OBJECTIVE: Develop a mobile recycling facility capable of cleaning, drying, and processing thermoplastics into pellets and filament for use in material extrusion equipment such as 3-D printers and injection molders in remote and austere environments. All equipment must fit within an intermodal container (conex).

 

DESCRIPTION: Logistics are the fundamental consideration in forward deployment, consuming one-third of the Department of Defense’s budget [Ref 1]. The former Commandant of the Marine Corps said that the U.S. supply lines in Afghanistan “represent an operational vulnerability” and “we are getting hit; we are losing Marines.” Although resupply can take in excess of 45 days, and a 600-warfighter forward operating base (FOB) requires 22 convoy trucks per day to supply the base, the majority of supplies are brought in rather than sourced locally [Ref 1]. Even a small reduction in the amount of supplies that need to be shipped in could greatly impact the warfighter’s safety and logistical costs. In addition, a significant amount of waste/scrap materials is generated on a daily basis on military operating bases. Plastics represent nearly 8% of the total waste, averaging approximately 450 lbs/Marine/yr [Ref 2]. These materials are either recycled or burned in open pit fires, inflicting damage to the environment and personnel health.

 

Additive manufacturing (AM) technologies are critical to maintaining operational readiness of the military by reducing the logistical supply chain dependence and allowing point-of-need manufacturing. Recent research has demonstrated the feasibility of turning plastic waste into 3-D printing feedstock in the laboratory [Ref 3].

Developing such methods to process waste into useful AM feedstocks in-field is expected to have a great impact on many parts of the Marine Corps, as well as other units in remote locations in which re-use of materials could present significant cost and energy savings. More automation of the process is critical to reduce the man-hours and training required. Currently there exists no such land-based automated recycling system (ARS) to reclaim waste plastics and failed 3-D prints into pellets and/or filament for AM or injection molding processes. NASA, together with Tethers Unlimited, have created the Refabricator for recycling select plastics in space [Ref 5]. Limitations of this technology include limited plastic types (Ultem and Acrylonitrile Butadiene Styrene (ABS) only) and low output. In addition, the system is not commercially available. A mobile plastic recycling extrusion laboratory does not exist.

 

This topic seeks the development of an Expeditionary Mobile Recycling Facility (MRF-X) that provides the capability of processing thermoplastics into pellets and filament for use in material extrusion equipment such as 3-D printers and injection molders in remote and austere environments. The MRF-X shall have all equipment housed in a standard or expandable 20-foot ISO container, with proper tie-downs and capable of meeting MIL-STD 810F/G necessary for transport by land and sea. The unit shall contain duct work to support a 60,000 BTU Environmental Control Unit (ECU) and meet OSHA standards of temperature range of 68-76 °F and humidity range of 20-60%. In addition, the power is limited to the power available on a forward operating base, approximately 180 KW for a typical 500-warfighter FOB [Ref 1]. The unit shall have plastic sorting, cleaning, drying and shredding capabilities. Automation of all or part of these capabilities is preferred. In addition, the unit shall have an ARS capable of processing a wide range of thermoplastics from consumer-grade packaging such as polyethylene terephthalate (PET), polypropylene, polyethylene, polystyrene as well as from failed 3-D prints made of materials such as ABS, PLA, Ultem, and Polyether ether ketone (PEEK). The ARS shall melt and reconstitute thermoplastics into 1.75 ± 0.1 and/or 2.85 ± 0.1 mm diameter filament spools or pellets at an output rate exceeding 2 kg per hour. Filament shall have sufficient flexibility to enable spooling and be free of defects such as particulate debris and air/moisture bubbles. The ARS until should be able to melt plastics with melting temperatures up to 400 °C. Mechanical testing (tensile) should be performed to verify that performance of reconstituted plastics is within expected range based on literature values for polymer type.

 

PHASE I: Develop concepts for a mobile plastic recycling facility that meets the requirements described above. Demonstrate the feasibility of the concepts in meeting Marine Corps needs and establish that the concepts can be developed into a useful product for the Marine Corps. Establish feasibility by material testing and analytical modeling, as appropriate. Provide a Phase II development plan with performance goals and key technical milestones, and that will address technical risk reduction.

 

PHASE II: Develop a scaled prototype evaluation. Evaluate the prototype to determine its capability in meeting the performance goals defined in the Phase II development plan and the Marine Corps requirements for the mobile plastic recycling facility. Demonstrate system performance through prototype evaluation and modeling or analytical methods over the required range of parameters including numerous deployment cycles. Use evaluation results to