Tracing and fingerprinting source material and printer of additively manufactured weapons and objects

Physical evidence discovered during crime investigations provides value when it can be identified by source and origin. Additive manufacturing (AM) has opened a world of possibilities for criminals to design and manufacture items used in crimes including firearms and explosives, and more innocuous items such as keys or banking card interfaces. When such items are discovered at the scene of a crime, forensics investigators are currently limited in their ability to identify or trace the origin of the raw materials and manufacturing devices. This project proposed to conduct fundamental research to identify the elemental, molecular, chemical, thermal, mechanical, and surface morphological properties that can be used to identify the materials, manufacturing processes, and potentially fingerprint the exact printer used to construct pieces of 3D printed evidence. This work will include materials research to increase the body of knowledge in forensic investigators toolkits. We intend to study various state-of-the-art 3D printers that use advanced materials and to evaluate possible methods to identify features and characteristics of 3D printing and raw print materials that investigators can use to identify unique markers in a weapon or product that would confirm the printer or class of printer that made it. This is a two-phase research proposal; 1) characterization of preprint materials and bulk print materials, and, 2) characterization of 3D printed firearms in pristine and stressed conditions. In Phase 1, a broad range of AM materials will be analyzed using TGA, DSC, SEM, EDS, CT scan, and FTIR. Analyzed materials will include traditional polymers (ABS and PLA) and state of the art fiber reinforced polymers, Vat-photo resins, and laser sintered metals. The material properties will be evaluated in raw, pre-print form and after printing. Critical parameters will be identified for tracing the part to the raw material and to the printer. Phase 2 will evaluate 3D printed firearms. The measured properties of the firearms will be evaluated before and after firing, and before and after exposure to chemical or thermal stimuli. These experiments will determine if the firearm can be traced to the raw material and printer in both pristine and stressed states. Primary deliverables will include proof of concept and best practices for characterization and source tracing of 3D printed objects. In addition, a database of characterization factors for the materials evaluated will be produced, and a set of characteristics to examine for linking an object to the source printer. Note: This project contains a research and/or development component, as defined in applicable law, and complies with Part 200 Uniform Requirements - 2 CFR 200.210(a)(14). CA/NCF