Integrated process control for highly parallel and contact-free micro array printing

This paper reports for the first time on an integrated process control of a highly parallel non-contact dispenser for microarray production. Monitoring the fundamental process parameters has become indispensable because of significantly increased demands on high quality microarrays. We integrated a pressure sensor in our pneumatically actuated dispenser to acquire the transient pressure pulse during droplet ejection. This enables the total process control for the dispenser and with it the adoption of operation parameters for varying liquid properties, like viscosity, surface tension and density. We optimised pressure parameter and the geometry of the actuation chamber. This made it possible to dispense liquid viscosities up to 10.8 mPas (four fold improvement) at frequencies up to 30 Hz (15 fold improvement) for all tested liquids. In addition, the integrated pressure sensor allows to detect failure modes, like flooded actuation chamber or empty printhead nozzles, leading to a higher quality of the fabricated microarrays.