A mesoscale compliant expansion chamber for a catalytic micro-engine

As engineering applications become increasingly complex, the need for miniaturization is present in several technological fields. Places hardly reachable by traditional tools and machines, can be accessed thanks to miniaturized devices and, especially when such devices are remotely controlled or autonomous, it implies the need for miniaturized, standalone actuators. Most high-energy density actuators for these applications can not be operated if untethered from an external power-supply.In this study, we investigate the manufacturing of a mesoscale compliant expansion chamber for a miniaturized chemical-based actuator. Photopolymerization and material jetting are used for manufacturing the prototypes, exhibiting dimensions of 9.8 mm diameter, 7.5 mm height and 140 μm thickness. These dimensions are such as to allow the device to fit inside of the flapping wings micro aerial vehicle (FWMAV) that it has to power. Fabrication of such dimensions, along with the peculiar geometry of the chamber, taps into the limitations of the photopolymerization process and highlights areas of improvement for this rapidly-developing technology. The devices are successfully tested for a linear motion, mimicking that of a cylinder-piston combination, as in a conventional expansion chamber, and are actuated by a pressure pulse.