Investment Casting Pattern Assembly Using Thermofusible Segments

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Solution Overview

Problem

The traditional investment casting pattern manufacturing process is costly and time-consuming, especially for small series production, due to the complexity and expense of creating specific molds, and the long time gap between digital model definition and mold availability.

Innovation Solution

A process involving the assembly of removable model portions made from thermofusible materials around an insert, which are sealed together to form a pattern that can be used directly for investment casting, allowing for flexibility in manufacturing methods and reducing the need for complex molds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional injection molding is used to manufacture investment casting patterns, then manufacturing precision and reliability are improved, but device complexity and manufacturing cost increase significantly

Engineering Contradiction:
Improvepattern precisionVSAvoidmold complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The pattern is divided into multiple separable portions that can be manufactured independently and then assembled together. This segmentation eliminates the need for complex multi-cavity injection molds while maintaining pattern precision through controlled assembly of simpler components.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If traditional injection molding is used to manufacture investment casting patterns, then manufacturing precision is improved, but productivity decreases due to long lead times

Engineering Contradiction:
Improvepattern precisionVSAvoidproduction speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

Pattern portions are pre-manufactured using additive manufacturing or other rapid methods before final assembly. This preliminary production of components allows parallel processing and eliminates the sequential bottleneck of traditional mold manufacturing, significantly reducing lead time while maintaining precision through controlled assembly.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If traditional injection molding is used to manufacture investment casting patterns, then manufacturing precision is improved, but loss of time increases due to mold manufacturing lead time

Engineering Contradiction:
Improvepattern precisionVSAvoidtime from digital definition to mold availability
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The traditional mechanical injection molding system is replaced with additive manufacturing or other direct digital manufacturing methods for producing pattern portions. This substitution eliminates the need for physical mold fabrication, reducing the time from digital definition to pattern availability while maintaining sufficient precision through digital control of the additive process.

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

4Manufacturing precision

If traditional injection molding is used to manufacture investment casting patterns, then manufacturing precision is improved, but manufacturing cost increases for small series production

Engineering Contradiction:
Improvepattern precisionVSAvoidmanufacturing cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The pattern portions are manufactured using cost-effective additive manufacturing or rapid prototyping methods instead of expensive injection molding. These patterns are designed for limited use (small series production) and can be easily replaced, making the disposable nature acceptable while significantly reducing manufacturing cost through simpler, more flexible production methods.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 significantly reduces production costs and time by enabling faster and more flexible manufacturing of investment casting patterns, allowing for the use of simpler methods and materials, while maintaining the integrity of the casting process.

Implementation Method 1

the models melt and/or burn (with the exception of any insert(s))

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

the models melt and/or burn (with the exception of any insert(s))

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP3288699B1Method for producing a pattern for investment casting
Publication Date: 2023.08.02 SAFRAN AIRCRAFT ENGINES SAS
  • EP3288699B1 patent drawingFigure 1
  • EP3288699B1 patent drawingFigure 2
  • EP3288699B1 patent drawingFigure 3

AI summary

The invention relates to a method for producing a pattern for investment casting, according to which at least one insert (10) is provided; at least two portions (12, 14) of the pattern are provided, said at least two portions being made of an eliminable material; and said at least two pattern portions are assembled in a tight manner around at least part of said at least one insert so as to form said pattern (16).