Establishment of process model for part strength in stereolithography

Stereolithography (SL) is one of the popular RP processes used for rapid tooling applications. The contribution of three parameters namely layer thickness, post-curing time and orientation are the most significant to the strength of SL product. In this paper, an attempt has been made to identify the process parameters that influence on the strength of parts made with CIBA TOOL 5530 in SL 5000 machine, one of the processes used for rapid tooling and optimize the parameter levels. Addition to the above, a process model (empirical relationship/regression model) between part strength (tensile, impact, flexural) and the above-mentioned process parameters (layer thickness, post-curing time and orientation) has been developed. The process model obtained by the empirical relation can predict how much strength can be achieved for a given set of the process parameters, thus providing prior knowledge of part strength before actually making a SL part. The process model is able to show the dependency of strength on process parameters, which is very useful information for machine designers as well as RP machine users.