Ajuste mecânico da peça da prensa dobradeira

Mechanical adjustment of the press brake part

May 3, 2024 Roberto Magalhães

Ram adjustment

After prolonged use of the press brake, the ram guide rail may become worn or loose due to the continuous reciprocating movement of the ram. This is evident in the significant shaking of the ram during movement and the low accuracy when bending sheet metal.

In this scenario, the ram guide rail clearance must be adjusted.

Loosening the guide rail may cause the ram to vibrate excessively during operation, resulting in poor bending accuracy of the workpiece.

Guide rail adjustment method:

Position the ram guide rail in the middle of the guide rail.
Loosen the lock nut and tighten all adjusting screws with an Allen wrench. Slightly loosen the adjustment screws and retighten the locknut.
Use a feeler gauge to measure the gap between the body guide rail and the ram guide rail to ensure that the maximum gap before and after the upper and lower guide rail positions does not exceed 0.03 mm. In diagnostic state, RAM should slide automatically. If this is not done, the guide rail gap is too tight and should be loosened slightly until the gap is adjusted properly.
Turn on the machine and observe the operation of the ram.

Rear beam parallelism adjustment

After a certain period of operation of the press brake, it is necessary to check the parallelism of the X-axis beam in relation to the center of the lower die.

If it is observed that the same stop pin is used for positioning, and the size of the bent part differs when the stop pin is positioned differently on the left and right sides of the lower die, the parallelism of the rear stop beam with the center of the die bottom needs to be adjusted.

Parallelism fine-tuning method:

Measure the specific value of the deviation of the parallelism of the rear retaining beam with respect to the center of the lower die.
Use a dial indicator to touch the end with a large distance from the center of the die to the bottom die so that the dial indicator reading is greater than the setting value and register the value indicated on the dial indicator.
Loosen the lock nut, adjust the position of the cross beam forward by adjusting the Allen screw, and observe the dial indicator during the adjustment process to ensure that it conforms to the predetermined offset value.
Tighten the locknut.
Run the press brake to check the adjusted accuracy and the parallelism between the beam and the bottom center of the die should be ≤ 0.1 mm.

Observation:

This adjustment method is suitable for parallelism deviations between the back retaining material and the bottom center of the die of less than 0.4 mm.

If the deviation is too large, loosen the timing belt on the X-axis and adjust the position of a front and rear end of the X-axis cross beam by turning either ball screw until the lower matrix.

If the error is small, it can be corrected by fine-tuning.

Back stop finger adjustment

When bending a workpiece, if there is a deviation in the size of the two stop fingers, first check the parallelism of the back stop beam.

If there is no problem with parallelism, adjust the backstop finger using the following method:

Measure the positioning deviation of the two rear stop fingers.
Use a dial indicator to touch the deflector plate end of the adjusted backstop finger, and the reading on the dial indicator should be greater than the offset value.
Loosen the two M10×30 Allen screws on the deflector seat to allow the deflector seat to move.
Adjust the M8 adjustment screw to move the rear deflector seat and observe the value displayed on the dial indicator to ensure it conforms to the measured deviation.
Tighten the two M10×30 hex screws on the deflector seat and ensure that the dial indicator reading remains unchanged during the tightening process.
Start the press brake, try to bend the workpiece, and check whether the accuracy of the backstop finger after adjustment meets the runout requirements. If the requirements are not met, repeat the above process.

X-axis synchronous belt adjustment

The rear retaining beam is driven by the X-axis servo motor to rotate the left and right lead screws synchronously through the synchronous pulley and synchronous belt, allowing the forward and backward movement of the rear retaining beam and retaining finger rear.

After prolonged use of the press brake, there may be looseness in the rear retaining synchronous belt. This is indicated by the excessive oscillation range of the synchronous belt during operation, and a too loose synchronous belt may affect the accuracy of the X-axis.

Press brake operators should regularly check the tightness of the synchronous belt. If the synchronous belt is too loose, the synchronous belt tension wheel must be readjusted to achieve a moderate level of tension.

The tension force must be adjusted accordingly.

If the parallelism of the rear retaining beam exceeds 0.4mm, the position between the synchronous belt and the right lead screw synchronous wheel needs to be adjusted. Each tooth adjusted between the synchronous belt and synchronous wheel will move the lead screw 0.71 mm in the X direction.