Concentric Shielding Gas Nozzle for Laminar Metal Printing Flow

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Solution Overview

Problem

Current printing heads in wire-based additive manufacturing face challenges in maintaining a stable laminar flow of shielding gas, leading to spatter buildup and poor material properties due to turbulent gas flow and inadequate gas coverage, which affects the continuous run time and quality of metallic parts.

Innovation Solution

The development of a printing nozzle with concentric fluid flow channels and diffuser holes that maintain a high-pressure shielding gas flow, ensuring a laminar gas flow around the feed material, reducing spatter buildup, and enhancing gas coverage by positioning the nozzle further back from the contact tip and using a secondary cup to increase gas flow velocity and coverage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional single-channel printing head is used, then the structure is simple, but the gas flow becomes turbulent leading to spatter buildup and poor material properties

Engineering Contradiction:
Improvematerial propertiesVSAvoidprinting head structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The printing head is divided into multiple functional channels: a central channel for feed material and concentric channels for shielding gas flow. This segmentation allows independent control of gas flow patterns, enabling laminar flow conditions that prevent spatter buildup while maintaining structural organization.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The printing head employs a nested channel configuration where inner channels for shielding gas are concentrically positioned within the outer structural housing. This nesting arrangement allows multiple gas flow paths to be integrated without increasing external dimensions, achieving complex flow control within a compact structure.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If the nozzle is positioned close to the contact tip, then gas coverage is limited, but positioning it further back increases gas coverage and reduces spatter buildup

Engineering Contradiction:
Improvegas coverageVSAvoidnozzle positioning
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

Instead of simply moving the nozzle further back along the axial direction, the invention introduces concentric radial channels that distribute shielding gas in a three-dimensional pattern around the feed material. This dimensional approach to gas distribution enhances coverage without requiring excessive axial distance from the contact tip.

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

3Reliability

If high gas flow velocity is used, then spatter buildup is reduced, but gas turbulence increases affecting material properties

Engineering Contradiction:
Improvespatter preventionVSAvoidgas flow stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The concentric channels are designed with varying cross-sectional areas and orientations to create localized flow characteristics. Inner channels provide high-velocity streams for spatter prevention, while outer channels deliver lower-velocity flow for stable shielding, achieving both spatter reduction and flow stability through spatially differentiated gas delivery.

Inventive Principle:
Principle #3Local quality

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 configuration improves the continuous run time by preventing spatter buildup, reducing cleaning time, and enhancing the quality of metallic parts by maintaining a stable laminar gas flow and increased gas coverage, thereby minimizing material defects and operational interruptions.

Implementation Method 1

a plurality of diffuser holes circumferentially disposed on the main cylindrical body wherein each of the plurality of diffuser holes connects the second fluid flow channel to an exterior surface of the main cylindrical body

Methodology Applied
Scientific EffectDiffusion: Diffusion

Implementation Method 2

produce concentric flows of shielding gas around a feed material... maintaining a stable laminar gas flow

Methodology Applied
Scientific EffectLaminar flow: Laminar Flow

Implementation Method 3

the second fluid flow channel is configured to maintain the second fluid at a pressure greater than or equal to a pressure of the first fluid... maintain a high-pressure shielding gas flow

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentEP4289540A1Printing heads
Publication Date: 2023.12.13 RELATIVITY SPACE INC
  • EP4289540A1 patent drawingFigure 1A~1B
  • EP4289540A1 patent drawingFigure 2A~2B
  • EP4289540A1 patent drawingFigure 2C~2D

AI summary

Many embodiments described herein are directed to a printing nozzle capable of producing a high-pressure flow of shielding gas that surrounds a lower pressure flow of shielding gas of the central channel. In certain embodiments, the high-pressure shield gas flow in the internal channels can blow out the material buildup in the nozzle. The high-pressure shielding gas can be concentrically produced around the first low-pressure shielding gas such that it helps to force the first shielding gas into a more laminar flow around the feed material. In several embodiments, a second low-pressure flow of shielding gas can be produced using a secondary cup to increase shielding gas coverage. In various embodiments, a secondary cup surrounds the inner cup, where the gas flow in the central channel and the outer channel can provide shielding gas coverage for the nozzle during printing.