1. 　　 Stay Machining of mechanical parts In process ， The closed-loop control system of servo mechanism does not use angular displacement detection device ， Instead, a linear position detection device is directly installed on the moving parts of the machine tool ， But there is no difference between the specific control process and the semi closed loop method ， Pictured 1-5 Shown 。

　　 The advantage of this installation is that it can eliminate the half closed loop ， Pitch error of lead screw 、 Meshing clearance of gears 、 Error caused by forward and reverse inter limit of synchronous belt ， A higher level of accuracy 。

　　 Stay Machining of mechanical parts Factory In the actual processing of ， These control elements often have some problems ， The machine cannot be operated due to alarm ， What is common is Hardware processing The encoder is loose due to large vibration 、 Alarm due to inaccurate reading ， Sometimes even the encoder of the spindle will be damaged, so it is necessary to pay attention to the vibration of the spindle during processing 。

　　 Another point is the maintenance of machine tools ， The protective cover of each shaft shall be sealed ， Prevent the iron scraps and oil from entering and affecting the grating scale work ， Production quality problems caused by inaccurate readings 。 Although it is said that the two-way check of the relative deviation between encoder and grating ruler can be done by machine tool MD Data to control the maximum offset value ， But if this value exceeds the precision of your workpiece, it's up to heaven ， Its error will also cause the machine to fail to return to the reference point ， But generally, there is no alarm of grating ruler 。 It depends on the experience of operators 。

　　 I talked about these position control methods ， Some people will say that the closed-loop system can guarantee the accuracy of the machine tool ， Machining of mechanical parts The factory doesn't quite agree with this statement ， Because grating ruler is used ， The position of the ruler head remains unchanged ， Other parts ， The parts it detects are distorted ， And the center of the twist is Stay Position of reading head of grating ruler ， Then the grating ruler can't detect the change of the machine tool 。