Cooling Aperture Drilling and De-burring in Combustion Chamber Heads
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Solution Overview
Problem
Conventional methods for producing cooling apertures in gas turbine engine combustion chamber heads, such as electro-discharge machining (EDM), are slow, prone to non-conformance, and generate burrs that are difficult and costly to remove due to inaccessible upstream sides.
Innovation Solution
A method and apparatus using a drilling machine to mechanically drill cooling apertures from the downstream side of the combustion chamber head, with a tool inserted through fuel injector apertures to rotate and supply fluid jets with radial and axial components to remove burrs and caps from the upstream side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If electro-discharge machining (EDM) is used to drill cooling apertures, then burrs are not produced, but the manufacturing time is increased and productivity is reduced
Solution Approach 1:
The process is segmented into two distinct stages: first, rapid mechanical drilling to create the aperture, and second, targeted fluid jet de-burring to clean the aperture exit. This segmentation allows each process to be optimized independently - mechanical drilling for speed and EDM fluid jet for precision cleaning, thereby resolving the contradiction between manufacturing time and aperture quality
Solution Approach 2:
The patent replaces the traditional mechanical de-burring process with an EDM fluid jet system. The EDM fluid jet uses electrical discharge to erode and remove burrs without physical contact, eliminating the need for manual de-burring operations and significantly reducing manufacturing time while maintaining high aperture quality
2Productivity
If conventional drilling is used to produce cooling apertures, then manufacturing time is reduced, but burrs are produced that are difficult and costly to remove
Solution Approach 1:
The patent introduces an EDM fluid jet as an intermediary between the mechanical drilling process and the final aperture. This fluid jet acts as a mediator that removes the harmful burrs created by mechanical drilling, allowing the benefits of fast conventional drilling to be retained while eliminating the disadvantage of burr formation
Solution Approach 2:
The patent changes the state of the drilling process by applying EDM parameters (electrical discharge, dielectric fluid) to the de-burring stage. By transforming the de-burring process from mechanical to electrical discharge-based, burrs are effectively removed without the need for additional mechanical operations, thus maintaining high productivity while eliminating harmful factors
3Ease of operation
If cooling apertures are drilled from the downstream side, then access to the upstream side is avoided, but de-burring becomes difficult and costly
Solution Approach 1:
The patent makes the downstream side universally functional by using it for both drilling and de-burring operations. The EDM fluid jet system can be directed through the drilled aperture to reach and clean the upstream side, eliminating the need for separate access to the upstream side and making the downstream side sufficient for both manufacturing and finishing operations
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 reduces manufacturing time by 40%, improves aperture quality with parallel sides and surface finish, and eliminates the need for additional de-burring operations, compared to EDM methods.
Implementation Method 1
mechanically drilling a plurality of cooling apertures through the combustion chamber head from the downstream side
Implementation Method 2
directing a jet of fluid from the tool with at least a radial component towards the cooling apertures on the upstream side
Implementation Method 3
supplying fluid from the drilling machine through the tool, directing a jet of fluid from the tool
Data Source
AI summary
A method of producing cooling apertures in a combustion chamber head includes mechanically drilling a plurality of cooling apertures through the combustion chamber head from the downstream side of the combustion chamber head. A tool is inserted through at least one aperture for a fuel injector from the downstream side of the combustion chamber head and the tool is rotated about its axis while within the aperture for a fuel injector. Fluid is supplied from the drilling machine through the tool and jets of fluid are directed from nozzles in the tool with at least a radial component towards the cooling apertures on the upstream side of the combustion chamber head to remove burrs and/or caps adjacent the cooling apertures. The present disclosure enables cooling apertures to be drilled through a combustion chamber head using conventional mechanical drilling in a viable and cost effective manner.