Experimental and numerical investigation for sheet thickness thinning in two-point incremental forming (TPIF)

Excessive sheet thickness thinning is the main shortcoming in incremental sheet metal forming (ISF). The focus of the previous studies was to improve the sheet thickness variation in vertical wall components having no inner feature. This study investigates a complex part containing convex, concave, and redundant features due to the frequent customized requirements of the aeronautic industries. In ISF, a redundant area is usually added to the target area to ensure a continuous toolpath. The redundant area effect on sheet thickness variation is the least investigated area. The best toolpath strategy from the literature was employed to see its effectiveness for the complex part investigated in this work. Two profiles in the redundant area were trialed with P-TPIF (positive) and N-TPIF (negative) based on numerical analyses and were verified experimentally. The redundant region profile significantly affects the sheet thickness distribution in the target area in both N-TPIF and P-TPIF. The previously best toolpath strategies, mainly for vertical wall components, do not work effectively for the complex component.