Arc Start Control for Welding Wire Torque Feedback
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Solution Overview
Problem
Existing arc start control methods in consumable electrode arc welding face challenges in preventing re-short circuits due to the removal of pressing force, leading to arc start performance issues, especially when insulating materials are adhered to the welding wire.
Innovation Solution
The method involves retracting the welding wire when the wire feed motor's torque value exceeds a reference torque value during the short circuit determination, thereby relaxing the tensed welding wire or lowering the lifted torch, preventing re-short circuits and ensuring a good arc start.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the welding wire is retracted immediately after short circuit to generate initial arc, then arc start is achieved, but re-short circuit occurs due to removal of pressing force when insulating material is present
Solution Approach 1:
The patent applies preliminary action by detecting the presence of insulating material before arc initiation and pre-relaxing the welding wire tension or lowering the torch in advance. This prevents the sudden re-short circuit that would occur if the wire were retracted immediately, as the pressing force is gradually removed rather than abruptly eliminated, allowing reliable arc start even with insulating materials present.
Solution Approach 2:
The patent employs feedback by continuously monitoring the torque value of the wire feed motor during the short circuit period. When the torque exceeds a predetermined threshold indicating insulating material presence, the system responds by controlling the wire retraction speed or torch lowering speed to maintain contact until torque decreases. This closed-loop feedback ensures arc initiation reliability while preventing re-short circuit hazards.
2Reliability
If the welding wire maintains contact with the base material during short circuit, then electrical connection is achieved, but pressing force causes wire deformation or torch lifting
Solution Approach 1:
The patent applies preliminary action by detecting insulating material presence through torque monitoring before significant wire deformation or torch lifting occurs. Once detected, the system pre-adjusts the wire feed speed or torch position to distribute the pressing force more evenly, preventing the wire from becoming excessively deformed or the torch from lifting, while maintaining reliable electrical connection for arc initiation.
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 re-short circuits and improves arc start performance by maintaining contact until the feed torque drops, ensuring a stable arc initiation even with insulating materials present.
Implementation Method 1
the welding power source PS outputs a welding voltage Vw and a welding current Iw to generate an arc
Data Source
Figure 1
Figure 2(A)~2(I)
Figure 3(A)~3(I)
AI summary
An arc start control method is comprised of step 1 for starting advance of a welding wire, step 2 for determining that a distal end of a welding wire contacts a base material and short circuit is caused, step 3 for proceeding to step 4 if a feed torque value is a reference torque value or greater at the time of determination of short circuit, and proceeding to step 5 if the feed torque value is smaller than the reference torque value, step 4 for starting retracting the welding wire and separating the distal end of the welding wire from the base material without generating an arc and returning to step 1, step 5 for starting retracting the welding wire and separating the distal end of the welding wire from the base material and generating an initial arc between the welding wire and the base material, step 6 for continuing retracting the welding wire while maintaining the initial arc to elongate an arc length, and step 7 for stopping retracting the welding wire and starting advance of the welding wire to change a state of the arc from the initial arc to a steady arc.