Process classification of stamping

The stamping process can be roughly divided into two categories: separation process and forming process (also divided into bending, drawing, and forming). The separation process is to separate the stamping part and the blank along a certain contour line during the stamping process, and the quality of the separated section of the stamping part must meet certain requirements; the forming process is to make the stamping blank undergo plastic deformation without damage. And transformed into the required finished shape, but also should meet the requirements of dimensional tolerances and other aspects. According to the temperature during stamping, there are two methods: cold stamping and hot stamping. This depends on the material's strength, plasticity, thickness, degree of deformation and equipment capabilities, etc. At the same time, the original heat treatment state and final use conditions of the material should be considered. 1. The processing of cold stamped metal at room temperature is generally suitable for blanks with a thickness of less than 4mm. The advantages are no heating, no scale, good surface quality, convenient operation and low cost. The disadvantage is that there is work hardening, which makes the metal lose its ability to deform further in severe cases. Cold stamping requires that the blank has a uniform thickness and a small fluctuation range, with a smooth surface, no spots, and no scratches. 2. Hot stamping is a stamping method in which metal is heated to a certain temperature range. The advantage is that it can eliminate internal stress, avoid work hardening, increase the plasticity of the material, reduce the deformation resistance, and reduce the power consumption of the equipment. 1. Die structure: A die is a tool that separates or deforms the sheet. A typical die structure is shown in Figure 317, which consists of two parts, an upper die and a lower die. The die handle of the upper die is fixed on the slide block of the punch press and moves up and down with the slide block, while the lower die is fixed on the work table of the punch press. The punch and the die are the working parts of the die that deform or separate the blank, and are fixed on the upper and lower templates with a pressure plate. The upper and lower templates are respectively equipped with guide sleeves and guide posts 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 length of the blank. The function of the discharge plate is to release the workpiece or blank from the punch after punching. 2. The classification of the punching die is an indispensable die in the stamping production. Punching dies can be basically divided into three types: simple dies, continuous dies and composite dies. (1) Simple die A simple die is a die that only completes one process in one stroke of the press. Figure 317 is a simple die for blanking or punching. The assembly drawing of the simple die is shown in Figure 3-18. When working, the strip is fed along the two guide plates 9 on the die until it hits the positioning pin 10. When the punch is punched downwards, the punched parts (or waste) enter the hole of the concave die, and the strips clamp the punch and move upward along with the punch. When the strip hits the discharge plate 8 (fixed on the die), it is pushed down, so that the strip continues to be fed between the guide plates. Repeat the above action to rush down the second part. (2) In one stroke of a continuous punching press, a mold that simultaneously completes several stamping processes on different parts of the mold is called a continuous mold, as shown in Figure 319. When working, the positioning pin 2 is aligned with the pre-punched positioning hole, the upper mold moves downward, the punch 1 performs blanking, and the punch 4 punches. When the upper mold returns, the unloading plate 6 pushes down the waste from the punch. At this time, the blank 7 is fed forward again, and the second punching is performed. This cycle is carried out, and each feeding distance is controlled by the stopper pin. (3) A composite die is a die that simultaneously completes several stamping processes on the same part of the die in one stroke, called a composite die, as shown in Figure 320. The biggest feature of the compound mold is that there is a convex and concave mold 1 in the mold. The outer circle of the convex and concave mold is the cutting edge of the blanking punch, and the inner hole becomes the drawing concave mold. When the slider moves downward with the convex and concave molds, the strips are firstly blanked in the convex and concave molds 1 and the blanking concave mold 4. The blanking piece is resisted by the drawing punch 2 in the lower die, and when the slider continues to move downward, the female die will move downward for drawing. The ejector 5 and the unloader 3 push the drawn part 9 out of the mold during the return stroke of the slider. The compound mold is suitable for stamping parts with large output and high precision. 3. The basic process of stamping The main basic processes of stamping are blanking, punching, bending and deep drawing. (1) Blanking and punching Blanking and punching is the process of separating blanks, as shown in Figure 3-21 below. The process of blanking and punching is exactly the same, but the purpose is different. When blanking, the separated part is the finished product, and the remaining periphery is the 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 blanking. Both the punch and the die of the blanking die have sharp cutting edges, and there is a gap between the punch and the die that is equivalent to 5%-10% of the plate thickness to ensure a neat cut and less burrs. (2) Bending bending is to make the workpiece obtain various different shapes of bend angles. The working part of the bending die that makes the workpiece bend should have an appropriate fillet radius r to avoid cracking when the workpiece is bent. (3) Deep drawing: Deep drawing is the process of making flat blanks into cup-shaped or box-shaped parts. The edge of the punch and die of the drawing die should be rounded to avoid the workpiece from being cracked. There should be a gap slightly larger than the thickness of the sheet between the punch and the die (generally 1.1-1.2 times the thickness of the sheet) to reduce friction. In order to prevent wrinkles, the edge of the blank needs to be pressed tightly with a pressing plate (edge u200bu200bholder). This article is first published from the original, if reprinted, please indicate the source and author