The Tensile Properties of Functionally Graded Materials in MSLA 3D Printing as a Function of Exposure Time

Functionally graded additive manufacturing (FGAM) emerged from the combination of Functionally Graded Materials into additive manufacturing. This work involved the production of FGAM specimens to alter the characteristics of both the outer and inner zones of tensile specimens. This was achieved by adjusting the exposure time without additional costs or equipment. During the assessment, the tensile specimen was separated into three zones. The exterior layers were initially created with a 3-second exposure time, followed by the interior layers with a 15-second exposure time. Then, the process was reversed, with the outer layers exposed for 15 seconds and the inner layers exposed for 3 seconds. Subsequently, all layers were generated using exposure durations of 3 seconds and 15 seconds, respectively, without any alterations, resulting in a total of 4 distinct samples. The hardness and tensile tests were conducted on all specimens, both with and without post-curing, in order to assess the impact of post-curing. The outcomes indicate that the levels of hardness and maximum tensile strength rise as the final curing process progresses, but the elongation capability diminishes. The highest ultimate tensile strength, achieved after 15 seconds of exposure time with post cure, was measured at 46.46 ± 0.9 MPa. The green FGAM specimens have a greater ultimate tensile strength (35.85 ± 0.4 MPa) when created with an exposure time of 15-3-15 s. However, the specimen produced with an exposure time of 3-15-3 s demonstrates a higher ultimate tensile strength (38.77 ± 0.7 MPa) following post curing.