Characteristics of photopolymeric material used in rapid prototypes .2. Mechanical properties at post-cured state

The mechanical properties of specimens fabricated by the laser solidification process using an acrylic-based photopolymer (De Solite SCR-300) and post-cured under intense UV light have been studied. A differential scanning calorimeter (DSC) was employed to monitor the degree of cure of the post-cured specimens. It was found that specimens subjected to post-curing do not contain any residual enthalpies, indicating fully polymerized structures. The post-cured specimens were also subjected to tensile tests to determine their mechanical properties. By comparing the results of both the post-cured and green-state specimens, it was observed that the post-cured specimens yielded higher measured values of elastic modulus, ultimate tensile strength, and elongation to fracture. It was also observed that these mechanical properties of the post-cured specimens were functions of the layer pitch and the laser exposure density used in generating its green-state counterparts. By increasing the laser exposure density and decreasing the layer pitch, the mechanical properties of the post-cured prototype can be increased, leading to a post-processed prototype with higher mechanical strength. (C) 1997 Elsevier Science S.A.