Pulse Arc Welding Control Apparatus for Spatter Suppression
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Solution Overview
Problem
Existing arc length control techniques for pulse arc welding using carbon dioxide or CO2-based gas mixtures struggle to precisely manage variations in arc length caused by disturbances, leading to spatter generation and irregular droplet transfer, especially when the tip-to-base material distance changes during welding.
Innovation Solution
A welding control apparatus that generates two types of pulse waveforms within one cycle, a first pulse waveform for droplet release and a second pulse waveform for droplet shaping, using detected welding current and voltage values to adjust the base period and peak current of the second pulse waveform, ensuring precise arc length control and minimizing spatter generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single pulse waveform is used for droplet release in CO2-based pulse arc welding, then the welding process is simpler, but arc length control precision deteriorates leading to spatter generation and irregular droplet transfer
Solution Approach 1:
The single pulse waveform is segmented into two distinct pulse waveforms: a first pulse waveform with a first peak current value for droplet release, and a second pulse waveform with a second peak current value for maintaining arc length. This segmentation allows independent optimization of droplet release and arc length control functions, resolving the contradiction between simplicity and precision.
Solution Approach 2:
The pulse waveform parameters (peak current values, pulse widths, intervals) are made dynamically adjustable based on detected arc length variations. The control apparatus modifies the second peak current value and pulse interval in real-time to compensate for disturbances, enabling precise arc length control while maintaining operational simplicity through adaptive parameter adjustment.
2Adaptability or versatility
If the tip-to-base material distance changes during welding, then welding adaptability improves, but arc length stability deteriorates causing spatter and irregular droplet transfer
Solution Approach 1:
The control apparatus incorporates feedback mechanisms that continuously detect arc length based on welding voltage and current values. When tip-to-base material distance changes are detected, the system automatically adjusts the second peak current value and pulse interval to maintain stable arc length, enabling the welding process to adapt to position changes while preserving arc length stability.
3Productivity
If pulse interval is shortened to increase welding speed, then productivity improves, but droplet transfer regularity deteriorates
Solution Approach 1:
The pulse interval is made dynamically adjustable rather than fixed. The control apparatus optimizes the pulse interval based on droplet formation rate and arc length conditions, allowing shorter intervals for increased productivity while maintaining droplet transfer regularity through real-time parameter adaptation. The second pulse waveform timing is specifically optimized to ensure regular droplet transfer even at higher welding speeds.
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
The solution effectively suppresses arc length variations and spatter generation by using the higher correlation between instantaneous welding voltage and arc length in the second pulse period, maintaining regular droplet transfer even with changes in the tip-to-base material distance.
Implementation Method 1
In general pulse arc welding of consumed electrode type, a gas mixture of Ar-5 to 30% of CO2 is used as shield gas (MAG pulse welding)
Implementation Method 2
a higher welding current than a mean welding current is supplied during a peak period Tp to release (separate) a droplet of molten metal
Data Source
AI summary
A welding control apparatus includes an integrator for starting calculation of a voltage error integral value Sv2 when a first pulse period ends and a second pulse period starts in a pulse cycle, based on various data. The apparatus also includes a comparator for comparatively determining whether a value of the voltage error integral value Sv2 provided as the calculation result has become 0, and a waveform generator for terminating the relevant pulse cycle and starting a next pulse cycle when the value of the voltage error integral value Sv2 is 0. WhereSv2=∫{Ks(Io2−Is2)+Vs2−Vo2}dt (1).