Improvement of stamping process and die design of

2022-08-15
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The stamping process improvement and die design of front bumper support

Abstract: the structural characteristics of automotive front bumper support parts are analyzed, and the process improvement scheme of parts and the design of sectioning and punching die are introduced

key words: front bumper support art improvement mold design

1 introduction

paladin is the latest model introduced by Zhengzhou Nissan from Japan. The front bumper support undertaken by our factory is two important supports of the front bumper, which is directly related to the appearance and safety of the car. In order to ensure the assembly accuracy and quality of the front bumper, we decided to rectify the front bumper support

2 process analysis

Figure 1 shows the supporting parts of the front bumper (left and right are symmetrical), the material is saph310, and the material thickness is 3.2mm. The shape of this part is complex. The ∮ 12mm and ∮ 9mm holes are assembly holes for installing the front bumper. The front bumper is a 1.5mm stainless steel part. If the profile at the two holes is uneven, the profile angle at the ∮ 12mm hole is wrong, and the opening size of profile 1 and profile 2 is wrong, the front bumper will be deformed and cracked. If the positions of ∮ 12mm and ∮ 9mm holes are not accurate, it will cause the position of the front bumper to change wrongly, and the surface difference between the front bumper and the front fender will be uneven, and even affect the installation of the lights and the appearance quality of the front face of the whole car. The ∮ 16mm hole and r8mm notch are not only the positioning holes for assembling the front bumper assembly, but also the fixed holes for connecting the front bumper assembly and the vehicle body. Therefore, the profile 3 is required to be flat and the hole position is accurate relative to the ∮ 12mm and ∮ 9mm holes. In order to ensure the flatness of profile 1, a set of leveling die is added to the original art. The original stamping process is: ① the left and right parts are pressed separately without affecting the quality shape; ② The left and right parts are cut and punched with r8mm long holes respectively; ③ Punch ∮ 16mm and ∮ 9mm holes on the left and right parts respectively; ④ The left and right parts are bent with small edges respectively; ⑤ Flanging of left and right parts respectively; ⑥ Punch ∮ 12mm holes on the left and right parts respectively; ⑦ Leveling. In the production process, it is found that this stamping process is asymmetric forming, and the force on the die is very uneven, resulting in severe wear of the die, increasing the gap, affecting the accuracy of the workpiece, and reducing the service life of the die. Asymmetric forming makes the workpiece very unstable, and it is difficult to ensure the positions of all profile surfaces and assembly holes. This stamping process makes the number of molds large (11 molds are required), the production cycle long, the operation process many, the production efficiency low, and increases the production cost. Moreover, in this process, the mold surface positioning and solid cavity in the subsequent sequence is relatively shallow and inaccurate, which makes it difficult to maintain the position of each hole and the space position of each hole, the opening size of mold surface 1 and 2 is extremely unstable, and it is also difficult to maintain the flatness of each surface and the forming angle and shape of the boss where the ∮ 12mm hole is located. Punch out the r8mm long notch first, which will cause notch deformation during flanging

3 process improvement

two spring testing machines of our company were ordered for advance deposit on the spot to overcome the above shortcomings, ensure the quality of the parts, improve the production efficiency and reduce the cost. After further process analysis and research of the parts, the original stamping process was improved, adopting the new process of pressing celery right parts at the same time, although it was later cut into two parts. The improved stamping process is: ① blanking and punching ∮ 16mm positioning hole; ② Forming; ③ Punching the incision and bending the small edge; ④ Flanging and shaping; ⑤ Wedge punching ∮ 16mm, ∮ 12mm, ∮ 9mm and r8mm long holes, sectioning. See Figure 2 for the process diagram. The improved stamping process adopts symmetrical forming, so that the positioning is accurate, the force is uniform, and the forming of the workpiece is stable. The quality of the parts is guaranteed, but the reversal of this kind of supply-demand relationship also causes the power of market-oriented capacity reduction. When the power decreases, the process is reduced, the productivity is improved, and the service life of chess tools is prolonged. Punch out the ∮ 16mm hole first, and then position it with the hole in the next sequence, with the help of pattern drawing, so as to ensure the accuracy of positioning. The shaping process after flanging ensures the flatness of profile 1, profile 2 and profile 3, the forming angle and shape of the convex hull where the ∮ 12mm hole is located, and the opening size of profile 1 and profile 2. Finally, the wedge punching ∮ 16mm, ∮ 12mm, ∮ 9mm holes and r8mm long holes at the same time ensures the positional degree and relative spatial position of ∮ 16mm, ∮ 12mm, ∮ 9mm holes and r8mmk holes, and r8mm long holes will not be deformed

4 mold design

according to the process analysis and the use requirements of the parts, in order to improve the quality of the parts, ensure the use requirements and improve the productivity, it is decided to use 5 pairs of molds to complete the improved process. The first blanking and punching compound die punches ∮ 16mm positioning holes at the same time of blanking, ensuring the accuracy of positioning hole position and the accuracy of positioning in subsequent processes. The second forming die locates the overall shape of the extruded part with the positioning hole. The third punching cut is to top bend the small edge, and pre bend the small edge while punching the cut, so as to prepare for the subsequent sectioning process and shaping process. The fourth pair is the flanging and reshaping composite mold. After climbing the high side, it is conducive to the reshaping of the whole workpiece. Make the shape of the formed object accurate and stable. It also ensures the flatness of the three main profiles, the shape and angle of the boss where the ∮ 12mm hole is located, and the opening size of profile 1 and profile 2

the fifth pair is the wedge hole cutting compound die, which cuts the workpiece into two pieces while punching. Punching ∮ 16mm hole, ∮ 12mm hole, ∮ 9mm hole and r8mm long hole ensures the accuracy of the relative position of each hole. Among them, the most characteristic is the wedge hole cutting die, and its die structure is shown in Figure 3

1 upper die base 2 inclined wedge 3 guide block 4 slider 5 fixed plate 6 figure die 1 7 polyurethane spring 8 figure die 2

9 female die 10 waste box 1 stretches, twists, tightens or pulls plastic material splines 1 lower die base 12 guide sleeve 13 guide post 14 side stopper 15 return spring

this figure only shows a part of the overall wedge, and the rest inclined wedge hole mechanism is basically the same as the figure. The wedge 2 is fixed on the upper mold base, and the application effect of the slider 45 is implemented. After the new process and new mold of the front bumper support parts are officially put into production, 20000 parts have been produced so far, with a 100% pass rate. The parts have been applied to Paladin and D22 pickup trucks, and the loading effect is good, reaching even more than KD parts. (end)

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