M.S. Thesis Presentation by Brian E. Davis
Thursday, September 14, 2001

(Dr. Janet Allen, advisor)

"Characterization and Calibration of Stereolithography Products and Processes"

Abstract

As with any machine tool, it is important to understand the capability of stereolithography apparatus (SLA) processes, equipment, and resins in terms of accuracy and reproducibility in order to produce high quality parts.  It is often difficult to determine theoretically whether a set of tolerances on a part can be obtained using a particular SLA machine-resin combination.  Characterization and calibration of a stereolithography apparatus has not been widely or uniformly done due to the state of this evolving technology.  In the area of SLA accuracy and inaccuracy, there has been research done.  However, the number of machine and resin combinations, as well as their innovations, leads to an overwhelming number of product outcomes.  Today, because of technological advances, these machines are beginning to be used to produce final products; accordingly, the tolerances are now important.  Quantitative relationships between part geometry, tolerances, and process variables must be determined.

In this thesis, the research addresses the input data needed to model the characterization and calibration of SLA products and processes as well as the characterization itself.  The study began on the 3Dsystems SLA-3500 machine with a single resin (SL7510); however, this work will provide a guideline for others to perform these experiments on any reasonable combination of machine and resin – just as previous researchers provided a premise for this work to proceed (Lynn-Charney, 1998).  It specifically produces a baseline of what can be expected from planar geometries when produced on this machine-resin combination with near-default values.  The knowledge baseline on known machine-resin combinations is widened with an additional resin (SLA-3500 and 8120) experiment, and comparing the information acquired from Lynn-Charney’s earlier work on the SLA-250, to determine relationships between geometries on the two machine-resin combinations.  Then the research advances the knowledge of accuracy and reproducibility of SLA parts by including the position in the vat as a build variable.  Flexibility in decisions is increased due to the expanded knowledge of equipment and material interaction.