How to select high quality automotive stamping parts?

2019-09-03 16:57:49

Automobile stamping parts should have good optimization design methods, so stamping manufacturers take stamping optimization design as an important way to reduce the cost of automobile manufacturing, which can make automobile appearance beautiful. The reduction of air resistance can also reduce the number of stamping parts and solder joints, which can effectively reduce costs.

Empirical methods. This method is mainly based on some empirical formulas, so its application scope is affected. It is mainly applied to the simple-shaped developable stamping parts (such as rotary parts, bending parts, or stamping parts composed of these simple parts). Generally speaking, the method of unfolding the free-form surface of plate parts by experience is a kind of method with the nature of convenience. Its accuracy is affected by many factors, such as the abundant experience of users, the empirical formula adopted and the selection of specific technological parameters. Its accuracy needs to be further improved.

The basic assumption of slip line method is that the thickness of flange is constant, and it is in the state of plane strain, the material is isotropic, no hardening, and the effect of friction distribution on plastic flow is not considered.

The description of slip line method shows that only stamping parts with relatively simple shape can establish the corresponding slip line field. And only under very simple boundary conditions can the mathematical expression of the slip line be given from the solution of the eigenvalue. Generally, the approximate slip line field is obtained by means of numerical integration of characteristic equation and recurrence point by point according to given boundary conditions. This method is based on the transformation of differential equation of characteristic line into finite difference relation and the characteristics of slip line. Therefore, the slip line method is difficult to be popularized and applied in practical production because of its complicated mathematical operation.

Geometric mapping method. They believe that the mapping of workpiece to blank can be realized according to some assumptions without considering the boundary conditions such as deformation force, stress-strain relationship and boundary friction. Firstly, the wooden model is meshed, and the coordinates of nodes are obtained by coordinate measuring instrument. Or the mesh can be directly divided by the CAD model in the computer. Assuming that the thickness of workpiece is constant and the area of mesh is constant before and after deformation, the three-dimensional space mesh is mapped to two-dimensional plane, thus the initial blank shape and the stress distribution of workpiece can be inferred.

The simulation method. The simulation method is based on the similarity of mathematical descriptions of many physical problems under certain assumptions. Through the theory of mathematical similarity, the metal flow of sheet metal flange is simulated by the model composed of other physical media. Laplace and Poising equations are widely used in sheet metal forming.