MIG Contact Tip Assembly With Insulated Wire Guide to Prevent Clogging

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Solution Overview

Problem

In metal inert gas welding (MIG-welding), the guidance channel often clogs due to spark erosion, leading to unstable electric arcs and deviations in metal wire positioning, which hampers the efficiency and accuracy of direct metal deposition in solid freeform fabrication.

Innovation Solution

The implementation of an electrically insulating guide channel with a separate electric contact tip assembly, where the metal wire is brought into contact with the contact tip after passing through the guide, ensuring a stable and insulated path for the wire, thereby preventing clogging and maintaining a consistent electric arc.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional guidance channel is used in MIG-welding, then the structure is simple and easy to manufacture, but the channel clogs due to spark erosion causing unstable arcs and wire positioning deviations

Engineering Contradiction:
Improvestability of electric arcVSAvoidstructure of guidance channel
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The guidance channel is divided into two separate functional components: an electrically insulating guidance channel that prevents spark erosion and guides the wire, and a separate contact tip assembly that provides electrical contact. This segmentation resolves the contradiction by allowing the guidance channel to focus on reliable wire guidance without electrical contact, eliminating clogging while maintaining structural simplicity through modular design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

An electrically insulating material is introduced as an intermediary between the metallic guidance channel and the electrically conductive metal wire. This intermediary layer prevents direct electrical contact that causes spark erosion and clogging, while still allowing mechanical guidance of the wire. The separate contact tip assembly acts as another intermediary to provide the necessary electrical contact at the deposition point.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the guidance channel is electrically conductive to maintain electric arc, then electric contact is ensured, but spark erosion causes clogging and wire positioning deviations

Engineering Contradiction:
Improveelectric contact stabilityVSAvoidwire positioning accuracy
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The system separates the electrical contact function from the wire guidance function. The electrically insulating guidance channel eliminates spark erosion and ensures precise wire positioning, while the separate contact tip assembly provides stable electrical contact at the deposition point. This segmentation resolves the contradiction by allowing each component to optimize its specific function without interfering with the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The electrical contact function is extracted from the guidance channel and placed in a separate contact tip assembly. This extraction eliminates the harmful spark erosion that occurs when the guidance channel is electrically conductive, while maintaining reliable electrical contact through the dedicated contact tip. The wire positioning accuracy is improved by the insulating channel, and electrical contact stability is maintained by the separate contact tip.

Inventive Principle:
Principle #2Taking out (Extraction)

3Manufacturing precision

If a separate contact tip assembly is added to prevent clogging, then deposition accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvedeposition boundary definitionVSAvoidcontact tip assembly structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The contact tip function is extracted as a separate, replaceable assembly from the guidance channel. This allows the guidance channel to remain simple and focused on wire positioning, while the contact tip assembly handles electrical contact and deposition. The extraction enables precise deposition boundaries through consistent electrical contact at the tip, while the modular design keeps overall device complexity manageable through standardization and ease of replacement.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The contact tip assembly is designed as a universal component that can be applied to various guidance channel configurations. The standardized contact tip design provides multi-functional capability: electrical contact, arc stabilization, and deposition control. This universality reduces overall device complexity by allowing the same contact tip design to work with different guidance channel types, rather than requiring custom integrated solutions.

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

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 solution significantly reduces clogging and enhances the throughput and yield of direct metal deposition, providing smooth, well-defined deposition boundaries and improved accuracy in forming metal objects.

Implementation Method 1

an electrically insulating lining (160) that is inside of the center bore (130) and that extends at least from the first end (140) to the second end (150) of the guide (120)

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Implementation Method 2

an electric contact unit (200) containing a contact tip (215) in electric contact with an electric energy source

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

a plasma arc to provide the heat for welding metallic materials

Methodology Applied
Scientific EffectPlasma arc heating: Plasma

Implementation Method 4

The plasma arc is usually protected by a gas being fed through the plasma torch forming a protective cover around the arc

Methodology Applied
Scientific EffectElectric arc: Electric Arc

Implementation Method 5

depositing successive deposits of a metallic material onto a base material

Methodology Applied
Scientific EffectMetal deposition: Deposition (physical)

Data Source

PatentEP3481580B1Association of a contact tip assembly for MIG metal welding and a PTA torch
Publication Date: 2021.11.24 NORSK TITANIUM AS
  • EP3481580B1 patent drawingFigure 1A~1B
  • EP3481580B1 patent drawingFigure 2
  • EP3481580B1 patent drawingFigure 3

AI summary

A contact tip assembly having an electric contact unit (200) containing a contact tip (215) with an electric energy source, where the electric contact unit (200) is positioned at a distance away from the outlet opening of a guide (120).