Post-motivation plate compression techniques and mold presets
With the process scheme of (2), since the hole is large before the deep drawing process, it is not guaranteed that the existing hole will not be deformed when the deep drawing is performed, so that the dimensional accuracy of the hole during punching cannot be ensured. In order to ensure that the size of the punching hole does not change, only the punching step is placed after the drawing step, so the (2) process plan is also not feasible.
Now analyze whether the process plan of (3) is feasible. From the process of (3), after punching, the punching hole is guaranteed to have no problem with the size of the hole. After the deep drawing and punching, trimming is performed so that the vertical edge size after the flanging is 10+0125. -0150mm is not a problem. It seems that the (3) process plan is feasible.
Now let's analyze why the boss breaks when it is formed. In the stamping process, the billet may be subjected to compressive stress, or it may be subjected to tensile stress. It is impossible to crack by the effect of compressive stress, and it can only be wrinkled. The effect of tensile stress is only possible to crack, and it is not limited by the tensile stress, but only when the tensile stress in the blank exceeds the tensile strength of the material.
It appears that when the process of (3) is adopted, the blank is subjected to a tensile stress exceeding the tensile strength of the material during deep drawing. Why the tensile stress in the billet exceeds the tensile strength of the material during deep drawing? The structure of the part is understood. The length dimension between the left and right bosses and the width dimension between the front and the back are compared with the dimensions of the boss periphery. All of them are relatively small, and in the stamping process, when the ratio of the dimension of the blank outside the deformation zone to the size of the deformation zone is greater than 3, only bulging deformation occurs, and no deep drawing deformation or deep drawing deformation and bulging deformation occurs. At the same time.
Here, the ratio between the size outside the calculated deformation area and the deformation area (the range of the boss size) is greater than 3, so that only the bulging deformation occurs in the boss area without the occurrence of deep drawing deformation or deep drawing deformation. Bulging deformation occurs at the same time. Due to the effect of two-way tensile stress on the interior of the billet in the bulging deformation zone, it is the effect of the two-way tensile stress that exceeds the tensile strength of the material. Now, through the above analysis, it is easier to know the cause of the boss crack. If you can think of ways to reduce the internal tensile stress of the billet or increase the tensile strength of the billet, you can achieve a satisfactory solution. Then, firstly, it is feasible to increase the tensile strength of the blank because the tensile strength of the blank is related to the type of the material. Once the material is determined, the tensile strength is determined.
Then what should we do? The reason why the boss breaks at the edge of the table is that it is due to the bulging deformation that occurs at the boss, which causes the internal tensile stress of the blank to exceed the tensile strength of the material. Then why is it convex? The bulging deformation occurs at the pedestal. This is because the deformation area is too small and its outer dimensions are too large. During the forming, the surrounding material cannot flow to the deformation area, resulting in insufficient material supply in the deformation area, and round corners of the boss. The internal tensile stress of the material exceeds the tensile strength of the material, and the material is pulled apart, causing the part to be scrapped. Since the material supply in the deformation area is insufficient, the internal tensile stress of the material exceeds the tensile strength of the material and the blank is cracked. If you can think of ways to form the boss, so that the material around the boss flow to the boss, the problem will be solved.
Die structure design According to the structural characteristics of the part, the resistance of the metal to the bosses is very high, especially when the stroke is close to the bottom dead center, the sheet material is basically on the bottom of the punch, and the bottom of the die and the turning point are pressed tightly. The material is difficult to flow to the round corners. Therefore, in the drawing die design, the top fillet radius is increased from R4mm to R8mm, and the turning point at A is designed as a straight line, and the final size of the part is The shape is further processed by flanging and shaping processes to meet the dimensional accuracy requirements of the parts and to obtain a clearly defined boss.
At the same time, the protruding part of the punch adopts a mosaic-type combination structure, and the purpose is to bring convenience to the trial molding and maintenance. This part belongs to the medium-thick plate stamping forming, forming force, in general, more use of multi-point crank press or hydraulic press, is conducive to protecting the accuracy of the mold and ensure the quality of stamping parts, improve the dimensional accuracy of stamping parts. However, due to the limitations of the factory conditions, the processing can only be carried out on a friction press, and the working characteristics of the friction press have brought certain difficulties to the design of the punching die and the deep drawing forming die. In the above problems, only measures are taken in the processing technology of the parts and the design of the mold structure. The working characteristic of the friction press is that the mold closing height cannot be accurately controlled, and now through the improvement of the mold structure to overcome the above-mentioned deficiencies, in order to achieve the ideal punching effect.
Motorcycle Wheel And Hub Parts
Motorcycle Wheel And Hub Parts,Motorcycle Hub Parts,Motorcycle Accessories Wheel,Motorcycle Wheel Parts For Monkey
ZETHS Vehicle Technology Co.,Ltd , https://www.zethscn.com