Beyond the blueprint: 3D printing and the future of energetic materials

Explosive, propellant, and pyrotechnic materials are among the most demanding substances in industry. Any change in composition, environmental conditions, or production stage can alter their behavior, sometimes in ways that are difficult to predict. Monique McClain from Purdue University has set out to change that using 3D printing.

McClain works on the early stages of the production of energetic materials. She studies binder selection, ingredient mixing methods, and the microstructure of the finished product. These are precisely the elements that determine how a material behaves during combustion or detonation. Her goal is complete control over every stage, down to the level of individual particles.

Traditional manufacturing methods, such as casting, injection molding, or CNC milling, work well for large production runs. However, customization is expensive, which limits the scope for experimentation. The use of 3D printing enables researchers to design complex geometries and precisely fine-tune material properties at every stage of the process while keeping production costs low.

The working environment also matters significantly. Improper or fluctuating room temperature and humidity can cause the same mixture, printed twice on the same day, to behave in completely different ways. McClain regularly emphasizes that environmental control is not a minor detail; it is the foundation of repeatability and safety.

One of the more surprising areas of McClain’s research is the deliberate introduction of pores into a material’s structure. Pores are microscopic voids within the material that affect its sensitivity to ignition upon contact with friction, impact, or high temperature. Rather than treating them as an unavoidable side effect, McClain designs them intentionally, controlling their size, distribution, and density.

3D printing makes this possible through precise nozzle programming. Researchers can specify exactly where and how pores should form, rather than struggle with their random distribution.

McClain also investigates combining materials with different mechanical properties. Printing hard thermoplastics and soft elastomers together in a single structure is a significant challenge. Surface texture and the material used determine how well the two bond. This aspect may seem like a technical detail, but in practice, it directly affects the safety and effectiveness of the finished product.

3D printing is an important part of McClain’s work, but not the only one. She has also developed a patented method for producing a powder used to form polymer-bonded explosives, known as PBX. The method shortens production time, reduces waste, and eliminates some potential hazards.

The key was precisely identifying the ideal moment for the binder to cure. Around eight hours into the process, the binder is solid enough not to leak during densification but still flexible enough not to crack. This narrow time window makes it possible to obtain a material with predictable and repeatable properties.

McClain approaches the entire production process holistically. Instead of adapting the material to the available machine, she first determines the necessary properties and geometries for the final product. Sometimes the answer is 3D printing, sometimes conventional methods, and sometimes a combination of both.

3D printing will not replace traditional manufacturing methods, but it gives researchers a tool they did not have before: the ability to consciously design a material’s behavior before it ever reaches the field.