Gas Turbine Blade Platform Repair via EDM Puck Brazing
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Solution Overview
Problem
Turbine components in gas turbine engines suffer from thermal-mechanical fatigue cracks due to pressure and temperature gradients, leading to frequent replacements and high economic costs, necessitating an efficient repair method.
Innovation Solution
The method involves electrical discharge machining a puck to create a near-perfect fit with the turbine component, followed by brazing to enhance the thickness and durability of the component, with an interface gap of less than 0.005 inches, using a braze presintered preform or casting, and incorporating features like chevron-shaped turbulators and ribs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If turbine components are replaced frequently due to thermal-mechanical fatigue cracks, then reliability is improved, but loss of time and economic cost increase
Solution Approach 1:
The patent applies the discarding and recovering principle by removing cracked portions of turbine components and replacing them with new sections through platform shortening and puck brazing. This allows the component to be recovered and returned to service without complete replacement, reducing downtime and cost while maintaining reliability.
2Reliability
If turbine components are replaced frequently, then reliability is improved, but economic cost increases
Solution Approach 1:
Instead of discarding entire turbine components that develop fatigue cracks, the patent recovers value by selectively removing only the cracked portions and brazing on new material. This partial recovery approach significantly reduces material waste and economic cost compared to complete replacement.
Solution Approach 2:
The patent changes the platform thickness parameter through controlled material removal and addition. By shortening the platform and brazing pucks with specific thicknesses, the component is restored to acceptable dimensional parameters without requiring complete replacement.
3Manufacturing precision
If electrical discharge machining is used to create near-perfect fit, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces conventional mechanical machining with electrical discharge machining (EDM). This substitution enables achievement of extremely tight interface gaps (less than 0.005 inches) between the puck and component platform through electrical erosion rather than mechanical cutting, achieving high precision without complex mechanical tooling.
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 effectively increases the thickness of turbine components, reduces the frequency of cracks, and provides a strong, durable repair with minimal thickness reduction, enhancing the engine's operational lifespan and reducing replacement costs.
Implementation Method 1
electrical discharge machining a puck via the turbine component to form an electrical discharged machined puck
Implementation Method 2
brazing the electrical discharged machined puck to the turbine component
Data Source
AI summary
A method of remanufacturing a turbine blade having a platform includes placing a puck against a surface of the platform. The method may include electrical discharge machining an interface between the puck and the platform and brazing the puck to the platform. A total radial thickness of a finally remanufactured platform of the remanufactured turbine blade is greater than an initial radial thickness of the platform before remanufacturing the turbine blade.