In recent years, the automotive industry has continued to rise. With the continuous development of the market, people have higher and higher requirements for the performance and quality of automobiles. However, in the automobile manufacturing process, due to various reasons, the automobile research and development cycle has become longer and the manufacturing is also very difficult. This also has a certain impact on the overall manufacturing progress and level of the automobile. 

Among them, the manufacturing of automobile stamping parts It is an important link that affects automobile manufacturing, so all automobile manufacturers gradually pay attention to the research and manufacture of automobile stamping parts. In the manufacturing process of automobile stamping parts, various links need to be closely coordinated to effectively avoid various problems that may occur in the production process of stamping parts. 

The problems that occur in the production process include springback problems, so how to effectively deal with the problems The spring problem is also an aspect to improve the overall accuracy of the car. The following will briefly analyze the types of springback problems of automobile stampings, the reasons for the springback problems and the factors that affect the springback.

1. Types of springback defects in automotive stampings

The first is the distortion defect, including shape distortion, shallow drawing distortion, multi-curve shape distortion, etc. Due to the punching force in the processing process, it will cause the shape of the stamping part to be distorted during the processing. During the punching process, The blanking gap is unreasonable, so that one side of the material is compressed, and the other side is stretched, so the shape of the stamping part will be distorted during the manufacturing process. There is also the defect of large curve changes. The reason for this is that the stress is different in the thicker part of the material. There are also warpage defects, which may be edges or surfaces. The reason for this is that the gap force and the reaction force are not in a straight line, resulting in torque, or the gap of some molds is too large. There are many other problems, such as positive and negative springback defects, these defects will have a certain impact on the quality and accuracy of the stamping parts, some can not even be reused, so improve the production process to find out the springback defects of automotive stamping parts The reason is very necessary.

2. Factors affecting rebound

(1) Material performance

Within the elastic limit of the material, the greater the degree of deformation of the material and the higher the yield limit, the greater the elastic modulus of the material. In this way, during the processing of the material, the greater the elastic modulus, the greater the elasticity of the material. If the material is larger, the work hardening will be more serious. If the elastic modulus of the material is smaller, the degree of rebound during processing will be smaller, and the ability to resist elastic deformation will be stronger.

(Two) bending center angle

The greater the value of the central angle of bending, the greater the cumulative value of springback, which will cause serious springback. The length of the deformation of the stamping part increases with the increase of the central angle of bending.

(3) Mold clearance fit

When the mold is designed, it is necessary to leave a gap that is twice the thickness of the material in the opposite working part, and the product is contained in the gap. In order to achieve a better flow of materials, parts of the mold must be researched and matched after the mold is processed. Especially for bending molds, the larger the gap between the working parts, the greater the springback. If the allowable range of sheet thickness error is, the larger the springback will be, and the mold gap will not be well. Sure.

(4) Relative bending radius

The value of the relative bending radius is proportional to the rebound value, so the larger the curvature of the stamping part, the less likely it is to be bent and formed.

(5) Part shape

The possibility of springback is different when the shape of the part is different. When the complicated bending stamping part is bent and formed at one time, the stamping part will be changed due to the mutual restraint of the various parts of the stamping part during the forming process and the friction between the mold and the material. The stress state of each part, so that the amount of springback changes.

(6) Molding process

The forming process of stamping parts is an important aspect that restricts its rebound value. Generally speaking, the rebound effect of corrected bending is better than that of free bending. If the same processing effect is to be achieved in the production of the same batch of stamping parts, the bending force required for correcting bending is much larger than that of free bending. Therefore, if the same bending force is used in the two methods, the final effect will be different. The greater the correction force required to correct the bending, the smaller the springback of the stamping part, and the correction bending force will stretch the outer fibers in the deformation zone to achieve the forming effect. After the bending force is unloaded, the inner and outer fibers will be shortened, but the rebound direction of the inner and outer sides is opposite, so that the outward rebound of the stamping parts can be relieved to a certain extent.

Three, the solution to the rebound defect

(1) Product design part

First of all, in terms of materials, materials play an important role in the manufacturing process of stamping parts. The material used in stamping parts has a great influence on its quality. Under the premise of meeting the requirements of the product, it is necessary to choose materials with low yield or The thickness of the material can also be appropriately increased. The second is the design of the shape of the stamping part. The shape of the stamping part’s springback also has a very important impact. In a bending of a complex stamping part, due to the complex stress in all directions, there are other factors such as friction. It is very difficult to eliminate springs, so when designing the shape of the product, a combination of several parts can be used for complex stamping parts to solve the springback problem. In addition, anti-rebound ribs can be set, which can also effectively solve the rebound defect. Under the premise of meeting the requirements of stamping parts, additional anti-rebound ribs can be set according to product requirements and rebound amount requirements, which can change the shape of the product. Finally, the rebound defect can also be solved by reducing the value of the R angle of the curved part.

(2) Process design

The first is the pre-forming process of mold design. Adding the pre-forming process can make the one-time forming stamping parts distributed in different processes, which can eliminate the internal stress during the forming process to a certain extent, thereby solving the springback defect. The second is to reduce the gap between the concave and convex molds, which can be adjusted to about double the thickness of the material to maximize the fit between the material and the mold. At the same time, the hardening of the mold can also effectively reduce the phenomenon of stamping parts. Wear of the mold. There is also shaping of the product. If the design of the product cannot be changed at will, the stamping can be shaped at the end, which is also the last resort. Finally, there are some other methods to solve the rebound defect, such as the use of hydraulic stamping equipment, the punch set footer, etc., can solve the rebound defect to a certain extent.

All in all, the springback problem of stamping parts is a major problem in automobile manufacturing, and it is also a very complex problem. How to better solve the springback problem requires the unremitting efforts of technicians. Through continuous exploration and hard work, practice can be achieved. Experience, and conduct a detailed analysis of the summarized experience, find out the factors that affect the rebound, and find a practical and effective method to solve the rebound defect, and comprehensively rectify the production process, so that the quality of the stamping parts can be improved.

Link to this article： How To Solve The Automobile Stamping Springback Problem

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