Direct Write 3D Printing of Functional Ceramics

Humidity sensors are used in many industries and are important for ensuring quality and safety. Ceramic sensors are preferred because of their quick response time, ability to withstand high temperatures and excellent Chemical and mechanical stability. The manufacturing world has been moving toward additive manufacturing which is a form of synthesizing 3D tangible layer by layer in witch minimal waste is produced. Additive manufacturing also is known as 3D printing has opened new possibilities to design engineers by giving them design freedom and access to the layers of a part to allow embedded sensors. There is a category of ceramics in which the material itself is functionalized and with the help of a 3D printer, we can manufacture complex functional parts. Additive manufacturing can be used to aid the current approach to make humidity sensors by adding a third dimension allowing for more surface area to be in contact with the environment that it wants to measure. In this experiment, a ceramic paste is formulated using Poly(vinyl-Alcohol) as a binder. The paste is extruded using a modified 3D printer with a paste extruder piston. A lattice humidity sensor is evaluated to determine the influence of the geometry. The binder concentration is also evaluated to determine its influence in the rheology of the paste which affects its printability and the water content effect on porosity. Both the response of the sensors and reaction time are examined and discussed