Turbine Blade Tip Well Machining via Localized Core Bumps

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Solution Overview

Problem

The manufacturing of turbine engine blades with complex internal shapes and additional cooling ribs is complicated by the constraints of the demolding process, leading to increased costs and scrap rates due to the inability to provide slots for ribs at the end of the second ceramic core, which are necessary for optimal aerodynamics and cooling performance.

Innovation Solution

A method involving a core with bumps at through-hole locations to achieve a nominal thickness greater than other walls and a reduced thickness at through-holes, allowing for machining to form relief shapes and internal ribs, enabling the production of blades with complex internal shapes without modifying the molding process or tools.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If slots for ribs are provided at the end of the second ceramic core to optimize aerodynamics and cooling, then cooling performance and aerodynamics are improved, but the demolding process becomes impossible due to undercut constraints

Engineering Contradiction:
Improvecooling performanceVSAvoiddemolding process
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by providing bumps on the second ceramic core before molding, which pre-form the closure wall thickness distribution. This allows slots for ribs to be created in the final blade without creating undercuts on the mold itself, enabling both optimal cooling geometry and straightforward demolding.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent applies local quality by creating localized bumps only at specific positions on the second ceramic core where through-holes are located. This results in the closure wall having greater thickness only at these specific locations, allowing rib slots to be formed without interfering with the overall demolding process.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If the closure wall thickness is increased to accommodate complex internal shapes and ribs, then manufacturing flexibility is improved, but the amount of material and complexity increase

Engineering Contradiction:
Improvemanufacturing flexibilityVSAvoidmaterial consumption
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent applies local quality by increasing the closure wall thickness only locally at positions where through-holes are located, rather than uniformly increasing the entire closure wall thickness. This provides the necessary material for complex internal shapes and ribs only where needed, maintaining manufacturing flexibility while minimizing overall material consumption.

Inventive Principle:
Principle #3Local quality

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 method allows for the manufacture of blades with complex internal shapes and ribs, optimizing aerodynamics and cooling without increasing the cost or scrap rate, by providing a high nominal thickness for the closure wall and reduced thickness at through-holes, facilitating efficient removal of alumina rods and formation of dust removal holes.

Implementation Method 1

a core etching operation and an alumina rod etching operation to remove this core and these rods after cast

Methodology Applied
Scientific EffectChemical etching: Oxidation

Implementation Method 2

an alumina rod etching operation to remove this core and these rods after cast

Methodology Applied
Scientific EffectChemical etching: Oxidation

Data Source

PatentEP3233328B1Method for manufacturing a turbine engine blade including a tip provided with a complex well
Publication Date: 2021.01.27 SAFRAN AIRCRAFT ENGINES SAS
  • EP3233328B1 patent drawingFigure 1~2
  • EP3233328B1 patent drawingFigure 3~6
  • EP3233328B1 patent drawingFigure 7~9

AI summary

The invention relates to a method for manufacturing a turbine engine blade (25) comprising a pressure side and a suction side separated from one another by an inner space for the circulation of cooling air, said blade (25) comprising a tip (S) with a closing wall (29) joining the pressure side and suction side walls in the region of this tip (S) in order to define a well shape, said closing wall including through-holes. The closing wall (29) obtained by moulding has a considerable nominal thickness with pits (36, 37) locally reducing this thickness at each through-hole in order to facilitate the removal by chemical etching of alumina rods defining said holes. Since the closing wall (29) thus has a large nominal thickness, it can then be machined in order to form raised patterns or complex shapes inside the well.