Shape error prediction and compensation of three-dimensional surface in flexibly-reconfigurable roll forming

The Flexibly-reconfigurable roll forming (FRRF) scheme as one of the advanced continuous roll forming processes consists of upper and lower flexible rollers that can be controlled by each reconfigurable punch module. The shape error in the FRRF process often results in undesirable changes in the shape of the deformed surface and brings about a deviation in the precision of the deformed product. This study considers the changes in the shape error of a deformed configuration by controlling the non-uniform gap between both flexible rollers in the transverse direction. A Non-uniform rational B-spline (NURBS) type control methodology is introduced based on the transverse target curve and the thickness reduction ratio. The function for the transverse target curve is reconstructed by using a NURBS curve, and the function of the reduction ratios of the thickness is assumed to have linear increments. Finite element simulations are conducted for the FRRF process with the AA5052-H32 sheet material by applying NURBS-type control methodology for both flexible rollers. The transverse shape error of the three-dimensional surface is predicted by using a numerical approach, and its results are experimentally verified. A Reverse displacement compensation (RDC) method is adopted to compensate the transverse shape error of the deformed surface. Consequently, the proposed RDC method is validated as a suitable approach to address the transverse shape error. This method contributes to further developing capabilities to modify the profiles of the upper and lower flexible rollers in the flexibly-reconfigurable roll forming process for various 3D surface parts.