Asymmetric Wire Feed Control for Arc Welding Bead Penetration
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Solution Overview
Problem
Conventional arc welding control methods that feed the welding wire in periodically alternating forward and backward directions result in a short circuit period that is 50% of the total cycle, leading to lower welding voltage, bead width, and penetration, making it difficult to achieve high-quality welds with large bead width and deep penetration.
Innovation Solution
The method involves controlling the welding wire feed speed to alternate between forward and backward directions at different velocity amplitudes, adjusting the ratio of short circuit and arc periods to 30:70, ensuring a higher welding voltage by reducing the velocity amplitude in the forward direction relative to the backward direction, thereby enhancing bead width and penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the welding wire is fed periodically alternating forward and backward directions at the same velocity amplitude, then the arc stability is improved and bead defects are reduced, but the welding voltage is lowered and bead penetration is insufficient
Solution Approach 1:
The patent applies asymmetry by setting different velocity amplitudes for forward and backward wire feeding directions. The backward feeding velocity amplitude is set to be larger than the forward feeding velocity amplitude, creating an asymmetric feeding pattern that increases the arc period proportion to 70% of the total cycle. This asymmetric control maintains arc stability while increasing welding voltage and bead penetration depth to match conventional short-circuit welding levels.
2Manufacturing precision
If the welding wire is fed periodically alternating forward and backward directions, then bead defects and poor penetration are reduced, but the bead width and penetration depth are smaller compared to general short-circuit welding
Solution Approach 1:
The patent uses asymmetric velocity amplitude control where backward feeding velocity exceeds forward feeding velocity. This creates a longer arc period (70% of cycle) compared to short circuit period (30% of cycle), allowing sufficient time for arc heating to achieve adequate bead width and penetration depth while maintaining the quality benefits of periodic feeding control.
3Reliability
If the welding wire is fed periodically alternating forward and backward directions, then arc stability is improved, but the welding productivity is reduced due to increased short circuit period proportion
Solution Approach 1:
The asymmetric velocity control optimizes the balance between stability and productivity by setting backward feeding velocity amplitude larger than forward feeding velocity amplitude. This creates a 70:30 ratio of arc period to short circuit period, maximizing arc time for productive welding while maintaining sufficient short circuit frequency for droplet detachment and arc stability.
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 provides a high welding voltage, resulting in a larger bead width and deeper penetration, comparable to general short-circuit welding, while stabilizing arcs and reducing defects, achieving welding performance similar to constant wire feed short-circuit welding.
Implementation Method 1
consumable electrode arc welding in which short-circuit welding is performed by alternating short-circuits and arcs
Implementation Method 2
the arc welding device first outputs an initial short-circuit current for a predetermined time, next outputs a first increase slope di/dt of the short-circuit current as the welding current I
Data Source
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AI summary
Disclosed is a consumable electrode arc welding in which short-circuit welding is performed by alternating short-circuits and arcs while a welding wire is fed automatically. In this method, a short-circuit state and an arc state are alternately generated by feeding the welding wire in periodically alternating forward and backward directions at a predetermined frequency and a predetermined velocity amplitude with reference to a basic wire feed speed based on a set current. The speed of periodic feeding of the welding wire is controlled in such a manner that the waveform to feed the welding wire is different between the forward and backward directions.