Effect of confining overlay in micro scale laser bulge forming

Micro scale laser bulge forming (μLBF) shows great potential in fabricating high precision and high-aspect-ratio metallic micro components. The present paper investigated the effect of the confining overlay in μLBF experimentally. The surface morphology of micro bulged parts of pure copper foils with and without confining overlay was explored through the scanning electron microscope. The surface features of quartz glasses with different thickness shocked by single and multiple laser pulses were observed using the optical microscope. The effect of thickness of the confining overlay on the maximum bulging height of micro parts was investigated. Experiments reveal that the application of the confining overlay in μLBF has significant influence on both the surface morphology and plastic deformation of micro bulged parts. The change of laser ablation mode is responsible for forming results. In addition, there is a moderate thickness of the confining overlay to induce noticeable plastic deformation without failure.