Abstract: Apparatus and a method for selectively vapor-coating an extrusion die to extrude honeycombs with desired distributions of web thicknesses, wherein at least one perforated impedance or preferential coating plate with a desired pattern of holes is positioned adjacent to, but spaced apart from, a face of the extrusion die to be coated, whereby a coating gas passed through the coating plate and into the die imparts a desired coating distribution to the extrusion die slots that is effective to closely control the web thickness distribution in honeycombs extruded therefrom.

Abstract: A method is provided for manufacturing a thin-walled honeycomb ceramic substrate by extruding a plasticized ceramic batch material through a filter screen having wedge shaped filter wires to remove foreign particulate and agglomerated batch material. The filter wires are supported by a set of support wires attached substantially perpendicular to the filter wires. The support wires are may also be advantageously wedge shaped. The filter screen of the present invention may have a wear resistant layer at the surface of the screen, typically a boride or a nitride. The wear resistant coating may also be a nickel-based coating.