Shell stretch stamping is a kind of stamping made by stretch technology. Drawing is to press the flat metal sheet into the die through the movement of the punch. The shell drawing stamping parts are widely used, such as automobile parts, household products, electronic equipment, etc.
The shell stretching stamping part can stretch the sheet metal into a cylindrical bottle type part; In the drawing operation, the diameter of the blank is affected by the circumference of the shell, and the circumference is affected by the fluidity of the stamping materials and the inward flow resistance and edge resistance of the peripheral materials; When the resistance of the edge material exceeds the limit, the edge will wrinkle and become unstable.
To avoid wrinkling, the stamping material must flow smoothly between the punch and the blank holder. The two main reasons for tensile fracture are: the ratio of the diameter of the drawn stamping part to the diameter of the blank exceeds the limit value, and the stretching radius is drawn from a flat blank to a shell, when the shell is stretched to a shell with a smaller diameter, there is a limit value for the inward flow distance of the material, usually called the stretching coefficient.
The ultimate tensile coefficient is affected by such factors as material fluidity, material compression resistance and flow resistance caused by compression. Excessive flow resistance causes the shell edge to be damaged and wrinkled, which is the area with the weakest material resistance.
