AC Pulse Welding Waveform for Suppressing Droplet Scattering

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Solution Overview

Problem

Existing welding technologies face challenges in improving welding quality due to inefficiencies in current waveform control, particularly in transitioning between positive and negative electrode peak periods and base periods, leading to droplet scattering and inconsistent welds.

Innovation Solution

The welding apparatus employs an AC pulse control unit to alternately control the welding power source, transitioning from a positive electrode peak period to a negative electrode peak period through positive and negative electrode base periods, optimizing the base current output to suppress droplet scattering and enhance welding quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a simple AC pulse waveform is used for welding, then the device complexity is reduced, but droplet scattering occurs and welding quality deteriorates

Engineering Contradiction:
Improvewaveform control complexityVSAvoidwelding quality
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The AC pulse waveform is segmented into distinct periods: positive electrode peak period, positive electrode base period, negative electrode base period, and negative electrode peak period. Each period has specific current characteristics that work together to prevent droplet scattering while maintaining welding quality

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The welding current is applied in periodic cycles with alternating polarity, where each cycle includes peak current pulses for penetration and base current periods for stable arc maintenance. This periodic structure prevents droplet scattering by controlling the timing and magnitude of current application

Inventive Principle:
Principle #19Periodic action

2Manufacturing precision

If base current is output during transition between peak periods, then welding quality improves, but energy consumption increases

Engineering Contradiction:
Improvewelding qualityVSAvoidenergy consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

Base current is output in advance during the base periods before the peak current is applied. This preliminary action stabilizes the arc and prepares the welding zone, preventing droplet scattering and improving welding quality while using energy efficiently

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The current parameters are dynamically changed between peak periods by switching between base current and peak current. The base current provides lower energy input for arc stabilization, while peak current provides higher energy for penetration, optimizing energy consumption across the welding cycle

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 effectively improves welding quality by reducing droplet scattering and ensuring consistent welds by carefully managing the base current periods between peak periods, thereby enhancing the overall welding process.

Implementation Method 1

a welding power source that outputs current between a consumable electrode and a workpiece

Methodology Applied
Scientific EffectElectric arc: Electric Arc

Data Source

PatentEP3628430B1Welding apparatus and welding method
Publication Date: 2023.11.15 YASKAWA DENKI KK
  • EP3628430B1 patent drawingFigure 1
  • EP3628430B1 patent drawingFigure 2
  • EP3628430B1 patent drawingFigure 3

AI summary

To provide a welding apparatus effective for improving welding quality. A welding apparatus 10 includes a welding power source 20 that outputs current between a consumable electrode and a workpiece W, and an AC pulse control unit 111 that controls the welding power source 20 to alternately repeat a positive electrode peak period PI0 for outputting a peak current with the workpiece W as a positive electrode and a negative electrode peak period P20 for outputting a peak current with the workpiece W as a negative electrode with interposing a base period P30 for outputting a base current. The AC pulse control unit 111 controls the welding power source 20 to make a transition, after the positive electrode peak period P10, to the negative electrode peak period P20, through a positive electrode base period P31 for outputting a base current with the workpiece W as a positive electrode and a negative electrode base period P32 for outputting a base current with the workpiece W as a negative electrode in this order.