数学与应用数学专业外文翻译几何原理基础Word下载.docx

数学与应用数学专业外文翻译几何原理基础Word下载.docx

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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