Turbine Blade Root Transverse Channel for Machining Precision
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Solution Overview
Problem
The existing methods for manufacturing turbine engine rotor blades face challenges in achieving precise machining tolerances, particularly with the radial dimension of the downstream face of the blade root, which is difficult to produce within the required +/−0.05 mm tolerance due to its large radial extent.
Innovation Solution
Incorporating a transverse channel in the axial extremity of the blade root blank casting that extends over its entire width, with a depth greater than the machining allowance, facilitates precise machining by limiting the radial extent of the machining allowance and allowing for easier removal of material, thereby improving the precision and ease of machining while maintaining the required tolerance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If machining is performed on a blank casting with a large radial dimension downstream face, then the blade root can be produced, but the machining precision deteriorates due to the large machining length making it difficult to achieve the required +/−0.05 mm tolerance
Solution Approach 1:
The downstream face is segmented into two separate machining zones by introducing a transverse channel. The channel divides the large radial dimension into two smaller, independent machining sections, each with its own machining allowance. This segmentation allows each section to be machined to the required +/−0.05 mm tolerance independently, overcoming the difficulty of machining the entire large radial dimension as a single continuous surface.
Solution Approach 2:
The transverse channel acts as an intermediary element that facilitates precise machining. By introducing this channel with controlled depth greater than the machining allowance, it creates reference surfaces and separates the machining zones, enabling the machining process to achieve the required precision that would be impossible on the original continuous large radial face.
2Manufacturing precision
If a transverse channel is introduced in the blank casting, then machining precision is improved, but the device complexity increases due to the additional structural feature
Solution Approach 1:
The transverse channel is created during the casting process itself, before machining begins. This preliminary action incorporates the channel into the blank casting structure, so that the subsequent machining operations can directly utilize these pre-formed surfaces as reference planes. The channel is cast with depth greater than the machining allowance, ensuring that the reference surfaces are established before any precision machining occurs, thereby simplifying the overall manufacturing process despite the added structural feature.
Data Source
AI summary
A blank casting for producing a turbine engine rotor blade, with a vane connected by a platform to a root, is provided. The root has an axial machining allowance intended to be removed by machining from each of its axial extremities. At least one of the axial extremities of the root includes at least one transverse channel that extends over the entire transverse width of the root and whose depth is greater than the machining allowance. A process for obtaining the blade by machining this blank casting is also provided.