Study on flexibly-reconfigurable roll forming process for multi-curved surface of sheet metal

Abstract

In order to manufacture three dimensional sheet metal parts for small-quantity batch production, several flexible forming technologies, including multi-point forming (MPF), have been made as alternatives to the conventional die forming one. However, the existing alternatives cause defects like dimples and wrinkles on the sheet metal during forming, due to their discrete punches. Long setup time and additional post-processing, like machining, of the products limits the feasibility of these technologies. The alternative processes may not be suitable for a skin structure in the aerospace industry, which requires precision machining. To alleviate these limitations, a new sheet metal forming process, named flexibly-reconfigurable roll forming (FRRF) process is proposed. This innovative technology utilizes adjustable punches mounted on two reconfigurable rollers. The shape of the reconfigurable rollers is maneuvered by the adjustable punches. Additional privilege of this innovation is that the blank size is unrestricted in its longitudinal direction. In this paper, the method and procedures of the FRRF process are presented. The feasibility of this FRRF process is demonstrated by finite element simulations of various shapes of convex, saddle, and twist-type surfaces which are typical to multicurved shapes used in sheet metal forming.