Rugged Materials for Structural Electronics

In-mold electronics (IME) is an emerging technology that has the potential to revolutionize manufacturing through design freedom and device simplification while delivering advantageous size, weight and power. IME uses flexible conductive inks that are printed onto substrates and subsequently molded into three dimensional shapes. IME allows for the creation of circuits that are much thinner and lighter than traditional circuit boards, buttons, wiring/cabling by merging the 3D mechanical design space with traditional 2D circuit patterning. Current IME approaches use nanoparticle-based inks and thermoplastics which have environmental, stability and aging issues. Our project seeks to develop IME materials and devices that are compatible with extreme environments and thus we are exploring new materials, combinations, processing and computational optimization to achieve more reliable and rugged IME components. In this presentation, we overview recent results whereby ink-based electronic interconnects are substituted with metal foils and tapes (e.g., Cu) and geometrically patterned to accommodate multi-material bending kinematics during 3D-forming. Forming of thermoset materials including molding compounds and silicones is achieved on rapid prototyped (3D printed) tooling and continuity of pattern leads is evaluated throughout device fabrication. We characterize interlayer adhesion and determine design limits for bending radii using these material sets. Radio frequency-based IME devices (NFCs) are fabricated and subjected to accelerated aging tests. Our results pave the way to simplify development, deployment and modification of devices in extreme environments using structural electronics.