Photonic Sintering for Granular Additive Manufacturing

Project Overview

The two predominant powder-based additive manufacturing techniques use either a polymer binder or laser to selectively solidify a pattern into a thin layer of powder. After solidification, a new layer is spread over the existing layer and the process is repeated, allowing creation of complex three-dimensional structures. However, both techniques are generally limited to a single material. As an alternative, powder-deposition techniques under development at Lawrence Livermore National Laboratory can selectively deposit material directly, eliminating the need for patterning during solidification. Photonic curing is a wide area, high speed solidification technique that uses a flash lamp to solidify particles. The technique has found success in flexible electronics, where nano-scale particles suspended in an ink are converted into conductive traces on polymer substrates that could not survive the high temperatures in conventional thermal solidification. The particles used in additive manufacturing are larger than the nanoparticles in the conductive ink and there are only a few reports in the literature that use photonic curing on larger particles.

This project examined the applicability of photonic curing to larger particles used in additive manufacturing. A commercially available photonic curing system was used to test powders of different materials and sizes across different exposure profiles. Inspection was done via microscopy, looking for changes in particle shape. A conductive nanoparticle ink was used as a reference, and it solidified as expected. However, of the larger metals, ceramics, and polymers particles, only nickel-coated glass solidified, indicating that this approach to the power used is not suitable for use in additive manufacturing applications.

Mission Impact

This study evaluated the potential for photonic curing to be used within additive manufacturing processes, but the results indicate that the current tools do not support this use. Development of particle-based additive manufacturing should focus on other approaches for solidification.