Turbomachine Coupon Grinding Depth Indicators
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Solution Overview
Problem
The challenge in manufacturing hot gas path components lies in achieving precise matching between coupons and cutouts for reliable joining, maintaining minimum wall thickness, and preventing clogging of cooling passages during coating applications, which is time-consuming and costly due to tight tolerances and lack of direct feedback during re-contouring and coating processes.
Innovation Solution
The solution involves a modular manufacturing concept using coupons with tapered ribs for enhanced brazing and grinding depth indicators for precise re-contouring, and modified near-wall cooling passages with enlarged exit volumes to prevent coating clogging, ensuring optimal fit and reducing the risk of tool breakage during reopening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the same machining path is used for wire EDM cutting of coupon and original component to achieve tight gap tolerances, then joining precision is improved, but manufacturing complexity increases due to requiring precise programming and compensation
Solution Approach 1:
The patent uses a physical master pattern that is copied onto both the coupon and the original component during wire EDM machining. This copying approach simplifies the machining process by providing a direct physical reference rather than requiring complex digital programming and compensation procedures, while still achieving the required tight gap tolerances
Solution Approach 2:
The patent introduces a master pattern as an intermediary element that mediates between the design specifications and the actual machining process. This master pattern serves as a physical intermediary that both the coupon and original component are machined against, simplifying the overall manufacturing complexity while ensuring precision
2Manufacturing precision
If manual re-contouring is performed after coupon joining to restore geometry, then shape accuracy is improved, but wall thickness may be violated and near wall cooling scheme damaged due to lack of direct feedback
Solution Approach 1:
The patent incorporates feedback mechanisms during the re-contouring process, such as measurement tools or monitoring systems that provide direct feedback to the operator about remaining wall thickness. This allows the operator to adjust the re-contouring process in real-time to maintain minimum wall thickness requirements while achieving the desired shape accuracy
Solution Approach 2:
The patent performs preliminary actions to establish minimum wall thickness requirements and planning before the re-contouring process begins. This includes pre-calculating material removal amounts, setting up stop indicators, or creating preliminary guides that prevent over-removal of material, thereby protecting the near wall cooling scheme while still achieving shape accuracy
3Reliability
If coating application is performed on joined component to provide protective layers, then component protection is improved, but cooling passages become clogged by coating overspray requiring time-consuming reopening
Solution Approach 1:
The patent extracts or removes the cooling passage openings from the coating application zone by using masking techniques, localized coating application, or by temporarily closing the passages during coating. This prevents coating overspray from entering and clogging the passages, eliminating the need for subsequent reopening operations while still providing comprehensive protective coating
Solution Approach 2:
The patent introduces intermediary elements such as masks, barriers, or protective plugs that temporarily block the cooling passages during coating application. These intermediaries prevent coating material from entering the passages, and are removed after coating is complete, avoiding the need for time-consuming reopening operations
4Productivity
If reamer tools are used to reopen clogged cooling passages, then passage clearance is improved, but tool breakage occurs creating additional clogging due to sharp bending angles
Solution Approach 1:
The patent performs preliminary actions to prevent clogging from occurring in the first place, such as using larger passage openings, designing passages with gentle angles from the start, or applying coating protection methods that avoid clogging. This eliminates the need for reopening operations and associated tool breakage risks
Solution Approach 2:
The patent uses disposable, inexpensive opening tools or methods that can be discarded if they break, rather than using expensive precision reamer tools. This might include using drill bits, abrasives, or other simple tools that are cheaper to replace than the original reamer tools, thereby reducing the impact of tool breakage and minimizing additional clogging
Data Source
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AI summary
A coupon (170, 300) for replacing a cutout (172) in a hot gas path component of a turbomachine (100) is provided. In one embodiment, the coupon (170, 300) includes a body (180, 268, 304) having an outer surface (182, 270, 304); and a plurality of grinding depth indicators (250) in the outer surface (182, 270, 304) of the body (180, 268, 304). In another embodiment, the coupon (170, 300) includes a body (180, 268, 304) having an edge periphery (200, 202) configured to mate with an edge periphery (200, 202) of the cutout (172), and at least a portion (210) of the edge periphery (200, 202) of the body (180, 268, 304) has a wall (305) thickness greater than a wall thickness of an edge periphery (200, 202) of the cutout (172). The embodiments may be used together or separately.