Contact Tube Wear Monitoring by Arc Conductance in Robot Welding
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Solution Overview
Problem
Existing methods for determining the wear of a contact tube during welding processes, such as MIG and MAG welding, are inadequate in providing accurate and timely information about the need for replacement, especially when maintaining constant arc length, leading to inconsistent welding quality and increased maintenance costs.
Innovation Solution
The method involves calculating the conductance or resistance by dividing the measured welding current by the welding voltage and comparing it to specified thresholds, allowing for reliable assessment of contact tube wear independent of arc length control variables, with warnings issued when thresholds are reached, enabling timely replacement and maintaining consistent welding quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If welding current and voltage are monitored separately, then monitoring simplicity is maintained, but wear detection accuracy deteriorates
Solution Approach 1:
The patent combines separate monitoring of welding current and voltage into a unified conductance-based wear detection system. By calculating the ratio of welding current to welding voltage (conductance), the system integrates two separate measurements into a single diagnostic parameter that accurately reflects contact tube wear, resolving the contradiction between monitoring simplicity and detection accuracy.
2Manufacturing precision
If arc length is maintained constant through parameter adjustment, then welding quality consistency is improved, but contact tube wear indication accuracy deteriorates
Solution Approach 1:
The patent introduces conductance (the ratio of welding current to welding voltage) as an intermediary parameter that decouples wear detection from arc length control. This intermediary measurement allows the system to maintain constant arc length through traditional parameter adjustments while simultaneously providing accurate wear indication through conductance monitoring, independent of the control variables used for arc length regulation.
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 more accurate and timely indication of contact tube wear, allowing for timely replacement and maintaining high-quality welding processes by using existing current and voltage measurements, reducing maintenance costs and ensuring consistent arc length.
Implementation Method 1
the contact tip feeds the welding wire towards the weld and transmits the welding current to form the arc
Implementation Method 2
the arc length, i.e., the distance between the end of the welding wire and the workpiece, changes
Implementation Method 3
the ratio of the welding current to the welding voltage is not directly the resistance or conductance of the arc
Data Source
Figure 1~2B
Figure 3~4
Figure 5
AI summary
The invention relates to a method for ascertaining the wear of a contact pipe (5) being welded to a workpiece (W) in a robot-supported manner using a welding torch (4) with a melting welding wire (6), wherein the welding current (I) is measured, and the wear of the contact pipe (5) is ascertained via the measured welding current (I). In order to improve the detection of the wear of the contact pipe (5), the measured welding current (I) is put into a ratio with a measured welding voltage (U), and the ratio of the welding current (I) to the welding voltage (U) is used to evaluate the wear of the contact pipe (5) and is compared with at least one ascertained threshold (SSi). A warning is output when at least one ascertained threshold (SSi) is reached.