Pulsed TIG Arc Ignition for Precise Weld Pool Energy Control

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Solution Overview

Problem

Non-consumable tungsten electrodes in TIG welding face ignition issues during breaks and require optimized energy input to maintain efficient welding, as they cool down and need reliable arc ignition with precise energy control to prevent excessive energy input.

Innovation Solution

A method and device that utilize a characteristic curve with adjustable parameters for welding cycles, including high-current and low-current phases, with high-frequency ignition pulses and current pulses to ensure reliable arc ignition and controlled energy input, allowing manual adjustment via a user interface for optimal welding conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the welding electrode is supplied with energy during welding, then the welding arc can be maintained and molten pool created, but excessive energy input may occur leading to poor weld quality

Engineering Contradiction:
Improvewelding arc ignition reliabilityVSAvoidenergy input control
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies periodic pulsed current instead of continuous current to the welding electrode. The control device switches the welding current in pulses, creating periodic action that allows the welding arc to be maintained reliably while controlling the average energy input to the workpiece. This pulsed operation enables precise energy management while ensuring consistent arc ignition and maintenance.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent implements dynamic control of welding parameters through a control device that adjusts current amplitude, pulse frequency, and duty cycle in real-time. This dynamic adjustment allows the system to adapt energy input levels to specific welding conditions, maintaining reliable arc ignition while preventing excessive energy accumulation in the workpiece.

Inventive Principle:
Principle #15Dynamics

2Use of energy by moving object

If intermittent welding is used to control energy input, then cooling occurs during breaks, but ignition problems arise when the electrode cools down

Engineering Contradiction:
Improveenergy input controlVSAvoidarc ignition reliability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent applies preliminary action by using high-frequency ignition pulses before the main welding current to initiate the arc. The control device generates these ignition pulses that precede the normal pulsed welding current, ensuring reliable arc ignition even after cooling periods in intermittent welding. This preliminary ignition action overcomes the ignition difficulties caused by electrode cooling.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If pulsed current is applied to control energy input, then molten pool formation is improved, but precise control of current amplitude and frequency is required increasing device complexity

Engineering Contradiction:
Improvemolten pool control precisionVSAvoidcontrol device complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements a multi-functional control device that integrates several functions: generating pulsed welding current, creating ignition pulses, adjusting current amplitude, controlling pulse frequency, and regulating duty cycle. By combining these functions into a single universal control device, the system achieves precise molten pool control without proportionally increasing overall device complexity.

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

Solution Approach 2:

The patent utilizes parameter changes by allowing dynamic adjustment of current amplitude, frequency, and duty cycle through the control device. These parameter variations enable precise control of molten pool formation and energy input. The control device can modify multiple parameters simultaneously or independently to optimize welding conditions for different applications.

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

This approach ensures reliable ignition and precise energy control during welding, improving the quality of the weld seam by adjusting parameters such as current amplitudes, pulse frequencies, and ignition pulses, allowing for flexible and efficient welding processes.

Implementation Method 1

a welding arc SLB is ignited between a non-consumable welding electrode 2 of the welding device 1 and the workpieces W and creates a molten pool there

Methodology Applied
Scientific EffectElectric arc: Electric Arc

Implementation Method 2

an electrical welding current I with a high current amplitude I HSP flows during the high-current welding phase HSP

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 3

additional current pulses SI are superimposed on the high current amplitude I HSP to generate oscillations in the weld pool

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4188630B1Method and device for welding workpieces including superimposed high frequency pulses
Publication Date: 2024.09.04 FRONIUS INT GMBH
  • EP4188630B1 patent drawingFigure 1
  • EP4188630B1 patent drawingFigure 2
  • EP4188630B1 patent drawingFigure 3

AI summary

The invention relates to a welding device (1) for welding workpieces (W) by means of a welding arc (SLB) which is ignited between a non-fusible welding electrode (2) of the welding device (1) and the workpieces (W) and creates a weld pool, wherein: workpieces (W) are welded in a welding process having a plurality of weld cycles (SZ), the parameters of which can be set via an interface (6) of the welding device (1); wherein each weld cycle (SZ) of the welding process has a high-current welding phase (HSP) during which a high welding current (I) flows, and a low-current welding phase (NSP) during which a low welding current (I) flows; wherein current pulses (SI) can be applied in the high-current welding phase (HSP) and/or in the low-current welding phase (NSP) of the weld cycle (SZ) when the relevant weld cycle (SZ) is correspondingly set; and high-frequency ignition pulses (ZI) can be applied at the start of the high-current welding phase (HSP) when the relevant weld cycle (SZ) is correspondingly set, in order to contactlessly ignite the welding arc (SLB).