What are the precautions for the die in the stamping die, and the experience

The die in the stamping die is one of the most critical components of the entire die. The quality of the die directly determines whether qualified stamping parts can be produced. All the following items must be paid attention to when designing the die: (1 ) The punching die hole cannot be made into a straight-walled cavity. In order for the workpiece or waste to fall easily, the die cavity cannot be made into a straight wall, but should be made into a tapered, cylindrical orifice taper or a cylindrical orifice stepped shape. The cylindrical hole die is more convenient to manufacture, the edge strength is high, and the size of the edge does not change after grinding. It is the most common structure of the punching die. If the inner wall of the die is straight, the punched workpiece or waste material will get stuck in the cavity due to its larger size. If it accumulates too much, the die will burst. (2) Die for punching round holes should not use rectangular blanks for punching round holes, and round blanks should be used as far as possible. This is because the round blank uses the least materials, and the cavity wall thickness is uniform, the heat treatment deformation is small, the cavity is easy to harden and harden, the mold life is long, and it is not easy to crack. In addition, the use of round blanks is also convenient for turning and grinding. (3) When punching complex contours, it is not advisable to use oblique blades. When the punching force exceeds the tonnage of the existing punching equipment, in order to reduce the punching force, methods such as oblique blade punching, step punch punching or heating punching can be adopted. When the flat-blade die is punched, the punching occurs at the same time along the periphery of the workpiece, so the required punching force is large. If an oblique blade die is used for punching, like an oblique blade shearing machine, the material is gradually separated along the length, and the punching force can be significantly reduced. For large-scale or thick material stamping parts, a punch or die insert structure is often used. In order to reduce the punching force, the punch (when punching) or the die (when blanking) can be made into a wave-shaped oblique edge. The blade should be symmetrical on both sides, and the dividing line is generally taken at the low or high point of the wave. The height of the oblique blade is generally not more than 13 times the thickness of the stamping material, so as to avoid the mold being damaged by the force on one side. However, when stamping complex contours with large undulations (when trimming covers), oblique blades are not suitable to avoid the complicated shape of the die edge, large undulations, low strength of the die edge, large stress and damage, and difficult mold processing and manufacturing. (4) The thickness of the punching die should not be too small. The thickness of the punching die directly affects the strength, rigidity and durability of the die, and its size is related to the punching force. The thickness of the punching die should not be too small, because the hole on the die seat or backing plate under the die is larger than the cavity of the die. If the thickness of the die is too small, the die will be bent and deformed during work, and even damaged. (5) The wall thickness of the punching die should not be too small. The wall thickness of the punching die will directly affect the strength of the die. If the wall thickness of the die is too small, the die will have insufficient strength during punching and may break. Due to the complicated force of the die during stamping, the die thickness is usually determined according to the empirical formula or mutual relationship (6) The height of the edge of the stamping die cannot be too large. There are two main types of stamping dies according to the shape of the edge. One is a cylindrical hole die, which has high cutting edge strength and high dimensional accuracy of stamping parts. One is the tapered hole die. The strength of the blade n is low, but the workpiece or waste is not easy to accumulate in the hole. The friction and expansion force on the hole wall is small, so the wear of the die and the amount of grinding each time are small. The size of the cutting edge is increased after grinding, but the increase is small, and has little effect on the life of the die. This type of die is generally used for stamping workpieces with low precision, simple shapes and thin material thickness. . The height of the cutting edge of the punching die cannot be too large. If the cutting edge is too high, the punching waste will accumulate more, increase the punching force, pushing force and wear of the hole wall. After the die is worn, the hole may form an inverted cone, causing the waste to fall on the working surface of the mold and damage the mold. . In this way, after the cutting edge is worn, the amount of grinding is large each time, and the total life of the die is relatively low. The height of the punching die blade U should not be too small. If the height of the cutting edge is too small, the number of sharpening after the die is worn is reduced, and the total life of the die is also reduced. (7) The cutting edge and the edge of the die, the distance between the cutting edge and the cutting edge should not be too small. The distance between the cutting edge of the die and the edge of the cavity, the distance between the cutting edge and the cutting edge, must have a sufficient distance , Its value cannot be too small. This is because if the distance is too small, the die strength is low. Under the action of the punching force and the expansion force of the workpiece (or waste), it will cause the die to burst. If the distance is too small, the die is easy to crack during heat treatment (quenching). The strength of the die edge is low, so the distance value cannot be too small. Generally, it is between 30 and 50mm, and the size of the die should be made of standard die blanks as much as possible. The distance between the edge and the edge can be selected according to the cavity. The die edge depends on the complexity of the die, the more complex one should be larger, and the round concave die can be appropriately reduced. (8) It is better not to open fastening holes for the quenched die to avoid loss of die strength and heat treatment deformation and cracking. Try to use the clamping cone sleeve to fix the die on the lower template. This method is often used for metal extrusion dies. This method is used to fix the die with small size, large force, difficulty in installing fasteners, or difficulty in machining holes on the die (such as a die made of cemented carbide). It is very important to install the die. (9) The position of the die hole should not be such that the corner of the die is on the diagonal of the concave module. The die hole should be arranged in the center of the module, but the corners of the die should not be on the diagonal of the module. In order to avoid cracking of the die during quenching. Previous post: I drive every day, do you know how cars are produced?