Honeycomb Structure Coating Crack Prevention

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Solution Overview

Problem

Conventional methods for manufacturing honeycomb structures with a coating member prone to cracking due to sudden shrinkage during compulsory drying, leading to increased manufacturing time and space requirements for natural drying.

Innovation Solution

A method involving machining a honeycomb substrate, applying slurry with a potsherd powder of 15 to 75 μm particle size and 26 to 34% water content, followed by compulsory drying using far-infrared ray or hot-air drying, to achieve a honeycomb structure with minimal cracking and improved adhesion between partition walls and the coating member.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If slurry is naturally dried in ambient air, then cracks in the coating member are avoided, but manufacturing time is increased and large storage space is required

Engineering Contradiction:

Improvecrack-free coating memberVSAvoidmanufacturing time

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The invention changes the physical parameters of the slurry by controlling water content (20-40% by mass) and aggregate particle size (0.03-0.6 mm) to enable compulsory drying without cracking. This parameter optimization allows the slurry to maintain structural integrity during rapid drying while achieving the desired coating properties

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention replaces the natural convection-based drying process with compulsory drying methods such as hot air drying or infrared radiation. This substitution accelerates the drying process significantly, reducing manufacturing time and storage space requirements while maintaining crack-free coating quality through proper slurry formulation

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If slurry is subjected to compulsory drying from the beginning, then manufacturing time is reduced, but cracks are easily caused in the coating member

Engineering Contradiction:

Improvemanufacturing timeVSAvoidcrack-free coating member

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The invention optimizes the water content parameter to 20-40% by mass, which is higher than conventional slurries. This increased water content allows for more gradual moisture removal during compulsory drying, reducing thermal stress and preventing cracks while still achieving rapid drying compared to natural drying methods

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention uses aggregate particles with specific size ranges (0.03-0.6 mm) that create a porous structure in the dried coating. This porous structure facilitates uniform moisture evaporation during compulsory drying, reducing internal stress concentration and preventing crack formation while maintaining coating integrity

Inventive Principle:

Principle #31Porous materials

3Reliability

If large space is provided for natural drying, then crack-free coating is achieved, but storage space requirements increase

Engineering Contradiction:

Improvecrack-free coating memberVSAvoidstorage space

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The invention replaces space-intensive natural drying with compact compulsory drying systems using hot air circulation or infrared radiation. This substitution dramatically reduces the storage space required during the drying process while maintaining crack-free coating quality through controlled drying parameters

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention enables continuous processing by implementing compulsory drying that can be performed in-line without requiring large storage areas for batch natural drying. The optimized slurry formulation allows continuous drying operations to proceed without interruption or cracking, reducing both space and time requirements

Inventive Principle:

Principle #20Continuity of useful action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method reduces manufacturing time and space requirements while ensuring almost no cracks in the coating member, with enhanced adhesion and improved dryability, resulting in a high-quality honeycomb structure suitable for applications like filters and catalyst carriers.

Implementation Method 1

subjecting the honeycomb body with slurry to heat-drying to obtain a honeycomb structure having the coat member

Methodology Applied

Scientific EffectEvaporation: Evaporation

Implementation Method 2

compulsory drying using far-infrared ray or hot-air drying

Methodology Applied

Scientific EffectHeating: Heating

Data Source

PatentUS7560154B2Method for manufacturing honeycomb structure and the honeycomb structure

Publication Date: 2009.07.14 NGK INSULATORS LTD

AI summary

A method for manufacturing a honeycomb structure includes: machining a peripheral portion of a honeycomb substrate having a plurality of cells separated by porous partition walls made of ceramic, applying slurry for forming a coating member on a face exposed to outer periphery of partition walls positioned in the outermost periphery to obtain a honeycomb body with slurry, and subjecting the honeycomb body with slurry to heat-drying to obtain a honeycomb structure having the coat member in the outer periphery. The slurry contains a powder of potsherd having a particle size of 15 to 75 μm, and has a water content of 26 to 34% by mass. In the method, even if the slurry is subjected to compulsory drying from the beginning, the coating member hardly has cracks, and a honeycomb structure having no cracks on the coating member can be obtained.