Quantification of the Effects of Print Parameters on the Mechanical Performance of Low Force Stereolithography Parts

Abstract

The objectives of this work are threefold: (1) quantify the effects that print parameters have on the mechanical performance of parts produced by a novel vat photopolymerization technology called Low Force Stereolithography (LFS), (2) demonstrate the relative impact of each print parameter on part performance through Signal-to-noise ratio (S/N) analysis and (3) propose theoretical parameter schemas to optimize part performance. This work presents the mechanical properties of LFS parts with respect to distinct LFS print parameters, namely print orientation (PO), print layer thickness (LT), post-print cure time (CM), and post-print cure temperature (CT) at three (3) levels apiece. To date, LFS has been largely unstudied; however, as a novel approach with unique engineering material availability, it is important to quantify. Using D638-22, it was found that the Segment Modulus (SE), Ultimate Strength (US), percent elongation (%e), Poisson’s ratio (ν) and Toughness (T) varied greatly across the nine (9) distinct sample families designed for study. Specifically, SE, US, %e, ν, and T achieved a minimum/maximum of 331/463 ksi, 4.39/9.07 ksi, 1.20/3.55%, .377/.450 and .033/.200 ksi, respectively, depending on the parameters chosen. This wide range of property data is important to quantify and couple to parameter schemas if LFS is to be implemented as a viable approach to manufacture end-use or provisional tooling. Furthermore, it is essential to understand the relationship between a given property and a specific parameter. S/N plots were used to quantify this relationship. The results indicate that all print parameters – but most notably PO – influence the mechanical performance of LFS parts.