Large stroke high force pneumatic actuators fabricated by SU-8 micromachining

Applications where a microsystem has to interface with the outside world are often face the rather small force output or stroke that a typical microfabricated actuator can generate. However, microscale piston-cylinder pneumatic or hydraulic actuators offer a significant improvement of the stroke and force output of microactuators. For the first time, a process is presented that enables batch fabrication of such actuators by a lithographic process based on SU-8 photoepoxy. The total volume of the smallest of these actuators is a mere ~1 mm³. The maximum force obtained is 37 mN for an applied pressure of 10 bars. The actuator stroke is 1.1 mm.