Use of volumetric additive manufacturing as an in-space manufacturing technology

Abstract

Computed Axial Lithography (CAL) is a recent advancement in volumetric additive manufacturing (VAM) that delivers a light dose to a photopolymer volume through tomographic reconstruction. The precursor liquid or gel itself generally supports the emerging object, eliminating the need for wasteful dedicated solid supporting structures. A challenge, however, is that desired geometry can shrink or expand during solidification and on Earth, if the precursor material's viscosity is low enough. These effects may result in sinking or floating of the component, which can blur the geometry.In principle, CAL is promising for in-space manufacturing because, unlike layer-based processes, CAL does not require a flat liquid–gas interface to be maintained during printing. With suitable development, CAL is potentially capable of manufacturing parts such as organic tissue, flexible seals, rigid trusses, and microstructures for space exploration, as well as repairing existing tools and parts. ‘SpaceCAL’ flew on a microgravity parabolic flight in May 2022 to demonstrate the capabilities of CAL and analyse a CAL system in a microgravity. Initial findings show that 0.12 Pa-s low viscosity precursor can be printed in microgravity with less geometric distortion than an Earth-based gravity counterpart.