Open-source computer vision software for advanced visualisation and quantification of melt electrowriting jets

Melt electrowriting (MEW) features a raised nozzle positioned several millimeters above the collector, enabling high-contrast videography of the molten polymer jet. Despite this exceptional visual access, routine process monitoring based on computer vision (CV) remains challenging due to the lack of user-friendly and interoperable software. Here, open-source CV software was developed for processing backlit jet images and analyzing various aspects of the MEW jet, including jet angle, lag, length, diameter, area and volume. The software extracts values frame-by-frame either post-process or in real-time, enabling quantitative temporal characterisation of the MEW jet. By enabling flexible specification of measurement locations for each metric, it becomes possible to tailor metric extraction to a wide range of applications and studies. Since MEW is a multiparametric technology, this study demonstrates that performing essential measurements contributes to identifying the optimal conditions for stable processing. Jet dynamics associated with fiber pulsing, a significant processing defect, were identified and visualised in detail by transitioning between stable and unstable processing regimes. Finally, real-time measurements were utilised to implement closed-loop process control and demonstrate the software’s adaptability to other printer systems. Available to users via GitHub, the open-source software provides advanced quantitative jet analysis to the broader MEW research community.