Creation of electrospray emitters from a flat polytetrafluoroethylene sheet through the use of laser micro-manufacturing

Abstract

Electrospray propulsion is a form of electrostatic propulsion that shows potential for use as a thruster on small satellites. Electrospray emitters traditionally use arrays of capillaries, however, this paper investigates the suitability of manufacturing an emitter by laser drilling holes in sheets of polytetrafluoroethylene (PTFE), also known as Teflon. This is done by examining factors such as the machining time, hole shape and degree of taper in holes drilled through different methods. Experimental work was done to determine the shape of holes drilled in a flat sheet, and a computational model was used to simulate the performance of these drilled holes. These results were used to judge if this would be a valid method to manufacture electrospray thrusters, and how these thrusters would compare to more traditional emitters. Based on these results, it was concluded that a PTFE sheet with a width of 0.81 mm would be sufficient to achieve electrospray at voltages lower than those needed for traditional emitters.