Two-Point Incremental Forming of Metal–Polymer Three-Layer Sheets

Abstract

Incremental forming process is a manufacturing process with many advantages, so it has received attention by many researchers, while further investigation is required for incremental forming of sandwich panels. In this study, the response surface method is employed to perform a series of experiments, and the effects of parameters, including vertical step down size, tool diameter, tool rotation speed and polymer type (as the core material) on incremental forming of metal–polymer three-layer sheets are studied. The results are used to evaluate the average tool force and uniformity of sheet thickness distribution. The results of variance analysis of the average tool force show that the vertical step size, tool diameter, polymer type and tool rotation speed have, respectively, the greatest effects on the average tool force. Moreover, the interactions between the pairs of vertical step size/tool rotation speed, vertical step size/tool diameter, vertical step size/polymer type and the tool rotational speed/tool diameter affect the average tool force. From the results of variance analysis of maximum thickness variation, it can be concluded that the vertical step size, polymer type, tool rotation speed and tool diameter have, respectively, the greatest effects on the maximum thickness variation; moreover, the interaction between vertical step size and polymer type also affects the maximum thickness variation. It is shown that the vertical tool force in incremental forming of a metal–polymer three-layer sheets is approximately 50% that of a single-layer aluminum sheet with similar bending moment.