This project focuses on the development of environmentally-acceptable, 3D printable igniter formulations and environmentally-friendly additive manufacturing (AM) techniques required to print these materials, to complement the AM propellant development currently underway at the Armament Research, Development and Engineering Center (ARDEC). This would permit embedding the igniters into complex and novel AM propelling charges.
Although there are current efforts underway to generate AM propellants, no work has been performed to produce AM igniters. This is necessary to ensure proper/enhanced ballistic performance of the complete AM propulsion charge. This effort will examine various binders and solid ratios to ensure that BKNO3, an excellent igniter material is amenable to the AM process. At the same time, a printer capable of 3D printing both the igniter and propellant will be developed concurrently. Throughout each step of the development process environmental and safety aspects of the materials and printers will be constantly examined. The final 3D printed propulsion charges will be gun fired in a legacy 30mm cartridge case to demonstrate their performance. In addition to performance testing, ingredients used in this effort will be evaluated for occupational, environmental and ecological toxicity and environmental impact criteria. Endpoints for hazard identification include: acute ingested and aquatic toxicity, skin and lung toxicity, genotoxicity potential, chronic aquatic toxicity, endocrine disruption potential, toxicity reference values (zooplankton, fish, EPA standard methods 821/R, DESHE and ASTM E2552-16, particle/volatile organic compound (VOC) emissions. Similarly, environmental and eco-toxicity testing at the formulation level will include: M-GRID determination of most relevant release scenarios and cost-effective risk testing strategy, life cycle assessment of printing, accelerated weathering, soil leachate testing, earthworm residue testing, combustion emissions, determination of personal protective equipment (PPE).
Current manufacturing approaches are inefficient - necessitating additional costs for chemical storage and disposal. 3D printing propulsion charges with embedded igniters are expected to reduce the environmental hazards versus legacy manufacturing methods with regard to VOC emissions, occupational health/safety, manufacturing footprint, and energy consumption, all at a lower cost. The combination of the two technologies (AM propellants and AM igniters) is expected to maximize gun efficiency leading to increased muzzle velocity and range, while not exceeding the operational pressures limits of the gun system. This will push the limits of current gun systems to generate extended range charges that can work in legacy systems.