The first 3D-printed z-axis accelerometers with differential capacitive sensing

In this work, additive manufacturing and wet metallization process are combined to fabricate three prototypes of differential electro-mechanical z-axis accelerometers. The smart combination of existing fabrication processes makes the proposed fabrication flow unique in the sensors field. The mechanical design of the three proposed devices exploits the three-dimensionality of the 3D-printing technique and the electrostatic differential readout is allowed thanks to the wet-metallization process of the printed structure. Experimental measurements show a very good agreement with theoretical predictions thus proving a good reliability of the proposed design flow and fabrication process. With their relative small footprints (minimum dimension in the order of hundreds of μ m), good performances (sensitivity > 12 fF/g, sub % linearity error up to 11 g of full scale and theoretical noise estimation of few tens of ng/√Hz) and high customizability, they represent an important step toward novel application fields of inertial sensors.