Common Defects and Solutions of Industrial Bending Parts

In actual production processes, industrial bending parts often face various quality issues, mainly including springback, bending cracks, deviations, twisting, and dimensional tolerances. The occurrence of these problems is often influenced by multiple factors; therefore, when formulating bending processes and designing bending dies, it is necessary to comprehensively consider the following factors and corresponding solutions.

Springback

Springback is one of the key factors affecting the accuracy of industrial bending parts. To reduce springback, the following measures can be taken:

• Optimizing workpiece structure design: Choose a structure with good rigidity to enhance anti-springback capability.

• Die design optimization: Consider reducing elastic recovery in die design, such as using dies with specific angles or shapes.

• Using stretch bending technology: Effectively control springback utilizing stretch bending technology.

Other process measures:

• If conditions permit, use heated bending to take advantage of material thermoplasticity to improve forming effects.

• For U-shaped industrial bending parts, try using smaller or even negative gaps to reduce springback.

• Strictly control blank thickness to avoid excessive deviation, which makes it difficult to control springback and thus affects dimensional accuracy.

Bending Cracks

Bending cracks usually occur when the outer layer material of industrial bending parts exceeds its limit during the bending process. Methods to solve bending cracks include:

• Material selection: Choose materials with good plasticity, such as soft materials in annealed or normalized states, to enhance the bending processing limit.

• Blank preparation: Ensure that the sheet metal surface is free of scratches, cracks, and that the edges (shear surfaces) are free of burrs, breaks, and cold work hardening defects.

• Identifying rolling direction: Before bending the blank, identify the rolling direction of the sheet or coil and arrange the bending direction reasonably to reduce the risk of bending cracks.

Deviation

Deviation is mainly caused by asymmetry in parts or dies, leading to unequal friction forces on both sides of the workpiece, causing horizontal movement during the bending process. Solutions include:

Designing pressing devices: Incorporate pressing devices in the design of industrial bending parts to gradually bend the blank under a compressed state, effectively preventing sliding and ensuring a flat bottom of the workpiece.

Uneven Bottom

Uneven bottom is usually caused when the sheet metal doesn't tightly align with the bottom of the punch during pressing. The solution strategy includes:

Using a pressing top plate: Use dies with a pressing top plate to ensure that the top plate exerts enough pressure on the blank at the beginning of pressing, making the bottom tightly fit the punch.

Surface Scratches

Surface scratches refer to the scratches on the outer surface of the workpiece after bending, mainly caused by hard particles on the working surface, too small a radius of the die's rounded corners, or improper punch-die clearance. Solutions include:

• Increasing the die's rounded corner radius: Appropriately increase it to reduce scratches.

• Reducing surface roughness: Optimize the die's surface roughness.

• Adjusting clearance: Use reasonable punch-die clearance values.

• Maintaining cleanliness: Regularly clean the dies and working parts of the workpieces to avoid the residue of hard particles.