Use of a PDMS spring element for ink jet printing applications

Results of the design, fabrication and testing of a proof-of-concept, microfabricated, diaphragm-type silicone sealing joint are presented. DRIE-etched cavities are filled with a flexible sealing element made of PDMS that support a silicon piston. A series of sealing joints are produced with variable widths, and the displacement of the piston is measured after applying pressure of up to 2 bar in 0.2 bar increments. Two masks were designed to produce several sets of silicone springs with widths of 2 to 10.5 mum, each consisting of a 20 mum thick silicon piston that is 2 mm long. Tests performed on the shear spring joints are found to give a displacement of 0.5 mum at 1 bar when the sealing width is 6 mum or more. The sealing joint with a 10 mum width was found to give a displacement of 0.9 mum and an elastic recovery of 88%. The results showed this type of joint in the form of an elastically-deforming seal provides sufficient displacement for propelling liquid droplets as part of a liquid propulsion system.