DLP Ceramic Core-Shell Molds for Turbine Blade Cooling

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Solution Overview

Problem

Conventional methods for manufacturing integrated core-shell molds lack the fine resolution capability to produce sufficiently small filaments between the core and shell for intricate cooling hole patterns in cast components, such as turbine blades, limiting the complexity and precision of internal geometries that can be achieved.

Innovation Solution

The use of direct light processing (DLP) to manufacture ceramic core-shell molds, which allows for the production of thin filaments spanning the core and shell without separate support structures, enabling the creation of fine cooling hole patterns and complex geometries by exposing the entire length of the filament between the window and build plate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional powder bed or selective laser activation processes are used to manufacture ceramic core-shell molds, then the manufacturing process is relatively simple and well-established, but the resolution capability is insufficient to produce sufficiently small filaments for intricate cooling hole patterns

Engineering Contradiction:
Improveresolution capability to produce small filamentsVSAvoidcomplexity of manufacturing process
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces conventional mechanical powder bed or selective laser activation processes with direct light processing (DLP) technology. The DLP system uses a digital light processor to project patterns of light that cure liquid photopolymer resin layer by layer, enabling precise fabrication of thin filaments with diameters down to 50 micrometers. This optical-based approach substitutes the mechanical limitations of traditional methods with optical precision, allowing intricate cooling hole patterns to be formed without increasing overall process complexity

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the key processing parameter from laser scanning or powder layer deposition to digital light projection with controlled exposure. By adjusting the light exposure parameters, layer thickness, and curing time, the system achieves superior resolution for filament fabrication. The ability to control the light intensity and exposure duration allows precise formation of thin filaments spanning the core and shell, directly addressing the resolution limitation of conventional methods

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If thin filaments are produced without separate support structures, then the manufacturing process is simplified and production time is reduced, but the structural stability during manufacturing becomes more challenging

Engineering Contradiction:
Improvesimplification of manufacturing processVSAvoidstructural stability of thin filaments
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies preliminary support during the DLP manufacturing process by maintaining the thin filaments in a partially cured state with adequate mechanical support from the surrounding uncured resin and build platform. As each layer is cured, the filament gains progressive structural integrity. Once the filament is fully cured and achieves sufficient self-support, the temporary support structures are removed. This preliminary support approach allows thin filaments to be manufactured without requiring permanent support structures, simplifying the overall process while ensuring structural stability during fabrication

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent utilizes the phase transition of the photopolymer resin from liquid to solid through light-induced curing. During manufacturing, the resin transitions from a fluid state that can support thin filaments to a solid state that provides self-support. This phase transition mechanism allows the filaments to be formed and stabilized without separate support structures, as the surrounding resin provides temporary support during the transition and the cured structure provides permanent stability

Inventive Principle:
Principle #36Phase transitions

3Manufacturing precision

If the entire length of the filament is exposed between the window and build plate, then fine cooling hole patterns can be created, but the risk of filament deformation or breakage increases

Engineering Contradiction:
Improveprecision of cooling hole patternsVSAvoidstructural integrity of filaments
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The patent employs periodic action by curing the thin filaments in incremental layers rather than exposing the entire length at once. The DLP system cures each layer sequentially, allowing the filament to gradually build structural integrity from the base upward. This staged curing process prevents thermal and mechanical stress concentration that would occur with full-length simultaneous exposure, thereby maintaining filament strength while achieving precise cooling hole patterns through the cumulative effect of multiple controlled exposure cycles

Inventive Principle:
Principle #19Periodic action

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

DLP enables the production of ceramic molds with precise, small-diameter filaments and cooling holes, enhancing the resolution and complexity of internal geometries in cast components, such as turbine blades, beyond the limitations of traditional powder bed and selective laser activation processes.

Implementation Method 1

A method for direct light processing (DLP) of a photopolymerizable material to prepare an integrated core-shell mold

Methodology Applied
Scientific EffectPhotopolymerisation: Photopolymerisation

Data Source

PatentEP3554743B1An integrated core-shell casting mould and filter and method of manufacturing the same
Publication Date: 2022.04.27 GENERAL ELECTRIC CO
  • EP3554743B1 patent drawingFigure 1
  • EP3554743B1 patent drawingFigure 2A
  • EP3554743B1 patent drawingFigure 2B

AI summary

The present disclosure generally relates to integrated core-shell investment casting molds that provide an integrated ceramic filter. These integrated core-shell investment casting molds also provide filament structures corresponding to cooling hole patterns on the surface of the turbine blade or stator vane, which provide a leaching pathway for the core portion after metal casting. The invention also relates to core filaments that can be used to supplement the leaching pathway, for example in a core tip portion of the mold.