25 Feb 2019
World innovation news
Materials & Manufacturing
3D Printing: New Prospects for Energy Materials
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As 3D printing gains new ground in industry, its techniques are becoming more refined and its range of materials is expanding. Energy materials offer special challenges to engineers because they require specific measures and control. Researchers at Purdue University have developed a new, faster, safer 3D printing method that can produce greener energy materials.
What Is an Energy Material?
Energy materials are characterized by their ability to release energy intensively over a very short time. They can be in a solid, liquid or gas form and are used in military and civil applications. The released energy can be used as thermal or mechanical energy. From these materials, explosives and pyrotechnics, for example, can be made.
The team used a simple inkjet printer to print a nano-thermite-based material. As explained in the following video, nano-thermites are composites made of oxidants and reductive agents mixed at the nanoscale. They are characterized by the large amounts of heat produced when ignited.
The printer must produce this type of material with care, without creating voids that can cause serious accidents. To do this, the team has equipped the printer with a device that allows to safely deposit energy materials, and achieve a high level of accuracy. The printer nozzle generates high amplitude ultrasonic vibrations, which reduces friction of highly viscous materials on its walls and facilitates their passage. The method also makes ensures a more accurate flow.
The team created this technology to print viscous materials with a consistency similar to clay. This type of material presents several constraints in the printing of high-resolution parts. Jeffrey Rhoads, professor at Purdue’s School of Mechanical Engineering and co-author of the study, said the method is notable for its ability to print energy materials without using solvents to reduce their viscosity. With this new technology production, is faster, more environmentally friendly, and cheaper. The method can also be used to print biomedical implants, foods, drugs, etc.
The study entitled “Selectively-deposited energetic materials: A feasibility study of the piezoelectric inkjet printing of nanothermites,” was co-authored by Allison K. Murray, Whitney A. Novotny, Trevor J. Fleck, I. Emre Gunduz, Steven F. Son, George T-C. Chiu, and Rhoads, and published in Science Direct in August 2018.
It demonstrated the feasibility and effectiveness of the proposed method. The researchers tested three piezoelectric inkjet printers to determine the ability of each system to make aluminum oxide and copper nano-thermite-based parts. They also tested the material’s propagation and combustion speeds from the samples obtained.
Rhoads launched the start-up Next Offset Solutions Inc., in collaboration with his colleagues. The company specializes in the manufacture of 3D printers and energy materials. Their aim is to supply their products to the US Department of Defense and Department of Energy as well as their subcontractors.
The new printing process was patented with the help of the Purdue Office of Technology Commercialization.