What are the common problems of CNC lathe?

What are the common problems of CNC lathe?

Simple CNC lathe, also known as economic CNC lathe, its active control system is mainly composed of single chip microcomputer. Through the control program, it controls the longitudinal and transverse feeding equipment and tool changing equipment of the machine tool, and actively completes the processing of parts. Therefore, simple CNC lathe is still mechatronics equipment, so when there are problems, it should also be comprehensively analyzed from the two aspects of mechanical structure and electrical control of the machine tool.

1. The stepping motor vibrates and does not rotate after program operation

This phenomenon is generally caused by the open phase of stepping motor or its control system. It may be the stepper motor itself or its driving circuit. First, check whether the connecting plug of the stepping motor has good touch. If it has good touch, you can exchange the motor without fault to verify whether the motor is good.

2. The worktable suddenly stops during program operation

First, power off, and then check whether the gap between the screw nut and the lead screw or the slide plate insert is too tight, whether there is foreign matter in the ball guide groove of the ball screw, whether the lead screw is tortuous and deformed, whether the flexible gear in the stepper motor reducer is loose or foreign matter is stuck, etc. If there is no abnormality in the manual turning, it is the fault of the control system, which should be checked according to fault 1.

3. The tool does not return to zero after the program is completed

It's usually a problem with the control system. When the tool is feeding or processing, the operation speed of the stepping motor is low, and when the program returns to zero, it is required to return quickly. High voltage driving power supply is selected for high-speed operation of stepping motor to increase the output torque.

4. The tool is offside when it returns to zero

Generally, it is caused by too much operation resistance of mechanical transmission system. During cutting feed, the tool holder operates at low speed, driven by low voltage, and the operating torque of stepping motor is small, which is not enough to overcome the resistance and form step loss. When returning to zero, the stepping motor is driven by high voltage, with high operation speed, large torque and no cutting resistance, and the stepping motor does not lose step. In this way, when you lose your step and come back, you will form a non-zero phenomenon. At this time, you can check whether there are iron filings and foreign matters on the transmission gear in the stepping motor reduction box or between the stepping motor and the lead screw, or whether the slide insert is too tight to increase the operation resistance, etc.

5. The workpiece size error after processing is very large

One possibility is that the connection between the lead screw or nut and the lathe is loose. There is no cutting resistance during empty travel, and the slide operation is normal. During processing, due to the increase of cutting resistance, the connection between the lead screw or nut and the lathe is loose, resulting in the scale drift of the processed workpiece. Fasten the connecting part, and the problem can be eliminated. Another possibility is the formation of electric tool holder.