A Universal Measuring Machine (UMM) is a measuring device for objects where geometric relationships are the most critical element, where dimensions are specified by geometric positions (see GD&T) rather than absolute coordinates. [1] The original use of these machines was to inspect gages and parts

During the calibration, the probe of the coordinate measuring machine will be affected by many factors, such as: dirty stylus, wrong input of stylus length, wrong input of sphere diameter, etc., which will affect the accuracy of the measurement.