Composite Boss for Gas Turbine Engine Case
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Solution Overview
Problem
The existing methods for manufacturing gas turbine engine cases with bosses are time-consuming and expensive due to machining requirements, and the choice of cast materials for bosses is limited by welding constraints, which also affects durability and weight optimization.
Innovation Solution
The use of metal injection molded (MIM) parts combined with a separately formed sheet metal flange, made from different materials, to create a composite boss that is lightweight and durable, with the flange embedded in the MIM part for secure mounting to the engine case.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If bosses are machined from solid directly on the case, then manufacturing precision and strength are improved, but manufacturing time and cost increase
Solution Approach 1:
The boss is divided into two separate components: a MIM part and a sheet metal flange. The MIM part is manufactured separately with high precision, then assembled with the flange. This segmentation allows each part to be optimized independently and reduces overall manufacturing time compared to machining from solid.
Solution Approach 2:
The boss uses a composite construction combining MIM (metal injection molded) material for the main body and sheet metal for the flange. This composite approach enables different materials to be selected for their optimal properties while reducing total manufacturing time and cost.
2Productivity
If bosses are separately produced as cast parts and welded to the case, then manufacturing time is reduced, but material selection is limited by welding constraints and durability is compromised
Solution Approach 1:
The flange portion is extracted as a separate sheet metal component rather than being cast or welded. This extraction allows the flange to be made from material compatible with the case (sheet metal) while eliminating the need for weld joints at the flange-case interface, thereby improving durability.
Solution Approach 2:
The sheet metal flange acts as an intermediary between the MIM boss body and the engine case. It provides a reliable mounting interface that eliminates direct welding between dissimilar materials, improving joint durability while maintaining productivity.
3Reliability
If traditional materials are used for bosses, then welding compatibility is maintained, but overall weight of the engine case increases
Solution Approach 1:
The material parameters of the boss are changed by using MIM technology, which allows for lighter materials to be used compared to traditional cast or welded approaches. The MIM process enables precise control over material properties and weight while maintaining structural integrity.
Solution Approach 2:
The composite construction of MIM and sheet metal allows selection of lighter materials for each component while maintaining overall structural strength and welding compatibility. This reduces the total weight of the engine case compared to traditional homogeneous materials.
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 reduces manufacturing time and costs, offers improved durability at weld joints, and allows for the selection of materials based on optimal properties for both the boss and the engine case, while minimizing overall weight.
Implementation Method 1
metal injection molding a boss about a central portion of a sheet metal flange to provide a composite metallic boss member
Implementation Method 2
the flange part having an inner portion imbedded in said MIM part and a peripheral outer portion fixedly joined to said annular shell
Data Source
AI summary
A gas turbine engine case has a metallic composite boss mounted thereto. The boss may have a main metal injection molded (MIM) part, and a separately formed flange part integrated to the main MIM part and projecting laterally outwardly therefrom. The MIM part and the flange part may be made of different materials. The material of the flange part is selected to provide a suitable mounting interface with the gas turbine engine case.