The working principle of the punching machine

The press machine experiences increased friction resistance when the lubrication is poor during the movement of the worktable. When the motor drives it, the worktable does not move forward, causing the ball screw to undergo elastic deformation and storing the motor's energy in the deformation. As the motor continues to drive, the elastic force generated by the stored energy exceeds the static friction force, causing the worktable of the press machine to creep forward in a repetitive motion, thereby generating the crawling phenomenon. However, this is not the case. By carefully observing the lubrication condition of the guide rail surface, it can be determined that this is not the problem. The crawling and vibration problems of the press machine are related to speed. Since it is a speed-related issue, the speed loop should be sought. The entire adjustment process of the press machine's speed is accomplished by the speed regulator.

The operation and monitoring of the CNC press machine are all completed in this CNC unit, which is the brain of the CNC press machine. It has high processing accuracy and stable processing quality; it can perform multi-coordinate linkage and process complex-shaped parts; when the parts to be processed change, generally only the CNC program needs to be modified, which can save production preparation time; the machine itself has high precision and rigidity, and the processing amount can be selected advantageously, with a high production rate (generally 3 to 5 times that of ordinary machines). Problems related to speed can only be found by checking the speed regulator. Therefore, the vibration problem of the press machine should also be checked by the speed regulator. The following areas can be searched for faults in the speed regulator: one is the input signal, one is the feedback signal, and the other is the speed regulator itself.

Since the vibration frequency of the press machine is in a certain ratio to the motor speed, the first thing to do is to check if the motor is faulty. Check its carbon brushes, the surface condition of the rectifier, and the mechanical vibration situation, and also check the lubrication condition of the ball bearings. This entire inspection does not require all to be disassembled; it can be observed through an inspection tool. The bearing can be checked by listening to the sound with your ear. If there are no problems, check the speed measuring generator. The speed measuring generator 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 have a linear relationship. As long as the speed is constant, its output voltage waveform should be a straight line, but due to the influence of the tooth槽 and the commutation of the rectifier， there is a small alternating component attached to this straight line. Therefore， a filtering circuit is added to the speed feedback circuit to weaken this alternating component attached to the voltage.

The feedback signal and the given signal for the regulator are exactly the same. Therefore， when the feedback signal fluctuates， it will inevitably cause the speed regulator to adjust in the opposite direction， thereby causing the vibration of the press machine. This situation is very easy to handle. Just remove the motor rear cover， and the rectifier of the speed measuring generator will be exposed. At this time， no disassembly is required； just use a sharp hook to carefully hook each slot， then sand down the burrs with fine sandpaper， re-wipe the surface of the rectifier with absolute alcohol， and then put the carbon brushes back. Here， it is particularly important to note that when using a sharp hook to hook the slot of the commutator， do not touch the winding， because the wire of the winding is very thin， and if it is broken， it cannot be repaired， only replaced. Another thing is that do not use water-based alcohol to wipe， as this will cause the insulation resistance to drop and make it impossible to dry， thus delaying the repair time.

A closed-loop system may also cause oscillation due to improper parameter setting， but the best way to eliminate this oscillation is to reduce its amplification factor. In the FANUC system， adjust RV1 in the counter-clockwise direction， and at this time， it can be seen that it will immediately improve significantly. However， since the range of the RV1 potentiometer for adjustment is relatively small， sometimes it cannot be adjusted， only the short-circuit bar can be changed， that is， to cut off the feedback resistance value， to reduce the amplification factor of the entire regulator.