Statistical analysis of the stereolithographic process to improve the accuracy

Stereolithography (SL) is a widely used technology in the field of rapid prototyping. However, the dimensional accuracy of SL products is today still limited; therefore, this technology needs to be optimized for high precision applications. This paper presents a statistical analysis of the stereolithographic process, in order to find out the combination of parameters leading to the best accuracy of the manufactured parts. A particular benchmark was designed and a global error index was introduced to evaluate the global distortion of built parts. The Taguchi methodology was employed for the optimization. A Viper Si"2 machine by 3D Systems was used in both the modalities allowed from this system: Normal and High Resolution. Moreover, a detailed analysis of the resin polymerization mechanism was performed; from this study it emerged that the post-curing process is not always necessary if the process parameters are chosen for not having uncured areas.