Reasons and solutions for defects in precision metal stamping processing and metal spring bending parts

1、 The curved end face bulges, and the outer surface of the curved rounded corner strip tilts at both ends

Analysis reason: When bending, the outer surface of the lotus harvesting is pulled along the circumferential direction, the material on the inner surface is compressed, and the two end faces in the lotus harvesting direction are squeezed. When the concave die has a small fillet, warping will occur.

Solution: 1. In the final stage of bending, there should be sufficient correction pressure; 2. Adapt the fillet radius of the concave mold to the outer fillet of the curved part; 3. Add subsequent molding processes.

2、 Bending causes deformation of the hole

Analysis reason: When the hole spacing is close to the bending curve, the pressure on the outside of the bending key causes the side of the hole near the bending curve to stretch outward.

Solution: 1. The edge distance of the hole of the bent part should not be less than the limit distance; 2. Correct the bending process by considering bending first and then punching.

3、 Cannot guarantee the hole size after bending

Reason analysis: 1. The unfolded size of the bent part is incorrect; 2. Caused by material rebound; 3. Unstable positioning.

Solution: 1. Accurately calculate the size of the blank; 2. Add calibration processes or improve the structure of bending molds; 3. Improve the bending process or increase process positioning.

4、 After bending, the axes of the two holes are misaligned

Analysis reason: The rebound of the material changed the bending angle, resulting in a misalignment of the centerline.

Solution: 1. Add a calibration process; 2. Improve the structure of the bending mold to reduce bending rebound; 3. To improve the manufacturing process, you can first bend and then punch the holes on both sides.

5、 The bending curve is not parallel to the centerline of the two holes

Reason analysis: 1. Unreliable positioning leading to material displacement errors; 2. Unbalanced bulges appear in the curved area where the bending height is less than the maximum height.

Solution: 1. Improve the positioning method of bending process, etc; 2. Increase the height dimension and then cut off the excess curved edges of the raised part.

6、 For parts with a pair of gaps in the middle, both feet will experience deflection

Analysis reason: Uneven force on the straight edges on both sides of the incision.

Solution: 1. Improve the structure of the bent part; 2. Increase the process allowance at the incision site, seal the incision, bend it, and then cut it off.

7、 After bending, deformation occurs in the width direction, and the bent part has a bow shaped deflection in the width direction

Analysis of the reason: The stretching and load-bearing capacity of the bent part in the width direction are inconsistent, resulting in twisting deformation and deflection.

Solution: 1. Increase pressure during the bending process; 2. Add a correction process; 3. Make the fiber direction of the material form a certain angle with the bending curve.

8、 The bending height dimension is unstable

Reason analysis: 1. The height dimension is too small; 2. Asymmetric rounded corners of concave molds; 3. The positioning of the raw material process is unreliable.

Solution: 1. The bending height dimension should not be less than the minimum limit. Public welfare compensation can be increased by bending first and then cutting off the compensation part; 2. Correct the rounded corners of the concave mold; 3. Add processes or adjust process positioning.

9、 There is a crack on the outer side of the bend

Analysis reason: 1. The radius of the curved inner corner is too small; 2. The direction of the material fibers is parallel to the bending curve; 3. The rough cutting burrs are bent outward; 4. Poor plasticity of materials.

Solution: 1. Increase the radius of the convex mold fillet; 2. Change the cutting layout; 3. Move the burrs to the inside of the curved part; 4. Annealing or using materials with good plasticity.

10、 There are indentations on the surface of the bent part

Reason analysis: 1. The fillet radius of the concave mold is too small; 2. The surface of the concave mold is rough, and the gap between the concave and convex molds is too small.

Solution: 1. Increase the fillet radius of the concave mold; 2. Adjust the gap between the concave and convex molds.

11、 The curved surface is compressed, causing the material to become thinner

Analysis reasons: 1. The concave die has too small rounded corners; 2. The gap between the concave and convex molds is too small.

Solution: 1. Increase the fillet radius of the concave mold; 2. Increase the gap between the concave convex films.

12、 The bottom of the U-shaped bent part forms an arch

Analysis reason: The concave mold does not have a top material device.

Solution: Add a top material device or add a calibration process.