Experimental evaluation of mechanical properties repeatability of SLA polymers for labs-on-chip and bio-MEMS

Stereolithography (SLA) is a rapid prototyping technique based on photo-polymerization of liquid resin by laser source. The process is well known for many prototyping activities and additive manufacturing operations and started to show its potential in bio-MEMS applications like lab-on-chips. Unfortunately, the strong linkage between process parameters setting and final properties of downscaled devices is at present the primary cause of design failure and delays. In fact, it is crucial to control geometrical tolerances and mechanical properties. The aim of this work is to investigate the interactions between the most influent SLA process parameters on final mechanical and topological properties of biomedical polymers. The cross-interactions of polymer transparency, port-curing time and hatching direction are analyzed. The terms of comparison used to analyze process performances are geometrical dimensions and mechanical properties (Young’s modulus, ultimate stress/strain). The analysis of variance (ANOVA) method is used to identify the factor of influence of each process parameter.