Simulation Study On Hole-flanging In Incremental Forming

Hole-flanging is an important method in the mental sheet forming process.In this work,the incremental forming technology with a die support dive was applied to form hole-flanging.Numerical simulation and experimental method was used to search single-stage,two-stage and three-stage incremental hole-flanging forming.The research has significant direction meaning for actual production.The analysis of the numerical simulation for incremental hole-flanging is based on the DYNAFORM-platform.By simulated the process of single-stage incremental hole-flanging forming,the influence of process parameters and geometric parameters on the distribution of wall thickness was analyzed,and the uniform wall thickness criterion and minimum wall thickness criterion are set out.The critical flanging coefficient met the uniform wall thickness criterion and the limit flanging coefficient met the minimum wall thickness criterion of the single-stage incremental hole-flanging forming were obtained respectively.The relationship between flanging height and other geometric parameters was analyzed.The theoretical flanging height was calculated according to the invariant principle of neutral layer.The experimental and simulated results showed that the theoretical flanging height value agrees with the actual value when the flanging coefficient is greater than the critical flanging coefficient.The influence of the path scheme on the results of the incremental hole-flanging forming was studied.Based on variable angle reaming path planning the two-stage and the three-stage path of incremental forming uniform wall thickness hole-flanging.The central thinning phenomenon in the single-stage incremental flanging forming was successfully eliminated,finally the parts with uniform wall thickness are obtained,and the forming limit was significantly improved.According to different criteria,the corresponding critical flanging coefficient,limit flanging coefficient calculation formula were obtained,appropriate amplification of the theoretical flanging height,to get the two-stage,three-stage forming a uniform wall thickness hole-flanging height calculation formulas.Finally,combined with single-stage,two-stage and three-stage incremental hole-flanging forming limit,flanging height and other aspects studies,this paper presented a process calculation method.Simulation and experimental results showed that the method can select the forming path according to the initial thickness of the blank,the final hole diameter,the height of the flanging,whether there is uniform wall thickness requirements,and calculate the size of the prefabricated hole diameter to obtain the target part.And provide guidance for the production and application of incremental hole-flanging forming process.