Composite Fan Blade Shield Repair With Laser Cooling Control
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Solution Overview
Problem
Turbomachine propeller blades, particularly those with organic matrix composite blades and metal shields, face challenges in repairing damaged areas, especially the leading edge, which is prone to wear and impact damage, requiring a method that is simple, effective, and economical without the need for removal or scrapping.
Innovation Solution
A method involving leading edge registration to measure the actual profile, cooling to maintain optimal temperature, reloading with metallic material, and laser fusion to repair the damaged zone in situ, allowing precise deposition and machining of the molten material without overheating, using a device capable of pivoting for both registration and reloading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If the shield is repaired by traditional methods requiring removal from the blade, then the damaged area can be replaced, but the repair process becomes complex and time-consuming
Solution Approach 1:
The patent combines multiple repair operations (resetting, cooling, reloading, and adjustment) into a single integrated process performed in-situ on the installed shield. The device merges the resetting probe, cooling system, laser reloading head, and machining tools into one unified repair system that operates without removing the shield from the blade, thereby simplifying the repair process while maintaining precision.
2Productivity
If laser melting is performed at high temperature to efficiently repair the damaged area, then the repair speed increases, but the blade material and adhesive may be degraded
Solution Approach 1:
The patent applies preliminary cooling to the blade and shield before laser reloading, and maintains cooling during the process, to preemptively counteract the thermal effects of laser melting. This pre-cooling and continuous cooling creates a thermal barrier that allows high-power laser operation without degrading the blade material or adhesive bonds, enabling fast repair while protecting sensitive components.
Solution Approach 2:
The cooling system acts as an intermediary between the laser heating process and the blade/adhesive materials. By introducing a controlled cooling field that interacts with the thermal field from the laser, the system mediates the thermal effects to allow efficient melting while preventing harmful temperature rise in the surrounding areas, thus protecting the blade and adhesive.
3Manufacturing precision
If the actual profile of the blade leading edge is not measured, then the repair process is simpler, but the repaired area will not match the original aerodynamic profile
Solution Approach 1:
The patent performs preliminary resetting of the leading edge profile using a contact probe before the reloading operation. This preliminary measurement and resetting action captures the actual deformed profile of the blade, which then serves as the reference for subsequent material deposition. By performing this measurement and initial shaping step first, the system ensures that the final repaired profile matches the original aerodynamic contours without requiring complex real-time measurement systems.
4Reliability
If the shield is removed and replaced when damaged, then a fresh shield can be installed, but the blade must be scrapped or the shield cannot be reused
Solution Approach 1:
The patent recovers and reuses the damaged shield by performing in-situ repair rather than discarding it. The reloading process restores the shield's integrity by adding material to the damaged areas, and the adjustment process ensures proper geometry. This allows the shield to be recovered and continued in service, preventing the loss of the expensive shield component and enabling its reuse after repair.
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
Enables quick, precise, and cost-effective repair of turbomachine propeller blades by adapting to the actual aerodynamic profile, avoiding unnecessary removal of the shield, and extending the lifespan of blades while minimizing deformation and scrapping.
Implementation Method 1
laser melting the material
Implementation Method 2
laser fusion to repair the damaged zone
Implementation Method 3
cooling to maintain optimal temperature
Data Source
Figure 1~3
Figure 4~5
AI summary
Method for repairing a blade (10) of a turbomachine rotor, particularly a turbomachine fan, this blade comprising a vane (12) made from an organic-matrix composite and a metallic shield (14) bonded to a leading edge of the vane, the metallic shield (14) having a damaged region (20), the method comprising a step of resetting the leading edge of the vane, a step of cooling the entire vane, followed by a step of refilling the damaged region (20) by adding a metallic material to this damaged region (20) and melting the material using a laser, and a step of tailoring the damaged region (20) by machining the molten material.