三次元知识普及篇

Co-ordinateMeasuringMachine座标测量仪（三次元）Objective目的KnowthetypesofCMM了解不同种类的座标测量器。KnowselectioncriteriaofCMM认识选择座标测量器的要求。UnderstandtheoperationprinciplesofCMM理解座标测量器的驱动原理。Understandthepracticalapplicationsandlimitations通晓其应用原理和极限。Introduction简介CMMisameasurementdevicethatcheckspartfeaturesfor（座标测量器是检查部份特点的测量设备，它可用于测量）:–Size（大小）–Location（位置）–Shape（形状）–distancefromotherfeatures（距离）CMMiswidespreaduseinindustryduetoitsaccuracy,speed,andflexibility.（由于它的准确性、速度和灵活性，座标测量器被普遍用于工业。）Introduction简介CMMrepresentsaradicaldeparturefromconventionalsurfaceplateinspectiontechniques.（座标测量器象征着一个从传统平面探测技术的革新）AdvantagesofCMM座标测量器的优点1)Faster,moreaccurate,andlesspronetohumanerrorthansurfaceplateequipment（与平面设备比较，能更快速、更准确且较少人为错误）2)Canmeasurealmostanykindofpart,ofteninonesetup（能测量几乎任一部份,而且往往只需要设定一次）3)measuresconsistentlyfromparttopart从零件到部份测量一致。AdvantagesofCMM座标测量器的优点4)hasthespeedandaccuracynecessarytoworkincombinationwithnumericallycontrolledmachinetools.5)enablesmanufacturerstoprovidecustomerswithdocumentationofpartqualityandadherencetodrawingspecifications.6)providesdataforstatisticalprocesscontrol(SPC)andcomputer-aideddesignandmanufacturing(CAD/CAM).BasicRequisitesofaCMM座标测量器的基本结构Abasiccoordinatemeasuringmachineconsistsoffourelements（一个基本的坐标测量器包括四个元素）:1)StagingTable2)MeasuringSuperstructure3)Probe4)ComputerandsoftwareBasicRequisitesofaCMM座标测量器的基本结构CMM座标测量器MachineConfigurations机器构造Basically,therearefivetypesofmachineconfigurations（基本上,座标测量器有五种类型）1.Cantilever（悬臂式）2.Bridge（桥梁式）3.Column(Jig-BoreType)（钻床式）4.Gantry（构台式）5.Horizontal（水平式）1.Cantilever悬臂式2.Bridge桥梁式3.Column(Jig-BoreType)钻床式4.Gantry构台式5.Horizontal水平式SelectionofConfiguration选择的考虑要素a)Accuracy（准确性）b)Size(measurementvolume)（大小（测量容量））c)Easeofaccess（便于使用）d)Thesizeandweighttheycansupport（能够支撑的大小和重量）e)Speedofmeasurement（测量速度）OperationPrinciplesofCMM座标测量器的运行原理Thecoordinatemetrologyisbasedonpoints.Everydetailofasurfaceofapartcanberepresentedbyapoint,thepointbeingassociatedbythreevalues(X,Y,Z)MeasuringusingaCMMisperformedbyreadingtheX,Y&Zvaluesofdifferentpointsonthesurfaceofapart.OperationPrinciplesofCMM座标测量器的运行原理Inatypicaloperation,i.ThepartisplacedonthetableoftheCMMatarandomlocation-approximatelycentraltothemachineaxes.ii.Theprobeisthenmovedmanuallyorbymachinecontrol,untilcontactismadewithdesiredpartfeatures.OperationPrinciplesofCMM座标测量器的运行原理iii.Themachinepositionistransferredthroughdigitaldisplaytothecomputerinterface.iv.Thedimensionalandgeometricelementsmaythenbecalculated,comparedandevaluated,orstored,orprintedoutasrequired.SystemforLocatingPointsandMeasurement定点和测量系统1.LinearorCartesianCoordinateSystem（线性或笛卡儿坐标系统）2.PolarCoordinateSystem（系极座标系统）LinearorCartesianCoordinateSystem线性和笛卡儿坐标系统Amethodoflocatingapointbyitsdistancefromzeropointandalonganyofthreeaxes,X,YandZ.PolarCoordinateSystem极坐标系统Amethodoflocatingapointbyitsdistancefromzeropointalongameasurementlineandbytheanglebetweenthemeasurementlineandareferenceline.Coordinatesystems坐标系统Coordinatesystems坐标系统Aspatialcurveiscompletelydescribedbythecoordinatesofthecurvepointsandthecorrespondingnormaldirections.ItdoesnotmatterwhetherthepointsinspaceareCartesiancoordinates,spherecoordinatesorcylindercoordinates.Ifrequired,thelocationcoordinatescanbeconvertedfromonecoordinatesystemtoanother.Coordinatesystems坐标系统Cartesiancoordinates（笛卡儿坐标）Spherecoordinates（球体坐标）Cylindercoordinates（柱体坐标）Cartesiancoordinates笛卡儿坐标系统ThepositionofapointPisdescribedby3coordinatesX,YandZ.Thecoordinatesareverticaltooneanother.Twoaxesfromthemeasuringplane,thethirdaxisisthespaceaxis.P点的位置是由3个座标（X,Y和Z轴）决定。它们相互垂直。前两个二个轴决定平面，而第三个轴则是立体轴。Spherecoordinates球体坐标系统Spherecoordinates球体坐标系统Thepositionofapointinspace(P)isdescribedbytheradialdistancefromthecoordinatezeropoint(R),therotationangleΦ(pi)tothereferenceaxisandthetiltangleθ(theta)tothepositivespaceaxis.Thecoordinatezeropointandthereferenceaxislieinthereferenceplane;thespaceaxisisverticaltothereferenceplane.Cylindercoordinates柱体坐标系统CylindercoordinatesUseofcylindercoordinatesisofparticularadvantagewithrotationallysymmetricalparts–thepositionofapointPinspaceisdescribedbytheverticaldistanceRfromthespaceaxis,theangleofrotationΦ(pi)tothereferenceaxisandtheheightHoverthereferenceplane(measuringplane).Thecoordinatezeropointandthereferenceaxislieinthereferenceplane,thespaceaxisisverticaltothereferenceplane.Cylindercoordinates柱体坐标系统Alignment校直TheprocessofrelatingtheCMM'scoordinatestothepartcoordinates.Machineaxesversuspartaxesa.ThecoordinatemeasuringmachinehasthreeunchangeableXYZaxes.b.Thepartbeingmeasuredhasitsownthreeaxeswhicharedifferentfromthemachine's.c.Themachine'saxesandthepart'saxesmustbealigned.Alignment校直Alignmentisnecessaryinorderto（因为下列原因，校直是必要的）:1)Locatemorethanonepartfeaturefromaspecificpoint（从一个指定点，找出超过一个特性）,2)Createadirectcomputercontrolpartprogram（创造一个直接计算机控制部分程式）.Alignment校直Alignmentisnotnecessarytomeasureindividualpartfeatures.Alignmentisdonebythecomputerandsoftware.Thecomputerandsoftwareautomaticallycompensateformisalignmentofthemachineaxesandpartaxeswhencalculatingmeasurementvalues.Alignment校直Beforeper