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his study examines the effect of major masked stereolithography (mSLA) process
variables, namely, layer thickness, build orientation, and exposure time, on hardness of
ultraviolet (UV) resin printed components. A Taguchi L9 orthogonal array design of
experiments was used to perform nine experimental runs with Shore D hardness as the
response variable measured per ASTM D2240. The parametric design allowed systematic
testing of the parameteric effects with minimum number of trials. The results were
interpreted using statistical methods, including analysis of variance (ANOVA), signal-tonoise (S/N) ratio analysis, regression modeling in order to determine the best processing
conditions. Results show that exposure time is the most noticeable variable, with a
contribution to the total variation in hardness of about 70 percent, build orientation and
layer thickness added 13.5 per cent and 12.8 per cent respectively, and showed significant,
but minor, effects on the response. The S/N ratios main effects plot indicated that the best
parameter set to obtain maximum hardness is 0.100 mm layer thickness, 45deg build
orientation, and 21 seconds exposure time. Finally, the exposure time is identified as the
essential control parameter of the hardness, and orientation and thickness as the secondary
refinements. The research provides a sound framework for process optimization within
SLA.