Horizontal machining center y-axis size error is too large

Fault phenomenon: XH755 horizontal machining center, the Y-axis positive (ten) direction error increases when working, the processed parts are scrapped, and the error range can be found from 0.01 to 0.50mm during measurement and inspection.

Analysis and repair process:

According to the fault situation, first checked the position display value of the machine tool, which is the same size as the program requires, that is, when the Y axis is required to move 100mm, the display is also 100mm on the screen, and there is no alarm message on the screen.

After checking the servo controller, no abnormality was found. Use a dial indicator to check in the Y-axis direction and find that the change in size is gradually increased according to the number of movements.

According to the analysis of the above inspection, the CNC system and servo amplifier are normal, and the cause of the fault is still on the coupling. The Y-axis coupling is shown in the figure.

Disassemble the motor, and after careful inspection and measurement of the coupling, the following problems are found: the key of the middle coupling block and the groove of the coupling sleeve on the shaft are too loose, and the depth of the key and groove contact is not enough, and there are 2/3 Gap. After being re-configured as an intermediate connecting block, the fault is eliminated after adjusting the contact depth.