Parkhurst & Oliff
Extrusion die for ceramic honeycomb structure
 An extrusion die for a ceramic honeycomb structure having a plurality of different wall thicknesses and at least two through-hole comprises discharge slots corresponding to the cross-sectional shape of the ceramic honeycomb structure and feed passageways formed in communication with said discharge slots. The hydraulic diameters of the feed passageways which communicates with discharge slots which result in thinner wall in the honeycomb structure are comparatively larger than the hydraulic diameters of the feed passageways which communicate with discharge slots which result in thicker walls in the honeycomb structure. The invention can also include a replaceable perforated plate attached on inlet portions of the feed passageways of an extrusion die. The completely novel extrusion die is suitable for use in obtaining a ceramic honeycomb structure having at least two difference types of wall thicknesses and defining through-holes of complex shapes. 
NGK Insulators, Ltd.
B
B28B
inventional
Kiminari
Kato