Photopolymer additive manufacturing (PAM) is fueling an explosion of opportunities and capabilities for US production of 3D printed products in a wide range of industries including automotive, healthcare, energy, and consumer goods. While digital light processing (DLP), a subset of PAM, relies heavily on patterned light sources with up to millions of individual pixels in the 1 µm to 100 µm length scale, recent research has revealed the dramatic dependence of the polymerization process on slight variations in photo-exposure conditions. Reliance by the PAM industry on non-uniform, poorly characterized light engines can convolve exposure variability with fundamental photochemistry and photo-physics, hindering advancements. Specifically, a lack of single pixel characterization and multi-pixel uniformity in the light engine hinders fundamental characterization of the photopolymerization reactions that underpin PAM. By developing a uniform, well-characterized light engine, this work provides a foundation to inform the comprehensive models required to improve the fidelity and integrity of PAM products. As such, this presentation will provide an overview of NIST's development of a state-of-the-art light engine, comparing prints from commercially available DLP systems to those from the uniform light-engine, while discussing our efforts to establish standard reference materials and methods to calibrate commercial light engines. This work highlights the need for rigorous characterization of sources to streamline PAM resin development for reliable, high-performance PAM.
- Upon completion, participants will be able to understand the dire implications on final part properties and fidelity of a non-uniform, uncorrected light engine.
- Upon completion, participants will be able to determine if a given light-engine is uniform and how it can be calibrated.
- Upon completion, participants will be able to apply a correction algorithm to their light engine to produce uniform part across a given built plate.