Belt Grinding Device for Turbomachine Blade Tip Shortening
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Solution Overview
Problem
Current methods for shortening turbomachine blades, such as grinding and milling, are costly, time-consuming, and complex, with high equipment costs and long processing times, and often require manual post-processing and risk damage to ceramic coatings.
Innovation Solution
A belt grinding device is used to shorten turbomachine blades, allowing the entire blade tip to be machined in one operation with a wider grinding belt, eliminating the need to move the belt along the contour, resulting in a compact, cost-effective, and time-efficient process with reduced manual post-processing and lower risk of coating damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a straight grinding wheel is used to shorten rotor blades, then the blade tip can be ground, but the grinding wheel must be moved along the contour requiring automatic feed and complex structure
Solution Approach 1:
The patent replaces the expensive, complex straight grinding wheel with a simpler, disposable abrasive belt. The belt is mounted on a flexible drum and can be easily replaced when worn, eliminating the need for complex automatic feed mechanisms and reducing overall device complexity while maintaining grinding effectiveness.
Solution Approach 2:
The patent transitions from a rigid straight grinding wheel to a flexible abrasive belt that can adapt to the blade tip contour. The belt is mounted on a flexible drum that can rotate and conform to the workpiece geometry, providing dynamic adaptability without requiring complex positioning mechanisms.
2Productivity
If a straight grinding wheel with automatic feed is used to shorten rotor blades, then the blade tip can be machined, but the machining time is long
Solution Approach 1:
The flexible abrasive belt allows for continuous machining action across the entire blade tip surface in a single operation. The belt can be fed continuously against the rotating blade tip, eliminating the intermittent motion and positioning delays associated with straight grinding wheels and automatic feed mechanisms.
Solution Approach 2:
The patent segments the grinding function from the positioning function. The flexible belt handles the material removal while the rotating blade tip naturally presents different surfaces to the belt, eliminating the need for complex multi-axis positioning and feed mechanisms.
3Productivity
If milling is used to shorten rotor blades, then the blade tip can be machined to required length, but the process is very slow and expensive
Solution Approach 1:
The patent replaces the slow, complex CNC milling system with a simpler abrasive belt grinding system. The belt grinding process removes material more rapidly than milling while requiring less expensive equipment, achieving both faster processing and reduced costs.
Solution Approach 2:
The patent changes the material removal mechanism from mechanical cutting (milling) to abrasive removal (grinding). This parameter change enables faster material removal rates while reducing equipment complexity and cost, particularly for the blade tip shortening operation.
4Area of stationary object
If a narrow grinding wheel is used to shorten rotor blades, then the blade tip can be ground, but the grinding wheel must be moved along the contour requiring complex feed mechanisms
Solution Approach 1:
The patent uses a flexible abrasive belt that can dynamically adapt to the blade tip contour. The belt's flexibility allows it to conform to the curved surface without requiring complex positioning mechanisms, while its width covers the entire blade tip in a single operation.
Solution Approach 2:
The flexible abrasive belt serves multiple functions simultaneously: it provides the grinding action, adapts to the contour, and covers the entire blade tip width. This single element replaces the combination of narrow grinding wheel plus complex feed and positioning mechanisms.
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
The method achieves significant time savings of 60% compared to grinding and 80-90% compared to milling, with lower equipment costs and reduced exposure time for personnel, while maintaining optimal blade gap tolerances and minimizing burrs and coating damage.
Implementation Method 1
A belt grinding device is used to shorten the moving blade, in which the entire blade tip can be machined in one operation using a grinding belt that is wider than the blade tip to be shortened
Data Source
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AI summary
The invention relates to a method for shortening one or more impeller blades (2) of a turbomachine (3) by removing material at the blade tip, and to devices (1; 19) for carrying out such a method, wherein, according to the invention, a belt grinding device (1; 19) is used to shorten the impeller blades (2) and the required conical contour is produced by a rotational movement of the blade along the stationary tool.