Still motion process for improving the accuracy of latticed microstructures in projection microstereolithography

Projection microstereolithography (PμSL), which involves fabricating a microstructure using patterned light with a dynamic mask such as a liquid crystal display (LCD) and a digital micromirror device (DMD), is one of the additive manufacturing technologies. A nonuniform light intensity distribution of the cross section to be illuminated affects the accuracy of the microstructure. In other words, under-cure or over-cure occurs by light superposition in the corner of a latticed microstructure. This phenomenon will offset the advantages of the PμSL (e.g., its simple process and fast fabrication time). Furthermore, accurate fabrication of a microstructure is indispensable for various applications such as a scaffold for tissue regeneration, and micro-devices for micro-actuators. In this study, the still motion method is introduced to improve the accuracy of latticed microstructure. We used continuous projection of a unit shape image, which is determined by the cross section in a layer. Some latticed microstructures have been more accurately fabricated by the still motion process compared to conventional PμSL processes.