When critical equipment fails, soldiers on the battlefield or at remote bases often have to wait a few weeks to replace parts. Now, researchers at the US Army Research Laboratory and the US Marine Corps have found a way to work in hours. These parts are made from waste plastics, such as water bottles, cardboard and other recyclable materials as starting materials for 3D printing.
Researchers presented their work yesterday at the 256th National Conference of Chemical Society (ACS) National Conference and Expo. 'The potential applications of additive manufacturing technology are very broad - from pre-production models and temporary parts to end-use aircraft parts and medical Implant, 'ARL researcher Dr. Nicole Zander said.
Providing food, fuel, ammunition and repair parts to combat forces is a daunting task that requires thousands of logistics support staff, contractors and manufacturers. According to the US Government Accountability Office, the US Department of Defense has a total of eight 5 million items distributed in different supply chains. However, few of these items are stored in front-line locations, which means that troops in these areas occasionally encounter shortages of important materials. Many of these units have spare parts that can be produced. And other equipment 3D printers, but they rely on traditional materials that must be requisitioned, such as commercially available plastic filaments, and they can take days, weeks or even months to arrive.
Zander and Capt.Anthony Molnar, a collaborator from the US Marine Corps, generated 3D printed filaments from recycled polyethylene terephthalate (PET), bottles and plastics without any chemical modification or Additives. PET plastics found in water and soda bottles are common wastes found around the base. Although PET is widely used in many applications, it is not widely used due to its high melting temperature, water absorption and crystallinity problems. FFF 3D printing raw materials.
The researchers used a process called solid-state shear pulverization to produce composite PP/cellulose filaments. In this method, shredded plastic and paper, cardboard or wood flour were comminuted in a twin-screw extruder to produce The fine powder is then melt processed into 3D printed filaments. The researchers performed mechanical tests on the filaments of PET plastics, and their work showed that the recycled PET filaments were as strong and flexible as the commercial filaments of the 3D printer. The team used recycled PET filaments to print vehicle radio brackets, a long-term military item. This process requires about 10 water bottles, which takes about two hours to complete.
Zander explained, 'In terms of mechanical properties, most of the polymers used in FFF have a volume strength between 30 and 100 MPa. The average strength of recycled PET is 70 MPa, so it may be a suitable 3D printing material.'
The team also studied 3D printing of other types of plastics, such as polypropylene (PP) for yogurt or cheese containers, or polystyrene (PS) for plastic containers. These plastics do not work well by themselves, but The team found that by blending them with other plastics, or adding fillers such as reinforcing agents or toughening agents, strong and flexible filaments can be produced.
Researchers say the motivation for this work is to increase the capabilities and readiness of combatants by reducing maintenance during deployment and to reduce the dependency of the logistics supply chain. Zander's team is building a mobile recycling trailer that will allow soldiers to plasticize Re-used for 3D printing. She is also exploring ways to print plastic pellets instead of filaments, which will help soldiers quickly produce larger 3D printed parts and machinery.