Effect of Incremental Forming Parameters and Annealing Condition on Principal Strain Distribution and Formability During Straight Groove Forming

Abstract

Incremental forming is a highly flexible sheet metal forming process that enables the production of complex components without the need for specialized molds or dies. In this study, the effects of key process parameters—including tool rotational speed, vertical step size, annealing condition, and tool movement direction—on the formability of aluminum 3105H14 sheets were systematically investigated through experimental testing. A Taguchi design of experiments was employed to efficiently examine the influence of these parameters on the maximum forming depth, principal strain distribution, and thickness variation. The results indicate that vertical step size and annealing condition are the most significant factors affecting sheet formability. A maximum forming depth of 10.5 mm and a minimum sheet thickness of 0.584 mm were achieved with a vertical step size of 0.25 mm, spindle speed of 2000 rpm, and tool movement parallel to the rolling direction. Annealed sheets exhibited higher principal strains in intact regions, confirming the positive influence of heat treatment on material ductility. Furthermore, increasing spindle speed enhanced frictional heating, further improving material formability, while forming direction primarily affected strain distribution and localized thinning.