Stamping is mainly classified according to the process, which can be divided into two categories: separation process and forming process. The separation process is also called cutting, and its purpose is to separate the stamping parts from the blank along a certain contour line, while ensuring the quality requirements of the separation section. The purpose of the forming process is to make the blank undergo plastic deformation under the condition of not breaking the blank, and to make the required shape and size of the workpiece. In actual production, it is often a combination of several processes to apply to a workpiece. Shearing, bending, punching, deep drawing, bulging, spinning and straightening are several main stamping processes.
Separation process
(Die cutting)
It is a basic stamping process for separating materials by using molds, which can directly make flat parts or prepare blanks for other stamping processes such as bending, deep drawing, forming, etc., and can also be carried out on already formed stamping parts, such as cutting, trimming, etc. Punching is widely used in automobile, household appliances, electronics, instruments and meters, machinery, railways, communication, chemical industry, light industry, textiles, and aerospace industries. Punching process accounts for about 50% ~ 60% of the total stamping process. Forming process
Bending: A plastic forming method that bends metal plates, tubes, and profiles into a certain angle, curvature, and shape. Bending is one of the main processes widely used in the production of stamped parts. The bending of metal materials is essentially an elastic-plastic deformation process, and after unloading, the workpiece will produce elastic recovery deformation in the direction, which is called springback. Springback affects the accuracy of the workpiece and is a technical key that must be considered in the bending process.
Deep drawing: Deep drawing is also called drawing or pressing, which is a kind of stamping processing method that uses molds to transform 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 thin-walled parts. If it is used in combination with other stamping forming processes, it can also be used to make parts of extremely complex shape. In stamping production, there are many kinds of deep-drawn parts. Because of their different geometric shape characteristics, the position of the deformation zone, the nature of the deformation, the distribution of the deformation and the stress state and distribution law of each part of the blank have considerable and even essential differences. Therefore, the determination methods of process parameters, the number and sequence of processes and the principles and methods of mold design are all different. According to the characteristics of deformation mechanics, various deep-drawn parts can be divided into four types: straight wall rotating body (cylindrical parts), straight wall non-rotating body (box-shaped parts), curved surface rotating body (curved surface parts) and curved surface non-rotating body.
Stretch forming is a process in which sheet metal is subjected to tensile forces through a stretch forming die, causing uneven tensile stress and strain in the sheet metal. As a result, the contact surface between the sheet metal and the stretch forming die gradually expands until it completely adheres to the die surface. Stretch forming is mainly used to manufacture materials with certain plasticity, large surface area, slow and smooth curvature changes, and high quality requirements (accurate shape, smooth and streamlined, stable quality) of double曲 surface蒙皮. Stretch forming has a low cost and great flexibility because of the simple process equipment and equipment used. However, the material utilization rate and production rate are low.
molding is a metal rotary processing process. During the processing, the blank rotates with the active rotation of the spinning mold or the spinning head rotates around the blank and the spinning mold, and the spinning head moves relatively to the core mold and the blank, so that the blank produces continuous local deformation to obtain the required hollow rotary parts.
Shaping is a secondary trimming of the product's shape using a predetermined mold shape. It mainly reflects in pressing flat, spring foot, etc. When some materials have elasticity and cannot guarantee the quality of the secondary molding, it is used as a secondary processing.
Deep drawing is a processing method that uses a mold to stretch the sheet metal, thinning the local surface area to obtain the parts. The common ones are the bulging forming, the deep drawing of cylindrical (or tubular) blank and the stretching forming of the plate blank, etc. Deep drawing can be achieved by different methods, such as rigid mold deep drawing, rubber deep drawing and hydraulic deep drawing, etc.
Flanging is a plastic deformation method that bends the narrow band area of material on the edge of a thin plate blank or on the edge of a pre-drilled hole on the blank into a vertical flange along a curve or straight line. Flanging is mainly used for edge reinforcement of parts, trimming, and making parts with other parts assembled, connected, or with complex special shapes and reasonable space for three-dimensional parts, while improving the rigidity of the parts. In large sheet metal forming, it can also be used as a means to control cracking or wrinkling. Therefore, it is widely used in industrial departments such as automobiles, aviation, aerospace, electronics, and household appliances.
Reduction is a stamping method for reducing the diameter of the open end of a previously stretched hollow workpiece or billet. The diameter change of the workpiece end before and after reduction should not be too large, otherwise, the material at the end will wrinkle due to the intense compression deformation. Therefore, a necking from a larger diameter to a very small diameter often requires multiple reductions.