Investigation on Process Parameters of Flexible Stretch Forming Process Using Orthogonal Experiment Design

The flexible stretch forming process (FSFP), is useful sheet metal forming method to produce the small batch three dimensional surfaces. Elastic recovery is one of the very important factors to influence the shape accuracy. The main purpose of this paper is to investigate the influence of design parameters on the elastic recovery. The prestrain, the punch size, the objective radius of surface and thickness of the elastic pad are selected as the design parameters. The value of elastic recovery is selected to evaluate the shape accuracy. The orthogonal experiment design is adopted to investigate the relationship between shape accuracy and design parameters. The analysis of variances (ANOVA) is applied to analyze the value of elastic recovery. The optimal combination is PS3R3PR2T2, which is 0.01 for the prestrain, 500mm for the objective surface radius, 10mm for punch radius and 5mm for elastic pad thickness. The orthogonal experiment design and ANOVA approach may provide a useful guidance to determine design parameters and improve the forming quality in FSFP.