Multi-Passage Hollow Casting via Integrated Ceramic Slurry

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Solution Overview

Problem

Current methods for casting high-temperature metals like iron, nickel, and cobalt are inefficient and costly due to the need for separate ceramic cores, which significantly increase manufacturing time and lead to complex internal passages being difficult to fill, especially when passages are small or narrow.

Innovation Solution

A method involving a mixture of ceramic powder and self-setting binder is used to create a solid mold around sacrificial patterns, which can be poured into small spaces, hardened, and then chemically or thermally treated to create porosity, allowing for the casting of high-temperature metals without cores, using techniques like agitation, vibration, or vacuum to ensure filling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If separate ceramic cores are made and inserted into the component pattern during injection, then complex internal passages can be formed, but manufacturing lead time and cost significantly increase

Engineering Contradiction:
Improvecomplex internal passages formationVSAvoidmanufacturing lead time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent merges the core material and mold material into a single integrated ceramic structure. The slurry contains both refractory ceramic particles and core-forming particles that are poured simultaneously to create both the mold walls and internal passages in one operation, eliminating the need for separate core making and insertion steps.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent performs preliminary action by pre-forming the core structure within the slurry mixture before pouring. The core-forming particles are pre-mixed with the binder and refractory particles, so when the slurry is poured, the core structure is already prepared and positioned correctly within the mold cavity.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If separate ceramic cores are made and inserted into the component pattern during injection, then complex internal passages can be formed, but manufacturing cost significantly increases

Engineering Contradiction:
Improvecomplex internal passages formationVSAvoidmanufacturing cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent merges the core material and mold material into a single integrated ceramic structure. The slurry contains both refractory ceramic particles and core-forming particles that are poured simultaneously to create both the mold walls and internal passages in one operation, eliminating the need for separate core making and insertion steps.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The slurry mixture serves multiple functions simultaneously: it forms the mold walls, creates internal passages, and eliminates the need for separate core tooling. The same material mixture performs what previously required multiple different materials and processes.

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

3Manufacturing precision

If conventional investment casting sequential dip layer processes are used, then hollow passages can be cast, but the process is time-consuming and costly

Engineering Contradiction:
Improvehollow passages castingVSAvoidcasting efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent performs preliminary action by pre-forming the core structure within the slurry mixture before pouring. The core-forming particles are pre-mixed with the binder and refractory particles, so when the slurry is poured, the core structure is already prepared and positioned correctly within the mold cavity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent skips the time-consuming sequential dipping and drying steps of conventional investment casting. By using a pourable slurry that sets chemically, the process rushes through multiple stages in one operation, eliminating repetitive cycles of dipping, drying, and repeating.

Inventive Principle:
Principle #21Skipping (Rushing through)

4Strength

If a fluid mold material like gypsum is poured into intricate passages, then sufficient strength can be formed, but this material cannot be used for high temperature castings

Engineering Contradiction:
Improvemold strengthVSAvoidtemperature resistance
Core Design Contradiction:
StrengthVSTemperature

Solution Approach 1:

The patent uses a composite material system combining refractory ceramic particles for heat resistance, core-forming particles for structural strength, and a chemical binder for cohesion. This composite slurry simultaneously achieves the fluidity needed to fill intricate passages and the temperature resistance required for high-temperature metal castings.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the material parameters by using a chemical binder system that allows the slurry to remain fluid during pouring but then set and harden after placement. This parameter change from fluid to solid state occurs after the material has already filled the intricate passages, allowing both fluidity and strength to be achieved at different stages.

Inventive Principle:
Principle #35Parameter changes

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 method enables the rapid and cost-effective production of complex high-temperature castings with internal passages by eliminating the need for core tooling, reducing processing time from multiple days to a single day and lowering production costs.

Implementation Method 1

a self-setting binder is used to create a solid mold

Methodology Applied
Scientific EffectChemical setting: Chemical Bonding

Implementation Method 2

using a second thermal treatment to subsequently remove the pattern from the mold

Methodology Applied
Scientific EffectThermal decomposition: Pyrolysis

Implementation Method 3

At least one of the third thermal treatment and the chemical treatment may remove about 10% or less of the binder from the solid mold

Methodology Applied
Scientific EffectThermal treatment: Heat Treatment

Implementation Method 4

At least one of the third thermal treatment and the chemical treatment may remove about 30% or more of the binder from the solid mold

Methodology Applied
Scientific EffectChemical treatment: Chemical Bonding

Implementation Method 5

filling the cavity in the mold with molten metal

Methodology Applied
Scientific EffectGravitational flow: Gravitation

Data Source

PatentEP3586993B1Production of multi-passage hollow casting
Publication Date: 2022.09.21 RTX CORP
  • EP3586993B1 patent drawingFigure 1~2
  • EP3586993B1 patent drawingFigure 3~4
  • EP3586993B1 patent drawingFigure 5~6

AI summary

A method of fabricating a casting is provided. The method includes creating a mixture (10) of ceramic powder and a binder, pouring the mixture around sacrificial patterns (20), executing a first thermal treatment to set the mixture into a solid mold (30) without damaging the sacrificial patterns, executing a second thermal treatment to remove the sacrificial patterns without removing any of the binder from the solid mold, executing at least one of a third thermal treatment and a chemical treatment to remove a quantity of the binder to transform the solid mold into a solid breakaway mold (50) and pouring molten metallic material into the solid breakaway mold.