Sintered Body Gravity Shaping for Complex Combustor Panels
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Solution Overview
Problem
Existing metal injection molding (MIM) techniques face challenges in shaping complex geometries due to issues like pouring blockage, deformation, and residual stress, which hinder the production of sintered bodies with intricate designs, such as combustor panels for turbine engines.
Innovation Solution
A method involving primary shaping followed by secondary shaping processes, including gravity shaping and torsion deformation, is employed to transform injection molded bodies into sintered bodies with complex geometries, utilizing a transfer mold to achieve the desired shape and structure while minimizing defects like warpage and cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a nickel-based alloy containing titanium is manufactured by the spraying method, then high strength at high temperature is achieved, but pouring blockage occurs in the fine powder manufacturing process
Solution Approach 1:
The invention changes the chemical composition parameters of the nickel-based alloy by strictly controlling the titanium content to 0.01 mass % or less and the niobium content to 0.9 mass % or less. This parameter adjustment prevents pouring blockage during the spraying method while maintaining high temperature strength through the base nickel-based alloy composition.
2Shape
If the molding green body is placed on a processing tray with the flat surface on the ground side, then softening deformation is prevented, but the process complexity increases
Solution Approach 1:
The invention performs preliminary action by designing the injection molded body with a specific structural feature (protrusion or recess) that enables self-positioning on the processing tray. This preliminary design prevents softening deformation during heating without requiring complex tray arrangements, as the part automatically assumes the correct orientation.
3Shape
If the binder is not fully removed from the molding green body, then shape maintenance is achieved, but residues remain among the metal powder grains
Solution Approach 1:
The invention changes the debindering process parameters by controlling the heating rate and temperature profile to achieve partial binder removal. The binder is removed at a controlled pace, maintaining structural integrity while eliminating excessive residues that would interfere with sintering and final product quality.
4Manufacturing precision
If the intermediate shaped body is pressed with high oppression force, then shape precision is improved, but warpage and cracks occur due to residual stress
Solution Approach 1:
The invention changes the pressing process parameters by optimizing the oppression force magnitude and distribution. The pressing force is carefully controlled to be sufficient for achieving the required shape precision but not excessive to cause residual stress, warpage, or cracks in the intermediate shaped body.
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 enables the production of sintered bodies with complex geometries, such as combustor panels, that maintain shape integrity and reduce defects, facilitating precise manufacturing and efficient heat radiation, while allowing for mass production without excessive effort.
Implementation Method 1
by carrying out a gravity shaping with a transformation due to the gravity
Implementation Method 2
by carrying out a sintering and a debindering to the injection molded body after the gravity shaping
Data Source
AI summary
By melting a shaping material in which a metal powder and a binder are mixed and by carrying out injection molding (primary shaping) in an injection mold, an injection molded body, or an intermediate shaped body are produced. The injection molded body or the intermediate shaped body is placed by a transfer mold and is subjected to a gravity shaping (secondary shaping) with a transformation. A sintered body is manufactured by carrying out debindering and sintering to the injection molded body.