Honeycomb Structure Plugging Material Shrinkage Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for manufacturing honeycomb structures as exhaust gas purification filters face challenges in maintaining dimensional tolerance and thermal shock resistance due to differences in firing shrinkage rates between the honeycomb body and the plugging material, leading to shape distortions and potential leakage or reduced thermal shock resistance.
Innovation Solution
A method involving the use of a plugging material with a cordierite forming raw material and resin balloon, with a controlled firing shrinkage rate difference of -1.0 to +2.0% from the honeycomb formed body, to reduce dimensional differences and promote integration, thereby omitting the need for post-firing grinding and coating, and enhancing thermal shock resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the plugging material has a firing shrinkage rate different from the honeycomb formed body, then the plugged portions are formed at the end faces, but the dimensional difference between end parts and central part increases causing shape distortion
Solution Approach 1:
The patent controls the firing shrinkage rate of the plugging material to be within ±2.0% of the honeycomb formed body's shrinkage rate. By adjusting and matching this critical parameter (shrinkage rate), the invention prevents excessive dimensional differences between end parts and central part, thereby maintaining manufacturing precision while enabling the formation of plugged portions.
Solution Approach 2:
The invention applies different materials with specifically controlled local properties: the plugging material is designed with a firing shrinkage rate matched to the honeycomb formed body, while the kneaded material maintains its own characteristics. This local differentiation with controlled parameters allows plugged portions to form at end faces without causing overall shape distortion.
2Ease of manufacture
If the plugging material shrinks more than the honeycomb formed body during firing, then the plugged portions are formed, but gaps are generated between plugged portions and partition walls causing leakage
Solution Approach 1:
The patent specifies that the firing shrinkage rate difference between plugging material and honeycomb formed body must be within ±2.0%. By controlling this parameter, the invention ensures that the plugging material shrinks appropriately during firing to maintain intimate contact with partition walls, preventing gap formation and ensuring reliable leakage prevention.
3Ease of manufacture
If the honeycomb formed body shrinks more than the plugging material during firing, then the plugged portions are formed, but compressive stress remains in the end face part reducing thermal shock resistance
Solution Approach 1:
The patent controls the firing shrinkage rate difference to be within ±2.0%, preventing excessive shrinkage of the honeycomb formed body relative to the plugging material. This parameter control avoids generating excessive compressive stress in the end face parts, thereby maintaining thermal shock resistance while still enabling plugged portion formation.
4Manufacturing precision
If post-firing grinding and coating are performed to correct shape distortion, then dimensional tolerance is achieved, but manufacturing complexity and time increase
Solution Approach 1:
The patent performs preliminary action by controlling the firing shrinkage rate of the plugging material to be within ±2.0% of the honeycomb formed body's shrinkage rate before firing occurs. This pre-control of shrinkage behavior prevents shape distortion from occurring in the first place, eliminating the need for subsequent grinding and coating operations, thereby reducing manufacturing complexity and time.
5Manufacturing precision
If the firing shrinkage rate difference is controlled within a narrow range, then shape distortion is suppressed, but material selection and formulation become more difficult
Solution Approach 1:
The patent establishes a specific parameter range (±2.0% firing shrinkage rate difference) that balances shape control requirements with material formulation feasibility. By defining this quantitative parameter range, the invention provides clear guidance for material selection and formulation, making it easier to achieve the desired balance between shape control and manufacturability.
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
The method effectively reduces dimensional differences between the end parts and central parts of the honeycomb structure, suppresses shape distortion, and improves thermal shock resistance by ensuring a controlled firing shrinkage rate, allowing for the omission of post-firing processing steps and maintaining filter efficiency.
Implementation Method 1
a plugging material which includes a forming raw material containing a cordierite forming raw material B and resin balloon of 5 to 7.5 mass% and has a difference in firing shrinkage rate of -1.0 to +2.0% from the honeycomb formed body
Data Source
Figure 1~2
AI summary
Provided is a technique to manufacture a honeycomb structure reducing a width of dimensional difference generated during firing between an end part and a central part in the cell extending direction and having excellent thermal shock resistance, and the method includes: a honeycomb formed body preparing step of extruding a kneaded material including a cordierite forming raw material A, to prepare a honeycomb formed body; a plugged honeycomb formed body preparing step of filling cell openings of the honeycomb formed body with a plugging material which includes a forming raw material containing a cordierite forming raw material B and resin balloon of 1.0 to 15 mass% and has a difference in firing shrinkage rate of -1.0 to +2.0% from the honeycomb formed body, to prepare a plugged honeycomb formed body; and a honeycomb structure preparing step of firing the prepared plugged honeycomb formed body, to prepare a honeycomb structure provided with porous plugged portions at an one end part of a predetermined cell and at another end part of a remaining cell.