Inkjet-printed thermite deposits energetic materials safely

Researchers have developed a method to deposit tiny amounts of energetic materials (explosives, propellants, and pyrotechnics) using the same technology as an inkjet printer. This research, which combines Purdue expertise in both energetic materials and additive manufacturing, allows energetic materials to be deposited with unprecedented levels of precision and safety. "Energetic materials is a fairly understood field, and so is additive manufacturing," said Allison Murray, a doctoral candidate in Purdue's School of Mechanical Engineering, who built the custom inkjet printer. "What's unique about this project is the intersection of those two fields and being able to safely deposit energetic materials with this level of precision." Many micromechanical systems incorporate energetic materials in their operation. For example, an automotive airbag deploys using a small amount of solid propellant. But as devices get smaller, the need for micro-level energetics becomes more critical. "Our solution is to combine two components as we're printing them," said Jeff Rhoads, professor of mechanical engineering, and principal investigator on the project. "We can have a fuel and an oxidizer in two separate suspensions, which are largely inert. Then, with this custom inkjet printer, we can deposit the two in a specific overlapping pattern, combining them on a substrate to form nanothermite."