Pulse Arc Welding Wire Feed Control for Spatter and Undercut
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Solution Overview
Problem
Conventional pulse arc welding methods face challenges in suppressing undercut and spattering during high-speed welding of mild steel, as they often result in insufficient molten metal at the edge of the weld pool and increased short-circuit current, leading to spatter generation.
Innovation Solution
A pulse arc welding device is controlled to maintain a constant arc length by varying the feeding speed of the welding wire between two speeds, one for the base current period and a higher speed for the peak current period, which helps in reducing spattering and undercut by ensuring stable molten droplet transfer and preventing short-circuiting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If welding voltage is lowered and arc length is shortened to suppress undercut, then undercut is reduced, but spattering increases due to high short-circuit current
Solution Approach 1:
The patent applies periodic pulse current with alternating peak and base current periods to control the welding process. During peak current periods, high current fills the weld pool; during base current periods, lower current allows controlled short-circuiting. This periodic action enables suppression of undercut while reducing spatter compared to continuous high current
Solution Approach 2:
The patent changes the current parameter dynamically by switching between peak current (higher value) and base current (lower value) periods. This parameter variation allows the system to achieve both undercut suppression and spatter reduction by timing the high current application to fill the weld pool before short-circuiting occurs
2Productivity
If welding speed is increased for high-speed welding, then productivity improves, but molten metal becomes insufficient at weld pool edge causing undercut
Solution Approach 1:
The periodic pulse current provides intervals of high current (peak periods) that deliver sufficient molten metal to the weld pool edge even at high welding speeds. The alternating pattern ensures continuous replenishment of molten metal, preventing undercut while maintaining high productivity
Solution Approach 2:
The peak current period acts as a preliminary action that pre-fills the weld pool with molten metal before the short-circuiting occurs during the base current period. This preliminary metal delivery ensures the weld pool edge remains adequately supplied even during high-speed welding
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 results in improved welding quality with reduced spattering and suppressed undercut, maintaining a stable arc length and molten pool size, thereby enhancing the appearance and integrity of the weld bead.
Implementation Method 1
generating an arc between the welding wire and the object by causing a welding current to flow through the welding wire
Implementation Method 2
causing a welding current to flow through the welding wire while feeding the welding wire to the object
Data Source
AI summary
A pulse arc welding device is controlled so as to alternately repeat a peak current period in which a welding current is a peak current and a base current period in which the welding current is a base current smaller than the peak current, feed a welding wire to an object at a feeding speed while the welding current flows through the welding wire, generate an arc between the welding wire and the object, and weld the object. So as to keep an arc length of the arc to be constant, in the base current period, the feeding speed is set to a first feeding speed and, in the peak current period, the feeding speed is set to a second feeding speed which is larger than the first feeding speed and corresponds to the first feeding speed. By this method, good welding quality with reduced spattering and suppressed undercut can be obtained.