In recent years, 3D printing and its applications have been extensively researched. One of the applications is to create sensors using conductive filaments. For these sensors, it is essential to have consistent print quality without printing defects. Hence, there is a need for a method of monitoring the print quality while printing without disrupting the printing process. This can be done using electrical impedance tomography (EIT). By placing multiple electrodes on the bed and one on the nozzle, electrical resistance paths in the printed part can be monitored.
This paper focuses on characterizing multiple methods of multiplexing these resistance paths. The methods looked at are multiplexing with switches, ratio multiplexing and frequency multiplexing. Key characteristics such as complexity, accuracy, resolution, and cost will be addressed. The methods are modelled first and then tested on a real 3D printer. The methods are then compared based on the aforementioned characteristics. Based on the experiments, it was concluded that ratio multiplexing is the best method. However, all methods are usable for application in 3D print monitoring.