Workpiece Encapsulation Cooling for Tight-Tolerance Fixturing
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Solution Overview
Problem
Fixturing workpieces with complex geometries, such as those in gas turbine engines, poses challenges due to their intricate shapes, particularly for smaller components where traditional methods are impractical, leading to inefficiencies in machining and dimensional inspection processes.
Innovation Solution
The use of encapsulation techniques with zinc or zinc alloys, where the encapsulation is cooled using pressurized air, often enhanced by vortex tubes or enclosures to manage temperature and airflow effectively, allowing for efficient cooling and handling within tight tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If encapsulation is performed using metals with lower melting points (e.g., tin bismuth at 150°C, tin zinc at 180°C), then energy consumption is reduced and the process is simplified, but the encapsulation may not maintain tight tolerances and secure hold as effectively as higher melting point metals
Solution Approach 1:
The patent changes the physical parameters of the encapsulation metal by selecting zinc or zinc alloys with melting points around 400°C, which provides better dimensional stability and tight tolerance maintenance compared to lower melting point alloys, while still being preferable due to lower toxicity and shrinkage characteristics
Solution Approach 2:
The patent uses zinc or zinc alloys as the encapsulation material, which combines multiple desirable properties including appropriate melting point, lower toxicity, controlled shrinkage, and ability to maintain tight tolerances, creating a composite solution that balances multiple competing requirements
2Manufacturing precision
If encapsulation is cooled rapidly to reduce thermal growth influences, then dimensional accuracy is improved, but thermal shock or uneven cooling may occur
Solution Approach 1:
The patent employs pressurized air for cooling the encapsulation, using pneumatic flow to efficiently remove heat and reduce thermal growth influences while maintaining dimensional accuracy, avoiding the need for liquid cooling systems
Solution Approach 2:
The patent utilizes the phase transition of air (from compressed to expanded state) through vortex tubes to generate cold air for cooling the encapsulation, converting the phase change energy into useful cooling effect without direct thermal contact
3Ease of operation
If traditional fixturing methods are used for workpieces with complex geometries, then the workpiece can be held during machining, but the fixturing precision and convenience are insufficient for intricate shapes
Solution Approach 1:
The patent introduces an encapsulation as an intermediary element between the workpiece and the fixture. The encapsulation, formed from zinc or zinc alloy, conforms to the complex geometry of the workpiece and provides precise positioning features that enable accurate fixturing without requiring complex custom fixtures for each workpiece shape
Solution Approach 2:
The encapsulation creates a precise copy or replica of the workpiece's external geometry, allowing the fixture to interact with the encapsulation's standardized features rather than the complex workpiece geometry itself, thereby simplifying the fixturing system while maintaining precision
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 enables rapid and precise cooling of encapsulations, reducing thermal growth influences and ensuring dimensional accuracy, thereby improving production efficiency and handling safety by maintaining tight tolerances and avoiding additional drying steps.
Implementation Method 1
cooling the encapsulation using cooling air at a first air temperature and a first flow rate from a vortex tube
Implementation Method 2
cooling the encapsulation using cooling air at a first air temperature and a first flow rate
Implementation Method 3
cooling the encapsulation using cooling air at a second air temperature and a second flow rate, the second air temperature and the second flow rate being lower than the first air temperature and the first flow rate, respectively
Data Source
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AI summary
The method can include : using a mold, casting an encapsulation (40) onto a workpiece (90) including solidifying the encapsulation (40) around the workpiece (90) in the mold and extracting the encapsulation (40) from the mold, and cooling the extracted encapsulation (40) using a vortex tube (42; 242).