Metal stamping is the use of punching and die to deform or break stainless steel, iron, aluminum, copper and other materials to achieve a certain shape and size.
Metal stamping is sometimes referred to as sheet forming, but with a slight difference. The term "sheet forming" refers to the use of a sheet material, a thin-walled tube, a thin profile, or the like as a raw material. The forming method of plastic working is collectively referred to as sheet forming, and at this time, the deformation in the direction of the thick plate is generally not considered.
The stamping process can be roughly divided into two categories: separation process and forming process (also divided into bending, deep drawing, and forming). The separation process is to separate the stamping parts and the blanks along a certain contour line in the stamping process, and the quality of the separated sections of the stamping parts also meets certain requirements; the forming process is to plastically deform the stamping blanks without breaking. And into the required shape of the finished product, but also meet the requirements of dimensional tolerances.
According to the temperature conditions at the time of stamping, there are two methods of cold stamping and hot stamping. This depends on the strength, plasticity, thickness, degree of deformation, and equipment capabilities of the material, as well as the original heat treatment state and end use conditions of the material.
1. Cold stamping metal processing at room temperature is generally suitable for blanks with a thickness of less than 4mm. The utility model has the advantages of no heating, no scale, good surface quality, convenient operation and low cost. The disadvantage is that there is work hardening, which causes the metal to lose further deformation ability. Cold stamping requires that the thickness of the blank is uniform and the fluctuation range is small, the surface is smooth, no spots, no scratches, and the like.
2. Hot stamping A stamping process that heats the metal to a certain temperature range. The utility model has the advantages that the internal stress can be eliminated, the work hardening is avoided, the plasticity of the material is increased, the deformation resistance is reduced, and the power consumption of the device is reduced. (Source: China Machinery Network)
1. Die structure: The die is a tool that separates or deforms the sheet. A typical die structure is shown in Figure 3-17, which consists of two parts, an upper die and a lower die. The mold shank of the upper mold is fixed on the slider of the punching machine, and the lower mold is fixed on the working table of the punching machine as the slider moves up and down.
The punch and the die are the working portions of the die for deforming or separating the blank, and are fixed to the upper die plate and the lower die plate by press plates, respectively. The upper and lower templates are respectively provided with a guide sleeve and a guide post to guide the alignment of the punch and the die. The guide plate and the positioning pin are respectively used to control the feeding direction and the feeding length of the blank. The function of the stripper is to remove the workpiece or blank from the punch after stamping.
2. Classification of die
The die is an indispensable mold in stamping production. The die can be basically divided into three types: simple mode, continuous mode and composite mode.
(1) Simple die A simple die is a die that performs only one process in one stroke of the press. Figure 3-17 is a simple die for blanking or punching. The assembly drawing of a simple die is shown in Figure 3-18. During operation, the strip is fed between the two guide plates 9 on the die and hits the positioning pin 10. When the punch is punched down, the punched part (or scrap) enters the die hole, and the strip clamps the punch and moves back up with the punch. When the strip hits the stripper 8 (fixed on the die), it is pushed down, so that the strip continues to feed between the guides. Repeat the above action and rush down the second part.
(2) Continuous die In a single stroke of a punch press, a mold that performs several stamping processes simultaneously on different parts of the die is called a continuous die, as shown in Figure 3-19. During operation, the positioning pin 2 is aligned with the positioning hole which is punched out in advance, the upper die moves downward, the punch 1 performs blanking, and the punch 4 punches. When the upper die is returned, the discharge plate 6 pushes the waste from the punch. At this time, the blank 7 is fed forward again, and the second punching is performed. This cycle is performed, and each feed distance is controlled by the stopper pin.
(3) Composite die In a single stroke, a mold that performs several stamping processes simultaneously on the same part of the mold is called a composite mold, as shown in Figure 3-20. The most important feature of the composite mold is that there is a convex and concave mold 1 in the mold. The outer circle of the convex and concave die is the blanking die edge, and the inner hole becomes the deep drawing die. When the slider moves downward with the male and female molds, the strip is first blanked in the male and female molds 1 and the blanking mold 4. The blanking member is held by the deep drawing punch 2 in the lower die, and when the slider continues to move downward, the female die is then moved downward to be deepened. The ejector 5 and the unloader 3 push the drawn member 9 out of the mold during the return stroke of the slider. The composite mold is suitable for stamping parts with large output and high precision.
3. The main basic processes of stamping basic process stamping include blanking, punching, bending and drawing.
(1) Blanking and punching blanking and punching are the steps of separating the blank, as shown in Figure 3-21 below.
The process of blanking and punching is exactly the same, but the use is different. When blanking, the separated part is the finished product, and the remaining periphery is waste; the punching is to obtain the hole, the punched sheet is the finished product, and the separated part is the waste. Blanking and punching are collectively referred to as punching. Both the punch and the die of the blanking die have a sharp edge, and there is a gap of 5%-10% between the punch and the die to ensure that the cut is neat and less burr.
(2) Bending and bending is to make the workpiece obtain various corners of different shapes. The working part of the bending die that bends the workpiece should have an appropriate fillet radius r to avoid cracking when the workpiece is bent, as shown in Figure 3-22.
(3) Drawing: Drawing is a process in which a flat blank is formed into a cup or a box. The punch and die edges of the drawing die should be rounded to avoid cracking of the workpiece. There should be a slightly larger gap (typically 1.1-1.2 times the thickness of the plate) between the punch and the die to reduce friction. In order to prevent wrinkles, the edge of the blank needs to be pressed with a pressure plate (crimbing ring), as shown in Figure 3-23. The actual drawing process of the product will produce a cracking defect, please see
Sheet metal stamping is a processing method that uses a die to separate or deform the sheet material. Because in most cases the sheet does not need to be heated, it is also called cold stamping, also referred to as cold stamping or stamping.
Commonly used plates are low carbon steel, stainless steel, aluminum, copper and their alloys. They have high plasticity and low deformation resistance, and are suitable for cold stamping.
Sheet metal stamping is easy to mechanize and automate, and the production efficiency is high; the stamping parts are accurate in size and interchangeable; the surface is smooth and free of mechanical processing; it is widely used in the manufacturing industries of automobiles, electrical appliances, instruments and aviation.
2, trimming: a stamping process that uses a metal stamping die to trim the edge of the forming process to have a certain diameter, a certain height, or a certain shape.
4, flanging: a stamping process that turns into a side short edge along the contour curve.
6, blanking: a stamping process that separates the material along the closed contour. The separated material becomes a workpiece or a process component, most of which is planar.
Seventh, shaping: a stamping process that relies on the flow of materials and changes the shape and size of the process pieces to ensure the accuracy of the workpiece.