Assessing the suitability of highly filled energetic composites for additive manufacture

There is currently significant interest in the development of additive manufacturing (AM) techniques suitable for various energetic materials, such as explosives and propellants. One potential approach in this application space is to use extrusion-based techniques, such as Direct Ink Writing (DIW), to print highly solids filled pastes based upon uncured polymer bonded explosives (PBXs) or composite propellants. In supporting the development of these techniques, it will be important to develop an understanding of how the rheological properties of the materials affect their overall printability, which can be defined as their suitability for a particular AM approach. Such an understanding could enable rapid selection and optimisation of suitable technologies or formulations based upon measurable parameters.This paper reviews the printability of energetic materials in extrusion-based systems, and considers applicable approaches, rheological models and experimental techniques. The design, assembly and testing of custom apparatus for assessing the extrusion properties of an energetic paste are also discussed.