Pneumatic free piston fabricated in SU-8 for MEMS applications

This paper presents a low-cost pneumatic micropiston fabricated using Printed Circuit Board for Microelec-tromechanical Systems (PCB-MEMS) technology in which the copper is used as sacrificial layer and the Flame Retardant 4 (FR4) as substrate. Also the typical process of the negative photoresist SU-8 is used to fabricated the structures, i.e, the cylinder and the piston. The geometric shape selected for the structures, its inexpensive fabrication and materials endorsed its design. The experimental results were performed using air as actuation fluid. The results provided a minimal control pressure of 15 mbar in the actuation, and a maximum stroke of 3 mm, in its bidirectional movement. The proposed device can be used to manufacture other more complex SU-8 devices with moving parts based on the piston behavior.