Analysis of Forming Parameters in Sheet Hydro-Forming Process

The aim of this paper is to develop a systematic method to analyze the effects of forming parameters on the quality of part formability and determine the optimal combination of the forming parameters for the sheet hydroforming process. In this paper، the effects of four important process parameters namely fluid pressure، friction coefficient at blank/punch interface، gap between die rim block and blank holder and die entrance radius in the process of hydrodynamic deep drawing assisted by radial pressure (HDDRP) were determined. A Finite Element (FE) model was developed for simulating the HDDRP process. After validation of the developed FE model by experimental results، by combining FE simulation with Taguchi method and using the analysis of variance test، the effect of mentioned parameters on the formability of the hydroformed cups was investigated. The applied materials were pure copper and St14 steel sheets. The results of analysis indicated that for both cases of maximum thinning ratio at the constant value of cup draw depth and maximum accessible draw depth، fluid pressure has the greatest influence on the formability of part in sheet hydroforming process. Moreover، using rough punch، having smaller gap between die rim block and blank holder or increasing the die entrance radius، the formability of sheet will improve.