Research On Forming Process Of Corner Leak Box

In applications such as shells,supports,and box parts,there are box-shaped parts made of sheet with a small radius of turning and no need to seal the corners,which are called leaky boxes in this article.The existing production process is generally welded or "stamping + welding",which has shortcomings such as poor integrity of parts,poor dimensional consistency,low production efficiency and low material utilization rate;It is difficult to form materials with poor weldability or non-weldability.In this paper,a weld-free "deep drawing + punching + shaping" combination forming method is proposed,and on the basis of understanding the relevant research status at home and abroad,the mold used for each forming step is designed with a long × width × height of 128×72×30(mm),an angle radius R of 0.5mm and a plate thickness of 1mm as the research object,the dies for pre punching and shaping the corner was designed.Numerical simulation experiments were conducted on the shaping process using Dynaform software to explore the pre-punched aperture Ф and the influence of pre punched hole shape and plate thickness t on shaping,results show that in addition to thinning at the four corners,wrinkling also occurs in the length and width directions,the thinning rate of the billet decreases with the increase of the hole diameter.Obtain the minimum value of pre punching aperture Ф=4mm for 304 stainless steel corner leakage boxes with t=1mm,it is recommended to pre-punched the hole diameter to achieve good shaping effect Ф ≥ 6mm.Under the premise of the same aperture and ensuring effective shaping,the shaping effect of circular holes with pre-punched holes is better than that of triangular holes.The larger the plate thickness t,the stronger the deformation resistance,the better the shaping effect of the corner leakage box,and the smaller the allowable pre-punched aperture value.The effects of pre-punched aperture diameter Ф size,hole shape and material thickness t on the shaping limit and effect were also studied,and the results showed that in addition to thinning in the corners,wrinkles also occurred in the length and width directions.Within a certain range,the larger the pre-punched aperture diameterФ and plate thickness t and the hole shape is a round hole,the thinning rate and thickening rate of the sheet metal can be reduced and improved to a certain extent,and the allowable pre-punching aperture value is also smaller.In order to explore the influence of multiple factors on the shaping effect of the leak box and establish the optimal parameter combination,three factors: pre-punched apertur diameter Ф size,hole shape and material thickness t were selected for orthogonal optimization experiments.Taking the maximum thinning rate and maximum thickening rate of the blank as the investigation index,nine sets of orthogonal test schemes were set up,and the primary and secondary relationship and change trend of the influence of each parameter on the investigation index were obtained through range analysis,and the significance of the influence of each parameter on the investigation index was obtained by anova and the difference in the level of evaluation of each factor was judged,and finally the parameter combination of pre-punched aperture Ф =10mm,hole shape was round hole,and plate thickness t=1.5mm was the best shaping effect.Through the simulation analysis and exploration of the weld-free integral forming process,various defects and deficiencies in the existing process can be improved,and the quality and effect of the leak box forming can be effectively improved,which can provide a certain reference for the forming of similar parts.