APT(programminglanguage)FromWikipedia,thefreeencyclopedia

APTorAutomaticallyProgrammedTool[1]isahighlevelcomputerprogramminglanguageusedtogenerateinstructionsfornumericallycontrolledmachinetools.DouglasT.RossisconsideredbymanytobethefatherofAPT:asheadofthenewlycreatedComputerApplicationsGroupoftheServomechanismsLaboratoryatMITin1956heleditstechnicaleffort.APTisalanguageandsystemthatmakesnumericallycontrolledmanufacturingpossible.Thisearlylanguagewasusedwidelyintothe1970sandisstillastandardinternationally.[2]DerivativesofAPTwerelaterdeveloped.

Contents

1Overview2ExampleProgram3Derivatives4Furtherreading5References

Overview

APTisusedtoprogramCNCmachinetoolstocreatecomplexpartsusingacuttingtoolmovinginspace.Itisusedtocalculateapaththatatoolmustfollowtogenerateadesiredform.APTisaspecialpurposelanguageandthepredecessortomodernCAMsystems.Itwascreatedandrefinedduringthelate1950sandearly1960stosimplifythetaskofcalculatinggeometrypointsthatatoolmusttraverseinspacetocutthecomplexpartsrequiredintheaerospaceindustry.Itwasadirectresultofthenewnumericalcontroltechnologybecomingavailableatthattimeandthedauntingtaskthatamachinistorengineerfacedcalculatingthemovementsofthemachineforthecomplexpartsforwhichitwascapable.It`sdevelopmentwascenteredatthesameMITlabsthathostedtheNumericalControlandtheMillingMachineProjects.APTalsowasAirForcesponsoredandisnotableforbeingtheworld'sfirstmajorcooperativeprogrammingventure,combininggovernmentagencies,universities,anda14companyteamorganizedwithintheAircraftIndustriesAssociation[nowAerospaceIndAssoc.].[3]APTwascreatedbeforegraphicalinterfaceswereavailable,andsoitreliesontexttospecifythegeometryandtoolpathsneededtomachineapart.TheoriginalversionwascreatedbeforeevenFORTRANwasavailableandwastheveryfirstANSIstandard.LaterversionswererewritteninFORTRAN.AsaU.S.governmentfundedprojectAPTwasplacedinthepublicdomain.

APTsharesmanysimilaritieswithothercomputerprogramminglanguagessuchasFORTRAN.Ageneralpurposecomputerlanguagetakessourcetextandconvertsthestatementstoinstructionsthatcanbeprocessedinternallybyacomputer.APTconvertssourcestatementsintoprogramsfordrivingnumericallycontrolledmachinetools.TheoutputfromanAPTprocessormaybeaCLor"CutterLocation"filewhichisthenrunthroughapostprocessorspecifictothedesiredcontrolmachinepair.Theresultingfileisthenrunbythecontrolofthemachinetogeneratetoolmotionsandothermachineactions.Mostcommonly,thisfileisinsomeformofRS274formatinstructions,commonlyknownasGcode.

ExampleProgram

ToolPathforprogram

PARTNO/APT1CLPRNTUNITS/MMNOPOSTCUTTER/10.0

$$GEOMETRYDEFINITIONSETPT=POINT/0.0,0.0,0.0STRTPT=POINT/70,70,0P1=POINT/50,50,0P2=POINT/20,20,0C1=CIRCLE/CENTER,P2,RADIUS,30P3=POINT/50,50,0P5=POINT/30,30,0C2=CIRCLE/CENTER,P5,RADIUS,20P4=POINT/50,20,0L1=LINE/P1,P4L2=LINE/P3,PERPTO,L1L3=LINE/P3,PARLEL,L1L4=LINE/P1,PERPTO,L1PLAN1=PLANE/P1,P2,P3PLAN2=PLANE/PARLEL,PLAN1,ZSMALL,16

$$MOTIONCOMMANDSSPINDL/3000,CWFEDRAT/100,0FROM/STRTPTGO/TO,L1,TO,PLAN2,TO,L4TLLFT,GOFWD/L1,TANTO,C1GOFWD/C1,TANTO,L2GOFWD/L2,PAST,L3GORGT/L3,TANTO,C2GOFWD/C2,TANTO,L4GOFWD/L4,PAST,L1NOPSGOTO/STRTPTFINI

Derivatives

FurtherderivativesofAPTweredeveloped,initiallymainlytoallowtheprogramstorunonminicomputersinsteadofmainframes.TheseincludedADAPTfromIBMEXAPTfromGermanyandUNIAPT,initiallyfromUnitedComputing,laterusedalongsidetheUnigraphicsCADCAMsystems.[4]Machinetoolmakers