Arc Welding Switch Timing for Stitch-to-Weaving Pulse Transitions

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Solution Overview

Problem

The stitch pulse welding method is not versatile enough for all types of workpieces, and switching between stitch pulse and non-stitch pulse welding processes can result in discontinuous bead shapes and welding failures due to improper timing of welding current application and weaving operations.

Innovation Solution

Modifying the switch timing from stitch pulse to non-stitch pulse welding based on whether the non-stitch pulse welding process includes a weaving operation, ensuring smooth transitions and maintaining bead shape continuity by adjusting the welding current steps accordingly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If stitch pulse welding process is used, then thermal influence on base material is suppressed and bead appearance is improved, but welding process versatility is reduced and cannot weld all types of workpieces

Engineering Contradiction:
Improvebead appearance qualityVSAvoidwelding process applicability
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The welding system dynamically switches between stitch pulse welding process and non-stitch pulse welding process based on workpiece requirements. The robot controller receives switching instructions and coordinates with the welding power source to transition between processes, enabling the system to adapt to different workpiece types while maintaining bead appearance quality when needed

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The welding system is designed to perform multiple welding processes (stitch pulse and non-stitch pulse) through a unified control architecture. The robot controller and welding power source can execute either process type depending on the workpiece characteristics, making the system universal and applicable to various welding scenarios

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

2Adaptability or versatility

If switching between stitch pulse and non-stitch pulse welding processes is performed, then welding process versatility is improved, but bead shape continuity is impaired and welding failures occur due to improper switching timing

Engineering Contradiction:
Improvewelding process flexibilityVSAvoidwelding quality consistency
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The robot controller receives switching instructions in advance and performs preliminary coordination with the welding power source before actual process switching occurs. The controller prepares the switching sequence by considering the current welding state and determines the optimal switching timing to maintain bead shape continuity

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from the welding state to determine switching timing. The robot controller monitors the welding process and coordinates with the welding power source to switch processes at appropriate moments, preventing welding failures and maintaining quality consistency

Inventive Principle:
Principle #23Feedback

3Strength

If non-stitch pulse welding process is used, then welding strength is sufficient, but thermal influence on base material increases and bead appearance deteriorates

Engineering Contradiction:
Improvewelding joint strengthVSAvoidbead appearance quality
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The welding system dynamically selects between non-stitch pulse welding process (for strength) and stitch pulse welding process (for appearance quality) based on the specific requirements of different workpiece sections. The robot controller coordinates switching between processes to optimize both strength and appearance where needed

Inventive Principle:
Principle #15Dynamics

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 seamless switching between welding processes without impairing bead appearance or causing welding failures, ensuring consistent bead shape and strength across different welding conditions.

Implementation Method 1

a welding power source that applies a welding current to the welding torch

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

an arc welding system... a welding power source that applies a welding current to the welding torch... generates an arc discharge between an electrode of the welding torch and the welding base material

Methodology Applied
Scientific EffectElectric arc: Electric Arc

Data Source

PatentEP3769891B1Arc welding method, arc welding system, and control device for welding power supply device
Publication Date: 2024.08.21 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP3769891B1 patent drawingFigure 1
  • EP3769891B1 patent drawingFigure 2(a)~2(b)
  • EP3769891B1 patent drawingFigure 3

AI summary

Disclosed is an arc welding method including: implementing a stitch pulse welding process; and implementing a non-stitch pulse welding process, wherein upon switching from the stitch pulse welding process to the non-stitch pulse welding process, a switch timing from the stitch pulse welding process to the non-stitch pulse welding process is modified based upon whether the non-stitch pulse welding process is implemented with or without a weaving operation of a welding torch. The stitch pulse welding process includes a welding-current starting step, a welding-current applying step, a welding-current ending step, and a welding-current suspending step, which are repeatedly carried out in series, and the switch timing is modified according to the step that is carried out at the time when a switch request for switching the stitch pulse welding process to the non-stitch pulse welding process with the weaving operation is made.