A 2nd generation electrohydrodynamic jet (e-jet) printing system, parametric studies of e-jet nozzles and integrated electrode e-jet deposition

摘要

As electrohydrodynamic jet (e-jet) printing technology developments have increased in magnitude over the past few years, a low-cost and user friendly, high-resolution desktop system was developed at the University of Illinois at Urbana-Champaign. The original desktop system provided great functionality but it could be improved upon. Along with bettering the hardware of the technology, a more in depth study of how the printing results differ with changes in printing parameters was required. Taking into account both the hardware and the way printing parameters affect printing results, a method for printing onto completely non-conducting substrates could be investigated.This thesis introduces basic e-jet printing technology as well as state-of-the-art e-jet printing capabilities then explains the need for an easily accessible desktop system. The original desktop system is presented followed by a more in depth description of the second generation system introducing higher resolution capabilities, a more user-friendly interface and the ability to quickly change nozzles. An in depth study of how nozzle size, ink type, pressure, offset height, and voltage affect the diameter, volume and frequency of droplets is explained in detail showing the main effects of each parameter. These studies were then sent to Singapore to validate a computational model of the e-jet process. Sub-micron studies using the same parameters were also carried out in order to create a better understanding of how they work so that the resolution of the printing process can be improved.The thesis finally wraps up with a method for applying the e-jet technology in a way that has not previously been explored. Much like an ion column, droplets are extracted from a nozzle and accelerated toward a grounded substrate. The droplets pass through a hole in the grounded substrate and through a focusing tube which has the same applied potential as the droplet creating an electrostatic lens. The droplets then converge to a point controlled by the potential of the focusing tube. The substrate to be printed on, which can be composed of any type of material, is attached to a 5-axis system and its height is held at the prescribed focal point.