A study of extrusion printed millimetre-scale MEMS transducers

Abstract

This thesis presents a comparison in performance of various microelectromechanical devices fabricated by both lithographic methods in a clean room facility and by means of extrusion printing of conductive ink. Traditional microelectromechanical systems (MEMS) fabrication practices involve costly, time-consuming and complex multi-step processes utilising high-end, high-maintenance cleanroom facilities. On the other hand, printed electronics (PE) offers quick turn-around time, low-cost, and simplicity. The work completed in this thesis involves taking candidate MEMS transducer designs intended for clean room fabrication and scaling them up to the resolution of a direct-ink write extrusion printer. Firstly, unknown ink parameters are determined through experimentation and simulation. Then, past MEMS designs for a Lorentz actuator and DC electric field sensor are scaled up and in some cases changed slightly to accommodate PE. A Lorentz actuator-based electromagnetic relay is designed as well. The devices are then fabricated using a direct ink writing (DIW) printer in conjunction with a laser micro-machining tool, and are tested to both verify the simulations and offer comparison to their respective MEMS counterparts and/or other similar devices from the literature. A key finding was comparable performance metrics between the PE devices fabricated in this thesis, and their respective lithographic or commercially available counterparts. This signifies that PE is a viable alternative to lithography for manufacturing some MEMS devices, or at least offers itself as a means of rapid prototyping. In addition, the ink used in this thesis was characterized for use in simulation models.