CNC Bending Machine Sheet Metal

We are a professional bending machine manufacturer with over 10 years of industry experience. Today, we would like to introduce the common faults and repair methods of bending machine to you:

In the face of the stringent requirements of industrial production, the bending machine can accurately bend high hardness sheet materials to achieve the desired bending effect, and effectively avoid the rebound problem.

However, if there is improper behavior during operation, or daily neglect of maintenance and repair, the bending machine is very prone to failure. Next, the common failures of the bending machine and its corresponding maintenance methods will be described in detail, aimed at helping operators to solve problems in a timely manner, to extend the service life of the equipment, to ensure the efficient and stable operation of the production process.

1, The main motor of the bending machine can not start

Fault causes:

(1)Abnormal starting circuit: The emergency stop button is not reset, resulting in circuit breakage; the cable wiring is loose, affecting current transmission; 24V control power supply failure, unable to provide stable voltage for the starting circuit.

(2)Failure of components: Thermal relays, circuit breakers, AC contactors and other key components of the starting part, due to overload triggering the protection mechanism, or has been damaged, resulting in the main motor can not start normally.

(3)Power supply problems: The external access power supply is abnormal, unable to provide suitable power for the main motor of the bending machine.

Solution:

(1)Check the starting circuit: carefully check the state of the emergency stop button to ensure that it has been reset normally; tighten the cable wiring to ensure a stable connection; at the same time, check whether the output of the 24V control power supply is normal.

(2)Check the components: For the components of the starting circuit, check whether there is overload protection action one by one. If overload is found, analyze the cause of overload in depth, and carefully check whether the components are damaged, and replace them in time if they are damaged.

(3) Power supply testing: Use professional tools to strictly test the parameters of the three-phase power supply to ensure that the power supply is normal.

2, Bending machine slider can not be fast downstream

Fault causes:

(1)Improper adjustment of the slider guide: The bending machine slider guide is adjusted too tight, increasing the friction of the slider downward, hindering its rapid movement.

(2)Abnormal position of the rear blocking shaft: The rear blocking shaft fails to reach the predetermined position accurately, affecting the downward movement of the slider.

(3)The initial position of the slider is wrong: The bending machine slider is not in the upper dead center position, resulting in the rapid downward function can not be triggered normally.

(4)Signal transmission failure: Control signals such as foot switches are not successfully transmitted to the module, resulting in the system not being able to receive the downward command.

(5)Proportional servo valve failure: Proportional servo valve failure, unable to accurately control the hydraulic oil flow and pressure, which in turn affects the downward speed of the slider.

Solution:

(1)Guide rail inspection and adjustment: Carefully check the elasticity of the bending machine slider guide rail to ensure that it is adjusted to the appropriate state to reduce the downward resistance of the slider.

(2)Rear stopper axis position confirmation: Check whether there is a cursor display at the actual position of X on the bending machine system; or in the manual operation interface, compare the programmed value of the rear stopper axis with the actual value to ensure that the two are consistent, and if they are not consistent with the need for timely adjustment.

(3)Slider position calibration: Confirm that the Y-axis status on the bending machine system should be “1”. If it is displayed as “6”, the actual Y-axis coordinates should be checked, and the value should be less than the difference between Y-axis and return, if it does not satisfy the condition, it should be corrected accordingly.

(4)Signal line inspection: Based on the electrical schematic diagram, comprehensively check the input signal lines such as foot switches to ensure that the signal transmission is normal and there are no breaks, shorts and other problems.

(5)Proportional servo valve detection: Test the feedback of the proportional servo valve to determine whether it is working properly. If the feedback is abnormal, it is necessary to further check or repair the proportional servo valve in order to guarantee its precise control of the downward speed of the slider.

3, The bending machine slider can not work into the bending or bending speed retardation

Fault causes:

(1)Speed conversion point has not arrived: The bending machine slider has not yet run to the speed conversion point, resulting in the inability to smoothly switch to work into the bending mode.

(2)System parameter setting deviation: The Y-axis bending part of the system parameters are not set reasonably, affecting the slider's work into the bending speed and effect.

(3)Insufficient pressure: Programming errors, machine parameters are not set properly, as well as hydraulic system failure and other factors, may lead to pressure can not meet the demand for work into the bending. For example, when programming the pressure value is set too low, the machine parameters of the pressure-related parameters are configured incorrectly, or there are components in the hydraulic system failure, fluid problems, etc., can be triggered by insufficient pressure.

Solution:

(1)Speed conversion point and Y-axis status check: Carefully verify the status of the Y-axis of the bending machine to confirm whether it changes from “2” to “3”. At the same time, compare the actual value of Y-axis with the value of speed conversion point, and require that the actual value of Y-axis is greater than the value of speed conversion point. If the above conditions are not met, it is necessary to adjust the parameters of the fast-forward part to make the slider reach the speed conversion point and switch the working state smoothly.

(2)Y-axis bending parameter readjustment: Reset and optimize the parameters of the Y-axis bending part of the bending machine to ensure that the parameters are in line with the operational requirements of the equipment and the actual processing needs, so as to ensure that the slider can carry out the work-feed bending operation at normal speed.

(3)Pressure-related problem identification: Adopt a systematic investigation process to determine the root cause of insufficient pressure. First, with the help of pressure gauges, multimeters and other professional testing tools, measure the main pressure value and the signal strength of the proportional pressure valve to determine whether the pressure value is up to standard and whether the signal transmission is normal. Secondly, check the proportional pressure valve, the main pressure reducing valve whether there is a spool stuck in the situation, if so, timely cleaning or repair. Furthermore, check and clean or replace the filter element, and test the quality and level of oil, if the oil is deteriorated or the level is too low, it needs to be dealt with in time. Finally, check the oil pump and its coupling, to see whether the oil pump works properly, whether the coupling is loose or damaged, if there are problems should be repaired or replaced accordingly.

4, Bending the slider sometimes can not return

Fault causes:

(1)No-load state can not return: This situation may arise from improper parameter settings, resulting in abnormal equipment control logic, can not trigger the return command; or there are failures in the hydraulic system, such as hydraulic pump failure, oil blockage, reversing valve failure, etc., resulting in the inability to provide sufficient power to drive the slider back.

(2)Processing slider can not return and the angle of the workpiece is not up to the set value: In the bending process, when the angle of the workpiece has not yet reached the pre-set value, the slider can not return, this is likely to be due to the angle of the detection device deviation, so that the system misjudged the bending state of the workpiece; it may also be a failure of the control system, failing to respond correctly to the pre-set angle of the return command; In addition, the mechanical transmission components appear to be In addition, the mechanical transmission components of the jamming, wear and tear and other problems, hindering the normal return movement of the slider, can also lead to such phenomena.

(3)Processing slider can not return and the workpiece angle has exceeded the set value: If the workpiece angle has exceeded the set value during processing, but the slider still can not return, may be due to the overload protection mechanism of the bending machine is triggered, for the purpose of protecting the equipment, restricting the return of the slider; it may also be the failure of the pressure control components in the hydraulic system, resulting in pressure abnormalities, unable to realize the return operation; in addition, the The relevant relays, contactors and other components in the electrical control system are sticky or damaged, resulting in control signal disorder, unable to perform the return operation, which will also trigger the fault.

Solution:

(1)Debugging bending machine Y-axis bending part of the parameters: Bending parameters need to be based on the actual situation for debugging. If part of the gain is too small, the slider can not bend or bending is not in place; while the gain is too large, the slider will make the phenomenon of jitter. Ideally, the parameters should be adjusted so that no jitter occurs when the slider moves, and the gain should be increased as much as possible under this premise. In addition, if the left and right valve bias settings in the diagnostic program are not reasonable, too small a bias will cause the Y-axis not to be in place, and too large a bias will prevent the Y-axis from being unloaded. For hydraulic failure, check the main pressure and see that PV valve S5 is always energized.

(2)Troubleshooting Y-axis bending part of the parameter gain and pressure problems: Y-axis bending part of the parameter gain may be set on the small side, can be increased moderately. If there is insufficient pressure, we need to deeply analyze the reasons for insufficient pressure, and determine whether it is programming, signal or hydraulic part of the reason. Programming reasons include mold selection, plate thickness, material, length of the workpiece, bending method, etc.; hydraulic reasons mainly include whether there is internal leakage of the pump, whether the proportional pressure valve is contaminated or damaged, whether the cartridge is clogged, whether the oil has been contaminated.

(3)Check the programming and operation links: The problem mainly originates from programming and operation. It is necessary to carefully check whether the programmed program matches the processed workpiece.

5, Slider action abnormal

Fault causes:

(1)The elasticity of the slider guide of the bending machine is not in a suitable state.

(2)The lock nut of the slider is loose.

(3)The relevant parameters of the machine tool deviate from the reasonable range, and need to be adjusted.

(4)The gain and zero position of the proportional servo valve amplifier need to be calibrated.

(5)There is a deviation in the backpressure valve pressure setting, or the pressure on both sides of the backpressure valve is not balanced. If the back pressure setting is too low, the slider is prone to slow decline phenomenon, and in the process of work in the jitter; if the back pressure valve pressure imbalance between the two sides of the slider in the operation of the torsion will occur.

Solution:

(1)Re-calibrate the gap of the guide rail of the bending machine so that it reaches a reasonable state.

(2)Retighten the locking nut of the slider operation. If the lock nut is found to be too loose with the screw after inspection, it should be replaced in time.

(3)If there is a reference curve, the machine parameters should be adjusted strictly according to the reference curve.

(4)Only BOSCH and REXROTH valves can be adjusted, but caution must be exercised during operation.

(5)Adjust the pressure of the backpressure valve with the aid of a pressure gauge to ensure that the pressure on both sides of the backpressure valve is equalized.

6, Sometimes the main motor of the bending machine automatically stop, thermal relay, circuit breaker protection

Failure causes:

(1)Proportional pressure valve or main pressure reducing valve stagnation occurs, resulting in the machine continuously under pressure.

(2)The filter element is clogged, resulting in the oil outlet path is not smooth, which in turn leads to the oil pump pressure is maintained at a high level for a long time.

(3)The length of time the oil is used exceeds the limit, has been contaminated and deteriorated.

(4)The oil used is of poor quality and cannot meet the operational requirements of the equipment.

(5)The circuit breaker or thermal relay is faulty and triggers action before the rated current is reached.

(6)Failure of the system control pressure output section, which sends out wrong signals and causes the proportional pressure valve to work continuously.

Solution:

(1)Carry out cleaning operations on the proportional pressure valve and main pressure reducing valve of the bending machine to restore their normal working condition.

(2)Replace the filter element in time and conduct a comprehensive inspection and assessment of the degree of oil contamination.

(3)Replace the oil and filter element immediately to guarantee the cleanliness of the oil and the normal operation of the system.

(4)Replace the existing oil fluid with the oil recommended for use in the equipment to ensure stable operation of the equipment.

(5)Replace the faulty circuit breaker and thermal relay to guarantee the normal function of equipment circuit protection.

(6)The bending machine system control pressure output part to carry out a comprehensive inspection, troubleshooting and repair.

If you are interested in bending machine, please contact us.