Basic Principles of Coordinate Measuring Machines

Manufacturing needs to develop, measurement needs to be current, and China's processing and manufacturing industry needs to improve its competitiveness. Quality technology is the premise of improving competitiveness. The value of the deviation generated by the three coordinates in the transformation of the production line is relatively large, and it has become an indispensable tool for the processing and manufacturing industry. So how does the CMM achieve precise measurement?
Any shape is composed of three-dimensional space points, and all geometric measurement can be attributed to the measurement of three-dimensional space points. Therefore, the high-precision collection of space point coordinates is the basis for evaluating any geometric shape. The basic principle of the CMM is to put the measured part into its allowable measurement space, measure the values of the points on the surface of the measured part in the three coordinate positions in space with high precision, and pass the coordinate values of these points through the computer. Processing, fitting to form measurement elements, such as circles, spheres, cylinders, cones, curved surfaces, etc., and their shape, position tolerance and other geometric data are obtained through mathematical calculation.

According to the above principles, a CMM can be defined as a detector that can move in three directions and moves on three mutually perpendicular guide rails. The detector transmits signals in a contact or non-contact manner, and the three axes The displacement measurement system (such as an optical ruler) of the workpiece is calculated by a data processor or a computer to calculate the coordinates (X, Y, Z) of each point of the workpiece and various instruments that can be measured.” During the measurement operation, the worker will fix the workpiece to be measured. On the special fixture, to ensure that the workpiece is stationary, the sensor of the measuring machine moves flexibly through the three coordinate axis guide rails, the probe system rotates, the measurement software completes the measurement of geometric dimensions and the evaluation of shape and position tolerance, and finally the measurement report is exported through SPC And calculate the evaluation index value to monitor the workpiece accuracy.”