Multi-objective optimization for part quality in stereolithography

The quality of a rapid prototype model built by using a stereolithography apparatus (SLA) is not always predictable due to its dependency on several SLA process parameters. The way to control these parameters with a view to optimize the multiple objectives of build quality requirements like accuracy, build time and surface finish is described. A benchmark part was designed for this purpose. Nine SLA parts were built with an epoxy-acrylate based resin and ACES build style following Taguchi method. The process parameters selected for control are layer thickness, hatch spacing, hatch overcure depth and post curing time. The detailed study of the effects of these parameters was carried out over the SLA parts. The data were analyzed by quantitative methods. The results obtained were utilized to select the main influencing parameters and the best parameter settings for yielding the optimum objectives. The predicted and the observed optima were compared to validate the additive model equation.