How to solve the problems of deep drawing cracks and rupture defects of stamping parts

2021-03-23 12:03:18 admin

How to solve the problems of deep drawing cracks and rupture defects of stamping parts




In the stamping process of metal stamping parts, cracks or ruptures sometimes occur, causing the stamping parts to be scrapped. The main reason is that the local tensile stress exceeds the strength of the sheet metal. There are many reasons for the cracking of stamping parts. In the process of solution, the cracked parts should be carefully checked, and the cause of the rupture should be inferred according to the specific situation, so as to work out a specific plan to solve the rupture problem to prevent the stamping part from rupturing.

1. Causes of deep drawing cracks and rupture defects

(1) The stamping performance of the material does not meet the process requirements. Sheets of different materials have different elongation and tensile strength. When the performance of the selected sheet does not meet the drawing requirements, the sheet will be cracked during the stamping process.

(2) The thickness of the sheet is out of tolerance. The thickness of the sheet is too poor, the gap becomes smaller during the deep drawing process, the compressive stress of the sheet increases, the drawing is difficult, and the sheet does not flow easily and is cracked.

(3) The surface quality of the sheet material is poor, with scratches, rust and impurities. There are scratches on the surface of the sheet metal, which easily cause stress concentration during the deep drawing process, and surface corrosion and impurities will increase the resistance of the sheet metal forming process.

(4) Lubricant is not applied in accordance with the requirements of the process regulations.

(5) The feed resistance of the pressing surface is too large. Large rough shape, small blanking rib clearance, small die fillet radius, high drawing beads, poor surface finish of blanking surface and drawing beads, will cause the flow resistance of the sheet to increase and cause rupture.

(6) The position of the sheet material is incorrect. During the production operation, the position of the sheet material is deviated, which leads to too much material on one side and too little material on the other. The excessive pressure on the side is subject to large compressive stress, which makes it difficult to feed the material, causing cracks.

(7) Improper mold installation or poor precision of the press will cause uneven blank holder force, and excessive local blank holder force will cause the sheet to rupture.

(8) The partial drawing amount is too large, and the drawing deformation exceeds the sheet material deformation.

2. Preventive measures for cracks and ruptures of stamping parts

(1) Select the appropriate sheet material in the design and development stage to meet the requirements of deep drawing performance.

(2) Check the surface quality of the sheet metal during the production process, and the surface of the sheet metal is rusted and impurity.

(3) Regularly check and maintain the stamping die, polish the surface of the die, and make the surface of the die rough.

(4) Standardized operations in the production process, and strict implementation of oiling requirements.

(5) Regularly check and maintain the accuracy of stamping equipment.

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How to solve the problems of deep drawing cracks and rupture defects of stamping parts