In addition to the cold stamping process, which is commonly used in mechanical manufacturing, there are some other special ways, such as rubber hydroforming, bending forming and shot peening.
1, rubber hydroforming: filling high pressure liquid in the rubber tyre installed in the frame so that it expands, thus pushing the wool to form parts according to the shape of the mold. The parts formed in this way are of high accuracy and no indentation on the surface. Rubber tyre is a versatile flexible die, so multiple moulds with different shapes can be placed on the worktable. This method is lower in cost and more efficient in production. After one cycle, multiple parts can be produced simultaneously.
2, stretch bending forming: first stretch the profile wool along the length direction to the yield limit, then maintain the tensile force and make the wool bending and forming according to the stretch bending die surface. Pre stretching can effectively change the stress distribution inside the wool when bending, thereby improving the forming accuracy of the parts.
3. Shot Peening: using compressed air (or high speed impeller), many steel balls with diameters of 0.3 to 2.5 mm are ejected from the nozzle. The high velocity elastoflow strikes one side of the surface of the wool material, which causes the surface metal to be squeezed and increase the area, producing pressure stress, so that the material will bend to the side of the shot not hit by the projectile and become a curved surface.
The above three kinds of forming methods have saved the cost to a large extent, which not only helps to enhance the fatigue strength of the parts, but also is of great significance to the realization of high efficiency production, which greatly promotes the promotion of productivity.