Cold stamping or sheet stamping is a processing method in which a metal sheet

Cold stamping or sheet stamping is a processing method in which a metal sheet is subjected to pressure in a die to be cut away or formed. Daily necessities, such as aluminum pans, lunch boxes, washbasins, etc., are made by cold stamping. For example, in order to manufacture a lunch box, it is first necessary to cut a rectangular shape and have four rounded blanks (known as blanking), and then press the blank into a concave mold by a punch to form it (the artist calls it a drawing). In the drawing process, the flat sheet becomes a box shape, the four sides of which are vertically bent upward, and the materials of the four corners are piled up and wrinkles are seen.

The parts used in cold stamping are: engine oil sump, brake bottom plate, automobile frame and most body parts. These parts are generally formed by blanking, punching, drawing, bending, flanging, trimming and other processes. .

In order to manufacture cold stamped parts, a die must be prepared. The die is usually divided into two pieces, one of which is mounted on the press and can slide up and down, and the other is installed under the press and fixed. At the time of production, the blank is placed between two dies, and when the upper and lower dies are closed, the stamping process is completed.

The welding method in which the common worker holds the mask in one hand and the welding tongs and the welding rod connected to the electric wire in the other hand is called manual arc welding, which is a high-temperature melting electrode and a weldment generated by arc discharge to be joined. Manual arc welding is not widely used in automobile manufacturing.

In automotive body manufacturing, the most widely used is spot welding. Spot welding is suitable for welding thin steel sheets. During operation, the two electrodes pressurize the two steel sheets to make them conform to each other, and at the same time, the bonding points pass current, and are heated and melted to be firmly joined. When two body parts are welded, the edges are welded every 50 points to form a discontinuous multi-point connection between the two parts. Welding the entire car body usually requires thousands of solder joints. The strength of the solder joints is very high. Each solder joint can withstand a tensile force of 5KN, and even the steel sheet is torn, and the solder joint portion cannot be separated.