Sensitivity analysis and optimization of the surface roughness in the incremental forming of mild steel sheets

Flexibility and simple tooling make the incremental sheet forming (ISF) a great process to create complex shapes from mild steel sheets. It is a significant issue to reduce the surface roughness (SR) which is a weakness in the manufacturing the mild steel parts in ISF process. The purpose of this study is to investigate the effects of the ISF process parameters on the SR of the mild steel sheets. Feed rate, tool diameter, vertical step and spindle speed are chosen as four input variables in the experimental tests. Taguchi design of experiment (DOE) and the analysis of variance (ANVOA) are used to optimize the SR by investigating the parameters effects and their interactions. According to the obtained results, the vertical step reduction and increase in tool diameter, decrease the roughness on the surface of the mild steel sheets during the single-point incremental forming (SPIF). In addition, the tool speed in term of both rotation and feed have little effect on the surface roughness. The results of a validation test demonstrates that the Taguchi technique and the ANOVA can effectively optimize the level of each variable to ensure the best SR.