Electrical characterization of inkjet printed conductive traces using LinuxCNC

This paper presents a method of measurement to characterize the quality of inkjet printed conductive traces created with a commercially available desktop printer. Its focus lies on the investigation of the electrical connectivity and the current density distribution within a trace, as these are the main indicators for the usability of printed conductive traces. Usually electrical circuit boards (PCBs) contain arbitrary plain geometries, but due to the flexibility of the substrate on which the traces are printed a 3D scanning measuring system is needed, this allows the traversing of all axes simultaneously which usually is not implemented in state-of-the-art measurement systems. To overcome this constraint the open-source project LinuxCNC was selected as a numerical control system to scan geometries, such as helical traces (e.g., coils), by using linear and circular movements. By combining this measurement system with a giant magnetoresistance sensor (GMR) and a four-point probe measurement method, rapid characterization of the quality of inkjet printed traces was possible.