Research On The Improvement Of Forming Process For A Radiator Uplifted Bottom Plate

Aiming at the problems such as insufficient width of front and rear flanks,wrinkling and thinning during the production process of a uplifted bottom plate in trial,according to the characteristic that the radiator uplifted bottom plate body has a cone-box-shaped part,the current process was optimized from ‘U-shaped bending'?‘W-shaped forming' to ‘drawing'?‘W-shaped forming'.And the corresponding molds were designed.Exploring the influence of different shapes of the blank and the shape of the process notch on the forming effect.And the window part was the first punching window or the last punching window.In addition,exploring the shape of the window before forming.The optimized forming process was numerical simulated and analyzed by DYNAFORM software from the aspects of mold structure and parameters such as holder force and friction condition.The results show that the problem of wrinkling on the inner side of the inboard curved side flaps and the thinning of the rounded corners of the upper surface is improved when the blank holder force is 200 kN,the differential friction coefficient is selected that the punch is 0.17,the die and the blank holder is 0.125,and the corner radius of die gradual change radius is increased from 4t~6t to 5t~8t.With the determined process parameters,the drawing depth h was explored,and it was confirmed that better forming result could be obtained when h=55 mm and the wavy shape of the blank process notch.The thinning rate of parts could be controlled within 17% after improvement.In order to avoid problems such as large gap to be welded,the process is changed from ‘drawing'?‘W-shaped forming' to ‘two-step forming',and the corresponding mold is designed.On the basis of the existing research results,the expansion experiment was carried out to explore the effect of two-step drawing.In the second drawing process,the defects of excessive thickness thinning tend to occur at the four corners of the left and right end faces in the longitudinal direction,and the holes are punched at the four corners which are easy to be thinned.In order to prevent cracking during the shaping stage,the effects of different shapes and different sizes of holes on the forming effect were studied.It was confirmed that the hole shape with relatively good forming effect was a parallelogram with rounded corners.In the shaping stage the fillet radius of the four sidewalls of the die is 0.In order to improve the four-corner thinning defect,a mold with a wedge mechanism was used.The simulation result showed that the maximum thinning rate was reduced by 2.33%.In order to study the influence of several factors on the forming quality of the uplifted bottom plate,three representative factors of the blanking force F,the friction coefficient ? and the die radius r? of the die were selected for orthogonal experiment.The maximum thinning rate of the blank thickness is the qualitative index,and the wrinkling and thinning conditions are set as 9 quantitative experiments.According to the range analysis,the order of the three factors affecting the forming is blank holder force > friction coefficient >die radius.According to the simulation conclusion,it is possible to overcome the shortage of front and rear flanks,wrinkling and thinning defects that occur during the trial production stage.