Turbine Blade Tip Shroud Datum Referencing for Accurate PSP Machining
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Solution Overview
Problem
Conventional methods for machining pre-sintered preforms on turbine components face challenges due to reliance on indirect reference points, leading to errors in translational and rotational data transformation, which amplifies inaccuracies in the machining process.
Innovation Solution
A datum surface is formed in the tip shroud, parallel to the pre-sintered preform, serving as a reference point for subsequent machining, ensuring accurate alignment and duplication of the pre-sintered preform's profile by controlling the machining tool's movement using this datum surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If indirect reference points are used for machining pre-sintered preforms, then the machining process can be performed, but errors in translational and rotational data transformation amplify inaccuracies
Solution Approach 1:
The patent extracts the reference surface directly from the component's own geometry (the pre-sintered preform surface or a related feature) rather than using separate indirect reference points. This eliminates the need for coordinate system transformations between different reference frames, thereby removing the source of cumulative errors in translational and rotational data while maintaining full machining capability.
2Manufacturing precision
If a datum surface is formed in the tip shroud as a direct reference, then machining accuracy is improved, but an additional machining step is required to create the datum surface
Solution Approach 1:
The datum surface is created as a preliminary action before the main machining operations. By establishing this reference surface first (either by forming it during pre-sintering or through a preliminary machining step), subsequent machining operations can directly reference this surface without requiring complex coordinate transformations, thereby improving overall machining accuracy despite the additional initial step.
Data Source
AI summary
A method of repairing a turbine blade includes positioning the turbine blade within a system including a machining tool and determining a first distance between a surface of a first pre-sintered preform (PSP) attached to a tip shroud of the turbine blade and a datum surface formed in the tip shroud. The method also includes removing the first PSP from the tip shroud, coupling a second PSP to the tip shroud, and machining a surface of the second PSP using the machining tool. Machining the second PSP surface includes controlling movement of the machining tool using the datum surface as a reference, such that the machined second PSP surface is located the first distance from the datum surface.