveEngineeringSouthChinaUniversityofTechnologyDifficultyofthechapterDifficulty:Explainthechangeoftoolworkingangles,understandthechangeoftoolgeometryfromonesystemtoanothersystem（刀具角度在不同坐标系之间的变换)Solution:Drawthe3-Dfigureofacuttingtoolandmarkthedifferentsurfaces,angles.0.IntroductionSchoolofMechanicalandAutomotiveEngineeringSouthChinaUniversityofTechnology1.1Basicdefinition1.1.2Essentialdefinitionsfortheworkingpartsofcuttingtools1.1.3Toolangleconversionindifferentsystems1.1.5Cuttinglayerparametersandcuttingmode1.1.4Workinganglesofcuttingtool1.1.1CuttingmotionsandparametersSchoolofMechanicalandAutomotiveEngineeringSouthChinaUniversityofTechnologyNomatterwhatmachiningprocess,itisainteractioncoursebetweenthecuttingtoolandtheworkpiece.1.1.1CuttingmotionsandparametersThemachine,clamper,workpieceandcuttingtoolconstituteamachiningprocessingsystem.SchoolofMechanicalandAutomotiveEngineeringSouthChinaUniversityofTechnologyInexternalcylinderturning,theworkpiecerotatesandthecuttingtoolmoveslongitudinally.Thetwomotionscomposetheexternalcylindricalsurface.Machinedsurface：meansthesurfaceinwhichthematerialhasbeenremoved.SurfacetobemachinedworkpiecerotatesMachinedsurfaceMachiningsurfaceMachiningsurface：meansthesurfacewhichisbeingmachinedbythecuttingedge.Surfacetobemachined：meansthesurfaceinwhichthematerialistoberemoved.1.1.1CuttingmotionsandparametersSchoolofMechanicalandAutomotiveEngineeringSouthChinaUniversityofTechnologyTherearesimilarthreesurfacesinothermachiningprocesses:Fig1.3Cuttingmotionsinplaning,drillingandmilling1.1.1CuttingmotionsandparametersSchoolofMechanicalandAutomotiveEngineeringSouthChinaUniversityofTechnology1.CuttingmotionThebasicmotionforamachineincludeslinearmotionandrotationalmotion.Ifclassifiedaccordingtotheircuttingfunctions,theymaybedividedintomainmotionandfeedingmotion.（1）mainmotionItisthemostnecessaryandimportantmotionintheprocessofremovingtheexcessmetalfromtheworkpiece.Mostofthemaincuttingmotionsarerotationalmotion,usuallyithasthehighestvelocityandconsumesmostofthemachinepower.Thereisonlyonemainmotioninamachiningprocess.1.1.1Cuttingmotionsandparameters（2）feedmotionItistherateatwhichthecuttingtooladvancesintotheworkpiece.Itbringsthenewmetalintocuttingconstantlysothatthemachinedsurfaceisproduced.Feedmotionmaybecontinuousmotionorintermittentmotion,ingeneralitutilizeslessmachinepower.Inamachiningprocesstheremaybetwoormorefeedmotions.SchoolofMechanicalandAutomotiveEngineeringSouthChinaUniversityofTechnology（3）resultantmotionandvelocityWhenthemainmotionandthefeedmotiontakepartincuttingsimultaneously,therelativemotionofacertainpointonthecuttingedgeagainsttheworkpiececalledresultantcuttingmotion.Fig.1.4Resultantcuttingmotioninturning1.Cuttingmotionve=vc+vf(1.1)1.1.1CuttingmotionsandparametersTheresultantvelocityofthecuttingmotionisrepresentedbythevectorve,itisequaltothevectorsumofthemainmotionplusthefeedingspeed.SchoolofMechanicalandAutomotiveEngineeringSouthChinaUniversityofTechnology2.CuttingparameterThespeedofthemainmotionisthecuttingspeedvc.Forarotatingmainmotion:m/sorm/min(1.2)whered－therotationaldiameterofonepointintherotatingworkpieceorcuttingtool（mm)n－numberofrevolutionpersecondorperminute(r/sorr/min)1000dnvcIncuttingprocess,therearethreecuttingparameters:cuttingspeedvc,feedforfeedingspeedvf,andbackengagementofthecuttingedgeap.（1）cuttingspeed1.1.1CuttingmotionsandparametersSchoolofMechanicalandAutomotiveEngineeringSouthChinaUniversityofTechnologyFeedfistherelativedisplacementbetweentheworkpieceandthecutteralongthedirectionoffeedingmotionperrevolutionorperstock(mm/r).Feedingspeedvfisthefeedinaunittime(m/sorm/min).Formultipleteethcuttingtools,suchasmilli