Airfoil Low-Angle Cooling Channel Drilling with Diffuser Stop Surface
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional drilling methods face challenges in forming low-angle cooling channels in turbine blade airfoils, leading to alignment difficulties such as slipping or skipping of the drilling tool, which complicates the precision required for film cooling applications.
Innovation Solution
The method involves creating a diffuser section on the exterior surface of the airfoil with converging outer and inner surfaces to form a stop surface, allowing the drilling element to be positioned and oriented at a precise angle, thereby facilitating the formation of cooling channels with angles less than 30° without slipping or skipping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional drilling methods are used to form cooling channels, then the drilling process is simpler, but alignment difficulties occur such as slipping or skipping of the drilling tool when starting the machining operation
Solution Approach 1:
A starting section is formed in the exterior surface of the airfoil before drilling the cooling channel. This starting section includes a stop surface that provides a stable starting point for the drilling tool, preventing slipping or skipping during the initial drilling phase. The stop surface is configured to receive the drilling tool at the desired angle, ensuring precise channel orientation from the beginning of the machining operation.
2Manufacturing precision
If low-angle channels are formed with conventional drilling methods, then the cooling channel angle is reduced, but alignment difficulties and tool slippage increase
Solution Approach 1:
The starting section is created in advance to provide a stable platform for low-angle drilling operations. The stop surface within the starting section is specifically designed to support the drilling tool at low angles (less than 30 degrees relative to the exterior surface), preventing tool slippage and ensuring reliable, repeatable drilling of precisely angled cooling channels.
Solution Approach 2:
The stop surface acts as an intermediary element between the drilling tool and the airfoil surface. It provides a stable intermediate platform that enables precise positioning and orientation of the drilling tool at low angles, mediating the interaction between the tool and the workpiece to achieve both low channel angles and high drilling reliability.
3Manufacturing precision
If the drilling tool is positioned at low angles on the airfoil surface, then the cooling channel orientation is optimized, but the tool slips or skips across the surface
Solution Approach 1:
The starting section and stop surface are prepared beforehand to provide a stable positioning feature for the drilling tool. This pre-formed structure allows the tool to be accurately positioned at low angles without slipping or skipping, making the drilling operation easier to control while maintaining precise channel orientation.
Solution Approach 2:
The stop surface serves as an intermediary structure that facilitates stable tool positioning at low angles. It provides a physical interface that prevents the drilling tool from slipping across the airfoil surface, enabling operators to easily position and maintain the desired low channel orientation throughout the drilling process.
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 reliable and precise drilling of low-angle cooling channels, reducing the risk of tool slippage and surface damage, and enhances the effectiveness of film cooling by ensuring accurate channel orientation.
Implementation Method 1
One known method of forming cooling holes uses electrical discharge machining, or 'EDM' drilling. During EDM drilling, an airfoil surface, the 'workpiece electrode' and a tool, i.e., the 'tool electrode ', are submersed in a dielectric fluid. Current is induced between the tool and the work piece to remove material from the workpiece.
Data Source
AI summary
A method for fabricating an airfoil includes forming a diffuser section in an exterior surface of the airfoil. The diffuser section is defined by at least an outer surface and an inner surface that converge at a stop surface. The method also includes positioning a drilling element of a drilling device on the stop surface. The method further includes orienting the drilling element at a first angle relative to the exterior surface. The method also includes forming, using the drilling element, a cooling channel extending through the airfoil from the stop surface to an interior surface, thereby forming the cooling channel at substantially the first angle.