PECM Disc Flange Tool for Scallops and Attachment Holes
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Solution Overview
Problem
The production of turbine disc flanges requires multiple machining operations, leading to increased cycle time and risks of deformation due to mechanical stress, especially during drilling of small thickness flanges, and existing tools are not suitable for simultaneously producing scallops and fastening holes efficiently.
Innovation Solution
A tool for electrochemical machining with a sinking tool comprising coaxial conductive cathodes, where the first cathode has radial machining projections for scallops and the second cathode has axial machining nozzles for holes, allowing simultaneous machining of both features using pulsed electrochemical machining with an electrolyte, minimizing mechanical stress and eliminating burrs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple machining operations (broaching, milling, drilling) are used to manufacture turbine disc flanges, then the required geometric tolerances can be achieved, but the cycle time significantly increases and mechanical stress induces deformations requiring additional machining steps
Solution Approach 1:
The patent combines multiple machining functions into a single electrochemical machining tool that can simultaneously perform scallop formation and hole drilling operations. The tool integrates multiple cathodes with different geometries (annular cathode for scallops, cylindrical cathodes for holes) that work together in one operation, eliminating the need for sequential broaching, milling, and drilling operations while maintaining geometric precision and reducing cycle time
Solution Approach 2:
The electrochemical machining tool is designed with multi-functionality to perform various machining operations (scallop creation, hole drilling, edge rounding) using a single tool platform. The tool can adapt different cathode configurations to achieve different geometric features, making it a universal machining solution that replaces multiple specialized tools and operations
2Ease of manufacture
If mechanical machining operations are used to create scallops and drill holes, then the features can be produced, but mechanical stress and cutting forces induce deformations in thin disc flanges
Solution Approach 1:
The patent replaces mechanical machining operations with electrochemical machining processes. Instead of using mechanical cutting forces and contact between tools and workpiece, the invention uses electrochemical reactions where current passes through an electrolyte to selectively remove material. This substitution eliminates mechanical stress and cutting forces that cause deformation in thin disc flanges while still achieving precise scallop and hole features
3Manufacturing precision
If conventional tools are used to machine scallops and holes separately, then each feature can be produced, but the process requires multiple operations and intermediate checks
Solution Approach 1:
The patent merges separate machining operations for scallops and holes into a single integrated electrochemical machining process. The tool simultaneously performs both operations in one setup without intermediate checks or repositioning, reducing process complexity while maintaining the precision required for turbine disc flange features
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 solution enables the efficient production of turbine disc flange scallops and fastening holes in a single operation, reducing cycle time and minimizing mechanical stress, with precise control and elimination of burrs, while maintaining the advantages of electrochemical machining such as natural edge shelving and reduced tool wear.
Implementation Method 1
electrochemical machining, and more specifically pulsed electrochemical machining (PECM)
Implementation Method 2
an absence of mechanical stress due to an anodic oxidation of the material
Data Source
Figure 1~2B
Figure 3~4
Figure 3A~6
AI summary
The invention relates to a tool for producing festoons and attachment holes of a disc flange (10) by electrochemical machining using an electrolyte, the tool comprising: an annular support plate (52) for receiving the disc; lower protectors (54) and upper protectors (56) configured to protect the disc from splashes of the electrolyte; a clamping lock (58A, 58B) for holding the disc in position during the machining; and a sinking tool (40) comprising, in a substantially cylindrical insulating body (42), a first (44) and a second (46) coaxial conductive cathode, the first and second cathodes being rigidly attached to each other, the first annular cathode comprising, at one outer periphery, a plurality of radial machining protrusions of shape complementary to that of the festoons to be machined and the second cathode comprises, on a same outer circumference as the first cathode with respect to the central axis of the disc, a plurality of axial machining nozzles similar in shape to that of the attachment holes to be machined.