Control of Self-Propagating Polymer Beams for Integration into Three-Dimensional Printing

Project Overview

The goal of this project was to discover if it is possible to accurately control the beam length of self-propagating photopolymer waveguides, independently of the beam diameter. Self-propagating photopolymer waveguide (SPPW) is a phenomenon caused by the change in the index of refraction between the cured and the liquid resin. When exposed to light, polymerization starts at the point of exposure, and the light is trapped in the polymer because of internal reflection, like an optical fiber. The overarching goal of this study was to understand the feasibility of pursuing a new manufacturing method, that would combine traditional stereolithography and self-propagating photopolymer waveguide processing. This new method would be faster than traditional stereolithography (like digital light processing, DLP, or projection microstereolythography, PuSL), and this new method will be more versatile than SPPW.

Towards our goal, we generated self-propagating polymer beams using three different techniques, and we analyzed the beam length as a function of the beam diameter, light intensity, and exposure time. Our analysis showed that the length of the beams is controllable; however, control the shape of the beams, which grow in a conical shape, instead of the desired cylindrical shape, remains as future work. 

Mission Impact

This project developed an improved understanding of self-propagating polymer waveguides, the formulations, and how to generate them. For the first time, we proved that a liquid crystal display (LCD) can be used as a digital mask to create self-propagating waveguides. These achievements are in line to contribute to scaling up additive manufacturing and creating more cost-effective systems, which is an important goal of the Accelerated Materials and Manufacturing Core Competency.