Robocasting Periodic Lattices for Advanced Filtration

Ceramic filters used in the casting of molten metals are commonly created by slurry impregnation of polymeric foams, yielding a fired ceramic foam structure. These foam structures have high part-to-part standard deviation in flow rates (~25%) and have weak sections which can fragment into the melt. In contrast, periodic lattice filters (PLF’s) made by robocasting have a cross-hatched face-centered-cubic arrangement of rods.. As such, the robocast filters have high strength and may be easily tailored to offer a specific internal pore structure to control the flow rate and pressure drop across the filters. Standard deviation of flow rates among PLF’s are less than 1%. This paper describes the methodology of creating PLF’s as possible foam filter replacements.