Turbine Blade Tip Additive Build on Cast Airfoils
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Solution Overview
Problem
Current methods for manufacturing and repairing turbine blade tips are time-consuming and costly, particularly due to the need for new materials and processes that do not effectively utilize existing resources in airfoil manufacturing facilities.
Innovation Solution
A method involving a ceramic casting mold with a ceramic core and shell is used to support additive manufacturing of blade tips, where a liquid metal is poured, ceramic mold is partially removed, and metallic powder is deposited and fused to form the tip layer by layer, utilizing existing materials and processes like direct metal laser melting (DMLM) to create a cost-effective and efficient manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional welding methods are used to join blade tips, then the blade tip can be attached, but weld solidification cracking and strain age cracking occur due to the susceptibility of superalloy materials
Solution Approach 1:
The patent replaces traditional mechanical welding processes with additive manufacturing (direct metal laser melting) to join blade tips. This substitution eliminates the thermal cycling and rapid solidification associated with welding, thereby preventing weld solidification cracking and strain age cracking while maintaining strong attachment of the blade tip to the airfoil.
2Manufacturing precision
If new materials and processes are used for blade tip manufacturing, then manufacturing precision and quality can be improved, but time and cost increase significantly
Solution Approach 1:
The patent merges additive manufacturing technology with existing investment casting processes. The blade tip is manufactured using direct metal laser melting and then integrated with the airfoil through the same additive manufacturing process, combining multiple operations into one unified process flow. This integration maintains high manufacturing precision while reducing overall cycle time compared to separate manufacturing and assembly operations.
Solution Approach 2:
The additive manufacturing process serves multiple functions: it manufactures the blade tip with high precision, creates the bonding interface directly on the airfoil surface, and joins the tip to the airfoil in a single operation. This multi-functionality eliminates the need for separate machining, surface preparation, and welding operations, thereby reducing time while maintaining precision.
3Ease of manufacture
If conventional blade tip manufacturing methods are used, then existing facilities can be utilized, but the process is time-consuming and costly
Solution Approach 1:
The patent replaces conventional mechanical manufacturing methods (such as machining and welding) with additive manufacturing technology. This substitution enables the use of existing investment casting facilities while dramatically improving productivity by manufacturing blade tips layer-by-layer directly on the airfoil, eliminating multiple sequential operations and reducing overall manufacturing time.
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 reduces time and cost by leveraging existing materials and facilities, ensuring crack-free and high-quality blade tips with controlled microstructures, suitable for aircraft engines and power generation turbines.
Implementation Method 1
pouring a liquid metal into a ceramic casting mold including a core portion and a shell portion to form a partial turbine blade workpiece upon solidification of the liquid metal
Implementation Method 2
irradiating at least a portion of the metallic powder to form a fused layer
Implementation Method 3
the metallic powder is deposited on the tip plate in one or more passes and is sintered together and bonded to the tip plate by directing laser energy at it
Implementation Method 4
the wax is melted and removed from the shell 12 leaving a corresponding void or space 13
Implementation Method 5
In order to provide a pathway for removing ceramic core material via a leaching process
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3C
AI summary
Methods of manufacturing or repairing a turbine blade or vane are described. The airfoil portions of these turbine components are typically manufactured by casting in a ceramic mold, and a surface made up of the cast airfoil and at the least the ceramic core serves as a build surface for a subsequent process of additively manufacturing the tip portions. The build surface is created by removing a top portion of the airfoil and the core, or by placing an ultra-thin shim on top of the airfoil and the core. The overhang projected by the shim is subsequently removed. These methods are not limited to turbine engine applications, but can be applied to any metallic object that can benefit from casting and additive manufacturing processes. The present disclosure also relates to finished and intermediate products prepared by these methods.