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: 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: A method and apparatus for homogenizing a flow stream of plasticized material supplied from an extruder, to reduce viscosity gradients causing defects in extruded products, wherein a flow inverting homogenizer positioned in the flow stream and incorporating a plurality of criss-crossing channels for simultaneously transferring portions of the flow stream from central to peripheral flow stream locations and other portions of the flow stream from peripheral to central flow stream locations.

Abstract: A honeycomb extrusion die including a feed section having a plurality of feedholes for the input of an extrudable material, a discharge section including a discharge opening for discharging the extrudable material as a channeled honeycomb body, and a multilayer transition section disposed between the feed section and the discharge section for conveying and conditioning the extrudable material from the feed to the discharge sections, is disclosed. Also disclosed are methods for making and using the die.