Stay Mechanical parts processing plant ， Parts processing The positioning accuracy refers to the coordinate axes of the machine tool Stay The position accuracy that can be achieved by the movement under the control of the numerical control device 。 The positioning accuracy of CNC machine tools can be understood as the kinematic accuracy of machine tools 。 The positioning accuracy of general machine tool is mainly determined by reading error by manual feeding ， The movement of CNC machine tool is realized by digital program instruction ， Therefore, the positioning accuracy depends on the CNC system and mechanical transmission error 。 Parts processing The movement of each moving part of the machine tool is Stay Under the control of numerical control device ， The accuracy of the moving parts under the control of the program directly reflects the accuracy of the machined parts ， Therefore ， Positioning accuracy is a very important test content 。

　　 The testing tools for measuring linear motion are ： Micrometer and group gauge 、 Standard scale 、 Optical reading microscope, dual frequency laser interferometer, etc 。 The standard length measurement is based on the dual frequency laser interferometer 。 Rotary motion detection tools include ：360 Standard turntable or angular polyhedron with accurate indexing of individual teeth 、 High precision circular grating and collimator 。

　　 Inspection contents ： Positioning accuracy and repeated positioning accuracy of linear axis ； Return to zero accuracy of linear axis ； Reverse error of linear axis ； Positioning accuracy and repeated positioning accuracy of rotary motion ； Return to zero accuracy of rotating motion axis ； Reverse error of rotary motion 。