对于箱体类零件所选取的用来建立坐标系的特征,需要满足以下要求:
1.满足检测工艺的要求,也就是说要方便测量和评价;
2.满足同类批量零件的测量,也就是说可重复定位;
3.满足装配、加工和设计中基准的要求。
方法一:3-2-1坐标系
箱体类零件一般都是一面两销或者三面定位加工,通常都使用3-2-1法建立零件坐标系:
3:一个平面(三个点)用来找正一个平面,确定第一基准;
2:一条线(两个点或圆)用来确定第二轴向;
1:确定原点
实际上建立零件坐标系的过程,可以理解为零件的定位过程。
方法二:多点拟合
此类方法在一般箱体类测量中基本上不会用到。
3-2-1建立零件坐标系
有CAD模型时3-2-1坐标系的建立
此方法适用于工件坐标系和CAD模型上的坐标系(各轴向的方向以及坐标原点的位置)完全一致的情况
可以使工件上建立的坐标系和CAD模型本身的坐标系统一
注意:应将装配、加工或设计的基准作为坐标系建立的特征元素
$$/* Header
DMISMN/'Created by [爱科腾瑞科技(北京)有限公司-091521-DEMO-11022(山涧果子)] on 星期一, 三月 22, 2021', 4.0
UNITS/MM, ANGDEC, MMPS
WKPLAN/XYPLAN
PRCOMP/ON
TECOMP/ON
FLY/1.0000
MODE/MAN
SNSET/APPRCH, 2.0000
SNSET/RETRCT, 2.0000
SNSET/DEPTH, 0.0000
SNSET/SEARCH, 10.0000
SNSET/CLRSRF, 20.0000
RECALL/D(MCS)
SNSLCT/S(40-D2)
GEOALG/BF, LSTSQR
GEOALG/ANGLB, DEFALT
GEOALG/CIRCLE, LSTSQR
GEOALG/ARC, LSTSQR
GEOALG/PLANE, LSTSQR
$$
$$
$$*/
MODE/MAN
F(PLN1)=FEAT/PLANE,CART,32.0262,35.9985,0.0000,0.0000,0.0000,1.0000
$$ Measurement points are created through actual points
MEAS/PLANE, F(PLN1), 4
PTMEAS/CART, 5.2627, 57.9779, 0.0000, 0.0000, 0.0000, 1.0000
PTMEAS/CART, 5.0506, 8.5471, 0.0000, 0.0000, 0.0000, 1.0000
PTMEAS/CART, 58.6048, 4.4704, 0.0000, 0.0000, 0.0000, 1.0000
PTMEAS/CART, 59.1869, 72.9987, 0.0000, 0.0000, 0.0000, 1.0000
ENDMES
F(LN1)=FEAT/LINE,BND,CART,5.6977,0.0000,-2.2125,62.9245,0.0000,-3.1226,0.0000,-1.0000,0.0000
$$ Measurement points are created through actual points
MEAS/LINE, F(LN1), 2
PTMEAS/CART, 5.6977, 0.0000, -2.2125, 0.0000, -1.0000, 0.0000
PTMEAS/CART, 62.9245, 0.0000, -3.1226, 0.0000, -1.0000, 0.0000
ENDMES
F(PT1)=FEAT/POINT,CART,0.0000,5.6265,-4.0233,-1.0000,0.0000,0.0000
MEAS/POINT, F(PT1), 1
PTMEAS/CART, 0.0000,5.6265,-4.0233,-1.0000,0.0000,0.0000
ENDMES
D(CRD1) = DATSET/FA(PLN1), ZDIR, ZORIG, FA(LN1), XDIR, YORIG, FA(PT1), XORIG
D(CRD1) = TRANS/ZORIG, -0, YORIG, -0, XORIG, -0
$$ Set.CAD2PCS.CADM_1