Grating ruler is often used in closed-loop servo system of NC machine tools, which can be used to detect linear displacement or angular displacement. The grating ruler is composed of two parts: the scale grating and the grating reading head. The ruler grating is generally fixed on the fixed parts of the machine tool. The grating reading head is mounted on the movable parts of the machine tool, and the indicating grating is mounted in the grating reading head.
Grating ruler is only a kind of detection device, which can not correct the errors. It just allows you to have a concept of the magnitude of the error generated, which can be quantified into numerical values. The grating ruler has the correction function only when it is connected with the control system (such as CNC system, motion controller, PLC, servo and other actuators), and the inherent accuracy of the machine itself should also be considered.
When the grating ruler is connected with the control system, the improvement of accuracy is not unlimited. It is affected by the rigidity of the machine tool, the processing conditions, the environment temperature and the performance of the control system.
Only when the accuracy of machine tool is not deteriorated seriously and the rigidity of machine tool meets the requirement, the grating ruler can improve the machining accuracy of machine tool to a certain extent.