Additive Manufacturing of Channels and Surface Features Using Wire-Arc Spray

Fabrication of devices such as micro-reactors and heat sinks that contain complex networks of sub-millimeter scale flow channels and features such as fins and vanes has been an active topic of research. Typical fabrication methods include micro-milling, direct metal laser sintering (DMLS) and electrical discharge machining (EDM) are limited by their high cost, low geometric accuracy at the micron scale, high energy consumption, and long processing times. This study presents a low-cost, additive manufacturing method using the twin-wire arc spray method, to make channels and surface features.

Water-soluble, polyvinyl alcohol (PVA) paste is first placed on a 3D printed negative of the desired channel plate and allowed to harden. The hardened paste is then removed from the negative and metal is sprayed onto the features in the PVA paste. The deposited metal film is backed by epoxy and the PVA paste is dissolved, resulting in a rigid metal-coated surface containing micron-scale features.