Warpage correction for vat photopolymerization 3D printing

Abstract

Warp or curl distortion significantly negatively impacts print accuracy and polymer characterization. This issue is exacerbated by the inherent mechanisms of vat photopolymerization (VP) 3d printing. In the VP irradiation step, the amount of the light energy absorbed in the prior layers accumulates, leading to a difference in the degree of curing compared to a newer layer. This causes uneven shrinkage of the individual printing layers, which causes bending deformation. In this study, we corrected the warpage by ensuring uniform light energy absorption across all layers using the modified Beer-Lambert’s law. We investigated the warpage angle of both warped and corrected samples, varying by layer and part thickness. Furthermore, we conducted three-point bending tests of dynamic mechanical analysis (DMA) to verify the consistency of measurements from the corrected samples. The results show significant improvements in warpage across various printing parameters and enhanced consistency in DMA tests. Significantly, this study offers straightforward, robust guidance for setting printing parameters of newly developed resins, ensuring reliable samples to characterize polymers.