Ceramic Core Machining for Turbomachine Blade Trailing Edges
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Solution Overview
Problem
The existing methods for manufacturing ceramic foundry cores with thin walls, particularly in turbomachine blades, face challenges such as premature tool wear, pressure drops, and defects like cracks due to the abrasive nature of ceramic materials and suboptimal filling conditions, leading to increased costs and core disposal.
Innovation Solution
A method involving the formation of a core with a thickened zone in the mold, which is then machined to create a sufficient opening for the ceramic paste injection, reducing pressure drops and enabling thinner wall thicknesses down to 0.1 mm without requiring more fluid pastes or altered injection parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If more fluid ceramic pastes or higher injection pressures are used to fill thin zones, then the filling of thin wall zones is improved, but tool wear increases and production stops increase
Solution Approach 1:
The mold cavity is pre-enlarged by machining before injection, creating a thicker zone that provides sufficient opening for paste flow. This preliminary geometric modification eliminates the need for high injection pressures or more fluid pastes, thereby preventing tool wear and production stoppages while ensuring complete filling of thin wall zones.
Solution Approach 2:
The mold cavity is selectively enlarged only in the thin wall zone areas where filling difficulties occur, while maintaining the original geometry elsewhere. This localized geometric modification provides sufficient paste flow passage only where needed, avoiding the need to modify the entire mold or use more fluid pastes throughout the process.
2Manufacturing precision
If more fluid ceramic pastes are used to fill thin zones, then the filling of thin wall zones is improved, but paste formulation complexity increases
Solution Approach 1:
The mold cavity is pre-enlarged by machining before injection, creating a thicker zone that provides sufficient opening for paste flow. This preliminary geometric modification eliminates the need for high injection pressures or more fluid pastes, thereby preventing tool wear and production stoppages while ensuring complete filling of thin wall zones.
3Manufacturing precision
If higher injection pressures are used to fill thin zones, then the filling of thin wall zones is improved, but core defects increase
Solution Approach 1:
The mold cavity is pre-enlarged by machining before injection, creating a thicker zone that provides sufficient opening for paste flow. This preliminary geometric modification eliminates the need for high injection pressures or more fluid pastes, thereby preventing tool wear and production stoppages while ensuring complete filling of thin wall zones.
4Length of moving object
If the wall thickness is reduced to achieve thinner trailing edges, then the blade performance is improved, but filling becomes impossible with traditional pastes
Solution Approach 1:
The mold cavity is pre-enlarged by machining before injection, creating a thicker zone that provides sufficient opening for paste flow. This preliminary geometric modification eliminates the need for high injection pressures or more fluid pastes, thereby preventing tool wear and production stoppages while ensuring complete filling of thin wall zones.
Solution Approach 2:
The mold cavity is selectively enlarged only in the thin wall zone areas where filling difficulties occur, while maintaining the original geometry elsewhere. This localized geometric modification provides sufficient paste flow passage only where needed, avoiding the need to modify the entire mold or use more fluid pastes throughout the process.
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 approach significantly reduces production costs and improves core quality by allowing thinner trailing edges, minimizing defects, and enabling the use of a single paste formulation for all blade core manufacturing, while maintaining dimensional stability and reducing tool wear.
Implementation Method 1
the flow of said mixture during its injection into the mould
Implementation Method 2
the organic fraction of the core is eliminated by means such as sublimation or thermal degradation
Implementation Method 3
The core is then consolidated by heat treatment in an oven
Data Source
Figure 1~9
Figure 3~7
Figure 5~6d
AI summary
The process for manufacturing a foundry core (100), comprises arranging a mixture having a load of ceramic particles and organic binder in a mold, extracting the core from the mold, and unbinding and thermally treating the core consolidation. The foundry core comprises several fine zones having a thickness of 0.1-0.5 mm in a trailing edge of turbomachine blade. The core zone is thickened in connection to an overlayer. The overlayer is machined after extracting the core from the mold in order to create an opening channel sufficient for the flow of the mixture. The process for manufacturing a foundry core (100), comprises arranging a mixture having a load of ceramic particles and organic binder in a mold, extracting the core from the mold, and unbinding and thermally treating the core consolidation. The foundry core comprises several fine zones having a thickness of 0.1-0.5 mm in a trailing edge of turbomachine blade. The core zone is thickened in connection to an overlayer. The overlayer is machined after extracting the core from the mold in order to create an opening channel sufficient for the flow of the mixture during its injection into the mold. The machining is mechanically carried out by milling with chip removal, abrasion and drilling of matter on a drilling machine to 4-5 axes, before and after the thermal treatment operation. The layer zone is situated proximate to the trailing edge and constitutes a tenon (100GH) as an evacuation channel for internal cooling of the turbomachine blade. A paste is supplied for the filling of mold in the tenon. The machining comprises a step of shelving of the tenon surface. The overlayer is applied to the several fine zone layers.