Honeycomb Extrusion Die Layout for Uniform Thin-Thick Wall Flow
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Solution Overview
Problem
Current extrusion die designs for ceramic honeycomb bodies with thin walls face challenges in achieving uniform flow and defect-free manufacturing, leading to lower strength and increased risk of fractures during canning operations, while also requiring a balance between thermal mass and isostatic strength.
Innovation Solution
The development of honeycomb extrusion dies with a matrix of intersecting wide and narrow slots, featuring specific surface indentation features and feedholes, and an impedance plate to control ceramic-forming mixture flow, allowing for the extrusion of honeycomb bodies with alternating thick and thin walls, enhancing isostatic strength and thermal mass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If thin wall thickness is used in ceramic honeycomb bodies, then thermal mass is reduced and exhaust aftertreatment efficiency is improved, but isostatic strength decreases and fracture risk increases during canning operations
Solution Approach 1:
The patent applies local quality by creating alternating thick and thin walls within the same honeycomb body. The thin walls reduce thermal mass for improved exhaust aftertreatment efficiency, while the thick walls provide isostatic strength to prevent fractures during canning operations. This is achieved through a die design with alternating wide and narrow slots that extrude material at different rates, producing the desired wall thickness variation.
2Manufacturing precision
If conventional extrusion die designs are used, then manufacturing process is simple, but uniform flow and defect-free manufacturing cannot be achieved
Solution Approach 1:
The patent applies segmentation by dividing the extrusion die into multiple zones with different slot widths (wide and narrow slots) and incorporating feedholes at specific locations. This segmented design allows different regions of the die to control material flow independently, achieving uniform flow and defect-free manufacturing of honeycomb bodies with alternating wall thicknesses.
Solution Approach 2:
The patent applies parameter changes by varying the slot width parameter along the extrusion path. The die includes alternating wide and narrow slots, with feedholes positioned to deliver ceramic-forming mixture at controlled rates. This parameter variation enables precise control over material distribution, achieving the desired alternating thick and thin wall pattern while maintaining uniform flow.
3Strength
If alternating thick and thin walls are produced, then isostatic strength and thermal mass are optimized, but die design and manufacturing complexity increases
Solution Approach 1:
The patent applies asymmetry by designing the extrusion die with alternating wide and narrow slots of different dimensions. This asymmetric slot configuration, combined with strategically positioned feedholes, creates the alternating thick and thin wall pattern in the extruded honeycomb body. The asymmetric design optimizes both isostatic strength (through thick walls) and thermal mass (through thin walls) while maintaining a systematic manufacturing approach.
Data Source
AI summary
A honeycomb extrusion die body (401) including inlet (414) and exit (402) faces, and a plurality of pins (406) on the exit face (402) defining a matrix of intersecting wide slots (425) and narrow slots (427). The wide slots (425) have an exit width (W1) greater than an exit width (W2) of the narrow slots (427). The die body (401) further includes feedholes (422) at the inlet face (414) and intersecting with inlet portions (416) to the wide slots (425) and/or the narrow slots (427). Some of the pins (406) defining the wide slots (425) include a first surface indentation feature (430) that is (i) located between the inlet portion (416) and the wide slot exit and (ii) spaced away from the wide slot exit. Some of the pins (406) defining the narrow slots (427) include a second surface indentation feature (434) that is (i) located between the inlet portion and the narrow slot exit and (ii) spaced away from the narrow slot exit.