Welding Torch Seam Detection for Accurate Robot Arc Welding
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Solution Overview
Problem
Existing automated arc welding processes face inaccuracies due to workpiece clamping device issues and tolerances, leading to deviations in the welding path followed by multi-axis robots, which affect the quality of weld seams.
Innovation Solution
A method where the welding torch with its welding wire is guided over the workpieces in detection travel steps, maintaining constant contact conditions, and detecting changes in the relative position of the welding wire tip to the arc welding torch, such as changes in length or rotational movements, to accurately determine the joining line between workpieces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If the welding torch is guided along a pre-programmed welding path, then the welding process can be automated, but inaccuracies arise due to workpiece clamping device issues and tolerances, affecting weld seam quality
Solution Approach 1:
The welding wire tip is used to perform preliminary detection of the actual joining line position before welding. The detection travel step determines the actual course of the joining line by detecting changes in relative axial position, allowing the system to pre-adjust the welding path to compensate for workpiece positioning inaccuracies and tolerances, thereby maintaining high weld seam quality in automated welding processes
Solution Approach 2:
The system uses the welding wire tip as a detection sensor that provides feedback about the actual joining line position. By detecting changes in the relative axial position of the welding wire tip during travel over the workpiece, the system obtains real-time information about deviations from the predetermined path and can adjust the welding trajectory accordingly to maintain manufacturing precision
2Measurement precision
If the welding wire tip is moved in a hammering motion to increase measurement accuracy, then detection precision improves, but additional time is required and the welding system productivity decreases
Solution Approach 1:
The welding wire tip maintains continuous contact with the workpiece surface during the detection travel step, moving smoothly from a starting point on one workpiece surface to the joining line without interrupting the detection process. This continuous action allows the system to determine the actual joining line position in a single pass, eliminating the need for repetitive hammering motions and multiple traversals, thereby maintaining high productivity while achieving accurate detection
Solution Approach 2:
The invention replaces the mechanical hammering motion with a more efficient detection mechanism. Instead of using impact-based measurement, the system detects changes in the relative axial position of the welding wire tip as it moves continuously over the workpiece surface. This substitution of the detection mechanism eliminates the time-consuming hammering motion while maintaining measurement precision
3Reliability
If the welding wire tip is guided over the workpiece surface with constant contact conditions, then the relative position change detection becomes more reliable, but the detection system complexity increases
Solution Approach 1:
The welding wire tip serves dual functions: it is both the welding tool and the detection sensor. By using the existing welding wire and its feed mechanism to detect changes in relative axial position, the system performs self-detection without requiring separate sensing equipment. This self-service approach maintains high detection reliability through constant contact conditions while avoiding the increased complexity that would result from adding dedicated sensors or detection systems
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 allows for precise determination of the weld seam path with high accuracy and minimal effort, reducing the need for repetitive path traversal and minimizing the risk of impeding the welding process, thereby enhancing the quality of weld seams.
Implementation Method 1
the welding wire is guided over the surface of at least one of the workpieces (2, 3) with constant contact conditions
Data Source
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AI summary
The invention aims to provide a method for determining a welding path to be followed by a welding robot, achieving high accuracy with comparatively little effort. This method involves determining a welding path to be followed by a multi-axis robot for a subsequent arc welding process using an arc welding device, in which a weld seam is to be produced between at least two workpieces along a joining line between the at least two workpieces. In at least one detection step, an arc welding torch provided for the subsequent execution of the arc welding process and guided by the multi-axis robot is automatically guided over at least one of the workpieces to determine information about the actual path of the joining line.that the welding torch with its welding wire is guided by the multi-axis robot in at least one detection step from a starting point on the surface of one of the workpieces to the joining line for the intended weld seam, at least substantially non-parallel to a target path of the joining line with - in particular with respect to the longitudinal axis of the welding wire - a consistently constant relative axial position of the welding wire tip to the arc welding torch across the surface of the workpiece, in order to infer a point on the joining line by detecting a change in the axial position of the welding wire tip to the arc welding torch.