Arc Welding Wire Feed Reversal for Stable Current Cycles
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Solution Overview
Problem
Arc welding techniques face challenges in maintaining a constant cycle of welding current due to short-circuits between the welding wire and the base material, leading to non-uniformity and potential deterioration in bead appearance.
Innovation Solution
An arc welding method and device that detect short-circuits and adjust the feeding speed of the welding wire from a positive to a negative feeding speed, allowing the welding current to alternate between reverse and positive polarity periods, thereby maintaining a consistent cycle and preventing non-uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If AC pulse arc welding is performed by alternately repeating reverse polarity period and positive polarity period, then welding quality is improved, but the cycle of welding current becomes non-uniform when short-circuit occurs
Solution Approach 1:
The controller detects a short-circuit between the welding wire and the base material in advance and changes the feeding speed before the short-circuit time can disrupt the welding current cycle. By performing the feeding speed change proactively upon detecting the short-circuit, the system prevents the short-circuit time from being added to the welding current cycle, thereby maintaining cycle uniformity and preventing bead appearance deterioration.
2Device complexity
If welding wire feeding speed is maintained constant, then welding process is simple, but short-circuit time is added to welding current cycle causing non-uniformity
Solution Approach 1:
The feeding speed of the welding wire is dynamically adjusted based on the welding state. The controller changes the feeding speed from a first feeding speed to a second feeding speed when a short-circuit is detected, making the feeding speed variable rather than constant. This dynamic adjustment prevents short-circuit time from disrupting the welding current cycle uniformity.
Solution Approach 2:
The controller continuously monitors the welding state by detecting short-circuits between the welding wire and the base material. Based on this feedback, the controller automatically adjusts the feeding speed to maintain welding current cycle uniformity. The feeding speed is changed in response to the detected short-circuit condition, creating a closed-loop control system that maintains precision without excessive complexity.
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 prevents non-uniformity in the welding current cycle, ensuring consistent bead quality by reducing the short-circuit time and promoting the opening of short-circuits, thus stabilizing the welding process.
Implementation Method 1
a welding current is caused to flow through the welding wire and the base material to alternately repeat a reverse polarity period in which the welding wire serves as a positive electrode and the base material serves as a negative electrode, and a positive polarity period in which the welding wire serves as the negative electrode and the base material serves as the positive electrode, and thus generating an arc between the welding wire and the base material to weld the base material
Data Source
AI summary
In arc welding in which a welding wire serving as a consumable electrode is fed toward a base material and a welding current is caused to flow through the welding wire and the base material to alternately repeat a reverse polarity period and a positive polarity period, after a short circuit between the welding wire and the base material is detected, a feeding speed of the welding wire is changed from a first feeding speed to a second feeding speed on a negative side of the first feeding speed when a speed in a direction toward the base material is defined as positive.