Turbomachine Blade Casting Core with Protuberances
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Solution Overview
Problem
The existing method for manufacturing metal turbine engine blades with internal cavities and communication holes for temperature probes involves additional operations like drilling, which generates inadequate mechanical properties and requires a blanking plate, leading to inefficiencies and potential core breakage.
Innovation Solution
A lost-wax casting method using a core with protuberances to hold the core in place during casting, eliminating the need for drilling and reducing core fragility, where the holes for temperature probes are formed directly in the casting process, and a radiated base shape prevents crack formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If drilling/machining is used to produce communication holes after casting, then the holes can be precisely formed, but additional operations are required and burnt zones with inadequate mechanical properties are generated
Solution Approach 1:
The core is designed with protuberances that protrude into the mold cavity before casting, so that the communication holes are formed during the casting process itself rather than requiring subsequent drilling operations. This preliminary formation of holes eliminates post-casting machining while maintaining precision through the controlled protuberance geometry.
Solution Approach 2:
The function of forming communication holes is merged into the casting process by integrating protuberances on the core. The core simultaneously serves as the cavity former and the hole-forming tool, combining what were previously separate operations (casting and hole drilling) into a single integrated process.
2Ease of manufacture
If traditional cores with tenons are used, then the core can be held in place during casting, but additional blanking plates requiring brazing are needed
Solution Approach 1:
The unnecessary blanking plate and brazing operation are extracted from the manufacturing process. The core design is modified to include protuberances that directly form the communication holes, eliminating the need for separate blanking plates and subsequent brazing operations while maintaining proper core positioning.
Solution Approach 2:
The complex assembly involving blanking plates and brazing is discarded in favor of a simpler core design. The protuberance-based core positioning system recovers the essential function of holding the core in place while simultaneously forming the holes, eliminating redundant components and operations.
3Ease of manufacture
If cores are held by traditional methods, then positioning is achieved, but core breakage risk increases due to fragility
Solution Approach 1:
The core is designed with localized protuberances at specific positions where strength is needed for positioning, rather than making the entire core more robust. These localized features provide adequate positioning and support while maintaining the overall lightweight and simple structure of the core, reducing unnecessary material and potential failure points.
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 saves production time and reduces scrap by eliminating drilling and soldering operations, improves mechanical properties by avoiding heat-affected zones, and simplifies core removal, while enabling the production of a single model for multiple blading sectors.
Implementation Method 1
The blading is obtained by pouring a molten metal which fills the voids between the inner wall of the shell mold and the core
Implementation Method 2
said core comprises, for each communication hole of said cavity, a protuberance penetrating into the internal surface of the mold and constituting the only element for holding the core in the casting mould
Data Source
Figure 1~4b
Figure 5~7
AI summary
The present invention relates to a method of manufacturing a sector of metal blading (1) for a turbomachine low pressure guide vane assembly in which at least one vane (14) comprises an internal cavity (13) intended to accept or communicate with a gas detection probe and at least one hole (19) formed in the wall constituting a passage for gas from the low-pressure zone of the turbomachine to the said cavity (13) and the probe by installing in a casting mould an insert that corresponds to the said cavity (13) and pouring molten metal into the cavity of the said casting mould. The method is characterized in that the insert (20) comprises, for each communication hole (19) of the said cavity (13), a protrusion (22) penetrating the internal surface of the mould and constituting the sole means of holding the insert (20) in the casting mould.