Dongguan CNC processing plant simple CNC lathe is also called economic CNC lathe, which is developed on the basis of ordinary lathe. Its automatic control system is mainly composed of single chip microcomputer. Through control program, the longitudinal and transverse feeding device and tool changing device of the machine tool are controlled, and the processing of parts is completed automatically. Therefore, the simple CNC lathe is still an integrated mechanical and electrical equipment, so it is necessary to analyze the mechanical structure and electrical control of the machine tool in case of failure.
1. the stepping motor will not shake after the program is running
The phenomenon of machining is usually caused by the phase break of the stepping motor or its control system. It is possible that the stepper motor itself is faulty or its drive circuit is faulty. First, check whether the connection plug of the stepping motor is in good contact. If the contact is good, the motor without fault can be replaced to verify whether the motor is good. If the motor is still not working normally after switching, it indicates that the control part is abnormal. The high power triode and the release diode of its protective element on the drive plate can be inspected emphatically. Generally, these two elements
2. the workbench stops suddenly during the program operation
This phenomenon is usually caused by mechanical failure, but it may also be caused by the failure of control system. At this time, the workbench can be returned to the original point and the processing procedure can be restarted. If the workbench is always running to a certain position, it should be damaged, deformed or stuck by foreign matters in a certain part of the transmission system. First, power off, then check whether the gap between the screw and the screw or the sliding plate insert is too tight, whether there is any foreign matter in the ball guide groove of the ball screw, whether the screw is bent or deformed, whether the flexible gear in the reducer of the stepping motor is loose or foreign matter is stuck, etc. If there is no abnormality in manual turning, it is a control system fault and it shall be checked according to fault 1.
3. step loss of stepping motor at high speed
It may be that the drive power voltage is reduced, which reduces the output torque of the stepper motor. The drive power supply should be inspected emphatically. When the high voltage switch triode is damaged, the high voltage power supply is connected by the day method. When the stepping motor output torque is reduced and the step is lost in high speed. There may be mechanical failure in some place, so check the screw, screw, slide plate, stepper motor reducer, etc. When there are parts bending, deformation or foreign matter, the running resistance will increase, and the phenomenon is not obvious when the low speed is running, but the resistance cannot be overcome completely at high speed.
4. the tool does not return to zero after the program is running
Dongguan CNC processing factory is generally a control system failure. When the tool is fed or processed, the running speed of the stepper motor is low, while when the program returns to zero, it is required to return quickly. The stepping motor is running at high speed, and high voltage drive power is used to increase the output torque. There is a switch triode which controls the output of high-voltage drive power supply. When the switch triode is damaged, the high-voltage power supply cannot be turned on when the high-speed return to zero, and the output torque of the stepping motor is not enough, which makes the tool not return to zero. Replace the switch triode to eliminate it.
5. offside when tool returns to zero
Generally, the mechanical transmission system is too high resistance to operation. When cutting feed, the tool holder operates at low speed, low voltage drives, and the running torque of the stepping motor is small, which is not enough to overcome the resistance and cause the step loss. When the motor is driven at high voltage, it has high speed, high torque and no cutting resistance. The stepping motor does not lose step. This way, when you lose step and return to normal will cause no return to zero. At this time, it can check whether there is iron debris on the transmission gear in the gearbox of the stepping motor or between the stepping motor and the screw, or whether the sliding plate insert is too tight to increase the running resistance, etc.
6. the dimension error of the workpiece after processing is very large
One may be that the screw or the screw mother is loose connected with the lathe. There is no cutting resistance during the empty walk, the sliding plate is running normally. Due to the increase of cutting resistance, the connection between the screw or screw and lathe is loose, resulting in the size drift of the workpiece. Fasten the connection part, and the fault can be eliminated. Another may be caused by an electric tool holder. If the tool holder cannot be locked automatically after changing the tool, the tool deviates from the machining point during cutting, which will also cause the above phenomenon. At this time, check the tool holder locking device and tool holder control box.
7. large error of part size of workpiece
The machining is mainly caused by the excessive gap between the screw and the screw. Because the thread and screw run in a certain section for a long time, the gap of the segment increases. At the beginning of the program, the measured screw gap is compensated to the program, but it cannot be compensated in the wear section, so that the part size of the workpiece is out of tolerance. The solution is to repair or replace the screw.
8. the electric tool holder cannot be positioned and rotated more than once
This is because when the program wants a tool, the electric tool holder is rotating the tool. When the tool is rotated to the tool, there is no response signal, so that the tool holder can not rotate more than one and cannot be positioned. Hall elements on the power tool holder shall be checked. When the hall element is damaged, the signal output is not detected when the tool is in place, which causes the above phenomenon. Replace the hall element of the tool.
9. return to monitoring status and stop working during program execution
Dongguan CNC processing plant is generally caused by monitoring program failure or strong magnetic interference. For strong magnetic interference, the method of grounding or shielding can be adopted. If the program is not executed or the program is started, the command will be returned to the monitoring state immediately. Generally, if there is a fault in the monitoring program or computer hardware, the suspect chip can be replaced, such as the off chip program memory chip, programmable interface chip or the single chip itself. Sometimes the out of chip data memory failure can cause this phenomenon. Otherwise, we have to find the manufacturer to readjust.
10. processing procedures are often lost
If the machining program is lost after the control system is cut off, and the machine tool is powered on and re-input the processing program, the machine tool can be processed normally, then the standby battery voltage may be reduced or disconnected, which will cause the processing procedure in the data memory to be lost after the machine tool is cut off. Replace the backup battery. If the processing program is often lost in part or all during the processing process, it is likely that the data memory is faulty. At this time, the off chip data memory or the MCU itself can be replaced.
In a word, the simple CNC lathe consists of mechanical and electrical parts. After the failure, it is necessary to analyze the mechanical and electrical aspects, judge whether it is a mechanical fault or an electrical fault, and then find out the fault point through in-depth analysis.