Airfoil Machining with Multi-Edge Cutting Tools
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Solution Overview
Problem
Current machining methods for integrally bladed rotors in gas turbine engines require multiple passes of cutting tools along complex paths, which is inefficient and may not fully achieve a single pass cut of airfoil surfaces, especially with straight-edge conical cutting tools.
Innovation Solution
The use of specifically designed first and second cutting tools with complex, mathematically determined cutting contours allows for machining of airfoil surfaces in a single pass, with one tool dedicated to the pressure side and another to the suction side, enabling efficient material removal between blades.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a straight-edge conical cutting tool is used to grind material from between the blades, then the tool structure is simple, but multiple passes are required and machining efficiency is low
Solution Approach 1:
The cutting tool is segmented into multiple cutting edges (first, second, third, and fourth cutting edges) arranged at different positions and orientations. Each cutting edge is responsible for machining specific portions of the airfoil surfaces, allowing all surfaces to be machined in a single pass through rotational movement of the tool, thereby eliminating the need for multiple passes and improving productivity.
Solution Approach 2:
The cutting tool transitions from a simple straight-edge conical structure to a multi-dimensional complex contour structure with cutting edges positioned in three-dimensional space. The cutting edges are arranged at different radial distances from the rotational axis and at different angular positions, enabling the tool to machine both pressure and suction sides of airfoils simultaneously through rotation, thus solving the productivity issue.
2Loss of substance
If multiple passes of cutting tools are used along complex cutting paths, then material removal is achieved, but tool changes are frequent and machining time increases
Solution Approach 1:
Multiple cutting edges that would traditionally require separate tools or multiple passes are merged into a single cutting tool structure. The tool incorporates first, second, third, and fourth cutting edges that can machine different airfoil surfaces simultaneously or sequentially in one pass, eliminating the need for frequent tool changes and reducing machining time while achieving complete material removal.
Solution Approach 2:
The cutting tool is designed to machine all required airfoil surfaces in a continuous single-pass operation without interruption. The rotational movement of the tool brings different cutting edges into position to machine pressure sides and suction sides consecutively, maintaining continuous material removal action and eliminating idle time associated with tool changes and repositioning.
3Productivity
If a single cutting tool with complex contour is used to machine all airfoil surfaces in one pass, then productivity is improved, but tool complexity increases
Solution Approach 1:
The complex cutting tool is segmented into distinct cutting edges (first, second, third, fourth cutting edges), each with specific functions for machining particular airfoil surfaces. This segmentation allows the tool to handle complex machining requirements through modular cutting edges positioned at different locations, making the complexity manageable while maintaining single-pass machining capability.
Solution Approach 2:
The cutting tool is designed as a multi-functional tool that can machine pressure sides, suction sides, and different portions of airfoil surfaces using its multiple cutting edges. This universality allows a single tool to perform what would traditionally require multiple specialized tools, improving productivity while the modular cutting edge design keeps the complexity manageable through functional integration.
4Manufacturing precision
If different cutting tools are used for pressure side and suction side machining, then surface finish quality is improved, but the number of tools and tool changes increases
Solution Approach 1:
The patent merges the functionality of separate cutting tools for pressure side and suction side machining into a single multi-edge cutting tool. The first and second cutting edges are configured to machine pressure sides, while the third and fourth cutting edges machine suction sides, allowing both surfaces to be machined with appropriate tooling in a single pass, thereby maintaining surface finish quality while reducing the number of tools required.
Solution Approach 2:
The cutting tool uses three-dimensional positioning of multiple cutting edges at different radial distances and angular positions to achieve specialized machining for different airfoil surfaces. This spatial arrangement allows the tool to provide differentiated cutting actions for pressure and suction sides without requiring separate tools, maintaining manufacturing precision while simplifying the tooling system.
Data Source
Figure 1~2
Figure 3A~3B
Figure 4A~5
AI summary
A method of machining an airfoil includes the steps of providing first and second cutting tools (40,140) respectively having first and second cutting contours (42;142) that are different than one another. A blank (19) is cut with the first cutting tool (40) to provide a first airfoil surface (54) on a first blade (24b). The blank (19) is cut with the second cutting tool (140) to provide a second airfoil surface (52) on a second blade (24a). An airfoil is produced having the first and second blades (24a,24b). A cutting tool (40) for machining the airfoil includes a shank (44). A cutting surface adjoins the shank (44) and provides a cutting contour (48) corresponding to an airfoil surface. The cutting surface extends along a cutting length axially from a nose to near a cutting boundary. The cutting length is configured to be greater than the blade length.