The maintenance process of a CNC bending machine failed in a CNC machine tool produced by CYBELEC. According to the operator's introduction, the fault phenomenon is that the Y axis of the machine tool is shaken, and sometimes it is not, and the time is large and small. The Y axis of the machine tool is to drive the DC permanent magnet servo motor with a DC servo system, and the servo motor drives the slider up and down through a worm gear drive pair. After observing and testing the necessary cold state of the machine from the inside to the outside, and understanding the state of the machine, I let the operator turn on the machine first. But after booting up, the faults they described did not occur and everything seemed normal. I walked to the Y-axis servo motor, followed by the cable of the encoder for position feedback. The motor randomly sounded the vibration, and then the cable was moved, and the motor vibrated again. I think the problem may be on the wiring, so after the power is turned off, the position encoder plug is opened and the shield is found to be ungrounded and no other processing is done. After the motor end of the position feedback cable is temporarily wrapped with insulating tape, the plug is connected, and then the power is applied. The cable is repeatedly driven, and the motor no longer vibrates. At this point, I thought the problem was solved, and it was judged to be an electrical fault. I asked the operator to operate the Y-axis repeatedly. However, after about ten minutes, the Y-axis motor vibrates again (in a stationary state). It can be clearly seen through the transmission wheel that the motor is in a frequent dynamic correction process. I think, this verified my original idea, that is, the problem is on the drive, so I repeatedly tested and adjusted the drive (ie, the servo unit), and repeatedly power off and power on, but the motor vibration still disappeared. No, including changing its gain, adjusting the zero drift, etc., no effect. Later, it was suspected that the motor was loaded, so the worm gear in the worm gear pair was removed, so that the motor did not have any load. When the power was turned on, the motor was still vibrating as it was. I don't want to adjust the drive anymore, because the rotation of the motor is made by the command. At this time, the NC does not give any command. The motor should be stationary. The reason why the motor rotates must be that the driver has received the command voltage. . After turning, it is immediately corrected back in the opposite direction. This is because the NC does not receive any motion commands from the operator and is corrected by the position encoder of the motor. So the problem is clearly in the command loop of the drive, the servo unit.
Re-energized, and sure enough, the motor is still, and there is no vibration. However, it is impossible to add the command voltage when the machine is in normal use. Then, is the NC's own instruction loop drifting, or the driver receives the external interference? After testing, changing the offset value of the NC command loop voltage proves that it is not NC. The command voltage drifts, so it can be determined that this jitter of the motor is due to the external interference received by the driver. Finally, by grounding the NC end of the Y-axis command cable, the interference is eliminated and the motor jitter is solved. Afterwards, according to the relevant technical personnel of the factory, when the machine tool arrived at the factory, the Y-axis command cable of the machine tool was not processed. Why didn’t this happen at the time? I think the most fundamental reason is still in the Y-axis of the machine tool. On the transmission mechanism. The Y axis of the machine tool is driven by a worm gear and worm gear. According to the general design principle: 1. The worm gear should be made of two different materials, such as steel brass. Second, the meshing application of the worm wheel and the worm is used to adjust the elastic device. However, the actual situation is that the worm wheel and the worm of the Y-axis of the machine tool are both steel parts, and serious scratches are found, and there is no adjustment device. In this way, when the Y-axis motor is static, the load is very uneven. It does not matter when running dynamically, but it is not normal when it is static. For long-term use, the static working point of the axis drive is offset, and each working parameter is different. Changes, the external disturbances are naturally introduced, so there is such a fault. Therefore, the drive of the CNC machine tool is a complete chain from the NCy drive y servo motor y drive mechanism y. If you want to work on one axis of the machine tool, you must take care of each link of the chain and coordinate and match each other. This problem should be solved in the initial design stage of the machine.
To meet the requirements of the PLC for installation and use environment and grounding; to prevent interference from the power supply, it is recommended to connect an isolation transformer or interference filter between the power supply and the PLC; for inductive actuators, the external arc-extinguishing circuit should be properly connected (for AC load) Or freewheeling diode (for DC load) and select its circuit parameters.
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Airless Spray Gun
This process occurs when paint is applied to an object through the use of an air-pressurized Spray Gun. The Sprayer Gun has a nozzle, paint basin, and air compressor. When the trigger is pressed the paint mixes with the compressed air stream and is released in a fine spray.
Types of nozzles and sprays
Due to a wide range of nozzle shapes and sizes, the consistency of the paint can be varied. The shape of the workpiece and the desired paint consistency and pattern are important factors when choosing a nozzle. The three most common nozzles are the full cone, hollow cone, and flat stream.There are two types of air-gun spraying processes. In a manual operation method the air-gun sprayer is held by a skilled operator, about 6 to 10 inches (15–25 cm) from the object, and moved back and forth over the surface, each stroke overlapping the previous to ensure a continuous coat.In an automatic process the gun head is attached to a mounting block and delivers the stream of paint from that position. The object being painted is usually placed on rollers or a turntable to ensure overall equal coverage of all sides.
Airless Spray Gun
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