Common Problems and Solutions in Bending Process of Metal Stamping Parts

Bending is a fundamental procedure in metal stamping.Improper operation,unqualified molds or raw materials will lead to various defects.Below are frequent problems,causes and practical solutions.

1.Springback

Phenomenon:The workpiece bounces back after bending,resulting in larger angles than required and unstable shape.

Causes:Material elasticity,insufficient pressing force and unreasonable bending radius.

Solutions:

Adopt over-bending to offset springback.Increase the clamping pressure during processing.Choose materials with good ductility.Optimize the die structure to restrict material rebound.

2.Inaccurate Bending Angle

Phenomenon:The final angle fails to conform to design standards.

Causes:Mismatched V-die opening,unstable machine stroke and uneven material thickness.

Solutions:

Select V-dies according to sheet thickness.Calibrate the bending machine regularly.Keep raw materials uniform in thickness and flatness.

3.Cracks at Bending Corners

Phenomenon:Cracks or fractures appear on the outer arc of the bending area.

Causes:Too small bending radius,sharp edge burrs,poor material ductility and excessive tensile force.

Solutions:

Properly enlarge the bending radius.Remove burrs on sheet edges before processing.Use high-ductility metal materials.Apply lubricant to reduce surface tension.

4.Surface Scratches

Phenomenon:Linear scratches on the workpiece surface,affecting appearance.

Causes:Rough die surface,friction between material and mold,no protective measures.

Solutions:

Polish and maintain dies routinely.Attach protective film on raw sheets.Add professional stamping lubricant.Control feeding speed to reduce friction.

5.Surface Indentation

Phenomenon:Obvious die marks or dents on the part surface.

Causes:Excessive pressing force and direct contact between hard mold and workpiece.

Solutions:

Install anti-mark accessories or soft protective pads on molds.Adjust pressing force to a reasonable range.

6.Workpiece Distortion&Twisting

Phenomenon:Parts twist,deform or have inconsistent sizes in mass production.

Causes:Unlevel equipment,loose fixtures and inaccurate positioning.

Solutions:

Keep the bending machine horizontal and fasten all fixtures firmly.Standardize workpiece positioning.Conduct random inspection during mass production.