数学与应用数学专业外文翻译几何原理基础.docx
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数学与应用数学专业外文翻译几何原理基础.docx
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数学与应用数学专业外文翻译几何原理基础
附件2:
外文原文
FundamentalGeometricalPrinciples
1.1Descriptionofworkpiecepoints
1.1.1Workpiececoordinatesystems
Inorderforthemachineorcontroltooperatewiththespecifiedpositions,thesedatamustbeenteredinareferencesystemthatcorrespondstothedirectionofmotionoftheaxisslides.AcoordinatesystemwiththeaxesX,YandZisusedforthispurpose.
DIN66217stipulatesthatmachinetoolsmustuseright-handed,rectangular(Cartesian)coordinatesystems.
Theworkpiecezero(W)istheoriginoftheworkpiececoordinatesystem.Sometimesitisadvisableorevennecessarytoworkwithnegativepositionaldata.Positionstotheleftoftheoriginareprefixedbyanegativesign(–).
1.1.2Definitionofworkpiecepositions
Tospecifyaposition,imaginethatarulerisplacedalongthecoordinateaxes.Youcannowdescribeeverypointinthecoordinatesystembyspecifyingthedirection(X,YandZ)andthreenumericalvalues.TheworkpiecezeroalwayshasthecoordinatesX0,Y0,andZ0.Theinfeeddepthmustalsobedescribedinmillingoperations.Oneplaneissufficienttodescribethecontouronalathe.
1.1.3Polarcoordinates
Themethodusedtodatetospecifypointsinthecoordinatesystemisknownasthe
"Cartesiancoordinate"method.
However,thereisanotherwaytospecifycoordinates,i.e.,asso-called"polarcoordinates".
Thepolarcoordinatemethodisusefulonlyifaworkpieceorpartofaworkpiecehasradiusandanglemeasurements.Thepoint,onwhichthemeasurementsarebased,iscalledthe"pole".
1.1.4Absolutedimensions
Withabsolutedimensions,allthepositionaldatarefertothecurrentlyvalidzeropoint.Appliedtotoolmovementthismeans:
theposition,towhichthetoolistotravel.
1.1.5Incrementaldimension
Productiondrawingsarefrequentlyencountered,however,wherethedimensionsrefernottotheorigin,buttoanotherpointontheworkpiece.Inordertoavoidhavingtoconvertsuchdimensions,itispossibletospecifytheminincrementaldimensions.Incrementaldimensionsrefertothepositionaldataforthepreviouspoint.Appliedtotoolmovementthismeans:
Theincrementaldimensionsdescribethedistancethetoolistotravel.
1.1.6Planedesignations
Whenprogramming,itisnecessarytospecifytheworkingplanesothatthecontrolsystemcancalculatethetooloffsetvaluescorrectly.Theplaneisalsorelevanttocertaintypesofcircularprogrammingandpolarcoordinates.
Thethirdcoordinateaxisisperpendiculartothisplaneanddeterminestheinfeeddirectionof
thetool(e.g.,for2Dmachining).Aplaneisdefinedbymeansoftwocoordinateaxes
.TheworkingplanesarespecifiedasfollowsintheNCprogramwithG17,G18andG19:
LevelDesignationInfeeddirection
X/YG17Z
Z/XG18Y
Y/ZG19X
1.2Positionofzeropoints
Thevariousorigins(zeropoints)andreferencepositionsaredefinedontheNCmachine.
Theyarereferencepoints
•forthemachinetoapproachand
•forprogrammingtheworkpiecedimensions.
Thediagramsshowthezeropointsandreferencepointsfordrilling/millingmachinesand
turningmachines.
Referencepoints
Theyare:
MMachinezero
ABlockingpoint.Cancoincidewiththeworkpiecezeropoint(onlyturningmachines).
WWorkpiecezero=Programzero
BStartpoint.Canbedefinedforeachprogram.Startpointofthefirsttoolformachining.
RReferencepoint.Positiondeterminedbycamsandmeasuringsystem.ThedistancetothemachinezeroMmustbeknown,sothattheaxispositioncanbesetatthisplaceexactlyonthisvalue
1.3Positionofcoordinatesystems
1.3.1Overviewofvariouscoordinatesystems
Wedistinguishbetweenthefollowingcoordinatesystems:
•ThemachinecoordinatesystemwiththemachinezeroM
•Thebasiccoordinatesystem(thiscanalsobetheworkpiececoordinatesystemW)
•TheworkpiececoordinatesystemwiththeworkpiecezeroW
•ThecurrentworkpiececoordinatesystemwiththecurrentoffsetworkpiecezeroWa
Incaseswheredifferentmachinecoordinatesystemsareinuse(e.g.,5-axistransformation),aninternaltransformationfunctionmirrorsthemachinekinematicsonthecoordinatesystemcurrentlyselectedforprogramming.
1.3.2Machinecoordinatesystem
Themachinecoordinatesystemcomprisesallthephysicallyexistingmachineaxes.
Referencepointsandtoolandpalletchangingpoints(fixedmachinepoints)aredefinedin
themachinecoordinatesystem.
Wherethemachinecoordinatesystemisusedforprogramming(thisispossiblewithsome
oftheGfunctions),thephysicalaxesofthemachineareaddresseddirectly.Noallowance
ismadeforworkpiececlamping.
Right-handrule
Theorientationofthecoordinatesystemrelativetothemachinedependsonthemachinetype.Theaxisdirectionsfollowtheso-called"three-fingerrule"oftherighthand(inaccordancewithDIN66217).
Seenfrominfrontofthemachine,themiddlefingeroftherighthandpointsintheopposite
directiontotheinfeedofthemainspindle.Therefore:
•thethumbpointsinthe+Xdirection
•theindexfingerpointsinthe+Ydirection
•themiddlefingerpointsinthe+Zdirection
1.3.3Basiccoordinatesystem
ThebasiccoordinatesystemisaCartesiancoordinatesystem,whichismirroredbykinematictransformation(forexample,5-axistransformationorbyusingTransmitwithperipheralsurfaces)ontothemachinecoordinatesystem.
Ifthereisnokinematictransformation,thebasiccoordinatesystemdiffersfromthemachine
coordinatesystemonlyintermsoftheaxisdesignations.
Theactivationofatransformationcanproducedeviationsintheparallelorientationofthe
axes.Thecoordinatesystemdoesnothavetobeatarightangle.
Zerooffsets,scaling,etc.,arealwaysexecutedinthebasiccoordinatesystem.
Thecoordinatesalsorefertothebasiccoordinatesystemwhenspecifyingtheworkingfield
limitation.
1.3.4Workpiececoordinatesystem
Thegeometryofaworkpieceisdescribedintheworkpiececoordinatesystem.Inotherwords,thedataintheNCprogramrefertotheworkpiececoordinatesystem.
TheworkpiececoordinatesystemisalwaysaCartesiancoordinatesystemandassignedto
aspecificworkpiece.
1.3.5Framesystem
Theframeisaself-containedarithmeticrulethattransformsoneCartesiancoordinatesystemintoanotherCartesiancoordinatesystem.
Itisaspatialdescriptionoftheworkpiececoordinatesystem
Thefollowingcomponentsareavailablewithinaframe:
•Zerooffset
•Rotate
•Mirroring
•Scaling
Thesecomponentscanbeusedindividuallyorinanycombination.
MirroringoftheZaxis
Shiftingandturningtheworkpiececoordinatesystem
Onewayofmachininginclinedcontoursistouseappropriatefixturestoaligntheworkpiece
paralleltothemachineaxes.
...Anotherwayistogenerateacoordinatesystem,whichisorientedtotheworkpiece.The
coordinatesystemcanbemovedand/orrotatedwithprogrammableframes.
Thisenablesyouto
•movethezeropointtoanypositionontheworkpiece
•alignthecoordinateaxesparalleltothedesiredworkingplanebyrotation
•andthusmachinesurfacesclampedininclinedpositions,producedrillholesatdifferent
angles.
•Performingmulti-sidemachiningoperations.
Theconventionsfortheworkingplaneandthetooloffsetsmustbeobserved–inaccordancewiththemachinekinematics–formachiningoperationsininclinedworkingplanes.
1.3.6Assignmentofworkpiececoordinatesystemtomachineaxes
Thelocationoftheworkpiececoordinatesysteminrelationtothebasiccoordinatesystem(ormachinecoordinatesystem)isdeterminedbysettableframes.
ThesettableframesareactivatedintheNCprogrambymeansofcommandssuchasG54.
1.3.7Currentworkpiececoordinatesystem
Sometimesitisadvisableornecessarytorepositionandtorotate,mirrorand/orscaletheoriginallyselectedworkpiececoordinatesystemwithinaprogram.
Theprogrammableframescanbeusedtoreposition(rotate,mirrorand/orscale)thecurrentzeropointatasuitablepointintheworkpiececoordinatesystem.Youwillthusobtainthecurrentworkpiececoordinatesystem.
Severalzerooffsetsarepossibleinthesameprogram.
1.4Axes
Adistinctionismadebetweenthefollowingtypesofaxeswhenprogramming:
•Machineaxes
•Channelaxes
•Geometryaxes
•Specialaxes
•Pathaxes
•Synchronizedaxes
•Positioningaxes
•Commandaxes(motion-synchronousactions)
•PLCaxes
•Linkaxes
•Leadlinkaxes
Behaviorofprogrammedaxistypes
Geometry,synchronizedandpositioningaxesareprogrammed.
•PathaxestraversewithfeedrateFinaccordancewiththeprogrammedtravelcommands.
•Synchronizedaxestraversesynchronouslytopathaxesandtakethesametimetotraverseasallpathaxes.
•Positioningaxestraverseasynchronouslytoallotheraxes.Thesetraversingmovementstakeplaceindependentlyofpathandsynchronizedmovements.
•Commandaxestraverseasynchronouslytoallotheraxes.Thesetraversingmovementstakeplaceindependentlyofpathandsynchronizedmovements.
•PLCaxesarecontrolledbythePLCandcantraverseasynchronouslytoallotheraxes.Thetraversingmovementstakeplaceindependentlyofpathandsynchronizedmovements.
1.4.1Mainaxes/Geometryaxes
Themainaxesdefinearight-angled,right-handedcoordinatesystem.Toolmovementsareprogrammedinthiscoordinatesystem.
InNCtechnology,themainaxesarecalledgeometryaxes.ThistermisalsousedinthisProgrammingGuide.
The"Switchablegeometryaxes"function(seeAdvanced)canbeusedtoalterthegeometryaxesgroupingconfiguredbymachinedata.Hereanygeometryaxiscanbereplacedbyachannelaxisdefinedas
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