Single Point Incremental Forming using a Dummy Plate - Multi Plate Forming

M. Skjoedt1, M. B. Silva2, N. Bay1, P. A. F. Martins2, T. Lenau1

1Technical University of Denmark, Department of Manufacturing Engineering and Management, DTU - Building 425, DK-2800, Kgs. Lyngby, Denmark
2 IDMEC, Instituto Superior Tecnico, TULisbon, Av. Rovisco Pais, 1049-001 Lisboa, Portugal

Keywords: Incremental forming, dummy plate, double plate, multi plate, wear, surface quality, roughness, bulging and friction.

Abstract:
A new version of single point incremental forming (SPIF) is presented. This version uses a dummy plate on top of the plate which is to be formed into a geometry. In this way two plates are formed instead of one. The top plate in contact with the rotating tool pin is a dummy plate, and can be discarded after forming. The use of such a dummy plate causes a number of changes in the process. It also offers the manufacturer a number of new possibilities for solving some of the remaining problems in SPIF. A hyperboloid and a truncated pyramid are used to investigate influence of using a dummy plate on: formability, wear, surface quality and bulging of planar sides. It is furthermore investigated whether the level of friction between the two plates plays a role. Use of a dummy plate reduces wear to a level close to zero, but also causes a decrease in formability. Bulging of the planar sides of the pyramid is reduced 10%. Surface roughness is increased. Use of lubrication or not between sheets does not have any influence. Suggestions for use of this new technique are discussed, among those forming of soft aluminum plates thicker than 1 mm.