Views: 127 Author: Site Editor Publish Time: 2023-01-05 Origin: Site
Due to poor lubrication of the punching machine, the frictional resistance increases when the worktable moves. When the motor is driven, the table does not move forward, so that the ball screw produces elastic deformation, and the energy of the motor is stored in the deformation. The motor continues to drive, and when the elastic force produced by the stored energy is greater than the static friction force, the punch table will creep forward and move like this repeatedly, resulting in the phenomenon of crawling. However, this is not the case. If you take a closer look at the lubrication of the guide rail surface, you can conclude that this is not the problem. Punch crawling and vibration issues are speed issues. Since it is a speed problem, it is necessary to find the speed ring. The entire adjustment process of the speed of the punching machine is completed by the speed regulator.
The operation and monitoring of the CNC punching machine are all completed in this CNC unit, which is the brain of the CNC punching machine. High machining accuracy and stable machining quality; multi-coordinate linkage can process parts with complex shapes; when the machined parts are changed, generally only need to change the NC program, which can save production preparation time; the bed itself has high precision and rigidity, Favorable processing dosage can be selected, and the productivity is high. For speed-related problems, only the speed regulator can be found. Therefore, the vibration problem of the punch press should also look for the speed regulator. The faults of the speed regulator can be found from the following places: one is the given signal, one is the feedback signal, and the other is the speed regulator itself.
Because the vibration frequency of the punching machine has a certain ratio to the motor speed, it is first necessary to check whether the motor is faulty, check its carbon brushes, the surface condition of the commutator, and the mechanical vibration, and check the lubrication of the ball bearings. For inspection, it is not necessary to disassemble all of them, it can be observed by the inspector, and the bearing can be checked by listening to the sound with the ear. If there is no problem, check the tachometer generator. The tachogenerator is generally DC.
The punch press tachogenerator is a small permanent magnet DC generator, and its output voltage should be proportional to the speed, that is, the output voltage and the speed are linearly related. As long as the speed is constant, its output voltage waveform should be a straight line, but due to the influence of cogging and the commutation of the commutator, there is a small alternating quantity attached to this straight line. For this reason, a filter circuit is added to the speed measurement feedback circuit, and this filter circuit is to weaken the AC component attached to the voltage.
The punch feedback signal and the given signal are exactly the same for the regulator. Therefore, the fluctuation of the feedback signal will inevitably cause the speed regulator to adjust in the opposite direction, which will cause the vibration of the punching machine. When this happens, it is very easy to deal with, as long as the rear cover of the motor is removed, the commutator of the tachogenerator will be exposed. At this time, there is no need to do any disassembly, just use a sharp hook to carefully hook each slot, then use fine sandpaper to lighten the raised burrs, wipe the surface of the rectifier with absolute alcohol, and then put charcoal on it. Just brush it. Special attention should be paid here that when using a sharp hook to hook the notch between the commutation plates, do not touch the winding, because the winding wire is very thin, once it is broken, it cannot be repaired, and the winding must be replaced. One more thing, don't use water-containing alcohol to wipe, so that the insulation resistance will drop and you can't dry it, which will delay the repair period.
A closed-loop system may also cause system oscillation due to poor parameter settings, but the way to eliminate this oscillation is to reduce its magnification. In the FANUC system, adjust RV1 and rotate it counterclockwise. At this time, it can be seen that it will be obvious immediately. It becomes better, but because the range of the RV1 adjustment potentiometer is relatively small, sometimes it cannot be adjusted, and the short-circuit bar can only be changed, that is, the value of the feedback resistance is cut off, and the magnification of the entire regulator is reduced.
The punching and forming of the press should follow the following regulations. When more than two people are operating, they should be assigned to drive and pay attention to coordination and cooperation. Before leaving get off work, the mold should be placed on the ground, the power supply should be disconnected, and the necessary cleaning should be carried out. The transmission parts exposed outside the press must be equipped with a protective cover, and it is forbidden to drive or test run with the protective cover removed. Empty test can be carried out if necessary. To install the mold, the slider must be opened to the bottom dead center, the closing height must be correct, and eccentric loads should be avoided as much as possible; the mold must be fastened firmly and have passed the pressure test inspection.
Attention should be concentrated during work, and it is strictly forbidden to put hands and tools into the dangerous area. If the press is found to be operating abnormally or has abnormal noise, stop feeding and check the cause. If the rotating parts are loose, the control device fails, and each time a workpiece is punched, the hand or foot must leave the button or pedal to prevent misoperation. Before working, check whether the protective device of the punch press is complete, whether the flywheel runs smoothly; whether the upper part and both sides of the pedal device are protected, and whether the operation is reliable and flexible; and remove objects that hinder the operation in the workplace.
The blanking force must be approved, and overload operation is strictly prohibited. When installing and disassembling the mold, the power supply must be cut off first. Mold installation must be firm and reliable. When adjusting the combined height, use manual or dynamic methods, and proceed step by step. Before the adjustment is confirmed, it is forbidden to connect the car. When operating, you must concentrate your thoughts, and it is strictly forbidden to do it while talking. You must cooperate with each other to ensure safe operation. Generally, it is forbidden for more than two people to operate the punching machine at the same time. If necessary, there must be a special person to direct and be responsible for the operation of the pedal device. It is strictly forbidden to carry out feeding and unloading in the mold range for any part of the body during work. Special tools should be provided.
Interlayer feed stamping is prohibited, and the second feed can only be carried out after the front punch or the remaining material has been removed. The installation of the mold must be checked regularly, and if there is any looseness or slippage, it should be adjusted in time. Before the edge of the knife wears to the point where the burr exceeds the standard, the edge of the knife should be repaired in time. When disassembling the mold, it must be carried out under the closed mold state. Take good care of stamping equipment, dies, tools, gauges and instruments. After the work is finished, the mold and punch should be wiped clean and ready for finishing. In the formal punching process, since the static difference rate of the main motor varies with different loads, when punching different parts, the electromagnetic counter set on the control board can be used to correct the speed.