Accuracy of stereolithography printed alumina with digital light processing

Digital light processing (DLP) stereolithography was used to prepare layers and samples for dimensional calibration from commercial alumina slurries. Single-layer squares were studied to understand the penetration depth and curing behavior, and samples with varying curing time and intensity were printed and sintered. Fourier-transform infrared spectroscopy (FTIR) of the squares was performed to measure the relative amount of curing based on the change of the bond transparency of the polymer during various printing conditions. X-ray computed tomography (XCT) scans were performed after printing of squares and parts as well as after sintering parts. The morphologies and structures of the squares and parts were studied after printing and after sintering. The dimensions were measured, and the differences before and after sintering are reported for the various printing conditions. The study shows how FTIR can monitor curing of printed parts, and dimensional accuracy of 0.20 mm can be achieved.