A process planning method for improving build performance in stereolithography

Abstract

A process planning method is presented to aid stereolithography users in selecting appropriate values of process variables in order to achieve characteristics desired in a part to be fabricated. To accomplish this, the method achieves a balance of objectives specified by geometric tolerances, surface finishes, and part build time, where the balance is specified through preferences on the objectives. Given these objectives and preferences, values are chosen for six process variables to best achieve the balance of objectives. The process variables include part orientation, layer thicknesses, and four recoat variables (Z-level wait time, sweep period, hatch overcure, and fill overcure). The process planning method is adapted from multiobjective optimization and utilizes empirical data, analytical models, and heuristics to quantitatively relate process variables to the objectives. Of particular importance, a new adaptive slicing algorithm has been developed. The process planning method is demonstrated on a part with non-trivial geometric features.