Abstract
<title>Abstract</title> <p>Stereolithography (SLA) produces high-resolution photopolymer parts whose mechanical and tribological performance depends heavily on post-print Ultraviolet (UV) curing. This study characterises SOMOS Watershed XC 11122, a commercial acrylate resin, printed at 50 µm layer thickness and 450 mW laser power and post-cured at 365 nm and 75°C for 0, 10, and 30 min. Tensile testing (ASTM D638) showed that 10 min curing gave the best results with Ultimate Tensile Strength of 61.1 ± 2.3 MPa and apparent modulus of 1408 ± 75 MPa, which are 17.7% and 35.9% above the uncured group. The 30 min condition fell between the two, confirming a non-monotonic response to cure time. No specimen fractured under three-point bending (ASTM D790), demonstrating good ductility across all conditions. Fourier Transform Infrared (FTIR) and Raman spectroscopy together confirmed near-complete acrylate C=C conversion by 10 min. Between 10 and 30 min, secondary structural changes continued, seen in the vinyl bending mode at 765 cm⁻¹, though the primary conversion peak had already disappeared. Pin-on-disc tribology across five load-speed combinations per cure group revealed that uncured specimens wore dramatically more up to 1943 µm at 20 N compared with cured specimens. At 15 N and 318 RPM, the 30 min specimen achieved the lowest wear depth (32 µm). Scanning Electron Microscopy (SEM) showed directional abrasive grooves on worn surfaces, with groove severity decreasing with cure extent. Energy Dispersive X-Ray Analysis (EDAX confirmed organic composition (C: 70–74 wt%, O: 21–23 wt%) with minor post-wear oxidation shifts. Surface roughness was 0.30–0.66 µm Ra, and dimensional deviations on uncured cubes ranged from −4.1% to +14.8%. Ten minutes of UV post-curing is recommended for strength-critical applications; 30 min offers better wear resistance at moderate loads.</p>