Topology-Aware Routing of Electric Wires in FDM-Printed Objects

The direct integration of electric connections into AM-fabricated plastic parts at printing time has recently attracted increasing attention. To make efficient use of such techniques, appropriate design and routing software is required. In prior work, we proposed the integration of Surface-Mounted Devices (SMD) and wiring into a slicing-software for FDM-based processes. This approach allows to consider process parameters, e.g. extrusion width, layer thickness or temperature for each specific printjob. In this work, we introduce an algorithm for local, topology-aware wire routing. The trace-width of a printed wire roughly equates the typical extrusion width of FDM-printers and the pitch of larger SMD-package types. For curved object surfaces and regions with high wire density, linear routing produces a high number of small islands and gaps. To mitigate this effect, we attempt to align wires with object perimeters and perimeters of already routed wires. A weighted graph representation is generated from all printable perimeters of each layer and direct connections between wire waypoints. An A*-based search is then employed to find optimal routes.