数控技术概述

NUMERICALCONTROLTECHNOLOGYChapter1IntroductiontoNumericalControlTeacherXuCijun1387208295362956.Chapter1INTRODUCTIONTONUMERICALCONTROL1.1、FundamentalofNCTechnology1.2、ClassificationsofNCMachines1.3、FeaturesofNumericalControlandItsApplicationAreasCourseDescription:�NCisoneofthemostimportantachievementsinmechanicalengineeringfieldin20century.�Itisacrossingandintegratingtechnologycomprisingofcomputertechnology,automaticcontroltechnology,informationtechnology,sensetechnology,andmachiningtechnology.�NumericalControlTechnologyhasbecameoneoftheimportanttechnicalbasicclassesofmechanicalengineeringspecialty.Toshibaevents.Chapter1INTRODUCTIONTONUMERICALCONTROL1.1.1、DevelopmentHistoryofNC1946-thefirstcomputerappearedintheworld,whichliftthecurtainonthemankindintoinformationtime.1948-ParsonsCorporationbroughtforwardusingcomputertocontrolmachinewhentheymachinedthesurfacecontoursofairfoilshape.ParsonsCorporationwasamini-helicoptermanufacturer.Themachiningaccuracyoftheairfoilshapewas±0.0381mm.Chapter1INTRODUCTIONTONUMERICALCONTROL1.1.1、DevelopmentHistoryofNCUnderthesupportbytheU.SAirForceResponsedbytheServomechanismsLaboratoryattheMIT(MassachusettsInstituteofTechnology).Chapter1INTRODUCTIONTONUMERICALCONTROL1.1.1、DevelopmentHistoryofNCThreeyearslater,in1952MITandParsonsCorporationcooperatedwitheachother,anddevelopedthefirstNCmachinewhichnamedCincinnatiHydrotelmillingmachine.Background,timeandplace.Chapter1INTRODUCTIONTONUMERICALCONTROL1.1.1、DevelopmentHistoryofNCThefirstgeneration,1952~1955vacuumtubes,electricalrelaysandcomplicatedmachinecontrolinterfaces.Thesecondgeneration,1955~1959miniatureelectronictubes,transistors.Thethirdgeneration,1959~1965smallscaleintegratedcircuits..Chapter1INTRODUCTIONTONUMERICALCONTROL1.1.1、DevelopmentHistoryofNCAbovethreegenerations,theirNCfunctionswereperformedbyhardware(electroniccircuits),sowecallthem“hardwiredNC”(硬线数控)195519591965.Chapter1INTRODUCTIONTONUMERICALCONTROL1.1.1、DevelopmentHistoryofNCThefourthgeneration,1970s(1970~1974)minicomputers.(CNC)Thefifthgeneration,1974-microprocessor.1979(VLIC)(MCNC)1994~PC-NC..Chapter1INTRODUCTIONTONUMERICALCONTROL1.1.1、DevelopmentHistoryofNCAfterthefourthgenerations,theirNCfunctionswereperformedbysoftware(basedoncomputer),sowecallthem“softwiredNC”or“computernumericalcontrol”(计算机数控CNC)197019741994.Chapter1INTRODUCTIONTONUMERICALCONTROL1.1.2ConceptofNCandCNC1、NC(NumericalControl,数字控制)NumericalControl（NC）isaformofprogrammableautomationinwhichthemechanicalactionsofamachinetoolorothermachinesarecontrolledbyaprogramcontainingcodedalphanumericdata..Chapter1INTRODUCTIONTONUMERICALCONTROL1.1.2ConceptofNCandCNC2、NumericalControlTechnology,(数控技术)ItmeansthetechnologywhichadoptsNCmethodstocontrolaworkprocesstorealizetheautomation..Chapter1INTRODUCTIONTONUMERICALCONTROL1.1.2ConceptofNCandCNC3、NumericalControlMachineTools,(数控机床)Itisakindofmachinetoolswhichadoptsthenumericalcontroltechnologytorealizetheworkprocessautomation.ItisatypicalexampleofNCapplication..Chapter1INTRODUCTIONTONUMERICALCONTROL1.1.2ConceptofNCandCNC4、NumericalControlSystem,(数控系统)Itistheequipmentwhichcanrealizethenumericalcontrol..Chapter1INTRODUCTIONTONUMERICALCONTROL1.1.2ConceptofNCandCNC5、CNC(ComputerNumericalControl,计算机数控)Themachinecontrolunitsarebasedoncomputertechnology..Chapter1INTRODUCTIONTONUMERICALCONTROL1.1.3BasicComponentsofNCMachineToolsThecontrolsystemofanumericallycontrolledmachinetoolcanhandlemanytaskscommonlydonebytheoperatorofaconventionalmachine.Thesystemhastheabilitytoperformthecontrolfunctionsthroughthenumericalinputinformation,whichisthecontrolprogram,alsocalledthepartprogram..Chapter1INTRODUCTIONTONUMERICALCONTROL1.1.3BasicComponentsofNCMachineToolsTheworkprocessofNCisshownastherightfigure.PartdrawingPartprogramControlcomputerServo-driveunitMachinetoolPartFirstly,thepartprogrammershouldstudythepartdrawingandtheprocesschart..Chapter1INTRODUCTIONTONUMERICALCONTROL1.1.3BasicComponentsofNCMachineToolsTheworkprocessofNCisshownintherightfigure.PartdrawingPartprogramControlcomputerServo-driveunitMachinetoolPartThenthepartprogrammershouldpreparethecontrolprogramonastandardforminthespecifiedformat.Itcontainsallthenecessarycontrolinformation.Chapter1INTRODUCTIONTONUMERICALCONTROL1.1.3BasicComponentsofNCMachineToolsTheworkprocessofNCisshownintherightfigure.PartdrawingPartprogramControlcomputerServo-driveunitMachinetoolPartNextthepartprogramistransferredintothecontrolcomputer(MDI).thecomputerconvertseachcommandintothesignalthattheservo-driveunitneeds.Chapter1INTRODUCTIONTONUMERICALCONTROL1.1.3BasicComponentsofNCMachineToolsTheworkprocessofNCisshownintherightfigure.PartdrawingPartprogramControlcomputerServo-driveunitMachinetoolPartAtlast,theservo-driveunitdrivesthemachinetooltomanufacturethefinishedpart.Chapter1INTRODUCTIONTONUMERICALCONTROL1.1.3BasicComponentsofNCMachineToolsAtypicalNCmachinetoolhasfivefundamentalunits:(1)theinputmedia;(2)themachinecontrolunit;(3)theservo-driveunit;(4)thefeedbacktransducer;(5)themechanicalmachinetoolunit.Chapter1INTRODUCTIONTONUMERICALCONTROL1.1.3BasicC