We saw yesterday how 3D printing in the field helped save the US Marines $70,000. Now, it turns out that the US Army is also using 3D printing to aid soldiers on remote bases.
The reason for turning to additive manufacturing is that it cuts out weeks of waiting for vital replacement parts. Scientists have proven that such vital parts could instead be printed within a base in just a few hours using recycled materials.
For example, waste materials such as plastic bottles can be recycled as a filament for 3D printing small parts that typically would not be stocked at a forward base. However, single-use plastics are not the only waste material the research found useful. Cardboard is also valuable when used as a composite material in conjunction with the plastic.
Nicole Zander, Ph.D., says: “Ideally, soldiers wouldn’t have to wait for the next supply truck to receive vital equipment. Instead, they could basically go into the cafeteria, gather discarded water bottles, milk jugs, cardboard boxes and other recyclable items, then use those materials as feedstocks for 3D printers to make tools, parts and other gadgets.”
This potentially “game-changing” work was presented at the 256th National Meeting & Exposition of the American Chemical Society (ACS).
The U.S. Army Research Laboratory researchers quickly found that using recycled polyethylene terephthalate (PET) plastic worked well as a starting material for 3D printers.
This material can be recycled from plastic bottles which are easily found around remote bases. In fact, they found that the recycled PET filament was just as strong and flexible as commercially available filaments.
To test the filament they printed a vehicle radio bracket — a part which typically requires a long lead time when replacing using the traditional process. Using 3D printing and materials recycled from around the base, this process was reduced to two hours. In total it required just 10 water bottles.
After finding that plastic bottles work well, the researchers turned to other plastics, including polypropylene (PP) and polystyrene (PS). These materials can be found in containers and plastic cutlery.
Initial findings saw that these plastics were not particularly useful. However, when mixed with other easy to find materials, their strength improved. The researchers mixed cardboard, wood fibers, and other cellulose waste materials to create composite filaments.
To create the composite PP/cellulose filaments, the researchers used a process called solid-state shear pulverization. This process involves shredding plastic and paper and pulverizing cardboard or wood flour in a twin-screw extruder to create a powder which is then melt-processed to create filaments.
Zander adds “We still have a lot to learn about how to best process these materials and what kinds of additives will improve their properties. We’re just scratching the surface of what we can ultimately do with these discarded plastics.”
Zander and her team are in the process of establishing a mobile recycling trailer. Here, trained soldiers will be able to create the recycled feedstock filaments on demand.
Hopefully, this technology will be able to reduce waiting times and dependence on supply chains, save money, enhance safety and improve operational readiness.
Source: Science Daily
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