Wax Injection Mould Core Assembly for Turbine Blade Precision
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Solution Overview
Problem
The existing methods for positioning ceramic cores in wax injection moulds for turbine engine blades lack precision when the core consists of multiple disjoint elements, leading to potential defects in blade wall thickness and internal cavity positioning, which can reduce the service life of the blades due to high temperature exposure.
Innovation Solution
A wax injection mould assembly that includes a core with a main element and secondary elements, where the secondary elements are held together by rod portions housed in slots of the main element, allowing for longitudinal thermal expansion and maintaining accuracy without modifying the functional parts of the core, using non-functional parts for clamping and expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If static support means (rods with fulcrums) are used to position the core in the injection mould, then the core positioning precision is improved, but the device complexity increases and the relative positioning of multiple core elements becomes difficult to maintain
Solution Approach 1:
The core is divided into multiple independent elements (main element and secondary elements) that can be assembled together. Each element has simplified positioning features (slots and rods) that enable precise relative positioning without complex support structures. The segmentation allows the core to be manufactured separately and assembled in the mould with maintained precision.
Solution Approach 2:
The rod portions housed in slots act as intermediary positioning elements between the main core element and secondary elements. These intermediaries enable precise relative positioning of multiple core elements without requiring complex direct support structures, reducing overall device complexity while maintaining positioning accuracy.
2Manufacturing precision
If the core elements are rigidly fixed together, then the positioning accuracy is improved, but the thermal expansion during high temperature casting process causes deformations
Solution Approach 1:
The connection between core elements allows for thermal expansion by permitting relative movement during temperature changes. The rod-in-slot mechanism maintains precise positioning at operating temperature while accommodating dimensional changes during heating, resolving the conflict between positioning accuracy and thermal stability.
Solution Approach 2:
The core element connection transitions from a static rigid fix to a dynamic system that adapts to thermal conditions. The rod portions can move within the slots during thermal expansion, allowing the core structure to dynamically adjust to temperature changes while maintaining functional integrity.
3Manufacturing precision
If the functional parts of the core are modified for clamping, then the positioning accuracy is improved, but the functional integrity of the core is compromised
Solution Approach 1:
The core elements are segmented into functional parts (that define blade geometry) and non-functional parts (that provide positioning features). The clamping rods are housed in slots formed in the non-functional parts, separating the positioning function from the functional geometry-defining parts and preserving their integrity.
Solution Approach 2:
The positioning and clamping functionality is extracted from the functional parts of the core and placed in dedicated non-functional parts (slots in the main element). This extraction allows precise positioning through rod-slot mechanisms without modifying the functional surfaces that define the final blade geometry.
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 solution enhances the precision and accuracy of blade production by allowing for thermal expansion and maintaining the core's functional integrity, reducing deformations and the need for modifying the core's functional parts, thereby improving the service life of turbine engine blades.
Implementation Method 1
the relative positioning as well as the maintenance of the various core elements must be made accurately without impacting the wax model which, it should be recalled, will form after casting the blade
Data Source
AI summary
An assembly for manufacturing a wax moulding of a turbine engine blade has a wax injection mould in which a core is able to be mounted in a predetermined moulding position, the core including a main element and at least a first secondary element each including at least one functional part and a non-functional part, wherein the non-functional part of the first secondary element includes a rod portion extending in a longitudinal direction of the blade and housed in a first slot of the non-functional part of the main member, the mould including a first internal boss clamping said rod portion at the bottom of the first slot.