Improved extrusion dies are described herein for manufacturing a honeycomb body structure (330) from honeycomb extrudate (104). An improved extrusion die (102) comprises a swell relief feature in a discharge slot (218) of the extrusion die (102) that is disposed upstream of a discharge surface (214) of the extrusion die (102). The swell relief feature comprises a change in the width (W) of the discharge slot (218).

A manufacturing method of a honeycomb structure, including a vertical extrusion process, wherein the vertical extrusion process includes: an extrusion step of extruding the molding compound in the vertically downward direction from an extrusion die attached to an extruder; a honeycomb formed body receiving step in which a transfer pallet is placed at a position near the extrusion die, and a honeycomb formed body formed by continuously extruding the molding compound in the extrusion step is received and supported from below by the transfer pallet; and a pallet lowering step of lowering the transfer pallet while receiving and supporting the honeycomb formed body in synchronization with an extrusion speed of the molding compound from the extrusion die, and the transfer pallet is constituted of a laminate structure including: a pallet substrate; and a tabular mesh plate.

An extrusion system (100) includes at least one sensor (102, 104) to detect localized presence of oil (701) on an exterior surface (715) or skin of wet extrudate material (714 e.g., ceramic material having a honeycomb cross-sectional shape), and at least one infrared emitting device (106, 108) configured to impinge infrared emissions on at least a portion of the exterior surface responsive to one or more sensor signals. Localized impingement of infrared emissions may reduce presence of oil streaks (701) without undue differential drying of the extrudate skin (715), and avoid surface fissures that would otherwise result in fired ceramic bodies. Separately controllable infrared emitters (502), or at least one controllable infrared blocking or redirecting element (603), may be used to impinge infrared emissions on selected areas. A humidification section (120) arranged downstream of infrared emitters (106, 108) may be used to at least partially rehydrate the wet extrudate material, if necessary.

An extrusion system (100) according to certain aspects includes at least one infrared emitting device (102) arranged in a generally cylindrical shape with a hollow interior. The at least one infrared emitting device (102) is positioned downstream of an outlet of an extrusion die (110) to irradiate a perimeter of wet extrudate material in a uniform manner to form stiffened wet extrudate material (116) before such material is received by an extrudate support channel (118). The at least one infrared emitting device (102) generally uniformly stiffens the skin of the wet extrudate material (116) to resist mechanical deformation of the extrudate material during subsequent handling steps. Such skin stiffening allows for increased tolerance of handling forces and permits extrusion of softer wet extrudate material without compromising the shape of a fired ceramic product.

Extrusion techniques for reducing bow of an extrudate formed from a ceramic forming mixture. Velocities of an outer surface of the extrudate are measured at a plurality of peripherally spaced measurement locations. The velocities are compared to determine whether there is a velocity bias, and the comparison is used to selectively alter the flow of the ceramic forming mixture.

A particulate filter having a honeycomb structure of a matrix of interconnected porous walls including inlet cells and outlet cells defining a plurality of inlet channels and outlet channels, respectively, wherein at least a portion of the outlet cells are larger than any of the inlet cells, and a cross-sectional shape of at least some of the outlet channels is rectangular. Honeycomb extrusion dies, honeycomb bodies, honeycomb structures, and methods of manufacture are described, as are other aspects.

A honeycomb structure includes a central area and a reinforced outer peripheral area. For a boundary cell having cell walls with different wall thicknesses on two sides parallel with an imaginary parallel line, a thin wall thickness t1<a thick wall thickness t3, an inner wall thickness t2<an outer wall thickness t4, t1=t2, and t3=t4. The honeycomb structure includes a cross-shaped unit having a thin wall, an inner wall, a cell wall, and a cell wall and a cross-shaped unit having a thick wall, an outer wall, a cell wall, and a cell wall. The honeycomb structure also includes cross-shaped units extending vertically and horizontally from alternate cell vertexes arranged from a cell vertex as a starting point. In the central area and the reinforced outer peripheral area, the cell walls of each cross-shaped unit have a substantially equal wall thickness.

A honeycomb structure includes a central area and a reinforced outer peripheral area. For a boundary cell having cell walls with different wall thicknesses on two sides parallel with an imaginary parallel line, a thin wall thickness t1<a thick wall thickness t3, an inner wall thickness t2<an outer wall thickness t4, t1=t2, and t3=t4. The honeycomb structure includes a cross-shaped unit having a thin wall, an inner wall, a cell wall, and a cell wall and a cross-shaped unit having a thick wall, an outer wall, a cell wall, and a cell wall. The honeycomb structure also includes cross-shaped units extending vertically and horizontally from alternate cell vertexes arranged from a cell vertex as a starting point. In the central area and the reinforced outer peripheral area, the cell walls of each cross-shaped unit have a substantially equal wall thickness.

A honeycomb extrusion die (120) includes a die body (342) including an inlet face (315) and an outlet face (341). A plurality of pins (330) extend from the die body (342), wherein the pins (330) are arranged to define primary (312P) and secondary slots (312S). Primary slots (312P) include primary slot inlets (320P) and primary slot outlets (3120) and the secondary slots (312S) include secondary slot inlets (312SI) and secondary slot outlets (312SO). Feedholes (317) extend within the die body (342), the feedholes (317) including feedhole outlets (319), wherein the feedhole outlets (319) intersect only with the primary slot inlets (320P). First surface indentation features (345) extend into side surfaces (332) of the plurality of pins (330) defining the primary slots (312P). The first surface indentation features (345) are spaced from the primary slot outlets (3120). The secondary slots (312S) are devoid of surface indentation features. Other die bodies, extruders, and methods are disclosed.

A method and extrusion die to form a laminar integral skin of a honeycomb structure is provided. The method includes extruding a ceramic precursor batch through a die with feedholes in entry side and slots in exit face of the die to form the honeycomb structure. In a region on the periphery of the die configured to form the cell matrix, a series of concentric slots around the matrix in the exit face of the die are configured to feed skin onto the matrix. Ring sections between concentric slots are angled away from the center and a mask is disposed on top of the periphery producing a channel for extruded skin to meet and bond to extruded matrix. Optionally, slots in the skin-forming ring sections enhance knitting between laminar skin layers.