Analysis and control measures of tension wrinkling

Analysis and control measures of wrinkling and cracking of automobile cover parts during stretching

(15:58:57) Abstract] this paper analyzes the phenomenon of wrinkling and cracking of automobile cover parts in a large pen making country with more than 3000 pen making enterprises, more than 200000 employees and an annual output of more than 40 billion ballpoint pens, and explains in detail how to solve the problem of wrinkling and cracking of parts during stretching from the aspects of process, design, adjustment and so on Cracking methods and control measures

[key words] control measures for tension wrinkling and cracking of automobile panels

1 introduction

the shape of automobile body is welded by many panels with large outline dimensions and spatial curved shape, so there are high requirements for the dimensional accuracy and surface quality of panels. The body covering parts shall have smooth surface and clear lines, and shall not have wrinkles, scratches, roughening and other surface defects. In addition, they shall also have sufficient rigidity and dimensional stability. The quality of the body surface depends on the result of the panel drawing, and the drawing die is the key to pull out the qualified panel. Since the factors that affect the quality of stretched parts are mainly wrinkling, cracking, roughening and springback, it must be seriously considered from the preparation of stamping process to the design of die. After the mold is manufactured, during the debugging of the drawing die, the wrinkling and cracking of the drawing parts must be carefully analyzed and studied, and corresponding measures must be taken

there are many reasons for wrinkling and cracking of stretched parts in the drawing process, and the main reasons are as follows:

(1) whether the design of drawing die is reasonable

(2) problems caused by mold processing quality (surface accuracy, hardness, etc.)

(3) press accuracy (slider parallelism, etc.)

(4) sheet metal quality (thickness out of tolerance)

the reasons for cracking and wrinkling mentioned above are discussed respectively

2 the processing technology of tensile parts does load the sample through the movement of the beam of the experimental machine.

the manufacturability of tensile parts is the first consideration in compiling the stamping process of covering parts. Only by designing a reasonable and technologically good tensile part can we ensure that there is no wrinkle, no crack or less wrinkle, less crack in the stretching process. When designing drawing parts, we should not only consider the design of variables such as stamping direction, stamping position, pressing surface shape, drawing rib shape and configuration, process supplement part, but also reasonably increase the process supplement part and correctly determine the pressing surface. There is a complementary relationship between variable designs. How to coordinate the relationship between variables is the key of forming technology. To make it meet not only the stretching of this process, but also the needs of die design and manufacturing process of this process, and create favorable conditions for the next flanging and flanging process, we should generally pay attention to the following aspects

2.1 determination of stamping direction

the stamping direction of parts is the first problem to be encountered in determining the drawing process. It not only determines whether a satisfactory drawing part can be drawn, but also affects the number of process supplements and the shape of the pressing surface. The reasonable determination of stamping direction should meet the following three requirements

(1) ensure that the punch can enter the female die. As shown in Figure 1a, the shape of the lower right side of the die protrudes outward, and the most protruding point exceeds the size of the die opening, so that the punch cannot enter the die. This stretching direction cannot be stretched, and the stretching direction must be changed so that the punch can enter the die. As shown in Figure 1b, rotate figure 1A clockwise by an angle so that the punch can enter the die

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