Curing characteristics of shape memory polymers in 3D projection and laser stereolithography

Abstract

The radical shift in 3D printing to fabricate soft active materials such as shape memory polymers (SMPs) has brought along other techniques in realising 4D printing. Stereolithography (SL) process has recently been one of the popular systems for printing SMPs. In this paper, the curing characteristics and behaviour of the SMPs fabricated via projection-type and laser-scanning-type SL process were analysed. Factors such as the UV exposure of the projection type and variation in resin compositions have significant differences in terms of energy density and curing depths when compared to the laser scanning type. Hence, theoretical calculations were made to determine the critical energy density and threshold penetration depth attainable, which enables newly developed SMP materials to be successfully printable using different types of UV-based 3D printing systems.