Additive manufacturing, also commonly referred to as 3D printing, stands to transform sand casting with binder jetting technology that can create sand molds with unmatched geometric complexity. With printed sand molds, castings can be optimized with regard to the strengthversus-weight trade-off and structures such as periodic lattices are now available within molds that are not possible with traditional casting technology. However, an increase in design complexity invites more challenges in terms of understanding and managing both the thermodynamics and physics of the casting process. Simulations of castings are more important than ever, and empirical in situ sensor data are required to validate high fidelity computer modeling (e.g., MAGMASOFT Ò ). One novel solution is to leverage the design freedom of CAD-based solid modeling to introduce unique mold features specifically for housing sensors (Internet of Things) within the mold to enable the collection of a diversity of data at manifold locations: temperature, pressure, moisture, gas chemistries, motion of the molds and internal cores (shifting or rotation), and magnetic field. This report describes a proof of concept in which unprecedented levels of process monitoring were integrated-both wirelessly and wired-at strategic locations throughout a printed mold and inside of internal cores. The collected data were used to validate the quality of a casting in situ as well as to provide feedback for optimizing the casting process, mold design, and simulations. A trade-off was explored between sensor survivability and disposability.

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New durable elastomeric materials are commercially available for 3D printing, enabling a new class of consumer wearable applications. The mechanical response of soft 3D printed lattices can now be tailored for improved safety and comfort by (a) leveraging functional grading and (b) customizing the outer envelope to conform specifically to the anatomy of the subject (e.g. patient, athlete, or consumer). Furthermore, electronics can be unobtrusively integrated into these 3D printed structures to provide feedback relating to athletic performance or physical activity. A proposed sensor system was developed that weaves unjacketed wires at two distinct layers in a lattice to form a complex capacitor; the capacitance increases as the lattice is compressed and can detect lattice deformation. A structure was fabricated and demonstrated with both static compression as well as low-velocity impact to highlight the utility for wearable applications. This work is focused on improving the performance of American football helmets as highlighted by the National Football League (NFL) Helmet Challenge Symposium; however, the lattice sensing concept can be extended to metal and ceramic lattices as well-relevant to the automotive and aerospace industries.

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