Investigation on laser cavitation micro-forming process: Deformation behavior of 1060 aluminum foil and bubble evolution in a gap

Abstract

Abstract The water-jet and shock waves generated by laser-induced cavitation were employed to the laser cavitation micro-forming (LCMF). The LCMF is a new method for fabricating micro features on two pieces of metal foils simultaneously. The mechanism of LCMF was investigated at the non-dimensional parameter γ (γ = L/2Req, where L is the width of the gap, and Req is the equivalent radius). The dynamic characteristics of laser-induced cavitation bubble in a gap were studied using a high-speed photography and numerical simulation. The shock waves were detected by the hydrophone and the velocity field distribution was obtained from numerical simulation. The 1060 aluminum foil was used in LCMF, and the surface morphology, forming depth, surface roughness and thickness distribution of the formed aluminum micropores were investigated. The results indicate that the non-dimensional parameter γ has a great impact on bubble evolution in a gap. At γ = 1.29, the pressure intensity of plasma shock wave, bubble collapse shock wave and water-jet are 72.7 MPa, 40 MPa and 65.3 MPa, respectively. The forming depth, surface roughness and thickness thinning ratio decreased with the increase of γ, and maximum thickness thinning occurred at the fillet.