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When operating a press brake, corner bending is one of the most challenging processes. Compared with straight-line bending, corners place higher demands on precision, tooling, and operator experience. If not handled correctly, several problems may occur that affect both product quality and production efficiency.

1. Angle deviation (inaccurate Angle）

Reason: Improper mold selection (such as the V-groove width not matching the material thickness).

The excessive opening of the lower die leads to an increase in springback.

Insufficient pressure or too fast bending speed.

Material properties (such as obvious rebound of stainless steel and high-carbon steel).

Solution: Adjust the pressure and compensation Angle (correct the rebound through trial folding).

Select an appropriate mold and reduce the bending speed to increase plastic deformation.

2. Bending dimensional error (length or position deviation)

Reason: Inaccurate positioning of the back gauge or mechanical wear.

The boards are placed unevenly or the reference surfaces are not close together.

Programming data input errors (such as bending sequence, size).

Solution: Calibrate the rear stopper and check the accuracy of the servo system.

Use laser detection or clamp-assisted positioning.

3. The bent line is twisted or uneven

The reason is that the burrs on the edge of the sheet were not treated, resulting in uneven stress during bending.

Mold wear or misalignment of the upper and lower molds (parallelism deviation).

Internal stress of materials (such as unannealed cold-rolled plates).

Solution: Deburr and ensure the board is smooth.

Adjust the parallelism of the mold and replace it if necessary.

4. Indentations or scratches on the surface of the workpiece

Reason: There are impurities or damages on the surface of the mold.

The protective film of the material was not removed or the mold was not cleaned adequately.

Excessive bending pressure causes metal adhesion.

Solution: Clean the mold and use a dedicated polishing mold or PE protective film.

Adjust the pressure or switch to a soft mold (such as polyurethane).

5. Springback

Reason: The material has a high elastic modulus (such as aluminum and stainless steel).

The bending radius is too large or the Angle is too small.

Solution: Adopt the compensation method (excessive bending).

Use a mold with correction function or add a flattening step.

6. Bending cracks or fractures

Reason: Poor ductility of the material (such as hard aluminum alloy, high carbon steel).

The bending direction is parallel to the rolling direction of the material.

The bending radius is too small (lower than the minimum bending radius).

Solution: Increase the bending radius or anneal the material.

Adjust the bending direction (perpendicular to the rolling direction).

7. Damage to equipment or molds

Reason: Overloading bending (such as thickness exceeding the die's load-bearing range).

The mold collided or was not fixed correctly.

Solution: Operate strictly in accordance with the equipment tonnage and mold specifications.

Regularly check the tightness of the mold.

8. Cumulative error of multiple bends

Reason: Multiple positioning causes the reference to shift.

The bending sequence is unreasonable (for example, bending at a large Angle first and then interfering with a small Angle).

Solution: Optimize the bending sequence (from inside to outside, from complex to simple).

Use multi-axis rear stoppers or robot-assisted positioning.

9. Warping or deformation of the sheet

Reason: Uneven distribution of bending force (such as no support in the middle of long plates).

Release of residual stress in materials.

Solution: Add support blocks or bend in multiple steps.

Select the material after stress release.

10. Operational safety issues

Risk: Hand pinching (near the mold area).

The sheet rebounds or slips off.

Protection: Use safety devices such as gratings and two-hand start buttons.

Train operators to standardize procedures.

If you have more ideas, please contact us!

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