Sheet metal forming, also known as stamping, is usually formed at room temperature, so it is also known as cold stamping. For a certain metal sheet part, it usually needs to go through multiple process steps before it can be directly used for assembly. There are several common technological processes as follows

(1) Punching and cutting

For the convenience of production and transportation, sheet materials are mostly rolled materials. Firstly, the sheet metal must be separated into shaped blanks before it can be used for stamping production. This is a complex plastic shear and failure process, where local hardening occurs at the edges of the sheet metal. Punching and trimming are also punching processes.

(2) Bending

A simpler scenario is to bend the sheet material along a straight line. Plastic deformation occurs only in the curved part. If the material ductility is insufficient, the outer surface of the bent part is prone to cracking. However, due to rebound, controlling the bending angle is very difficult. One side of the sheet material is clamped and stationary, while the other side is clamped and rotated around the edge; The punch moves downwards to press the material into the V-shaped mold; In rolling machinery, complete sets of rolling rods, large panels, and complex groove sections can be manufactured using this process; 2.2 (d) is a flange, usually used for processing the edges of stamped parts. Bending the edge of the sheet until it adheres to the back of the sheet, thereby forming a rounded edge on the part, is called edge wrapping.

(3) Deep drawing forming

Deep drawing, also known as drawing, is a stamping process that uses a mold to turn the punched blank into an open hollow part. Usually, a drawing die consists of a convex die, a concave die, and a blank holder. The drawing process is widely used in automotive panels, and in combination with other processes, extremely complex shaped parts can be manufactured. According to the characteristics of deformation mechanics, it can be divided into four types: straight walled cylindrical parts, box shaped parts, curved shaped parts (referring to curved rotating bodies), and non rotating curved shaped parts.

In addition, there are various process methods such as bulging, hydraulic forming, tube bulging, and hot forming. Usually, the forming process of an industrial part involves many basic forming processes. Automotive panels are a complex part in sheet metal stamping processing, which generally requires multiple processes such as deep drawing, trimming, flanging, punching, etc. in order to be a usable part for assembly. The key to qualified covering parts lies in the feasibility of stamping. The quality of stamping directly determines the final quality of the part. This article is based on the simulation of the stamping process of the cover plate to optimize the structure and analyze the stress of the drawing die.

In order to provide accurate load information for subsequent mold structure optimization and analysis, the simulation of the panel drawing process achieves the following goals:

(1) In the simulation of drawing forming, the same mold surface grid as in the optimization and analysis of mold structure needs to be used. In this way, the surface node forces of the mold simulated by forming can be directly applied to the structural optimization and analysis model;

(2) The drawing forming simulation needs to simulate the good forming performance of the parts, that is, the parts can be produced;

(3) The material parameters and process conditions in the simulation of drawing forming should be as close as possible to the actual production situation, in order to ensure comparability between the results and the actual situation.

Due to the fact that sheet metal forming is a large deformation problem that includes geometric nonlinearity, material nonlinearity, and boundary condition nonlinearity, the selection of finite element algorithms, element types, material models, and handling of contact and friction will all affect