Movable Arc Welding Gap Control for Dissimilar Workpieces

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Solution Overview

Problem

Existing welding devices are limited in their ability to effectively weld workpieces with different melting behaviors, materials, and wall thicknesses, often requiring post-annealing processes and struggling with uneven heating and gravitational influences on the melt.

Innovation Solution

A welding technique that allows for controlled adjustment of the axial distance between workpieces during heating, enabling targeted influence of the heating and melting process, and coordinated control of welding current and arc movement to manage droplet formation and melting behavior, particularly useful for vertical or inclined orientations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the axial distance between workpieces is kept constant during heating, then the welding process is simpler to control, but the heating uniformity deteriorates and droplet formation cannot be prevented

Engineering Contradiction:
Improvecontrol simplicityVSAvoidheating uniformity
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent applies dynamics by making the axial distance between workpieces variable rather than fixed. The distance is dynamically adjusted during the heating process based on real-time monitoring of heating uniformity and droplet formation, allowing the system to adapt to changing thermal conditions and material behavior.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements feedback control by monitoring the heating process and using this information to adjust the axial distance between workpieces. Sensors detect temperature distribution and droplet formation, and this feedback is used to modulate the gap distance to maintain optimal heating conditions.

Inventive Principle:
Principle #23Feedback

2Manufacturing precision

If the axial distance between workpieces is varied during heating, then the heating uniformity and droplet control improve, but the device complexity increases

Engineering Contradiction:
Improveheating uniformityVSAvoidcontrol system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent uses an intermediary control system that coordinates the relationship between heating parameters and axial distance. This intermediary layer processes sensor data and translates it into appropriate distance adjustments, simplifying the overall control architecture while achieving precise heating uniformity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If workpieces are welded in horizontal orientation, then the equipment design is simpler, but gravitational influence on molten metal causes uneven distribution

Engineering Contradiction:
Improveequipment designVSAvoidmolten metal distribution
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent applies dynamics by enabling the workpiece orientation to be variable rather than fixed in horizontal position. The system can dynamically adjust the orientation angle to optimize molten metal distribution while maintaining reasonable equipment complexity through modular design.

Inventive Principle:
Principle #15Dynamics

4Ease of operation

If fixed current and gap settings are used, then the welding process is easier to operate, but only uniform workpieces with identical melting behavior can be welded

Engineering Contradiction:
Improveprocess simplicityVSAvoidworkpiece compatibility
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent makes both the welding current and gap distance dynamic parameters that can be adjusted in real-time based on workpiece characteristics. This allows the system to adapt to different materials, wall thicknesses, and geometries while maintaining ease of operation through automated control.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by varying the welding current and gap distance according to the specific workpiece being welded. The system automatically adjusts these parameters based on detected workpiece properties, enabling versatile welding of dissimilar materials and geometries.

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

Enables reliable and high-quality welding of dissimilar workpieces, reducing the need for post-annealing and improving evenness of heating, thus enhancing the versatility and cost-effectiveness of the welding process.

Implementation Method 1

the arc is ignited, which then heats and melts the end faces of the workpieces

Methodology Applied
Scientific EffectElectric arc: Electric Arc

Implementation Method 2

a magnetically moved arc

Methodology Applied
Scientific EffectMagnetic movement of arc: Magnetic Field

Data Source

PatentEP2296840B1Welding device and welding method having movable arc
Publication Date: 2023.01.18 KUKA IND
  • EP2296840B1 patent drawingFigure 1
  • EP2296840B1 patent drawingFigure 2
  • EP2296840B1 patent drawingFigure 3

AI summary

The invention relates to a welding device (1) for welding workpieces (3, 4) having a movable arc (8), wherein the welding device (1) comprises a controlled welding current source (25) having a current controller (27) and a positioning and compressing device (15) for the workpieces (3, 4), said device holding the workpieces (3, 4) at a distance (s) during heating and then compressing them. The welding device (1) comprises a device (28) for determining and analyzing process parameters, particularly the arc voltage, and a device for correspondingly controlling and changing (?s) the distance (s) between the workpieces (3, 4) during heating. The welding device (1) can further comprise a driving device (21) for moving the arc (8), designed as a controllable magnet device having one or more inner and/or outer coils (22, 23) for electromagnetically moving the arc (S). The invention further relates to a method for welding workpieces (3, 4) having a movable arc (8), wherein the workpieces (3, 4) have a controlled welding current applied thereto by welding device (1) having a controlled welding current source (25), and are held at a distance (s) during warming and then compressed by a positioning and compressing device (15). Using the device (28), the arc voltage particularly can be determined and analyzed, wherein the distance (s) between the workpieces (3, 4) is correspondingly controlled and changed (?s) by a device (16) during warming. Depending on the process parameter or parameters determined, the welding current and/or the distance (s) can be controlled during heating. Electrically conductive, particularly metal, workpieces (3, 4) made of different, particularly differently melting, materials can be welded.