Refractory Metal Core Lamination for Complex Casting Shapes

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Solution Overview

Problem

Current production methods for refractory metal cores are limited by the availability of only certain thicknesses of molybdenum sheets in monolithic flat forms and unreliable shape variability when forming non-flat patterns, making it difficult to use highly non-flat cores in casting processes.

Innovation Solution

A process of forming a laminate structure by stacking refractory metal cores during a powder bed coating process, where additional powder bed material is deposited and fused over the cores, allowing for the creation of thicker, more complex shapes, including three-dimensional forms, and enabling the production of solid and cancellous RMCs with varying cross-sections and intersecting cores without additional forming steps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If refractory metal cores are formed by rolling and bending monolithic sheets, then the manufacturing process is simple, but the shape variability is unreliable and highly non-flat cores cannot be produced

Engineering Contradiction:
Improveshape consistencyVSAvoidforming process complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The refractory metal core is divided into multiple laminated sheets that are stacked together. Each sheet can be independently formed with consistent flat patterns, and the stacking process enables complex three-dimensional shapes without requiring unreliable bending operations on monolithic sheets.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from two-dimensional flat pattern forming through bending to three-dimensional shape creation through stacking multiple layers. This dimensional approach allows complex geometries to be achieved by combining multiple flat sheets rather than attempting to form them from a single monolithic sheet.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If only certain thicknesses of molybdenum sheets are used from suppliers, then the material availability is ensured, but the customization of core thickness is limited

Engineering Contradiction:
Improvethickness customizationVSAvoidmaterial availability
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

Instead of relying on suppliers to provide monolithic sheets in all desired thicknesses, the invention segments the thickness requirement into multiple standard-thickness sheets that are stacked together. This allows customization of total thickness by varying the number of layers while using readily available standard sheet thicknesses.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The laminated sheet structure serves multiple functions: it provides the required thickness customization, ensures material availability by using standard sheet thicknesses, and enables complex shape formation through the stacking process.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Shape

If monolithic flat forms are used, then the material supply is reliable, but complex three-dimensional shapes cannot be achieved

Engineering Contradiction:
Improvegeometric complexityVSAvoidforming process reliability
Core Design Contradiction:
ShapeVSEase of manufacture

Solution Approach 1:

The complex three-dimensional shape is achieved by segmenting the core into multiple laminated sheets that are stacked together. Each sheet maintains a reliable flat pattern form, while the stacking arrangement creates the desired geometric complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention achieves geometric complexity by adding the stacking dimension to the traditional flat pattern approach. Multiple flat sheets are arranged in layers to create three-dimensional shapes, transforming the manufacturing approach from two-dimensional forming to three-dimensional assembly.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 the production of refractory metal core laminate assemblies with customized thicknesses and shapes not achievable through traditional methods, enhancing the usability of refractory metal cores in casting processes by providing more sturdy and complex structures.

Implementation Method 1

depositing additional powder bed material over the at least one additional refractory metal core second side and exterior surfaces; and fusing the powder bed material and the additional powder bed material

Methodology Applied
Scientific EffectPowder bed fusion: Selective Laser Sintering

Data Source

PatentEP3527302B1Construction of multi-layered refractory metal core for investment casting
Publication Date: 2021.05.26 RTX CORP
  • EP3527302B1 patent drawingFigure 1
  • EP3527302B1 patent drawingFigure 2~3

AI summary

A refractory metal core laminate assembly, comprising: a first refractory metal core (64) having exterior surfaces (66) and a first side (68) and a second side (70) opposite the first side (68); a second refractory metal core (72) having exterior surfaces (74) and a first side (76) and a second side (78) opposite the first side (76), the second refractory metal core (72) being arranged above the first refractory metal core (64) with the second refractory metal core first side (76) facing the first refractory metal core second side (70); a layer (82) of a powder bed material (80) between the first refractory metal core second side (70) and the second refractory metal core first side (76); and a coating (92) of the powder bed material (80) coupled to the first refractory metal core exterior surfaces (66) and the second refractory metal core exterior surfaces (74).