Stamping is mainly classified according to the process, which can be divided into two categories: the separation process and the molding process. The separation process is also called stamping, and its purpose is to separate the stamping parts from the sheet material along a certain contour line, while ensuring the quality requirements of the separation section. The purpose of the forming process is to plastically deform the sheet without destroying the workpiece in order to obtain a workpiece of the desired shape and size. In real production, several processes are often applied in complex to one workpiece. Punching, bending, cutting, stretching, protruding, rotating and straightening are the main processes of stamping.
Punching is a basic stamping process that uses a mold to separate materials. It can be directly made into flat parts or prepare blanks for other stamping processes such as bending, deep drawing, molding, etc. like automobiles, household appliances, electronics, instruments, machinery, railways, communications, chemical industry, light industry, textiles and aerospace. The stamping process accounts for 50% to 60% of the entire stamping process. Bending: A plastic forming method in which sheet metal, fittings, and profiles are bent into angles, curves, and shapes.
Bending is one of the main processes widely used in the production of stamped parts. The bending of metallic materials is an elastic-plastic deformation process. After unloading, the workpiece will produce a directional elastic recovery deformation, which is called elastic return. Springback affects the accuracy of the workpiece and is a key technology to consider in the bending process.
Deep drawing. Deep drawing, also known as drawing or calendering, is a stamping method that uses a die to turn a flat blank obtained after stamping into an open hollow part. The deep drawing process can be used to produce cylindrical, stepped, conical, spherical, box-shaped, and other thin-walled, irregularly shaped parts. If it is combined with other stamping processes, it can also produce extremely intricately shaped parts. There are many types of deep-drawn parts in the stamping industry. Due to various geometric characteristics, the position of the deformation zone, the nature of deformation, the distribution of deformation, the stress state and the law of distribution of each part of the workpiece have significant, even significant differences. Therefore, the way to determine the process parameters, the number and sequence of processes, the principles and methods of designing molds are different. According to the characteristics of deformation mechanics, various deep drawing parts can be divided into four types: straight wall rotating body (cylindrical part), straight wall non-rotating body (box body), curved surface rotating body (curved surface shape). parts) and curved surfaces of non-rotating bodies.
Drawing consists of applying stress to the sheet through the drawing die, so that the sheet creates uneven tensile stress and tensile strain, and then the surface of the sheet and the drawing die gradually expand until it is fully connected to the drawing model. surface fitting. Applicable stretching object is mainly double curvature skin with a certain plasticityew, large surface area, moderate and smooth change in curvature and high quality requirements (precise shape, smooth streamlining, stable quality). Due to the relatively simple processing equipment and equipment used in painting, the cost is low and the flexibility is large, but the material utilization rate and productivity are low.
Spinning is a rotary metalworking process. During processing, the workpiece is actively rotated by the spinning die, or the spinning head is actively rotated around the workpiece and the spinning die, and the spinning head is fed relative to the mandrel and workpiece, causing continuous local deformation of the workpiece until the desired hollow body parts of rotation are obtained. Molding consists in using a fixed abrasive mold to carry out secondary cutting to the shape of the product. Mainly reflected in the pressing plane, spring legs and so on. Reprocessing is used when some materials are elastic and the quality of a single mold cannot be guaranteed.
Bumping is a machining method that uses a mold to stretch and thin the sheet to increase the local surface area to produce a part. Waveforming, buckling of cylindrical (or tubular) workpieces, and stretching of flat workpieces are commonly used. Bloating can be achieved by a variety of methods such as hard molded inflation, rubber inflation, and hydraulic inflation. Flanging is a plastic processing method in which the edge of a thin sheet workpiece or material in a narrow place of the edge of a prefabricated hole on the workpiece is bent into a vertical edge along a curve or a straight line.
Flanging is mainly used to reinforce the edge of a part, remove scraps, and make parts on parts that are assembled and connected with other parts or 3D parts of complex special shape and reasonable spaces, while at the same time increasing the rigidity of the parts. It can also be used as a cracking or wrinkle control when forming large metal sheets. Therefore, it is widely used in industrial sectors such as automotive, aviation, aerospace, electronics and household appliances.
Tapering is a stamping method in which the diameter of the open end of a stretched hollow part without flanges or tubular stock is reduced. The end diameter of the workpiece before and after shrinkage should not change too much, otherwise the material at the end will wrinkle due to strong compression deformation. Therefore, shrinking the neck from a larger diameter to a smaller diameter often requires multiple shrinks.