17 Press Brakes Common Malfunction Analysis

Mechanical press brake

Mechanical press brake

Malfunction 1: too large gap between slider and guide rail, make an abnormal sound. This type of malfunction is due to the long use of rails, increased gap caused by wear. It is necessary to check the degree of wear of the guide plate, to determine whether to replace the rail plate depending on the degree of wear, re-adjust the gap to meet the requirements.

Malfunction 2: transmission failure of the back gauge. The back-gauge transmission fails because the drive shaft is disengaged from the timing belt of the timing pulley or the belt is slipping. This malfunction requires reassembling the chain and timing belt, then checking the electrical section.

Malfunction 3: parallel misalignment too much between the cross-beam guide rail of back gauge and the mold center line. Such failure needs to release the “X” axis synchronous belt, re-adjust to the parallelism tolerance range, reinstall the synchronous belt.

Malfunction 4: cylinder and slider connection loosening, causing bending angle not accurate or the machine cannot find the reference point. This type of fault requires re-checking the tightened slider and the cylinder connection nut.

Hydraulic press brake

CNC Press Brake

Malfunction 1: the hydraulic system without pressure.
1. Check whether the proportional relief valve solenoid coil is power on. If the electromagnetic coil voltage meets the requirements. For the above reasons, please check the relevant electrical parts.

  1. Check whether the cartridge valve is stuck or the main spool is stuck as well as damp hole clogging. If this is the reason, please remove the relief valve and clean it.
  2. three-phase power phase modulation, resulting in motor reversal.

Malfunction 2: slider speed turn to slow from fast, pause too long.

  1. Check whether the tank oil surface is too low, the filling mouth was not flooded. When fast forward the cylinder chamber filled with liquid and air which leads to the insufficient filling. For the above reasons, the tank oil can be added to the filling tank 5mm above the filling mouth until it been completely flooded.
  2. Check whether fast forward speed is too fast, causing insufficient filling. For the reasons described above, you can reduce the fast forward speed by modifying the system parameters.
  3. Check whether the filling valve is completely open if it is because of oil pollution so that the valve spool activity is not flexible and stuck issue lead to insufficient oil filling. Need to clean the filling valve and re-install it, make the spool flexible.

Malfunction 3: slider return normal, fast forward normal, manual cannot slow down, bending weak.

  1. Check whether the reversing valve, which controls oil circuit, is working properly. If so, it causes the filling valve is not closed, so that the upper chamber and the tank filling port connected, cannot build pressure. The reason why the valve does not work properly is that it is not energized or stuck.
  2. Check whether the filling valve is stuck, if so, please clean the filling valve, reinstalled, so that the spool flexible.

Malfunction 4: the slider return speed is too slow. The malfunction like high return pressure is mainly because the filling valve is not open. This phenomenon is just contrary to the logical of above malfunction 3. This can be handled by referring to the solution of the malfunction 3.

Electric system type CNC press brake

Malfunction 1: after starting the pump of CNC bending machine, low voltage disconnect switch. The following checks are required for such failures:

  1. Check the lack of power supply phenomenon.
  2. Check whether the high-pressure filter blockage, resulting in pump motor current is too large.
  3. Check whether the low-voltage switch is set too small.

Malfunction 2: after start the CNC press brakes, the reference point cannot be found during the return.

  1. Due to the reading head connection parts of grating ruler get loose, cause the reading head cannot coincide with the reference point of the grating ruler in return stroke. At this time, the cylinder has run out of the stroke, the pump is working in the overload state. If this is the case, you need to press the red stop button of the CNC system, stop the reference point, reconnect the connector to correct the grating ruler, and then enter the manual mode, manually let the slider down, make the slider re-enter the manual or semi-automatic mode when coincide with lower die. Again, back to reference point and remedy of the trouble.
  2. After the last operation of the press brakes, because the operator did not shut down the press brake machine strictly in accordance with the operation rule – Before power off the CNC press brakes, the slider stops at the top dead center position, and in the next boot, the slider is not manually down, place at the overlap position of upper and lower mold, and carry out the reference point operation, causing the operation cannot find the reference point. If this is the case, you need to switch the system to manual mode, manual mode will adjust the slider down to the overlap position of upper and lower mold, and then enter the semi-automatic or automatic mode, re-find the reference point.

Malfunction 3: for DNC60 or DNC600 CNC bending machine, CNC system did not display, gray-white programming key indicator light flashing.

This malfunction is mainly because the controller operator did not timely and effectively clear the original not used product program during the product programming operation, and directly modify the program of last product. After repeated several times causing the system filled with the buffer memory program which makes the system program cannot run properly. First, disconnect the main motor power, press the “+ +” “- -” key on the keyboard at the same time, then turn the power on to make the system into the initial state. Then, you will need to clear the project before you input: “1” indicates that the item is cleared, after entering the password “817”, press the enter key to confirm, the screen will prompt you “has been executed”. At this time, the required empty content has been completed.

Malfunction 4: “count is not accurate” of CNC bending machine grating ruler cause bending angle error.

This kind of malfunction mainly reflects the cumulative increase of “Y1” “Y2” axis repositioning accuracy error increase the workpiece angle error after bending, and the angular error increases in the previous base. The main reason is the grating ruler feedback signal count leaks out of the pulse. Need to remove the grating ruler, clean and prepare a good job of dust and vibration measures. Redesign and re-install it to the reasonable level for those irrational installations. For the damaged grating ruler, need to return to the manufacturer repair or replacement.

Malfunction 5: After the product is programmed, the safe distance alarmed for back gauge “X” axis and “R” axis.

This type of malfunction is mainly because the setting of upper/lower mold safe distance as well as the X-axis R-axis limit position contradicts the programmed position. For the sake of safety, the system prompts the alarm and will not run, also can’t be operated. You need to re-program the product or modify the product or modify the parameters of the mold to meet the requirements, that is, the alarm can be removed before operation.

Malfunction 6: Back gauge X-axis and R-axis, an error occurs in the drive motor

This type of failure need to first open the CNC bending machine electric box, check the driver display alarm code, check out the cause of the alarm according to the prompt alarm code with reference of the user manual.

There are two common alarms:

16 # alarm, suggesting that the drive motor overload. We can check whether the transmission of X-axis Y-axis drive is flexible, resistance and whether the X-axis and R-axis have reached the mechanical limit. If so, to solve mechanical problems.

22 # alarm, suggesting that the encoder feedback signal alarm, maybe “joint” poor contact, unsoldering or disconnection and signal interference, etc., need to check one by one.

Malfunction 7: Y1, Y2 computer display location does not match the actual location.

This type of failure is mainly due to changes in the original reference point of NC bending machine are not accurate, need to reinitialize the reference point.

Malfunction 8: X-axis R-axis controller positioning does not match the actual positioning.

This type of malfunction is mainly because the position of X-axis and R-axis under power off state has been changed. At this point, the computer still remembers the location before the shutdown, resulting in X-axis R-axis actual position changes. The position of the X-axis R-axis needs to be reinitialized.

Malfunction 9: Y1 axis and Y2 axis position deviation exceed the allowed synchronization deviation distance, the slider cannot move up and down.

This type of failure is mainly because before we shut down the press brake machine, the slider is not placed in the upper and lower mold contact position and power off, at this time due to the fall of punch, the real position at both ends of Y1, Y2 axis exceeds the limit. It is necessary to adjust the actual position of the Y1 axis Y2 axis at both ends. The controller should display the current value of the position. Then the press brakes can be operated normally.

Solution: increase the data in the controller of CNC press brake machine for 5mm on the original basis, then enter into manual mode, manual down, the system will automatically correct the location and return to normal work.

>> You can also check out The Ultimate Guide to Press Brake (2018 Updated) to fully understand things about press brake.

2018-01-17T10:32:52+00:00 Bending|

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