CAD/CAE/CAM integration for increasing the accuracy of mask rapid prototyping system

Stereolithography is a rapid prototyping (RP) process that uses photopolymers as the raw materials from which the prototypes are built. The photo-polymeric RP system uses lasers or other light sources to expose selectively the surface of the liquid resin. The absorption of energy causes photo-polymerization that changes the liquid resin into a solid, expanding the cured volume expanding but shrinking simultaneously. The volume shrinkage and curl distortion of the resin during photo-polymerization are the main reasons for the poor accuracy of the built prototype, especially when the part is hollow, in which case the bending is greater because of the bending stress and cannot be compensated for. Normally, a designer builds a support in this stage to limit the further bending and deformation of the prototype. However, after the support has been removed from the built prototype, the geometric profile is easily damaged and deformed, so time is wasted. This study initially uses dynamic finite element simulation code to simulate photo-polymerization, to determine the distortion of the outer profile of the part and thus reduce the deformation. Then, a reverse distortion correction is applied to the outer profile of the part. A new reverse compensation CAD model is produced and loaded into a RP machine for practical prototype processing, to increase the accuracy of the process. Finally, the “H-4” diagnostic part is used as an example to verify the experimental results. The results of the simulation and experiment on the final after compensation were accurate.