Multi-Objective Six-Sigma Approach for Robust Optimization of Multi-Point Dieless Forming Process

The significance of the stochastic nature of a multi-point dieless forming (MDF) process for final product accuracy has been extensively recognized. It is an under-research area in terms of effective techniques and computational tools for easy industrial applications and implementation. It is also recognized that wrinkling and dimpling are the most MDF product defects. Deterministic optimization using the finite element (FE) analysis have been used to improve the formability of the MDF process; however, not considering the noises of the system could affect the variation of the final product quality. In this study, the uncertainty parameters are considered to avoid the random variation of the final product accuracy while using the same control process parameters. In addition, to avoiding computationally expensive FE analysis, the approximation model has been used for both product defects. A six-sigma robust optimization is applied to obtain both reliable and robust MDF products. Finally a numerical simulation with one experimental result of a given target shape shows that the wrinkling and dimpling defect is controlled using the obtained optimal process parameter setup.