An investigation on photopolymer solidification considering laser irradiation energy in micro-stereolithography

Abstract

Micro-stereolithography technology has made it possible to fabricate freeform three-dimensional microstructures. This technology is based on conventional stereolithography, in which a UV laser beam irradiates the free surface of a UV-curable liquid photopolymer, causing it to solidify. In micro-stereolithography, a laser beam that is a few mum in diameter is used to solidify a very small area of the photopolymer. Photopolymer solidification phenomena in response to variations in the scanning pitch of a focused laser beam were investigated experimentally in this study according to the irradiation energy. The effect of the layer thickness on the solidification width and depth was also examined. The study was conducted using both a relatively low laser power and high scanning speed ( low irradiation energy method), and a relatively high laser power and low scanning speed ( high irradiation energy method). The experimental results were compared with those obtained using a photopolymer solidification model. Based on these results, a new laser-scanning scheme is proposed according to the three-dimensional microstructure shape desired. Samples were successfully fabricated using both methods.