Welding Control Method for Arc Length Stabilization

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional welding control methods take a long time to stabilize arc length due to external influences such as workpiece displacement and operator error, leading to unstable arcs and increased defects like irregular short circuits and spatters.

Innovation Solution

A welding control method that shifts output characteristics in parallel to quickly adjust welding voltage and current, actively stabilizing the arc length by changing the target welding voltage and current based on deviations from the initial settings, allowing for early recovery to the proper arc length.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If conventional self-regulation control is used, then arc length stability is achieved, but stabilization time is excessively long

Engineering Contradiction:
Improvearc length stabilityVSAvoidstabilization time
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The control method performs preliminary detection of arc length deviation from the set value and proactively adjusts welding parameters before the arc length fully deviates. By detecting the deviation trend early and adjusting the wire feed speed or welding current in advance, the system prevents large arc length variations rather than merely responding to them, thereby achieving faster stabilization.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention implements a closed-loop feedback control system that continuously monitors the actual arc length (or arc voltage as a proxy) and compares it with the set arc length. Based on the detected deviation, the system dynamically adjusts the wire feed speed or welding current to correct the arc length, enabling rapid convergence to the target value and significantly reducing stabilization time compared to conventional open-loop self-regulation.

Inventive Principle:
Principle #23Feedback

2Stability of the object's composition

If pulse frequency is changed to stabilize arc, then arc stability improves, but response speed to external influences decreases

Engineering Contradiction:
Improvearc stabilityVSAvoidresponse speed
Core Design Contradiction:
Stability of the object's compositionVSSpeed

Solution Approach 1:

The invention expands the controllable parameter space beyond pulse frequency to include wire feed speed and welding current. By utilizing these additional parameters, the system can achieve arc stabilization through multiple control pathways, allowing for faster response to external disturbances without being constrained by the slower dynamics of pulse frequency adjustment.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If base current or peak current is adjusted to correct large voltage changes, then arc length stabilization is achieved, but spatters and irregular short circuits increase

Engineering Contradiction:
Improvearc length stabilizationVSAvoidspatters and irregular short circuits
Core Design Contradiction:
Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The invention introduces wire feed speed as an additional control parameter alongside base current and peak current. By distributing the correction burden across multiple parameters, the system can achieve arc length stabilization with more moderate adjustments to each individual parameter, avoiding excessive current changes that cause spatters and irregular short circuits.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The control system dynamically determines the optimal combination of parameter adjustments based on real-time arc conditions. This dynamic control strategy allows the system to select the most appropriate control approach for each situation, minimizing harmful effects while achieving stabilization.

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

This method enables rapid stabilization of the arc length, reducing irregular short circuits and spatters, thereby improving productivity and product quality by allowing for stable droplet transfer and consistent weld beads.

Implementation Method 1

arc welding in which an arc is generated between a welding wire as a consumable electrode and a base material as a material to be welded

Methodology Applied
Scientific EffectElectric arc: Electric Arc

Implementation Method 2

when a wire is fed at a constant speed by using a welding power-supply device having a constant voltage characteristic

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP2338627B1Method of controlling welding
Publication Date: 2018.02.14 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP2338627B1 patent drawingFigure 1~2
  • EP2338627B1 patent drawingFigure 3~4
  • EP2338627B1 patent drawingFigure 5

AI summary

A welding control method for a welding device having an output characteristic with a predetermined gradient showing a relation between a welding output voltage and a welding output current. By setting a set target welding voltage that is higher than the set initial welding voltage according to a difference between the set initial welding voltage and the welding output voltage, the welding output voltage is controlled to be the set target welding voltage. Thus, a proper arc length can be achieved early by correcting the change of the arc length due to, for example, motion of the hands of a welding operator.