Plasma Arc Torch Gas Channel for Low-Spatter Thick-Plate Piercing

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Solution Overview

Problem

Conventional plasma cutting systems face challenges in minimizing molten puddles and top spatter during piercing of thick workpieces, which limits the ability to cut small holes of acceptable quality due to excessive top spatter exceeding the hole diameter.

Innovation Solution

A plasma arc torch system that utilizes a nozzle body, shield cap, and a gas flow channel to direct a pressurized gas flow, known as molten metal clearing gas, to blow molten material away from the pierce hole, accompanied by an additive like anti-spatter liquid to prevent sticking, reducing pierce time and spatter size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional plasma arc torch is used to pierce thick workpieces, then piercing operation can be completed, but excessive top spatter is generated making it difficult to cut small holes of acceptable quality

Engineering Contradiction:
Improvehole qualityVSAvoidtop spatter
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent extracts the harmful molten material from the piercing zone by introducing a dedicated molten metal clearing gas flow through the sleeve and gas flow channel. This separate extraction system removes spatter-generating molten material before it can solidify as top spatter, thereby improving hole quality without requiring larger clearance zones.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an intermediary molten metal clearing gas flow that acts as a mediator between the plasma arc and the workpiece surface. This intermediary gas flow carries anti-spatter liquid to the piercing zone and simultaneously removes molten material, preventing direct contact between molten material and the workpiece upper surface that would cause top spatter.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If conventional plasma arc torch pierces thick workpieces, then piercing can be achieved, but pierce time is excessive reducing productivity

Engineering Contradiction:
Improvepierce timeVSAvoidpiercing duration
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-heating and pre-conditioning the piercing zone with the molten metal clearing gas flow before the actual piercing occurs. The anti-spatter liquid is delivered in advance to the workpiece surface, and the gas flow channel is pre-positioned to immediately clear molten material as soon as piercing begins, thereby reducing overall pierce time.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent maintains continuous useful action by keeping the molten metal clearing gas flow active throughout the entire piercing process. The gas flow continuously removes molten material and delivers anti-spatter liquid without interruption, ensuring that the piercing operation proceeds efficiently without pauses or delays for spatter management.

Inventive Principle:
Principle #20Continuity of useful action

3Manufacturing precision

If molten metal clearing gas flow is applied during piercing, then top spatter is minimized and hole quality improves, but device complexity increases due to additional components

Engineering Contradiction:
Improvehole qualityVSAvoidtorch structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies multi-functionality by designing the sleeve to serve multiple purposes: it provides structural support for the torch, guides the plasma arc, and simultaneously channels the molten metal clearing gas flow to the piercing zone. The gas flow channel is integrated into existing torch components rather than adding completely separate structures, thereby reducing overall device complexity while achieving spatter minimization.

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

Solution Approach 2:

The patent merges the molten metal clearing gas delivery system with the existing torch structure by integrating the gas flow channel into the sleeve and insulator components. This consolidation combines multiple functions (structural support, arc guidance, and spatter clearance) into unified components, avoiding the need for entirely separate complex subsystems.

Inventive Principle:
Principle #5Merging (Combining)

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 system achieves a 30% reduction in pierce time and minimizes top spatter to less than twice the material thickness, allowing for 1:1 hole diameters and smaller holes to be cut with acceptable quality, as the molten metal clearing gas and additive effectively manage molten material during piercing.

Implementation Method 1

A sleeve is located radially outward from the outer retaining cap and is configured to receive a flow of pressurized gas

Methodology Applied
Scientific EffectPressurized gas flow: Pressure Gradient

Implementation Method 2

plasma arc torch for cutting workpieces using a plasma arc

Methodology Applied
Scientific EffectPlasma arc: Electric Arc

Data Source

PatentEP4017222A1Plasma arc torch and cutting system
Publication Date: 2022.06.22 LINCOLN GLOBAL INC
  • EP4017222A1 patent drawingFigure 1
  • EP4017222A1 patent drawingFigure 2
  • EP4017222A1 patent drawingFigure 3

AI summary

A plasma arc torch includes a nozzle body, a nozzle extending from the nozzle body, and a shield cap. An outer retaining cap is attached to the plasma arc torch and secures the shield cap to the plasma arc torch. A sleeve is located radially outward from the outer retaining cap and is configured to receive a flow of pressurized gas. An insulator is located between the outer retaining cap and the sleeve. At least one of the sleeve and the insulator forms a gas flow channel configured to direct a gas flow from the sleeve to a distal portion of the outer retaining cap.