Covering parts mainly refer to the sheet steel parts covering the engine, chassis or forming the cab, surface and interior of the car. Compared with the common stamping parts, the panel has the characteristics of complex shape, thin material, high surface quality, good rigidity, large structure size and mostly space curved surface. The stamping process of panel is usually completed by blanking (or cutting), forming, trimming, punching and flanging. The forming process of panel is mainly drawing, including bulging, flanging and bending. In most cases, forming is the key to manufacturing such parts, which directly affects the product quality, material utilization, production efficiency and manufacturing cost.

As for mold material, HT300 or HT250 is usually used for common mold base; In the forming part, alloy cast iron such as mocr cast iron or nodular cast iron is usually used in large and medium batch production, and HT300 is used in small batch production; Air cooled steel (7CrSiMnMoV) can be used if the material thickness is less than 1.0 mm.

Drawing, trimming and flanging are the most basic processes, among which the drawing process is the key one, which directly affects the product quality, material utilization, production efficiency and manufacturing cost.

There are many kinds of cutting tools involved in panel die processing, such as plane milling cutter, corn milling cutter, end milling cutter, drill and tap with different diameters are needed in processing guide plate, discharge plate, pressing plate groove, support surface and ejector hole.

(article from Kaihang plastics)