Simple CNC lathes, also known as economical CNC lathes, are widely recognized and widely used in the machining industry due to their high degree of economical automation. Simple CNC lathes have been developed on the basis of ordinary lathes, but their automation has been greatly improved. The automatic control system is mainly composed of a single-chip microcomputer, and the longitudinal and lateral feeding device and the tool changing device of the machine tool are controlled by the control program, and the processing of the parts is automatically completed. Therefore, the simple CNC lathe is a more complex machine-electrical integrated device, so it should be comprehensively analyzed from the mechanical structure and electrical control of the machine tool in the event of failure.
Combining with my own experience in actual maintenance work, I will analyze several common faults.
1. After the program is started, the stepping motor will not shake. This phenomenon is generally caused by the phase failure of the stepper motor or its control system. It is possible that the failure of the stepper motor itself may also be the failure of its drive circuit. First check if the connection plug of the stepping motor is in good contact. If the connection plug is in good contact, the one-phase motor without fault can be exchanged. If the motor is normal after the motor is replaced, the original stepper motor is faulty. If it still does not work properly, it means that the control part is not normal. You can focus on checking the high-power triode on the driver board to protect the components from releasing the diode. Under normal circumstances, the probability of damage to these two components is relatively large.
2. During the operation of the machining program, the workbench suddenly stops running, and the stepper motor does not turn. This phenomenon is generally caused by mechanical failure, but it may also be caused by the failure of the control system. At this time, the workbench can be returned to the origin first, and the machining program can be restarted. If the workbench always runs to a certain position and stops running, it should be caused by damage, deformation or being stuck by foreign matter. . First, the control system is powered off, and then the screw is turned by hand. If the resistance is felt to be extremely large or even unable to move at a certain location, it proves that the position is faulty. Check whether the thread and the screw gap or the slide strip are too tight, whether there is any foreign matter in the ball guide groove of the ball screw, whether the screw is bent or not, whether the flexible gear in the stepper motor reducer is loose or whether there is any foreign matter. Stuck and so on. If the manual drive is not abnormal, the control system is faulty and should be checked according to the procedure of 1.
3. The stepping motor runs normally at low speed, and the stepping motor loses step at high speed. This phenomenon may be caused by the decrease of the driving power supply voltage and the reduction of the output torque of the stepping motor. Therefore, it is important to check the drive power section. When the high voltage starting transistor is damaged, the high voltage power supply cannot be turned on, which reduces the output torque of the stepping motor at high speed, resulting in lost steps. It may also be caused by a mechanical failure. Therefore, in the case of checking the above-mentioned components, check the screw, the nut, the slide, the stepper motor reducer, etc., and when the parts are bent, deformed, or have foreign objects stuck, the running resistance will increase. When running at low speed, the phenomenon is not obvious, but when running at high speed, it can not completely overcome the running resistance and cause lost steps.
4. When the program runs, the tool returns to zero. This phenomenon is generally caused by the control system failure. The tool requires low speed operation during feeding or machining. At this time, the stepping motor runs at a low speed and is powered by a low voltage power supply. When the program returns to zero, it needs to be quickly retracted. At this time, the stepping motor is required to run at a high speed, and the high voltage driving power source is used. , so that the output torque is increased to ensure normal zero return. A switch triode that controls the output of the 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 the zero point, and the output torque of the stepping motor is not enough, causing the return to zero, causing the tool to return to the origin. This fault can be eliminated by replacing the switch transistor.
5. The end of the program operation, the offside when the tool returns to the origin, this phenomenon is generally caused by the running resistance of the mechanical transmission system is too large. When the cutting feed is in progress, the tool holder runs at a low speed, and the low voltage is driven. The stepping motor has a small running torque, which is insufficient to overcome the resistance and cause lost steps. When returning to zero, the stepping motor is driven by high voltage, the running speed is high, the torque is large, and there is no force resistance. The stepping motor runs normally without losing steps. This will cause the above phenomenon when you go back and lose when you go back. At this time, it can be checked whether there is any iron filings on the transmission gear between the stepping motor gearbox or the stepping motor and the lead screw, or whether the slide plate is too tight to increase the running resistance.
6. Everything is normal when the knife is empty, but the dimensional error is large when machining the workpiece. One phenomenon may be caused by the loose connection between the screw or the nut and the lathe. There is no knife resistance when walking, the slide is running normally, the resistance of the knife is increased when the workpiece is processed, and the screw or the connection between the screw and the lathe is loose, causing the size of the workpiece to drift. With a solid connection, the fault can be eliminated. Another possibility is caused by the electric tool holder. If the tool holder cannot be automatically locked after changing the tool, the tool will deviate from the machining point when eating the knife, which will also cause the above phenomenon. In this case, check the tool holder locking device and the tool holder control box.
7. The local size error of the workpiece is large. This phenomenon is mainly caused by the gap between the nut and the lead screw. Since the thread and the lead screw run in a certain section for a long time, the gap of the section is increased. At the beginning of the program, the measured screw gap is compensated into the program, but when the wear section cannot be compensated, the workpiece is partially out of size. . The solution is to repair or replace the lead screw. (http:// Copyright)
8. The electric tool holder rotates more than when it is changed, and can't be positioned. This is because when the program wants a certain knife, the electric tool holder rotates to select the tool. When it is rotated to the tool, there is no response signal, so the tool holder rotates. More than that, you can't locate it. At this time, the Hall element on the electric tool holder should be inspected. When the Hall element is damaged, there will be no detection signal output when the desired tool is in place, thus causing the above phenomenon. At this time, the Hall element of the knife can be replaced. .
9. During the execution of the program, the computer returns to the monitoring state, and all work cannot be performed. This phenomenon is generally caused by the failure of the monitoring program, or it may be caused by strong magnetic interference. For strong magnetic interference, grounding or shielding can be used. If you do not follow the program to execute or start the program without returning to the monitoring state immediately, the monitoring program or the computer hardware is faulty. You can replace the suspect chip, such as the off-chip program memory chip, the programmable interface chip or the microcontroller itself. Sometimes an off-chip data memory failure can also cause this phenomenon. If it can't be solved, you can find the manufacturer to re-commission.
10. The machining program is often lost. In severe cases, the control system cannot work normally. If the machining program is lost after the control system is powered off, and the machine tool can be processed normally after the machine is powered on, the backup battery voltage may be reduced or broken. On, the processing program in the data memory cannot be maintained and lost after the machine is powered off. In this case, the spare battery can be replaced. If the machining program is often partially or completely lost during the machining process, it is most likely caused by a data memory failure. In this case, the off-chip data memory or the microcontroller itself can be replaced. In short, the simple CNC lathe consists of two parts: mechanical and electrical. After failure, it should be analyzed from both mechanical and electrical aspects to determine whether it is a mechanical fault or an electrical fault. Then analyze it in depth, find the fault point, and deal with the fault accurately and quickly. Improve machine tool maintenance efficiency.
Barrier Strip Connector ,Barrier Type Terminal Block ,Dual Row Terminal Block ,Barrier Terminal
Cixi Xinke Electronic Technology Co., Ltd. , https://www.cxxinke.com