Development and Characterizations of a Projection Stereolithography

Stereolithography is a manufacturing process capable of building a truly high resolution 3D structure by solidifying the liquid monomer in a layer by layer fashion. Currently, there are many developments toward new 3D printing techniques leading to needs for methods of characterization to improve printing process for higher performance. In this study, we propose to create a bottom-up projection stereolithography to accommodate a 3D printing technique. Our system was designed for combining with a regular fused deposition modeling (FDM) process for multi-material application. In addition, we developed a method for characterizations different specifications of a custom-made projection stereolithography. Our 3D printer can create an object up to 25 mm x 25 mm x 15 mm of length, width and height, respectively. We minimized the layer thickness error by modifying a screw and spring components in order to precisely control the movement of the vertical stepping. The light source distance and the calibration factor were also importance factors to obtain the better precision of finished parts. Based on the proposed characterization method, the 3D printer was able to achieve the lateral resolution of 0.05 mm and a vertical step resolution of 0.01 mm. The average percentage error of built part were 0.32 % on X-axis and 0.25 % on Y-axis laterally and 0.60 % error on the layer thickness.