Release time:

2021-04-26

【Summary】Sheet metal processing is a series of processes for bending, riveting, welding, and other treatments of metal materials. Below are the problems encountered in the bending process of sheet metal processing and their solutions. Problem 1: The bending edge is not straight, and the size is unstable Reasons: 1. The design process did not arrange for pressure lines or pre-bending 2. The material pressing force is insufficient 3. The round corners of the male and female molds are asymmetrically worn or the bending force is uneven 4. The height size is too small Solutions: 1. Design pressure lines or pre-bending processes 2. Increase the pressing force 3. Ensure uniform gaps between male and female molds and polish the round corners 4. The height size should not be less than the minimum limit size Problem 2: The surface of the workpiece is scratched after bending Reasons: 1. The surface of the raw material is not smooth 2. The bending radius of the male mold is too small 3. The bending gap is too small Solutions: 1. Improve the smoothness of the male and female molds 2. Increase the bending radius of the male mold 3. Adjust the bending gap Problem 3: Cracks at the bending angle Reasons: 1. The inner bending radius is too small 2. The material grain direction is parallel to the bending line 3. The burr side of the blank faces outward 4. Poor metal plasticity Solutions: 1. Increase the bending radius of the male mold 2. Change the layout of the blanking 3. Move the burr to the inner corner of the workpiece 4. Anneal or use soft materials Problem 4: Deformation of holes due to bending Reasons: When using pressure bending and positioning with holes, the outer side of the bending arm is pulled due to friction between the die surface and the outer surface of the workpiece, causing deformation of the positioning hole. Solutions: 1. Use shape bending 2. Increase the pressure of the top plate 3. Add a textured pattern to the top plate to increase friction and prevent the workpiece from slipping during bending Problem 5: The bending surface is thinned due to extrusion Reasons: 1. The round corner of the female mold is too small 2. The gap between the male and female molds is too small Solutions: 1. Increase the radius of the round corner of the female mold 2. Adjust the gap between the male and female molds Problem 6: The end face of the workpiece is bulging or uneven Reasons: 1. During bending, the outer surface of the material is pulled in the circumferential direction, causing shrinkage deformation, while the inner surface is compressed in the circumferential direction, causing elongation deformation, resulting in a bulging phenomenon along the bending direction. Solutions: 1. There should be sufficient pressure from the male and female molds during the final stage of stamping the workpiece 2. Create a corresponding round corner radius for the female mold matching the outer round corner of the workpiece 3. Increase the process to improve Problem 7: The bottom of the concave part is uneven Reasons: 1. The material itself is uneven 2. The contact area between the top plate and the material is small or the pressing force is insufficient 3. There is no pressing device inside the female mold Solutions: 1. Level the material 2. Adjust the pressing device and increase the pressing force 3. Add or correct the pressing device 4. Add a shaping process Problem 8: The axis of the two holes on opposite sides is misaligned after bending Reasons: Material rebound changes the bending angle, causing the centerline to shift Solutions: 1. Increase the correction process 2. Improve the structure of the bending mold to reduce material rebound Problem 9: Cannot guarantee the dimensional accuracy of hole positions after bending Reasons: 1. The unfolded size of the workpiece is incorrect 2. Caused by material rebound 3. Unstable positioning Solutions: 1. Accurately calculate the size of the blank 2. Increase the correction process or improve the forming structure of the bending mold 3. Change the processing method or increase process positioning Problem 10: The bending line is not parallel to the centerline of the two holes Reasons: When the bending height is less than the minimum bending limit height, the bending part shows an outward bulging phenomenon Solutions: 1. Increase the height size of the bending part 2. Improve the process method of the bending part Problem 11: Deformation in the width direction after bending, with bowing deflection appearing in the width direction of the bent part Reasons: Due to inconsistent deep drawing and shrinkage in the width direction of the workpiece, twisting and deflection occur Solutions: 1. Increase the bending pressure 2. Increase the correction process 3. Ensure that the material grain direction has a certain angle with the bending direction Problem 12: The workpiece with a notch bends downward Reasons: The notch causes the two straight edges to spread left and right, resulting in deflection at the bottom of the workpiece Solutions: 1. Improve the structure of the workpiece 2. Increase the process allowance at the notch to connect the notch, and then cut off the process allowance after bending.

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