Ceramic Honeycomb Structure Circumferential Coating Uniformity
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Solution Overview
Problem
The existing methods for manufacturing honeycomb structures with circumferential coat layers face challenges in achieving uniform thickness and stability due to difficulties in adjusting the viscosity of the slurry-like circumferential coating material, leading to non-uniform coating, potential cracking, and increased processing costs.
Innovation Solution
A method involving controlling the discharge speed of the circumferential coating material from 50 to 120 mm/s, adjusting the discharge opening area to 200-600 mm², and optimizing the rotation speed of the honeycomb structure to 5-15 rpm, along with a discharge-amount/coating-amount ratio of 1.1 to 3.5, to ensure uniform coating and prevent material dripping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the viscosity of the circumferential coating material is adjusted by changing moisture content, then the coating can be applied, but the coating thickness becomes non-uniform and cracking occurs
Solution Approach 1:
The patent changes the discharge speed parameter of the coating material from 30 mm/s to 50-120 mm/s, which fundamentally alters the coating formation process. This parameter change enables uniform coating thickness (100-200 μm) while preventing cracking, resolving both the manufacturing precision and reliability issues simultaneously.
2Manufacturing precision
If a large-sized honeycomb structure is integrally formed by extrusion molding, then the structure can be manufactured, but the partition wall shape at the circumferential periphery is not stabilized and dimensional accuracy decreases
Solution Approach 1:
The patent divides the manufacturing process into two independent stages: (1) integral extrusion molding of the honeycomb structure, and (2) separate circumferential coating application. This segmentation allows the base structure to be manufactured simply while the circumferential coating provides the necessary dimensional accuracy and shape stabilization.
Solution Approach 2:
The circumferential coating is applied as a preliminary action after extrusion but before final use. This coating layer pre-compensates for dimensional variations and stabilizes the partition wall shape at the circumferential periphery, ensuring dimensional accuracy is achieved through the coating process rather than requiring complex extrusion control.
3Manufacturing precision
If the discharge speed of the circumferential coating material is increased, then the coating thickness becomes uniform, but the material may drip and processing costs increase
Solution Approach 1:
The patent optimizes the discharge speed parameter to a specific range of 50-120 mm/s, which is fast enough to ensure uniform coating thickness distribution but controlled enough to prevent material dripping. This precise parameter control achieves uniform coating (100-200 μm) while minimizing material waste.
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 approach allows for the formation of a circumferential coat layer with uniform thickness and improved dimensional stability, reducing the risk of cracking and processing costs while maintaining the mechanical strength and shape accuracy of the honeycomb structure.
Implementation Method 1
applying a circumferential coating material that contains a powdery ceramic raw material and is prepared in a slurry state on the circumferential surface (grinding surface) of the honeycomb structure
Implementation Method 2
a rotating process of matching an axial direction of the honeycomb structure with a vertical direction to rotate the honeycomb structure by using the axial direction as a rotation center
Data Source
AI summary
A method of applying a circumferential coating material on a circumferential surface of a ceramic honeycomb structure to form a circumferential coat layer.The method includes vertically aligning the longitudinal axis of the ceramic honeycomb structure, rotating the ceramic honeycomb structure around the vertically-aligned longitudinal axis, and applying the circumferential coating material on the circumferential surface of the rotating honeycomb structure at a discharge speed of 50 to 120 mm/s, calculated byDischarge speed V [mm/s]=Supplied amount q [g/s] of circumferential coating material÷(Density ρ [g/mm3] of circumferential coating material×Area S [mm2] of discharge opening).