Corning Glass Works

Corning Incorporated

Corning Inorporated

George M Cunningham

Lawrence S Rajnik

Irwin M Lachman

Rodney I Frost

G Daniel Lipp

Louis S Socha, Jr

Peter J Majestic

Daniel W Corbett

A method for making a composite extrusion die for making a cellular honeycomb structure with thin cell walls. The method includes the steps of drilling a grid of separate feed holes/channels into an inlet face of an extrusion die base element, and cutting a grid of intersecting primary outlet slots into an outlet face of the base element, where every alternate one of the primary outlet slots is in direct communication with a plurality of the feed channels. Further, the method includes cutting a grid of intersecting secondary outlet slots into the outlet face, where each one of the secondary outlet slots bisects each one of the primary outlet slots. The method further includes scoring a plurality of indentations into that region of the outlet face that does not contain any of the primary and secondary outlet slots, and filling each of the feed channels and each of the primary and secondary outlet slots with a filler material. Further, the method includes placing a bonding material onto the outlet face and into each of the plurality of indentations, and permanently attaching to the outlet face, a first side of a capping plate having a plate thickness not greater than 0.060 inches. Finally, the method includes cutting through the capping plate a grid of cap slots having a slot width not greater than 0.007 inches. The method further comprises eliminating the filler material from each of the feed channels and each of the primary and secondary outlet slots.

Extrusion die and method

An extrusion die for forming a cellular honeycomb structure having a finned protrusion extending from at least one cell wall of the honeycomb structure. The extrusion die is a composite extrusion die that comprises a primary extrusion die body having an inlet face and an outlet face, and at least a first insert member that is secured into a first intersection formed by a pair of intersecting slots at the outlet face of the primary extrusion die body. More preferably, a plurality of insert members are secured into a plurality of intersections, each intersection being formed by a pair of intersecting slots and each of the intersections being defined by four pegs/pins at the outlet face of the primary extrusion die body. Each of the insert members is adapted to fit into one of the intersections of the die body, where the size and shape of the insert members and the positioning of the insert members into a plurality of the intersections cuts off the flow path of an extrudable material through the plurality of the intersections. Thereby, when a cellular honeycomb structure is extruded through the composite extrusion die, the honeycomb structure comprises a plurality of finned protrusions extending from a plurality of the cell walls of the honeycomb structure corresponding to the plurality of the intersections of the die body into which the insert members are secured.

Cellular extrusion die

Secondary discharge slots are cut into the face of newly made or used extrusion dies such that the secondary discharge slots communicate transversely and longitudinally with primary discharge slots but do not communicate with the feed holes. The novel extrusion die arrangement is set forth for the production of ceramic honeycomb structures which produce a greater number of cells per square inch, protrusions on the cell walls, or a combination of both dependent upon the Primary Slots' Volume to Secondary Slots' volume ratio. The secondary discharge slots can produce honeycomb substrates with much greater surface areas, using an extrusion die with a significantly reduced number of feed holes and a greater number of discharge slots.

Extrusion die for protrusion and/or high cell density ceramic honeycomb

A multi-part extrusion die is disclosed which not only permits the formation of thin discharge slots down to about 0.003 or 0.002 inches, but also provides the ability to produce a die for forming a honeycomb article with different cell densities and web thicknesses in various sections. A plurality of individual die parts are each provided with discharge slots in a discharge face thereof of desired width and spacing, and then a plurality of such individual die parts are secured together in a desired alignment such that the discharge face of each of the plurality of die parts forms a continuous discharge face for the multi-part extrusion die.

Multi-part extrusion die

Secondary discharge slots are cut into the face of newly made or used extrusion dies such that the secondary discharge slots communicate transversely and longitudinally with primary discharge slots but do not communicate with the feed holes. The novel extrusion die arrangement is set forth for the production of ceramic honeycomb structures which produce a greater number of cells per square inch, protrusions on the cell walls, or a combination of both dependent upon the Primary Slots' Volume to Secondary Slots' Volume ratio. The secondary discharge slots can produce honeycomb substrates with much greater surface areas, using an extrusion die with a significantly reduced number of feed holes and a greater number of discharge slots.

An extrusion die for extruding a honeycombshaped structure having rectangular channels. The die is formed of a hard, rigid material, preferably metal, and includes a body plate and an abutting face plate. The outlet face of the body plate is brazed to the inlet face of the face plate. The body plate has a plurality of slightly staggered primary feed holes, the outlet ends of each communicating with an associated feed reservoir, the latter each defined by a recess or depression in the inlet surface of the face plate. Each feed reservoir communicates with the inlet ends of three associated secondary feed holes. The outlet surface of the face plate integrally carries a plurality of intersecting slot segments defining rectangular pins. The outlet end of each secondary feed hole communicates with and feeds an associated intersection of groove segments. The arrangement is such that the number of slot intersections is greater than the number of secondary feed holes, with two diagonally opposite corners of any pin communicating with a secondary feed hole. The combination of rectangular pins (discharge slots) and staggering of the main feed holes maximizes the die interface brazing area to thereby realize honeycomb cell densities of 900-1400 cells per square inch.

Extrusion die for forming thin-walled honeycomb structures

Method and apparatus is set forth for extruding honeycomb structures having cohesive cellular walls from an extrusion die. Deflector means are provided within flow passageways of the die, wherein the deflector means has a secondary feed system such that the batch flow from the main feed system is broken up into a multi-channel stream system which improves the flow of the batch material into the discharge slots, thus improving product quality and knitting or cohesiveness of the material prior to discharge from the die.

Extrusion dies for thin wall substrates

A process of wire cutting electrical discharge machining is set forth including the steps of initially machining a counter slot to a depth greater than 0.03' in the surface of a workpiece having a width at least 1.5 times the width of a desired slot, machining the desired slot with dielectric fluid beginning at the bottom of the counter slot, utilizing the counter slot to facilitate the flushing out of such fluid, and removing the counter slot.

Electrical discharge machining utilizing a counter slot

Disclosed is a novel extrusion die mask for use in the extrusion of honeycomb structures. The mask includes a stationary portion with an orifice extending longitudinally therethrough. A movable recess means is provided which forms a recess communicating between the outlet face of an extrusion die and the central orifice which receives and compacts extruded batch material from the die to form the skin of the extruded honeycomb structure. An adjustment means is provided for controlling the depth of the recess whereby the amount of material directed to the skin of the structure may be varied as batch viscosity varies and as product requirements indicate.

Method and apparatus for extruding honeycomb structures with skins

Certain portions of the discharge slots of an existing extrusion die for forming honeycomb structures are blocked off by selectively positioning a plurality of tabs within such discharge slots so as to convert the cellular configuration originally formed by the discharge slots of such die to that of a desired cellular configuration.

Extrusion die conversion

Disclosed is an improved ceramic heat recovery wheel driven on a shaft containing a metal hub which may be driven without slippage between the wheel and the hub. The wheel includes a splined metal shaft which mates with the disk including a plurality of radially extending keys equi-angularly spaced about its circumference. The ceramic disk includes an equal plurality of radially extending keyways which mate with the keys. In one embodiment, the keys are situated on only one side of the bore of the ceramic disk and the keyways do not extend through the bore. On the opposite face of the disk, a retainer plate surrounds the shaft. An axial force is applied to the retainer plate for restraining movement of the wheel in the axial direction.

Heat recovery wheel

Disclosed is an extrusion die for use in forming extruded honeycomb structures employing a face plate having a plurality of discharge slots and a back plate having a plurality of feed passageways. The face plate and the back plate are joined to one another by means of bonding, e.g. brazing, at the joint formed by abutting surfaces of the plates. Proper orientation between the face plate and the back plate are maintained during brazing such that the feed passageways and discharge slots remain properly associated by means of a plurality of alignment cavities having walls opening to and diverging toward and to the joint between the face plate and back plate. Pedestals project across the joint and mate with the alignment cavities such that movement between the back plate and face plate is permitted during the thermal expansion caused by brazing only in the direction perpendicular to the joint, thus assuring proper registry between feed holes and discharge slots which precludes failure of the brazed joint during extrusion.

Extrusion die

A mask or face plate, having an orifice or opening formed therethrough of desired size and configuration, is positioned against the discharge face of an extrusion die. The mask restricts the flow of extrudable material through the die so that such material will conform to the size and configuration of the opening or orifice formed through the mask. A recess formed in the face of the mask adjacent the discharge face of the extrusion die, surrounds the orifice formed therethrough, and communicates with said orifice by means of a gap formed in the inlet face of the mask between said recess and said orifice. The method of extrusion set forth with respect to the recessed or scalloped mask has particular utility when utilized with an extrusion die for forming cellular or honeycomb structures, in that the predetermined gap meters a controlled flow of additional batch material from the recess to the outer boundaries of the extruded honeycomb article passing through the orifice in said mask to encapsulate the honeycomb structure with a smooth uniform skin having improved isostatic crushing strength.

Extrusion die mask

A mask or face plate, having an orifice or opening formed therethrough of desired size and configuration, is positioned against the discharge face of an extrusion die. The mask restricts the flow of extrudable material through the die so that such material will conform to the size and configuration of the opening or orifice formed through the mask. A recess formed in the face of the mask adjacent the discharge face of the extrusion die, surrounds the orifice formed therethrough, and communicates with said orifice by means of a gap formed in the inlet face of the mask between said recess and said orifice. The recessed or scalloped mask has particular utility when utilized with an extrusion die for forming cellular or honeycomb structures, in that the predetermined gap meters a controlled flow of additional batch material from the recess to the outer boundaries of the extruded honeycomb article passing through the orifice in said mask to encapsulate the honeycomb structure with a smooth uniform skin having improved isostatic crushing strength.

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Horseheads, NY, United States of America

George M Cunningham