Laser micro spin forming

Abstract

Laser forming has been shown effective as a non-contact bending technique for 0.15 mm thickness cantilever beams made from Neyoro G, a high-strength, high-reflectivity, high thermal conductivity material. The current work reports on efforts to extend laser forming to miniature 3-D axisymmetric shapes from similar thickness originally flat discs.In conventional spin forming, a rotating sheet metal disk is formed over a shaped mandrel by a mechanical tool. In preliminary experiments performed on both cold-worked and annealed discs of 0.127 mm thick 304L stainless steel, a scanned laser beam replaced the spinning apparatus. A scan head steered ∼25W of laser power (1.064 µm) onto the disc. A laser-based sensor was incorporated to measure surface movements.Temperature and surface displacement measurements are compared to FEA modeling results. Laser powers, beam trajectories, temperature gradient changes and bend results for single and multiple passes will be presented.Finally, the information developed was used to design a micro forming apparatus (MFA), which was then assembled and tested. Motor speeds and control methodologies, mandrel-collet-tailstock-carrier design considerations, and beam scanning path geometry concerns will be discussed. CAD renderings of the system, along with the final assembly, will be shown.Laser forming has been shown effective as a non-contact bending technique for 0.15 mm thickness cantilever beams made from Neyoro G, a high-strength, high-reflectivity, high thermal conductivity material. The current work reports on efforts to extend laser forming to miniature 3-D axisymmetric shapes from similar thickness originally flat discs.In conventional spin forming, a rotating sheet metal disk is formed over a shaped mandrel by a mechanical tool. In preliminary experiments performed on both cold-worked and annealed discs of 0.127 mm thick 304L stainless steel, a scanned laser beam replaced the spinning apparatus. A scan head steered ∼25W of laser power (1.064 µm) onto the disc. A laser-based sensor was incorporated to measure surface movements.Temperature and surface displacement measurements are compared to FEA modeling results. Laser powers, beam trajectories, temperature gradient changes and bend results for single and multiple passes will be presented.Finally, the information developed was use...