The car body is welded by many covering parts with larger contours and curved space. The dimensional accuracy and surface quality of the covering parts are very high, because the quality of the covering parts will directly affect the quality of the car body. Covers generally require smooth surfaces, clear ridges, sufficient rigidity and dimensional stability, and no wrinkles, scratches, napping and other defects. However, defects such as rough surface, insufficient dimensional accuracy, insufficient rigidity, surface cracking, and indentation often occur during stamping production. In particular, problems such as indentation, scratches, and pitting are the most likely to occur, and defects such as indentation and pitting are caused by defects on the mold surface or foreign matter or sand particles on the pressing surface or rough surface of the mold.
When the automobile metal stamping parts are stretched, the flange wrinkle and the side wall wrinkle will be generated due to compression deformation. To avoid this phenomenon, the inner tensile stress of the plate can be increased to eliminate the wrinkles. You can also increase the tensile ribs, Reduce the corner radius of the die, adjust the gap of the blanking surface and the stretching gap to increase the blank holder force.
First, the blanking method is used to cut the material to ensure the quality of the edge section of the blank, thereby improving the edge state of the blank, and appropriately increasing the material size to effectively determine the size of the concave flanging blank. If the size of the blank becomes larger or the shape is improper, it is necessary to change its size or shape and adjust the stamping process to overcome edge cracks.
For cracks caused by stretching, it is necessary to increase the corner radius of the convex and concave die, adjust the blank holder force appropriately, and reduce the deformation resistance of the flange deformation zone. Without affecting the use, properly increase the corner, reduce the local forming depth, increase the process cut or process hole, and increase the flow of material inside the local shape to reduce deformation. Moreover, the factors affecting the forming quality are the stretching temperature and lubrication state. Because if the temperature is low, the sheet forming will be poor, and the quality of the stretched parts will be poor.
