第1页共9页编号：时间：2021年x月x日书山有路勤为径，学海无涯苦作舟页码：第1页共9页FromPeterSmid,CNCProgrammingHandbook:AComprehensiveGuidetoPracticalCNCProgramming,SecondEdition,IndustrialPress,Inc.200MadisonAvenue,NewYork,2003.CHAPTER6:PROGRAMMINGPLANNINGThedevelopmentofanyCNCprogrambeginswithaverycarefullyplannedprocess.Suchaprocessstartswiththeengineeringdrawingoftherequiredpart.Beforethepartismachined,severalstepshavetoconsideredandcarefullyevaluated.Themoreeffortisputintotheplanningstageoftheprogram,thebetterresultsmaybeexpectedattheend.STEPSINPROGRAMPLANNINGThestepsrequiredinprogramplanningaredecidedbythenatureofthework.Thereisnoformulaforallthejobs,butsomebasicstepsshouldbeconsidered:*Initialinformation/Machinetoolsfeatures*Partcomplexity*Manualprogramming/computerizedprogramming*Typicalprogrammingprocedure*Partdrawing/Engineeringdata*Methodssheet/Materialsspecifications*Machiningsequence*Toolingselection*Partsetup*Technologicaldecisions*Worksketchandcalculations*QualityconsiderationsinCNCprogrammingThestepsinthelistaresuggestionsonlyaguideline.Theyarequiteflexibleandshouldalwaysbeadaptedforeachjobandtothespecificconditionsofthework.INITIALINFORMATIONMostdrawingsdefineonlytheshapeandsizeofthecompletedpartandnormallydonot第2页共9页第1页共9页编号：时间：2021年x月x日书山有路勤为径，学海无涯苦作舟页码：第2页共9页specifydataabouttheinitialblankmaterial.Forprogramming,agoodknowledgeofthematerialisanessentialstart-mainlyintermsofitssize,type,shape,condition,hardness,etc.Thedrawingandmaterialdataaretheprimaryinformationaboutthepart.Atthispoint,CNCprogramcanbeplanned.Theobjectiveofsuchaplanistousetheinitialinformationandestablishthemostefficientmethodofmachining,withallrelatedconsideration–mainlypartaccuracy,productivity,safetyandconvenience.Theinitialpartinformationisnotlimitedtothedrawingandthematerialdata,italsoincludesconditionsnotcoveredinthedrawing,suchaspro-andpost-machining,grindingallowances,assemblyfeatures,requirementsforhardening,nextmachinesetup,andothers.CollectingallthisinformationprovidesenoughmaterialtostartplanningtheCNCprogram.MACHINETOOLSFEATURESNoamountofinitialinformationisusefuliftheCNCmachineisnotsuitableforthejob.Duringprogramplanning,programmerconcentratesonaparticularmachinetool,usingaparticularCNCsystem.Eachparthastobesetupinafixture,theCNCmachinehastobelargeenoughtohandlethesizeofthepart,thepartshouldnotbeheavierthanthemaximumweightallowed.Thecontrolsystemmustbecapabletoprovidetheneededtoolpath,andsoon.Inthemostcases,theCNCequipmentisalreadyavailableintheshop.VeryfewcompaniesgoandbuyanewCNCmachinejusttosuitaparticularjob.Suchcasesareratherrareandhappenoniftheymakeeconomicsense.*MachineTypeandSizeThemostimportantconsiderationsinprogramplanningarethetypeandthesizeoftheCNCmachine,particularlyitsworkspaceorworkarea.Otherfeatures,equallyimportant,arethemachinepowerrating,spindlespeedandfeedraterange,numberoftoolstations,toolchangingsystem,availableaccessories,etc.Typically,smallCNCmachineshavehigherspindlespeedsandlowerpowerrating,largemachineshavelowerspindlespeedsavailable,buttheirpowerratingishigher.*ControlSystemThecontrolsystemistheheartofaCNCmachine.Beingfamiliarwithallthestandardandoptionalfeaturesavailableonthecontrolisamust.Thisknowledgeallowstheuseofavarietyofadvancedprogrammingmethods,suchasthemachiningcycles,subprograms,macrosandothertim...
