Liquid Guided Laser and EDM Machining for Deep Cooling Holes
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Solution Overview
Problem
Current machining techniques face limitations in efficiently and precisely drilling small, deep holes in hard materials like turbine blades, particularly with thermal barrier coatings, due to limitations in both liquid guided laser and electrical discharge machining methods.
Innovation Solution
A combined method and system using liquid guided laser machining to create intermediate features and electrical discharge machining to finish these features, with a common positioning system for alignment and data integration between the two tools, allowing for efficient and precise creation of complex features like diffuser shapes and cooling holes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If liquid guided laser is used to machine hard materials, then machining capability on hard materials is improved, but depth of small hole drilling and non-line-of-sight holes is limited
Solution Approach 1:
The machining process is segmented into two distinct stages: liquid guided laser drilling creates initial holes through the thermal barrier coating and into the base material, then EDM processes continue and finish the holes to achieve the required depth and precision. This segmentation allows each process to operate within its optimal capability range.
Solution Approach 2:
The liquid guided laser performs preliminary action by drilling initial holes through the coating and creating starting points, which enables the subsequent EDM process to access and complete the holes. The preliminary laser drilling overcomes the coating barrier that would otherwise prevent EDM electrode access.
2Length of moving object
If EDM is used to drill small deep holes in hard materials, then drilling capability is improved, but efficiency and precision for small and complex features is limited
Solution Approach 1:
The process segments the machining tasks by material type and feature complexity: liquid guided laser handles the coating removal and initial hole creation (high efficiency for through-coating drilling), while EDM handles the precision finishing and deep hole completion (high precision for final dimensions). This segmentation optimizes overall productivity by assigning each process to its strength.
Solution Approach 2:
The liquid guided laser acts as an intermediary process that prepares the workpiece for EDM by removing the thermal barrier coating and creating initial hole openings. This intermediary step enables the EDM process to operate efficiently on the base material without being hindered by the coating.
3Strength
If EDM is used to machine workpieces with thermal barrier coating, then machining of base material is improved, but difficulty removing the thermal barrier coating is increased
Solution Approach 1:
The thermal barrier coating is extracted and removed separately by the liquid guided laser process before the EDM process begins. The laser ablates and removes the coating material, extracting this harmful element that would otherwise interfere with the EDM machining of the base material.
Solution Approach 2:
The liquid guided laser serves as an intermediary process that eliminates the thermal barrier coating, creating a clean interface for subsequent EDM processing. This intermediary step resolves the conflict between needing to machine the base material with EDM while avoiding the problems caused by the coating.
4Adaptability or versatility
If separate machines are used for liquid guided laser and EDM, then versatility of machining methods is improved, but complexity of aligning features is increased
Solution Approach 1:
A single workholding device and positioning system is designed to serve both the liquid guided laser process and the EDM process. This universal positioning system maintains consistent workpiece location and orientation across both machining operations, eliminating the need for separate alignment procedures and reducing complexity.
Solution Approach 2:
The positioning and workholding functions are merged into a single integrated system that accommodates both liquid guided laser and EDM processes. By combining these functions rather than using separate systems, the overall device complexity is reduced while maintaining the versatility of using both machining methods.
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 enhances design flexibility and efficiency by leveraging the strengths of both methods, overcoming material and accessibility limitations, and reduces the complexity of aligning features across separate machines, enabling reliable machining through coatings and precise feature creation.
Implementation Method 1
liquid guided laser machining to create at least one intermediate feature in the workpiece
Implementation Method 2
electrical discharge machining is then used on the workpiece using the EDM device to modify the at least one intermediate feature
Data Source
AI summary
This disclosure provides a system, method, and resulting workpiece combining liquid guided laser and electrical discharge machining to create a common feature. The workpiece is positioned in a liquid guided laser cutting path and machined by the liquid guided laser device to create an intermediate feature in the workpiece. The work piece is then positioned in an electrical discharge machining (EDM) device so that an electrode of the EDM device is operatively positioned proximate the intermediate feature and machined using the EDM device to modify the intermediate feature in the workpiece to create the finished common feature in the workpiece.