Analysis of wall thickness evolution and forming quality of sheet metal manufactured by wrinkles-free forming method

Sheet metal wrinkles-free forming method is a novel sheet metal forming technology which deforms a blank to the target part using low-melting point alloy (LMA) without the blank holder, increasing materials utilization rate and reducing the trimming process. The LMA medium used as a blank holder inhibiting wrinkles transfers forming load onto the surface of sheet metal, deforming and flowing as the deformation of the sheet metal, which affects the plastic flow state of the sheet metal. This paper aims to investigate the effect of the rheological behavior of LMA on the wall thickness distribution of sheet metal, combining  numerical simulation and experiments. The stress–strain relationship is obtained by high-temperature tensile test of LMA under different temperature conditions, and numerical modeling of sheet metal forming with LMA medium is established by ABAQUS software. The influence of the process parameters on the surface pressure distribution of the sheet metal is investigated. The effect of forming temperature and medium layer thickness on the thinning is analyzed for revealing the intrinsic correlation of the surface pressure distribution and the thinning. Furthermore, the research on influence of the LMA medium rheological behavior on the distribution of the wall thickness of the formed part is performed. The experimental results are consistent with the numerical simulation results.