Compressible Crown Holding Tools for Preform Shape Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Composite material preforms deform during high-temperature treatments like debinding or sintering due to the lack of matrix precursor binding, especially in thin or slender parts, leading to unwanted shape changes.
Innovation Solution
A sintering installation with holding tools featuring a disk and a compressible crown made of material that oxidizes at high temperatures, maintaining preform shape by compensating for thermal expansion and allowing easy separation post-sintering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If stiffeners are integrated into the parts or thickness is increased to prevent deformation during sintering, then the shape stability is improved, but the mass of the parts increases undesirably
Solution Approach 1:
A holding tool acts as an intermediary device between the preform and the sintering furnace. The holding tool comprises a disk and a crown made of compressible material that supports the preform during sintering, preventing deformation without adding mass to the final part. The crown is designed to be eliminated by thermal oxidation after serving its supporting function.
Solution Approach 2:
The holding tool utilizes thermal expansion parameter changes to its advantage. The crown is made of compressible material that can accommodate radial thermal expansions between the disk and the preform during heating, maintaining contact and support throughout the sintering process while preventing preform deformation.
2Manufacturing precision
If a holding tool with compressible crown is used to maintain preform shape during sintering, then the shape precision is improved, but the device complexity increases
Solution Approach 1:
The holding tool is segmented into two distinct functional parts: a disk that provides structural support and a crown made of compressible material that provides adaptive contact with the preform. This segmentation allows each component to perform its specific function optimally while keeping the overall structure relatively simple.
Solution Approach 2:
The crown is designed as a disposable component made of material capable of being eliminated by thermal oxidation. It serves its purpose of supporting the preform during sintering and then decomposes, simplifying the removal of the holding tool from the sintered part without requiring complex extraction mechanisms.
3Strength
If the crown material remains stable during sintering to support the preform, then the holding capability is improved, but the ease of separation between part and holding tool deteriorates
Solution Approach 1:
The crown material exhibits dynamic behavior during the sintering process. It remains stable and maintains holding capability during the early stages when the preform needs support, then undergoes thermal oxidation and decomposition at higher temperatures, transforming from a stable supporting structure to a removable residue that facilitates easy separation from the sintered part.
Solution Approach 2:
The crown material undergoes a phase transition through thermal oxidation during sintering. It starts as a stable compressible material providing mechanical support, then transitions through decomposition and oxidation reactions, ultimately converting to gaseous products or removable residues that allow easy separation from the final sintered part.
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
Maintains preform shape without increasing part mass, ensuring precise sintered parts can be easily detached from the holding tools, reducing deformation risks.
Implementation Method 1
The presence of a layer of compressible material between the disk and the preform allows to compensate for radial thermal expansions between said disk and said preform
Implementation Method 2
the crown being made of compressible material capable of being eliminated by thermal oxidation
Implementation Method 3
the crown made of such a material is capable of holding the fiber preform during a possible debinding operation and preferably until the start of sintering, then can sufficiently decompose by oxidation to allow a clearance to be created between the part obtained by sintering and the holding tool oxidized on its edges
Implementation Method 4
the matrix precursor particles present in the fibrous preform are sintered in order to form the matrix in the porosities of said preform
Data Source
AI summary
An installation for sintering a preform includes a sintering furnace in which a load is disposed, wherein the load includes a revolution preform disposed around at least one holding tool, the at least one holding tool including a disk and a crown present on the periphery of the disk, the crown being made of compressible material capable of being eliminated by thermal oxidation, a portion of the preform being in contact with the crown before sintering.