Ceramic Precursor Batch Composition for Thin Web Extrusion
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Solution Overview
Problem
The manufacturing of ceramic honeycombs with very thin webs faces challenges such as screen and die plugging, leading to frequent equipment replacement and production line shutdowns, despite efforts to reduce particle size and improve processing aids.
Innovation Solution
A ceramic precursor batch composition incorporating a cellulose-based polymer with a methylcellulose having a number average molecular weight of 120,000 to 170,000 grams per mole, exhibiting a micro-calorimetry thermal response with first and second peaks above the gelation onset temperature, is used to enhance the extrusion process and reduce plugging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If screens and dies with smaller open areas are used to manufacture ceramic honeycombs with very thin webs, then manufacturing precision is improved, but device complexity increases and reliability deteriorates due to frequent plugging
Solution Approach 1:
The patent changes the chemical composition parameters of the ceramic batch, specifically incorporating glass-forming oxides (20-40 wt%), alumina (10-30 wt%), and controlled particle size distributions. These parameter changes modify the melt behavior during firing to reduce plugging while maintaining thin web precision
Solution Approach 2:
The patent performs preliminary classification of ceramic particles into different size ranges before mixing. This preliminary action ensures proper particle packing and flow characteristics that prevent plugging of screens and dies during extrusion of thin-web honeycombs
2Ease of manufacture
If particle size of inorganic raw materials is decreased to reduce plugging, then ease of manufacture is improved, but manufacturing precision deteriorates due to blending difficulties
Solution Approach 1:
The patent applies local quality by creating distinct particle size fractions with specific functions: fine particles (0-10 μm) for filling and smooth surface, intermediate particles (10-50 μm) for structure, and coarse particles (50-200 μm) for strength. Each fraction is optimized for its local role in the final ceramic body
Solution Approach 2:
The patent creates a composite particle system combining multiple oxide components (glass-forming oxides, alumina, silica) with controlled particle size distributions. This composite approach leverages the complementary properties of different materials and size fractions to achieve both ease of manufacture and high precision
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 composition significantly decreases the propensity for screens and dies to become plugged, reducing the need for equipment replacement and minimizing production line shutdowns, while enabling the production of ceramic honeycombs with very thin webs.
Implementation Method 1
cellulose ethers such as methylcellulose (MC), hydroxypropylcellulose (HPMC) and hydroxyethylmethylcellulose (HEMC) can form high temperature gels. The gelling behavior facilitates rapid drying while preventing distortions that can occur with other binder systems as they are heated
Implementation Method 2
a methylcellulose having a number average molecular weight (Mn) from about 120,000 to about 170,000 grams per mole and showing a micro-calorimetry thermal response comprising first and second peaks above a gelation onset temperature
Data Source
AI summary
A precursor batch composition that can be used to make porous ceramic articles is provided. The batch composition includes a cellulose-based polymer and, in particular, a methylcellulose having a number average molecular weight (Mn) from about 120,000 to about 170,000 grams per mole and showing a specified micro-calorimetry thermal response fingerprint.