Mask Image Planning for Deformation Control in Projection Based Stereolithography Process

Abstract

The maskimageprojectionbased stereolithography process (MIPSL) using a digital micromirror device (DMD) is an areaprocessingbased additive manufacturing (AM) process. In the MIPSL process, a set of mask images are dynamically projected onto a resin surface to selectively cure liquid resin into layers of an object. Consequently, the MIPSL process can be faster with a lower cost than the laserbased stereolithography apparatus (SLA) process. Currently an increasing number of companies are developing lowcost 3D printers based on the MIPSL process. However, current commercially available MIPSL systems are mostly based on Acrylate resins, which have larger shrinkages when compared to epoxy resins used in the laserbased SLA process. Consequently, controlling the shrinkagerelated shape deformation in the MIPSL process is challenging. In this research, we evaluate different mask image exposing strategies for building part layers and their effects on the deformation control in the MIPSL process. Accordingly, a mask image planning method and related algorithms have been developed for a given computeraided design (CAD) model. The planned mask images have been tested by using a commercial MIPSL machine. The experimental results illustrate that our method can effectively reduce the deformation by as much as 32%. A discussion on the advantages and disadvantages of the mask image planning method and future research directions are also presented.