Effect of Layer Thickness and Orientation of 3D Printed Parts on the Mechanical Properties

With the many advancements in 3D printing technology in the last few decades, there is an increased need for a greater understanding of fundamental print variables. Additive manufacturing (AM) is becoming more viable for large commercial processes and more accessible to 3D printing hobbyists. The field of additive manufacturing would benefit from stronger prints to allow for a wider range of applications and innovations. Stereolithography additive manufacturing (SLA) is used to investigate the effect of layer thickness and print orientation of 3D printed parts on the mechanical properties. Using clear resin, parts were 3D printed with three layer thicknesses (25$\mu m50\mu$m and 100$\mu$m) and three print orientations (0°, 45°, 90°). Tensile tests were performed in accordance with ASTM D638 and results showed a positive correlation between the Young’s modulus and print orientation for parts with 100 micron layers, with the 90° specimens being the stiffest of the three print orientations in the 100 micron layer thickness group. Among all samples, the 25$\mu$m0° print proved to be the stiffest parts-a sacrifice for its brittle nature with low strain. Even so, the almost linear trends present in the 100$\mu$m samples were absent from the thinner layer prints, raising the belief that at a certain thickness, the print orientation provides no significant trends. These results raise the understanding of SLA printing parameters and the effect on printed parts, enabling more efficiency and raising the ceiling on the upper limits of 3D printing.