The geometric basis for the design of a new process to form sheet metal into a flat, corrugated product is described. The underlying principle is to determine a surface between entry of the sheet into the device and the exit of the formed product such that all points across the width of the sheet under go as nearly as possible similar deformation histories and also that longitudinal strain in the sheet is minimized. The surface for forming a product having a sinusoidal profile and also that for a trapezoidal profile are presented as examples. For the sinusoidal product, an empirical equation is developed that relates the strain during forming with the initial and final width, the forming length and the number of profile segments. A physical model shows that a sheet can be formed to such a surface without straining or buckling. Although this paper does not describe the type of tooling or forming machine that would be used to plastically deform steel sheet, the authors believe such a device can be constructed. The results suggest that the new approach would reduce defects such as edge-wave, oil-canning and splitting and that the overall length of the forming device could be an order of magnitude smaller than that for existing roll-forming lines. (c) 2009 Elsevier Ltd. All rights reserved.