Laser shock hydraulic forming for micro-bowl with miniature concave

Abstract

A novel laser shock forming process called micro-laser shock hydraulic forming (MLSHF) was proposed to fabricate a micro-bowl with miniature concave at the apex of the bottom. Liquid water, used as a soft punch, can generate pressure waves under the action of laser shock to deform a 30-μm-thick copper foil. The influence of laser energy on morphology, forming accuracy, thickness distribution, and surface quality under MLSHF process was discussed through experimental means. Experimental results showed that the miniature concave was fabricated at 1050 mJ, and the whole micro-bowl was formed at 1550 mJ. With the increase of laser energy, the fittability improved and rebound became increasingly severe. Serious thinning occurred at the fillet of the miniature concave. Moreover, the die with great surface quality reduced the surface roughness of the workpiece surface that contacted with the die. A numerical finite element analysis (FEA) model was established by Hypermesh/LS-DANA. The FEA model was firstly verified through an experiment, and then it was used to investigate the deformation behavior including dynamic forming process and strain distribution.