3D Metal Wire Feed Duct Overpressure Against Oxidation

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Solution Overview

Problem

Three-dimensional printing using Laser Metal Deposition (LMD) faces challenges due to the introduction of external air into the enclosure, which pollutes the inert atmosphere and oxidizes molten metal layers, leading to contamination and reaction with the deposited material.

Innovation Solution

Incorporating means for injecting an inert gas into the metal wire guide duct to generate overpressure, preventing external air from entering the enclosure, using an inert gas supply conduit connected to the guide duct and oriented to block external air flow, with a flow rate of 2-6 bars to ensure an inert atmosphere within the enclosure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a guide duct is used to guide metal wire from outside the enclosure, then wire feeding is enabled, but external air enters the enclosure through the duct and oxidizes molten metal layers

Engineering Contradiction:
Improvewire feedingVSAvoidoxidation of molten metal
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

An inert gas is introduced as an intermediary substance into the guide duct to displace external air. The inert gas flows through the duct alongside the metal wire, creating a protective atmosphere that prevents oxidation of the molten metal while allowing continuous wire feeding through the enclosure wall.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The guide duct is transformed into an inert atmosphere environment by injecting inert gas (such as argon or nitrogen) through injection means. This creates a protective gas flow that fills the duct and prevents external air from contacting the molten metal, thereby eliminating oxidation while maintaining wire feedability.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

2Ease of operation

If the guide duct allows wire movement with annular clearance, then wire can travel to the distal end, but external air flows into the enclosure through the duct

Engineering Contradiction:
Improvewire movementVSAvoidatmosphere purity
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The solution uses pneumatic principles by injecting inert gas into the guide duct at controlled pressure. The gas flow is directed along the wire path, utilizing fluid dynamics to push air molecules away from the molten metal zone while accommodating wire movement through the annular clearance without compromising atmosphere purity.

Inventive Principle:
Principle #29Pneumatics and hydraulics

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

Prevents oxidation of molten metal layers by maintaining an inert atmosphere, reducing contamination and ensuring the quality of the printed parts by blocking oxygen-rich air from entering the enclosure, thereby protecting the deposited metal from reacting with external atmosphere components.

Implementation Method 1

The injection means are configured to inject the inert gas with a flow rate of between 2 and 6 bars. A flow of inert gas between 2 and 6 bars generates an overpressure and stops the movement of outside air in the metal wire guide duct.

Methodology Applied
Scientific EffectGas pressure: Pressure Increase

Data Source

PatentEP3741496B1Tridimensional printing device
Publication Date: 2022.03.30 SAFRAN AIRCRAFT ENGINES SAS
  • EP3741496B1 patent drawingFigure 1~2
  • EP3741496B1 patent drawingFigure 3~4

AI summary

The invention relates to an assembly of a three-dimensional printing device by metal deposition comprising a guide conduit (16b) for a metal wire (18) and opening into the interior of an enclosure under an inert atmosphere, where the device includes means for injecting (30) an inert gas into the guide conduit (38).