Gradient Printing of Energetic Materials–First Results

Abstract

This paper presents TNO’s first results on functional gradient printing of energetic materials. A multi-material 3D-printer with UV-curing capability was designed and constructed. This printer can handle highly viscous materials (> 200 Pa·s), allowing for solid loads above 70 wt%. Also included in the effort was the development of the software required to translate a multi-material propellant grain concept into printer command code, as well as the user control interface through which the printer can be controlled. For the first gradient printing demonstration, two materials were selected with a difference in burn rate large enough to lead to a significant performance increase when applied in a gun propellant grain. These materials were then used to print the first energetic propellant grain with a functional gradient. Finally, a continuous gradient was produced using co-extrusion of two (inert) material feeds, demonstrating the feasibility of this technique.