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 certain print parameters have on the mechanical performance of parts produced by Low Force Stereolithography (LFS), (2) demonstrate the relative impact that certain print parameters have on the mechanical performance of LFS parts and (3) propose theoretical parameter schemas to optimize LFS prints. This work presents the mechanical properties of LFS parts with respect to distinct LFS print parameters, namely print orientation (P_O), print layer thickness (L_T), post-print cure time (C_M) and post-print cure temperature (C_T) 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 its overall performance. Using D638-22 to analyze this additive method, it was found that the Segment Modulus (SE), Ultimate Strength (US), percent elongation (%e), Poisson's ratio (ν) and Toughness (T) all varied greatly across the nine (9) distinct sample types designed for the 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%, 0.377/.450 and 0.033/.200 ksi, respectively, depending on the parameters chosen. This wide range of property data must be coupled to LFS print parameters if the technology 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 both of these relationships. The results indicate that all print parameters influence the mechanical performance of LFS parts.