Comprehensively Analyze the Metrological Verification of CMM

CMM is a complex measuring system integrating optical, mechanical, electrical, computer and control technology, so there are many uncertain factors affecting the measurement results, but for small and medium-sized machine tools, the ambient temperature deviation from the standard temperature (20℃) is the main factor affecting the measurement uncertainty. In order to make the CMM measure accurate results, the ambient temperature should be strictly controlled within the range of the CMM specification.

1. Does the detection system of the coordinate machine affect the measurement results?

We know that when the coordinate machine is measuring, the probe sends a signal after contacting the workpiece to be measured, and then the coordinate position of the probe is collected by the control system and the computer, and then the necessary calculation is carried out to get the measurement results we need. At present, most of the three-coordinate probes are switch type, whose design principle leads to different switch contact points in different positions, which brings detection errors. The error directly affects the uncertainty of coordinate measurement results. So you want the error to be as small as possible.

2. What are the 21 errors of three coordinates?

There are three axes of motion, each with one positioning error and five geometric errors. Geometric errors include straightness errors in two directions and angular errors in two directions. There are 18 errors in the three axes, and 21 errors in the verticality between the three axes.

3. When need to do to calibrate 21 errors?

The foundation, precision and calibration of three coordinates are complicated. Although not listed in the specification, a calibration error of 21 is necessary in the following cases: re-acceptance; Length measurement error Calibration result error; Coordinates after machine movement; The coordinate machine is fixed.

4. What equipment is needed to calibrate coordinates?

The standards required to calibrate the three coordinates are: the size of the corresponding grade of the measuring block is 1000mm; Laser interferometer. Electronic level; Square ruler; Standard ball, etc.

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