Development Of Multidimensional Auto Coordinate Measuring Machines Used For Crystallizer

I iron is an I-shaped strip steel. It is abroad used in steel structure both in civil buildings and industry constructs as its excellent performance. I iron crystallizer is the mold in billet production. The precision of the inside and outside dimension affects not only the precision of I iron billet, but also the production process. What's the worse, molten steel may effuse out causing serious accident. So, in order to measure the inside and outside dimension of crystallizer, we design the measuring machine for Ma Steel company.The coordinate measuring machine using close industry local and the working environment of it is very bad. It calls for that the CMM must have very strong capability of anti-jamming. So, the driving and guiding system which have very good performance are adopted. The lumen dimension of measuring object is very deep and the shape of it is especially. So, the mainframe also can't adopt the tradition movable bridge-type structure.Because the working environment of CMM and the shape of measuring object is especially. Mainframe adopts L bridge type structure. The coordinate measuring machine is a rectangular Cartesian CMM. The rectilinear movement of every axis is achieved through Servo motor drives ball screw pair bringing with the slide carriage to move along the spherical guide. The three dimension movement of probe is realized by the rectilinear movement of three axes: X, Y, Z axis. High precision touch trigger probe of TESA is used and the three axial displacements are measured by high precision grating. Industry computer control the running of the motors with servo motor control cards. The functions of motor control card are secondary developed in Visual C++ 6.0 and the complex control of probe movement can be realized.The 21 geometric errors in the moving processor of coordinate measuring machine are analyzed in detail in this paper. The model of probe center relative to reference coordinate in the base is built by transformation matrix of homogeneous coordinates. The 21 geometric errors, which have great impact on measurement accuracy, are separated through experiments. Measuring accuracy is improved by means of CAA. Manufacture cost doesn't increase and program design is also simple. The program of auto measurement, path layout and data processing are compiled in Visual C++ 6.0. The measuring objects of this machine are special and with low requirement on environment, low cost. It can satisfy the measuring demands of corporation.