Improving Quality Characteristics and Structural Integrity of Parts by SLA

Stereolithography is one of the most popular techniques of the additive manufacturing process that produces parts from a 3D CAD model by scanning an ultra violet laser beam over a resin liquid. This work studied the SLA parameters such as layer thickness, hatch overcure, and part orientation, which result in better part characteristics such as density, surface finish, and ultimate tensile strength. The optimum process parameters to achieve these part characteristics were also determined through an optimization study. Standard tensile test bars were manufactured using the SLA 5000 machine with different process parameters, and then the part properties were tested. For each part, the density was calculated through water immersion Archimedes method. Next, the surface roughness was measured using an Alicona Infinite Focus G4 optical scanner. Moreover tensile tests were carried out on each specimen using a MecmesinMultiTest5-Xt machine to find out the ultimate tensile strength. Design of experiments (DOE) was then used to correlate the process parameters to the part characteristics. Finally, the experimental data was analysed using design-expert software to predict the optimum process parameters based on the objective function which is to maximize the density and UTS of the SLA parts, while achieving minimum surface roughness.