laser micro-forming

J.L. Ocaña, M. Morales, C. Molpeceres, O. García, J.A. Porro, J.J. García-Ballesteros
Centro Láser UPM. Ctra. de Valencia, km. 7,3. 28031 Madrid. Spain

Abstract

Continuous and long-pulse lasers have been extensively used for the forming of metal sheets for macroscopic mechanical applications. However, for the manufacturing of micro-mechanical systems (MMS), the applicability of such type of lasers is limited by the long relaxation time of the thermal fields responsible for the forming phenomena. As a consequence, the final sheet deformation state is attained only after a certain time, what makes the generated internal residual stress fields more dependent on ambient conditions and might difficult the subsequent assembly process. The use of short pulse (ns) lasers provides a suitable parameter matching for the laser forming of an important range of sheet components used in MMS. The short interaction time scale required for the predominantly mechanic (shock) induction of deformation residual stresses allows the successful processing of components in a medium range of miniaturization (particularly important according to its frequent use in such systems). In the present paper, a discussion is presented on the specific features of laser interaction in the timescale and intensity range needed for thin sheet micro-forming with ns-pulse lasers along with relevant modelling and experimental results and a primary delimitation of the parametric space of the considered class of lasers for the referred processes.