Stamping Process Classification

Stamping is mainly classified according to process and 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 material 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.
Separation process
(Blanking)
It 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, drawing, forming, etc. It can also perform incisions, trimming, etc. on formed stamping parts. . Blanking is widely used in industrial sectors such as automobiles, household appliances, electronics, instrumentation, machinery, railways, communications, chemicals, light industry, textiles, and aerospace. Blanking processing accounts for about 50% to 60% of the entire stamping process.
Forming process
Bending: A plastic forming method that bends metal sheets, pipes and profiles into certain angles, curvatures and shapes. Bending is one of the main processes widely used in the production of stamping parts. The bending of metal materials is essentially an elastic-plastic deformation process. After unloading, the workpiece will produce directional elastic recovery deformation, which is called springback. Springback affects the accuracy of the workpiece and is a key technical issue that must be considered in the bending process.
Deep drawing: Deep drawing, also called drawing or calendering, is a stamping processing method that uses a mold to turn the flat blank obtained after punching into an open hollow part. The deep drawing process can be used to make cylindrical, stepped, conical, spherical, box-shaped and other irregular-shaped thin-walled parts. If combined with other stamping forming processes, parts with extremely complex shapes can also be manufactured. In stamping production, there are many types of deep-drawn parts. Due to their different geometric characteristics, there are considerable or even essential differences in the location of the deformation zone, the nature of the deformation, the distribution of the deformation, and the stress state and distribution of each part of the blank. Therefore, the determination methods of process parameters, number and sequence of processes, and mold design principles and methods are different. According to the characteristics of deformation mechanics, various deep-drawn parts can be divided into four types: straight-walled rotary bodies (cylindrical parts), straight-wall non-rotating bodies (box-shaped bodies), curved surface rotary bodies (curved surface shape parts) and curved surface non-rotating bodies. type.
Drawing is to apply tensile force to the sheet through the drawing die, which causes uneven tensile stress and tensile strain in the sheet. Then the joint surface of the sheet and the drawing die gradually expands until it completely fits the drawing model surface. The applicable object of drawing is mainly to manufacture hyperbolic skins whose materials have certain plasticity, large surface area, gentle and smooth curvature changes, and high quality requirements (accurate appearance, smooth streamlines, and stable quality). Because the process equipment and equipment used in drawing are relatively simple, the cost is low and the flexibility is high; however, the material utilization rate and productivity are low.
Spinning is a metal rotation processing process. During the processing, the blank actively rotates with the spinning die or the spinning head actively rotates around the blank and the spinning die. The spinning head makes feed motion relative to the mandrel and the blank, causing continuous local deformation of the blank to obtain the required hollow rotation. body parts.
Shaping is to use the established grinding tool shape to reshape the appearance of the product. Mainly reflected in the pressing surface, elastic feet, etc. For some materials that are elastic and cannot guarantee the quality of one-time molding, reprocessing is used.
Bulging is a processing method that uses a mold to stretch and thin the sheet to increase the local surface area to obtain parts. Commonly used ones include relief forming, bulging of cylindrical (or tubular) blanks and tension forming of flat blanks. Bulging can be achieved by different methods, such as rigid die bulging, rubber bulging and hydraulic bulging.
Flanging is a plastic processing method that bends the edge of a thin plate blank or the material in the narrow area of ​​the edge of a pre-made hole on the blank into a vertical edge along a curve or straight line. Flanging is mainly used to strengthen the edges of parts, remove trimmed edges, and create parts that are assembled and connected with other parts or three-dimensional parts with complex and special shapes and reasonable spaces, and at the same time improve the stiffness of the parts. It can also be used as a means to control cracks or wrinkles when forming large sheet metal. Therefore, it is widely used in industrial sectors such as automobiles, aviation, aerospace, electronics and household appliances.
Reducing is a stamping method that reduces the diameter of the open end of a stretched flangeless hollow piece or tube blank. The diameter change at the end of the workpiece before and after shrinkage should not be too large, otherwise the end material will wrinkle due to severe compression deformation. Therefore, shrinking the neck opening from a larger diameter to a smaller diameter often requires multiple neck openings.