The powder pressing die is a stamper and a press. The key to the design of the stamper is to consider the elastic expansion of the compact volume, that is, the elastic aftereffect, due to the relaxation of the internal stress after the pressure is removed or the film is removed. The three principles of stamper design are accurate mold size, small surface roughness and uniform density, so as to give full play to the characteristics of powder metallurgy without cutting and cutting. At the same time, it is necessary to reasonably select the mold material and the die structure and processing requirements.
The presses for powder pressing die are divided into two types: mechanical presses and hydraulic presses. Both types of presses can produce the same product. In theory, the required pressing energy is almost the same, but each has its own characteristics. The mechanical press has a high productivity of 1.5 to 5 times that of the hydraulic press; the disadvantage is that the pressure is small, the stroke is short, and the punching is not smooth enough. It is difficult to hold pressure and is not suitable for pressing large and long products.
The pressure of the hydraulic press is large, the stroke is long, and it is relatively stable. It can realize multi-stage speed regulation and pressure keeping, and the equipment cost is low (about 1/2 to 3/4 of the mechanical press). It is suitable for pressing products with larger size and longer length. The disadvantage is that the pressing speed is slow, the productivity is low, and the maintenance cost is high (1.5 to 2 times that of the mechanical press).www.yxhgmould.com