Stamping is mainly classified by process, can be divided into two major categories of separation processes and forming processes. Separation process, also known as blanking, the purpose is to make stampings along a certain contour from the sheet separation, while ensuring the quality of the separation section. The purpose of the forming process is to make the sheet without plastic deformation under plastic deformation conditions, the desired shape and size of the workpiece. In actual production, often a variety of processes integrated application of a workpiece. Blanking, bending, shearing, stretching, bulging, spinning, leveling are several major stamping processes.
Separation process
(Blanking)
　　Is a basic stamping process that uses mold release material to make flat parts directly or to prepare blanks for other stamping processes such as bending, drawing, forming, etc., as well as cutting, trimming, etc., on formed stampings . Blanking is widely used in automotive, household appliances, electronics, instrumentation, machinery, railways, telecommunications, chemicals, light industry, textiles and aerospace and other industrial sectors. Blanching processing accounts for about 50% to 60% of the entire stamping process. [2]
Forming process
　　Bending: the sheet metal, pipe fittings and profiles bent into a certain angle, curvature and shape of the plastic molding method. Bending is one of the major processes widely used in stamping parts. Metal bending is essentially a plastic deformation process, after unloading, the workpiece will have the direction of elastic recovery deformation, said rebound. Rebound affect the accuracy of the workpiece, the bending process must be considered the key technology.
Drawing: drawing is also called drawing or rolling, is the use of the mold so that after blanking the flat blank into an open hollow parts of the stamping method. With the drawing process can be made into cylindrical, stepped, tapered, spherical, box-shaped and other irregular shape of the thin-walled parts. When used in conjunction with other stamping processes, it is also possible to manufacture extremely complex parts. In the stamping production, drawing a wide range of types. Due to their different geometric characteristics, the location of the deformation zone, the nature of the deformation, the distribution of the deformation, and the stress state and distribution of the various parts of the blank have considerable or even substantial differences. Therefore, the process parameters, the number of procedures and the order of determination and mold design principles and methods are not the same. According to the characteristics of deformation mechanics, various drawing parts can be divided into four kinds: straight wall rotating body (cylindrical part), straight wall non-rotating body (box body), curved surface rotating part (curved surface part) and curved non-rotating body Types of.
　　Tensile is the tensile force exerted on the sheet through the tensile mold, which causes uneven tensile stress and tensile strain on the sheet, and then gradually expands until the sheet and the tensile mold surface fit completely. The main application of the object is to create the material of a certain plasticity, surface area, curvature changes and smooth and smooth, high quality (accurate shape, smooth streamline, stable quality) double curvature of the skin. Due to the drawing process equipment and equipment used is relatively simple, so the lower cost, flexibility; but material utilization and lower productivity.
Spinning is a metal turning process. In the process of machining, the blanks are actively rotated by the spinning mold or the spinning head is rotated around the blanks and the spinning molds. The spinning heads are fed and moved relative to the mandrel and the blanks, so that the blanks are continuously deformed locally to obtain the desired hollow revolution Body parts.
　　Shaping is the use of established shape of the abrasive shape of the product for the second trimming. Mainly reflected in the pressure plane, such as foot shells. Some materials for the existence of flexibility, can not guarantee a molding quality, the use of re-processing.
Bulging is the use of the mold so that the sheet material is thinning the surface area increases to obtain parts processing methods. Commonly used are ups and downs, cylindrical (or tube) rough bulging and flat blank stretch forming. Bulging can be achieved using different methods, such as rigid mold bulging, rubber bulging and hydraulic bulging.
　　Flanging is a plastic processing method of bending a material of a narrow strip region on a side edge of a preform hole in a sheet blank or a blank along a curve or a straight line into a vertical edge. Flanging is mainly used for the edge of the part to strengthen the removal of trimming and the parts made with other parts assembly, connection parts or complex shapes, reasonable space, three-dimensional parts, while improving the rigidity of the parts. In the large sheet metal forming, but also as a means of control rupture or wrinkles. So in the automotive, aerospace, aerospace, electronics and household appliances and other industrial sectors have been very widely used.
　　Necking is a stamping method that reduces the diameter of a flanged hollow part that has been drawn or the open end of a tube. Necking before and after the end of the workpiece diameter changes should not be too large, or the end of the material due to severe compressive deformation and wrinkling. Therefore, the smaller diameter necked neck from a larger diameter, often require multiple necking.