How to solve the problem of springback and cracking of automobile stamping parts?

2019-05-31 17:10:19

The quality inspection of automotive stamping parts needs to achieve: smooth surface, clear edges, enough rigidity and dimensional stability, and can not have wrinkles, scratches, brushing and other defects.

Common quality problems in the production of automotive stamping parts are: rough surface, inadequate dimensional accuracy, inadequate stiffness, surface cracking, indentation and other defects. Especially indentation, scratch, pitting and other problems are easy to occur, and the occurrence of indentation, pitting and other defects is due to defects on the surface of the die or foreign bodies or sand particles on the surface of the die or blank. There will be abnormal marks in the production process of automotive stamping parts. There will be bright spots and bright marks when polishing the surface with asphalt. Scratches and bumps usually occur when workers are not careful in operation. They are also easy to occur when parts are turning around. The more turnaround times, the more chance of bumps and scratches.

How to avoid similar situations and improve the quality of automobile stamping parts?

Causes of cracking and solutions: When automobile stamping parts are stretched, flange wrinkling and side wall wrinkling will occur because of compression deformation. To avoid this phenomenon, wrinkling can be eliminated by increasing the tensile stress in the plate, and blank holder force can be increased by increasing the drawing rib, reducing the radius of the fillet of the die, adjusting the gap between the blank surface and the drawing gap. The tensile deformation force of the stamping part formed locally inside is higher than that of the side wall material, which will lead to two-way elongation deformation. If the external material can not supplement the internal part, it will cause fracture because of the excessive deformation. How to overcome this problem?

Firstly, the blanking method can ensure the quality of the edge section of the blank and improve the edge state of the blank. The size of the concave flanging blank can be determined effectively by increasing the material size appropriately. If the size of the blank becomes larger or the shape is inappropriate, it is necessary to change its size or shape and adjust the stamping process to overcome the edge cracking.

Secondly, the clearance between the punch and the concave die should be uniform, and the fillet of the punch and the concave die should be properly enlarged to increase the drawing or shaping process, so as to ensure the uniform resistance of materials entering the concave die everywhere, so as to effectively overcome the shear fracture.

Reasons for rebound and solutions:

The springback of automobile stamping parts is caused by the inappropriate process and the unreasonable die structure, which leads to the insufficient plastic deformation of materials in the deformation zone. To solve this problem, first of all, we should adopt reasonable process to improve the stress state of sheet metal in the forming process, and secondly, we can also adopt springback angle, springback radius and die clearance to solve this problem.

In order to ensure that the car will not produce resonance, noise and so on in the course of driving, it is necessary to ensure that the panel has certain stiffness requirements. When the size and shape of the panel structure do not change, the greater the plastic deformation, the better the stiffness during the stamping process. In order to ensure sufficient stiffness, the drawing depth should be increased appropriately in the design, or the process supplement should be selected to increase. In order to improve the rigidity of stamping parts, the methods of stretching bar, stretching threshold and increasing blank holder force are used to increase the plastic deformation.