Using Local Heat Treatment for Producing Uniform Profile Hollow Components by Radial Rotation Profile-Forming

Abstract

AbstractThe incremental forming process Radial Rotation Profile-Forming (RRPF) has been developed at the Professorship Virtual Production Engineering of the Technical University of Chemnitz. The aim is to enable the production of profiled hollow parts with low sheet thinning and high geometrical accuracy. Because of low thinning due to the process, a smaller initial sheet thickness can be used, whereby material and weight can be saved. RRPF is a two-step forming process. The two principal steps are the production of the preform by Rotational Swing-Folding and the subsequent radial profile-forming of the hollow part in one clamping position. During the preform production, wrinkles occur and these wrinkles can be directly formed in the indentation of the mandrel. In the second process step, the wrinkles are used to form the finished profile of the component. However, due to the geometrical stiffness and the material behavior, there is no wrinkle formed in every indentation of the mandrel. An indentation without wrinkle lead to a high sheet thinning, wich occurs due to forming of the final profile. The best component with less sheet thinning and uniform properties is created for a preform with uniform wrinkles in each indentation of the mandrel. Therefore, the approach of a local laser heat treatment is carried out to control the wrinkling for the first time. This extends the original two-step forming process by a further process step. Before forming, local heat treatment creates a tailored blank with locally varying strength. Therefore, wrinkling occurs in the area with the lower strength of the basic material. The approach and experimental basic investigations of the laser heat treatment are shown in this paper.KeywordsLocal heat treatmentLaserWrinklingIncremental formingRotational Swing-FoldingRadial Rotation Profile-Forming