Improving Conductivity of 3D Printed Conductive Pastes for RF & High Performance Electronics

The low conductivity of 3D printed conductive lines is one of the main obstacles in successful 3D printed electronics. These low conductivities lead to lossy transmission lines, poorly performing antennas, and pose many challenges from a circuit design prospective. In this work, two techniques are demonstrated for improving the conductivity of 3D printed silver paste: photonic sintering and selective electroplating. The silver lines were direct write extruded onto a FFF 3D printed substrate and dried before curing. As an alternative to traditional heat curing, parts printed on a uniaxial double sloped 3D surface are photonically sintered using a commercial PulseForge system, resulting in an increase of the line conductivity by 806%. The lines were then electroplated in a copper plating solution, selectively depositing a layer of copper to obtain a further increase in the line conductivity of 886%, a total improvement of 7,150%. Line conductivities were verified using a 4-point measurement setup along with an X-Ray CT scanning system to determine the cross sectional area of the lines. Bringing high resolution 3D printed metal lines closer to bulk conductivities is critical in enabling 3D printed RF and high performance electronics.