Professional analysis of stamping in mechanical process technology
In actual production, process tests similar to the stamping process, such as drawing performance tests, bulging performance tests, etc., are commonly used to test the stamping performance of materials to ensure the quality of finished products and a high pass rate.
Stamping is a forming processing method that relies on presses and molds to apply external force to plates, strips, pipes and profiles to cause plastic deformation or separation, thereby obtaining workpieces (stamping parts) of the required shape and size. Stamping and forging both belong to plastic processing (or pressure processing), and are collectively called forging. The blanks for stamping are mainly hot-rolled and cold-rolled steel plates and strips.
Compared with castings and forgings, stamping parts are thin, uniform, light and strong. Stamping can produce workpieces with reinforced ribs, ribs, undulations or flanges that are difficult to manufacture by other methods to improve their rigidity. Due to the use of precision molds, the workpiece accuracy can reach micron level, with high repeatability and consistent specifications, and holes, bosses, etc. can be punched out.
Cold stamping parts generally no longer undergo cutting processing, or only require a small amount of cutting processing. The accuracy and surface condition of hot stamping parts are lower than those of cold stamping parts, but they are still better than castings and forgings, and the amount of cutting processing is small.
Stamping is an efficient production method. The use of composite dies, especially multi-station progressive dies, can complete multiple stamping processes on one press, realizing the entire process from strip uncoiling, leveling, punching to forming and finishing. Automatic production. The production efficiency is high, the labor conditions are good, and the production cost is low. It can generally produce hundreds of pieces per minute.
According to process classification, it can be divided into two categories: separation process and forming process. The separation process is also called blanking. Its purpose is to separate the stamping parts from the sheet along a certain contour line while ensuring the quality requirements of the separated section. The purpose of the forming process is to plastically deform the sheet metal without breaking the blank and make a workpiece of the required shape and size. In actual production, multiple processes are often applied to one workpiece. Blanking, bending, shearing, drawing, bulging, spinning, and correction are the main stamping processes.
The surface and internal properties of stamping sheets have a great influence on the quality of stamped products. The thickness of stamping materials is required to be accurate and uniform; the surface is smooth, no spots, no scars, no scratches, no surface cracks, etc.; the yield strength is uniform and has no obvious Directionality; high uniform elongation; low yield-to-strength ratio; low work hardening.
In addition to the hydraulic press forming of thick plates, stamping equipment generally uses mechanical presses. With a modern high-speed multi-station mechanical press as the center, it is equipped with uncoiling, leveling, finished product collection, transportation and other machinery as well as a mold library and a quick mold change device, and is controlled by a computer program to form a high-productivity automatic stamping production line.
