Ceramic Core Impregnation for Complex Lost-Wax Cooling Channels
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Solution Overview
Problem
Existing ceramic core manufacturing processes for lost-wax casting of turbomachinery blades are inadequate for complex cooling circuits due to geometric limitations and require new methods that ensure mechanical properties while avoiding regulated compounds.
Innovation Solution
A manufacturing process involving additive manufacturing of ceramic cores, impregnation with a reinforcing composition of aqueous polyvinyl alcohol solution at specific concentrations and pressures, followed by controlled draining and drying, to enhance mechanical strength and surface finish.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If ceramic injection processes are used to manufacture cores, then manufacturing complexity is reduced, but geometric resolution is insufficient for new cooling circuits
Solution Approach 1:
The patent changes the manufacturing method from ceramic injection to additive manufacturing, which fundamentally alters the geometric capabilities. Additive manufacturing enables the production of complex internal geometries and fine details that are impossible to achieve with traditional injection processes, directly resolving the geometric resolution limitation while maintaining manufacturing feasibility
Solution Approach 2:
The patent replaces the mechanical ceramic injection process with an additive manufacturing process (such as stereolithography or selective laser sintering). This substitution enables the creation of complex three-dimensional geometries with fine features that cannot be produced by conventional injection molding, thereby achieving the required geometric resolution for new cooling circuits
2Strength
If core impregnation resins are used to increase mechanical properties, then core strength is improved, but regulated compounds are introduced that must be avoided
Solution Approach 1:
The patent changes the chemical composition of the impregnation resin from traditional epoxy-based formulations to an aqueous polyvinyl alcohol solution. This parameter change eliminates the need for regulated organic compounds while maintaining the essential function of improving core mechanical properties and surface finish
Solution Approach 2:
The patent uses a biodegradable, water-based polyvinyl alcohol impregnation composition that can be easily applied and then removed or decomposed after serving its reinforcing purpose. This approach replaces persistent, regulated organic resins with a temporary, environmentally friendly alternative that achieves the same mechanical reinforcement without long-term harmful effects
3Manufacturing precision
If additive manufacturing is used to obtain ceramic cores, then geometric precision is improved, but mechanical strength is insufficient without impregnation
Solution Approach 1:
The patent creates a composite structure by impregnating the additive-manufactured ceramic core with polyvinyl alcohol solution. The polymer penetrates the porous structure of the ceramic, forming a composite material that combines the geometric precision of additive manufacturing with the mechanical strength and surface quality provided by the polymer impregnation
Solution Approach 2:
The patent utilizes the inherent porosity of additive-manufactured ceramic cores as a feature rather than a defect. The porous structure allows deep penetration of the polyvinyl alcohol impregnation solution, ensuring thorough reinforcement throughout the core structure and achieving the necessary mechanical properties while maintaining the geometric advantages of additive manufacturing
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
The process enables ceramic cores with precise geometries and improved mechanical properties suitable for lost-wax casting, overcoming geometric constraints and ensuring mechanical integrity during wax injection.
Implementation Method 1
a step of impregnating the open porosity of the core with a reinforcing composition, the reinforcing composition comprising an aqueous solution of polyvinyl alcohol
Implementation Method 2
The subsequent removal of the core allows the cooling circuit to be formed in the metal blade
Data Source
Figure 1~2
AI summary
The invention relates to a method for manufacturing a core for a lost-wax casting process comprising: - a step of obtaining the core 100 in ceramic material by an additive manufacturing process; - a step of impregnating the open porosity of the core with a reinforcing composition, the reinforcing composition comprising an aqueous solution of polyvinyl alcohol with a degree of hydrolysis between 82% and 98.4%, and at a concentration between 35 gL-1 and 165 gL-1; the impregnation step being carried out at a pressure less than or equal to 1 bar, - a draining step; then - a drying step.