Abstract: Disclosed is a method and apparatus for forming a circumferential skin surrounding a central cellular structure of an extruded honeycomb article. The method and apparatus may be used to produce defect-free skins and/or skins having large thickness and a high degree of particle alignment thereby preferably exhibiting CTE comparable to the extruded webs. These benefits are achieved by providing a die and method wherein a flow, Q, exiting any two active ones of a plurality of peripheral slots forming the skin is substantially equal. Also disclosed is a thick-skinned ceramic article having a thick extruded skin (ts?>5 tw?) with an I-value comparable to the webs.

Abstract: Variations in extrusion speed or flowfront shape across the outlet faces of honeycomb extrusion dies are predicted from variations in die geometry across multiple die extrusion zones, based on data correlating the variables to the variations in extrusion speed or flowfront shape, or on calculations of the pressure drops to be experienced by extrudable materials traversing the extrusion zones, adjusting the variations through die processing as desired to appropriately modify die geometry prior to use of the die in an extruder.