Multi-Material Digital Light Processing Printer With Material Tower and Spray Cleaning

Abstract

Digital light processing (DLP) three-dimensional (3D) printing is a type of stereolithography (SLA) process that uses a digital projector to selectively cure resin according to a mask image. Each exposure solidifies a planar component of the printed part, allowing full layers to be cured at once. The DLP approach produces better quality parts at a faster rate compared to other 3D printing methods. One of the challenges with DLP printing is the difficulty of incorporating multiple materials within the same part. As the part is cured within a liquid basin, resin switching introduces issues of cross-contamination, layer height variability, and significantly increased print times. In this paper, a novel technique for printing with multiple materials using the DLP method is introduced. The material handling challenges are addressed with the design of a material swapping mechanism, a material tower, and an active part cleaning system. The material tower is a compact design to facilitate the storage and retrieval of different materials during the printing process. A spray mechanism is used for cleaning excess resin from the part between material changes. Challenges encountered within the 3D printing research community are addressed, with a focus on improving the shortcomings of modern multi-material DLP printers.