Design of side bending forming die for microwave o

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Design of side bending forming die for microwave oven door

Abstract: the microwave oven door shell is formed by backward bending of inner and outer wedges. The structural characteristics of side bending forming die are introduced

key words: door shell wedge bending forming

1 part process analysis

microwave oven door parts are shown in Figure 1. The material used is 08 steel plate with a thickness of o.6mm. The door shell is an important appearance part of the microwave oven. The surface quality requirements are very strict, and no damage is allowed. After forming, it must ensure that the opposite side size is 373 mm, and the thickness size is 20.5mm. Since it is difficult to ensure the dimensional accuracy due to single forming, a manual correction process needs to be added, which will affect the surface quality of the workpiece and increase the internal stress of the workpiece. For this reason, a wedge-shaped lateral bending die as shown in Figure 2 is designed

2 die structure characteristics

the lateral bending forming die adopts the internal and external wedge, semi fixed and semi movable forming structure. The upper die part is mainly woven by an inner stopper, a wedge, a sliding block, a forming punch and a small guide post guide sleeve. The chess playing part is mainly composed of bending forming die, sliding block, positioning plate and reset mechanism, as shown in Figure 2

the equipment selected for the die is a 3150kN oil press. Four small guide pillars and guide sleeves are used to guide the inner block and the movable forming punch. The upper and lower die parts are guided by wedges. The forming punch and the bending forming die slide on the inner and outer guide rails in a symmetrical form respectively. During manufacturing, it is necessary to ensure that the symmetrical surface dimensions are accurate and consistent, move freely on the guide rails, and maintain their correct positions. The forming punch and the bending forming die are reset under the action of the spring. The angle and stroke of the wedge and guide rail must be properly determined to ensure that the actions of all moving parts are coordinated and orderly. The wedge, guide rail and sliding block shall be subject to heat treatment, and the contact surface shall be ground and polished. During use, lubricating oil shall be applied to reduce friction. In addition, transmission efficiency and die life shall be improved

the movable ejector block is the part that first contacts with the forming punch. The strain rate during the yield of the parallel length of the sample shall be between 0.00025/s and 0.0025/s. In order to prevent damage to the door shell parts and to increase the pressing area and friction, a thin polyurethane rubber plate is bonded to its surface

3 part forming process

the part is placed on the positioning plate, and the oil press drives the upper die downward. When the forming punch contacts the part and the inner stop continues to move downward with the upper die, the forming punch continues to press the part under the action of the spring, and moves laterally under the action of the inner stop, as shown in Figure 3

when the upper die continues to descend, the wedge forces the bending forming die to move to the middle, and the bending part begins to form until the upper die part and the lower die part are in full contact, that is, the inner stopper is completely gnawed with the forming punch, and the part is bent and formed

when the hydraulic press returns, the forming punch and bending forming die return to their original positions under the action of the return spring, and the movable ejector block ejects the formed parts under the action of the spring

4 conclusion

the die has been put into use, and the microwave oven door body only needs one bending forming process in the die. Practice has proved that the die has ensured the technical requirements of the product and achieved good results


1 wangxiaodu stamping manual. Mechanical Industry Press, 1990

2 Hunan forging society. Stamping process. Changsha: Hu 80% Nan science and Technology Press.1984. (end)


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