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 honeycomb substrate includes an inner body having an inner skin and an array of inner webs defining an array of inner cells within the inner skin. The honeycomb substrate further includes an outer body having an outer skin formed concentric with the inner skin and an array of outer webs defining an array of triangle cells between the inner skin and the outer skin. The triangle cells are oriented along a radial direction with respect to a center of the inner body. An extrusion assembly for forming the honeycomb substrate includes an inner cell forming die, an outer cell forming die, and a skin forming mask, all mounted coaxially. An outer skin slot formed between the outer cell forming die and the skin forming mask is in communication with feedholes in the inner cell forming die through an opening in the outer cell forming die.

Abstract: A honeycomb substrate includes an inner body having an inner skin and an array of inner webs defining an array of inner cells within the inner skin. The honeycomb substrate further includes an outer body having an outer skin formed concentric with the inner skin and an array of outer webs defining an array of triangle cells between the inner skin and the outer skin. The triangle cells are oriented along a radial direction with respect to a center of the inner body. An extrusion assembly for forming the honeycomb substrate includes an inner cell forming die, an outer cell forming die, and a skin forming mask, all mounted coaxially. An outer skin slot formed between the outer cell forming die and the skin forming mask is in communication with feedholes in the inner cell forming die through an opening in the outer cell forming die.

Abstract: There is provided ceramic honeycomb body including a plurality of parallel cells defined by intersecting internal walls, and arranged in horizontal and vertical rows at and between opposing ends of the honeycomb body, an outer peripheral wall surrounding the cells, and further being interconnected to the internal walls, wherein the cells are divided into a first region including a portion of the cells adjacent the outer peripheral wall, and a second region including the remaining cells, wherein the cells in the first region have a wall thickness that is continuously increased along an axis extending to the outer peripheral wall, and, wherein fillets are formed at least at intersections between the interior walls in the first region of cells.

Abstract: There is provided ceramic honeycomb body including a plurality of parallel cells defined by intersecting internal walls, and arranged in horizontal and vertical rows at and between opposing ends of the honeycomb body, an outer peripheral wall surrounding the cells, and further being interconnected to the internal walls, wherein the cells are divided into a first region including a portion of the cells adjacent the outer peripheral wall, and a second region including the remaining cells, wherein the cells in the first region have a wall thickness that is continuously increased along an axis extending to the outer peripheral wall, and, wherein fillets are formed at least at intersections between the interior walls in the first region of cells.

Abstract: Fine circumferential skin cracking in extruded thin-walled cordierite honeycombs having channel wall thicknesses not exceeding about 0.004 inches (100 &mgr;m) but skin layers of substantially higher thickness is prevented by extruding the honeycombs under conditions that enhance cordierite crystal alignment in the skin; thin-walled honeycomb products having skins free of fine cracks that are well-matched in thermal expansion to the honeycomb cores are provided.

Abstract: Fine circumferential skin cracking in extruded thin-walled cordierite honeycombs having channel wall thicknesses not exceeding about 0.004 inches (100 &mgr;m) but skin layers of substantially higher thickness is prevented by extruding the honeycombs under conditions that enhance cordierite crystal alignment in the skin; thin-walled honeycomb products having skins free of fine cracks that are well-matched in thermal expansion to the honeycomb cores are provided.

Abstract: Improved batch uniformity delivered to the discharge slots of an extrusion die is obtained by providing a stressor component of reduced cross-sectional area from the feedholes which suddenly increases the linear flow velocity due to its reduced cross-sectional area, and then just as suddenly restores the original flow conditions as it exits the stressor component into a larger diameter channel. A rapid change in particle alignment, due to the cross-sectional flow change, produces a shearing influence on the batch, and functions to produce a more uniform flow as it enters the discharge slot sections of the extrusion die.

Abstract: A honeycomb extrusion die comprising a die body incorporating an inlet face, a discharge face opposite the inlet face, a plurality of feedholes extending from the inlet face into the body, and an array of intersecting discharge slots extending into the body from the discharge face and interconnecting with the feed holes, the intersecting discharge slots being formed by the side surfaces of a plurality of pins bounded by the slots and extending into the die body from the discharge face, wherein a plurality of the pins include one or more multi-textured side surfaces, each side surface including at least two surface regions differing in surface finish from each other.

Abstract: Apparatus and a method for extruding a honeycomb, providing reductions in curvature or bowing of the extruded honeycomb structure, employs a bow deflector positioned upstream of the extrusion die, the bow deflector comprising adjoining, independently rotatable, first and second aperture plates of tapering thickness, the degree of bow reduction depending on the relative rotational position of the aperture plates and the resulting magnitude of the pressure/flow velocity gradient imparted by the plates on the flow stream entering the die.

Abstract: In a metal honeycomb extrusion die which incorporates apertures for the conveyance of extrudable material through the die body toward a discharge opening in the face of the die, the aperture sidewalls are shaped by electrochemical machining or the like to develop a periodically varying aperture size, surface shape or surface finish, superimposed on the conventional randomly varying machined aperture sidewall surface, in order to reduce the adverse effects of random surface variations on extrusion process stability and extruded product quality.

Abstract: A process is set forth for electrochemically machining holes in a workpiece, such as a die, in such a manner so as to virtually eliminate surface finish patterns normally introduced by the electrochemical machining process, by randomly forming sequences of patterns of holes extending in rows across the workpiece along its extent, and then rotating the workpiece 180.degree. and randomly forming additional sequences of patterns of holes across the workpiece adjacent those sequences of holes which were formed prior to rotating the workpiece 180.degree..