Tall Ceramic Filter Sintering Retainer and Coating
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Solution Overview
Problem
Conventional methods for manufacturing tall integrally-formed ceramic filters for molten metal filtration are limited by the collapse of the side wall during sintering, preventing the production of filters with heights of 300 mm or more due to fragility and deformation caused by atmospheric convection and internal stress.
Innovation Solution
A manufacturing method involving the use of a retainer to support the side wall during sintering, combined with a coating layer of a material stable against molten metal and having a lower sintering temperature than the ceramic particles, to prevent collapse and enhance mechanical rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the side wall of the precursor is made tall to increase filtering area, then the filtering capability is improved, but the side wall collapses during sintering due to fragility and internal stress
Solution Approach 1:
A coating layer is applied to the side wall surface before sintering. This coating layer has a lower sintering temperature than the ceramic particles, so it vitrifies first during sintering to form a rigid shell that prevents side wall collapse. This preliminary protective action enables the production of tall filters with heights of 300 mm or more without deformation.
Solution Approach 2:
The coating layer acts as an intermediary substance between the fragile dough precursor and the high-temperature sintering environment. It provides mechanical support during the critical sintering phase, allowing the tall structure to maintain its shape. After sintering, the retainer is removed, leaving the stable ceramic filter structure.
2Strength
If the side wall thickness is increased to prevent collapse, then the mechanical strength is improved, but the permeability to molten metal decreases
Solution Approach 1:
The invention changes the physical-chemical parameters of the side wall surface by applying a coating layer that vitrifies at a lower temperature. This creates a high-strength surface layer that provides mechanical support without requiring increased wall thickness. The interior structure remains porous with appropriate thickness for molten metal passage, thus resolving the contradiction between strength and permeability.
3Area of stationary object
If the side wall is made tall to increase filtering area, then the filtering capability is improved, but the side wall deforms due to atmospheric convection during sintering
Solution Approach 1:
The coating layer is applied in advance to protect the side wall during sintering. As the coating vitrifies first, it forms a stable shell that resists deformation from atmospheric convection and thermal stresses, enabling tall structures to maintain their shape throughout the sintering process.
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
Enables the production of ceramic filters with side walls exceeding 300 mm in height without collapse, maximizing the filtering area and durability, particularly when immersed in molten metal baths.
Implementation Method 1
the material of the coating layer has a sintering temperature lower than that of the dough, and is therefore first vitrified during sintering to have increased mechanical rigidity
Implementation Method 2
setting up a retainer for the dried precursor to support a side wall of the precursor
Implementation Method 3
A ceramic filter is used to remove contaminant from the molten metal of aluminum
Data Source
AI summary
In order to enable stable provision of an upward release tube-type ceramic filter used in a molten metal bath and having a side wall with a height of 300 mm or greater, this method for manufacturing a ceramic filter, which is an upward release tube-type integrally molded article for removing unwanted substances from molten metal, has: a step for kneading a mixture of an aggregate comprising ceramic particles, a prescribed binding agent, and water to prepare a base material; a step for integrally forming an upward release tube-type ceramic filter precursor from the prepared base material; step for drying the precursor; a step for providing a retainer for the dried precursor for supporting a side wall of the precursor; a step for subsequently sintering the precursor; and a step for removing the retainer after sintering.