The position detection device on CNC machines is typically installed on the machine table or screw. This device acts as the equivalent of the dials and operator’s eyes on a conventional machine tool. It continuously and automatically detects the displacement of the table and provides feedback to the control system.

A vast amount of evidence has shown that the machining accuracy and positioning accuracy of a well-designed high-precision CNC machine largely depend on its detection device. As a result, precision testing equipment is crucial in ensuring the quality of high-precision CNC machine tools.
In general, the inspection devices used on CNC machines should possess the following characteristics:
1. Reliability and robustness against interference.
2. Adherence to precision and speed requirements.
3. User-friendly and easy to maintain, suitable for the working environment of machine tools.
4. Cost-effectiveness with a reasonable and attractive price.
Typically, the detection accuracy of a CNC machine tool’s detection device ranges from 0.001 to 0.01mm/m, with a resolution of 0.001 to 0.01mm/m. This level of accuracy can accommodate machine tool tables moving at speeds of 1 to 10m/min.