Honeycomb Extrusion Die Layout for Uniform Slit Material Flow
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Solution Overview
Problem
Existing extrusion dies for producing honeycomb structured bodies used in gasoline engine exhaust gas filtration face challenges with high pressure loss and cell wall breakage due to insufficient material mixing and void formation, especially when using high-hardness silicon carbide powder.
Innovation Solution
An extrusion die design with first through holes formed between adjacent intersections of slits, allowing for uniform material supply and mixing at intersection portions, and a grid-shaped second through hole configuration that includes outermost peripheral, peripheral, and inner slits with varying widths to ensure adequate heat capacity and strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the cell wall thickness is reduced to achieve low pressure loss, then the pressure loss decreases, but the strength and heat capacity of the honeycomb structured body deteriorate
Solution Approach 1:
The patent applies local quality by differentiating the thickness of cell walls based on their location. The outermost peripheral cell walls are made thicker than the inner cell walls. This allows the majority of the structure to maintain thin walls for low pressure loss, while the peripheral regions provide the necessary strength and heat capacity support.
2Loss of energy
If the cell wall thickness is reduced to achieve low pressure loss, then the pressure loss decreases, but the heat capacity of the honeycomb structured body deteriorates
Solution Approach 1:
The patent applies local quality by differentiating the thickness of cell walls based on their location. The outermost peripheral cell walls are made thicker than the inner cell walls. This allows the majority of the structure to maintain thin walls for low pressure loss, while the peripheral regions provide the necessary strength and heat capacity support.
3Ease of manufacture
If material supply holes are positioned at slit intersections, then the molding process is simplified, but void formation and cell wall breakage occur due to insufficient material mixing
Solution Approach 1:
The patent transitions from a two-dimensional grid pattern (material supply holes at intersections) to a three-dimensional staggered arrangement. The material supply holes are positioned offset from the slit intersections, creating a more complex but effective three-dimensional material flow path that ensures proper mixing and eliminates void formation.
4Strength
If high-hardness silicon carbide powder is used to increase strength, then the strength improves, but the extrusion die suffers from abrasion and reduced durability
Solution Approach 1:
The patent introduces a material mixing mechanism as an intermediary process. By ensuring thorough mixing of the molding material before extrusion, the material flows more uniformly through the die, reducing localized stress concentrations and abrasive effects on the die walls, thereby extending die life while maintaining product strength.
Data Source
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Figure 3(a)~3(e)
AI summary
The present invention provides an extrusion die capable of supplying a molding material having passed through material supply holes uniformly throughout slits. The extrusion die of the present invention is for use in production of a honeycomb molded body including a plurality of cells arranged in parallel with one another in a longitudinal direction with a cell wall therebetween, with the cell wall having a thickness of 0.21 mm or less, the extrusion die including a first face; a second face formed opposite to the first face; a material supply section having first through holes extending from the first face to the second face; and a molding section having second through holes extending from the second face to the first face to communicate with the first through holes, wherein the second through holes viewed from the second face form slits in a grid shape, and each first through hole viewed from the first face is formed between adjacent intersections of the slits viewed from the first face.