Conductive Particle Coating for Plasma Tool Mechanical Joints

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Solution Overview

Problem

Existing mechanical connections in plasma processing tools, such as those used in TIG and plasma cutting, face issues with precise thermal and electrical conductivity, leading to quality losses and wear-related damage, particularly due to the inhomogeneous application and release of conductive pastes.

Innovation Solution

A mechanically connectable component and holding element with a surface coating of electrically and thermally conductive particles, such as graphite or carbon nanotubes, which adhere without a binder, providing improved conductivity and simplifying interchangeability by forming a secure, easily releasable connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conductive paste is applied to improve thermal and electrical conductivity, then conductivity is enhanced, but precise dosing and homogeneous application cannot be achieved leading to quality losses

Engineering Contradiction:
Improveconductivity consistencyVSAvoidpaste application precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the physical state of the conductive material from a paste (viscous liquid) to particles (solid), which can be applied as a dry coating. This parameter change enables precise dosing and homogeneous application through controlled particle deposition, eliminating the dosing and application precision problems associated with paste application while maintaining thermal and electrical conductivity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical application method of conductive paste (which requires manual or automated spreading tools) with a particle-based coating system. The particles are applied as a dry suspension or aerosol, allowing for more precise and controlled deposition. This substitution eliminates the need for paste spreading mechanisms and enables better dosing precision and surface coverage uniformity.

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

2Temperature

If conductive paste is applied to ensure thermal conductivity, then heat transfer is improved, but inhomogeneous distribution leads to local welding (galling)

Engineering Contradiction:
Improvethermal conductivityVSAvoidconnection stability
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent changes the conductive material from paste to particles, which can be distributed more uniformly across the connection surface. The particle-based coating achieves homogeneous thermal conductivity distribution, preventing local hot spots and inhomogeneous heating that cause galling and local welding. The particles conform to surface irregularities and provide consistent thermal contact across the entire interface.

Inventive Principle:
Principle #35Parameter changes

3Strength

If mechanical connection areas are designed to be complementary for secure connection, then connection strength is improved, but replacement of wearing parts becomes problematic

Engineering Contradiction:
Improveconnection strengthVSAvoidcomponent replaceability
Core Design Contradiction:
StrengthVSEase of repair

Solution Approach 1:

The patent applies a particle-based coating that can be easily applied and removed, allowing the connection components to be segmented into replaceable parts. The coating on wearing parts can be reapplied after replacement, maintaining connection strength while enabling easy component interchange. This contrasts with permanent bonding methods that would prevent replacement.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent enables easy replacement of wearing parts by using a coating system that does not permanently bond components. The particle-based coating can be applied to new parts and provides sufficient connection strength, allowing worn components to be discarded and replaced without damaging the mating components. The coating itself can be recovered or reapplied as needed.

Inventive Principle:
Principle #34Discarding and recovering

4Reliability

If conductive paste is used to achieve electrical conductivity, then electrical connection is improved, but paste release during operation contaminates workpiece surface

Engineering Contradiction:
Improveelectrical conductivityVSAvoidpaste release contamination
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the conductive material from paste (which can release and migrate) to particles that form a stable, fixed coating. The particle-based coating does not release during operation, eliminating contamination of the workpiece surface. The particles are mechanically interlocked or chemically bonded to the surface, providing stable electrical conductivity without the release problems of paste.

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

The solution ensures consistent thermal and electrical conductivity, preventing 'seizing' and allowing for easy replacement of wearing parts without the drawbacks of conductive pastes, maintaining performance and reducing maintenance costs.

Implementation Method 1

the particles are electrically and thermally conductive

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

the particles are electrically and thermally conductive

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

the particles are held to the surface by adhesive forces without the need for an organic or inorganic binder

Methodology Applied
Scientific EffectAdhesive forces: Adhesive

Data Source

PatentEP3573780B1Component or retaining element which is usable for the plasma processing of workpieces and method for producing a mechanical connection between a component and a retaining element
Publication Date: 2024.12.25 KJELLBERG STIFTUNG
  • EP3573780B1 patent drawingFigure 1

AI summary

In a component or retaining element which is usable for the plasma processing or the thermal processing of workpieces using an electric arc, on a component that is mechanically connectable by way of a retaining element in a region formed in a complementary manner, the surface of a component or of a retaining element is provided, in the region formed in a complementary manner, only with a coating formed with particles. The particles are electrically and thermally conductive. The coating can be formed with a purely organic chemical compound which is formed with fluorine, or the coating can be formed with a polyamide.