Laser Seam Position Control via Deviation Feedback
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Solution Overview
Problem
Current laser welding processes face challenges in maintaining precision and reliability due to disruptions such as mechanical damage, faulty clamping, thermal distortions, and sensor malfunctions, leading to deviations in seam position control that exceed tolerance ranges, necessitating manual inspection and potential defects in weld seams.
Innovation Solution
A method and apparatus for determining the precision of seam position control in laser welding by calculating deviations between the actual and estimated courses of the positioning device and joint, using a continuous mathematical function to assess and correct for errors, and generating parameters for acceptability, which includes determining mean and amplitude values, run-out, and hysteresis to classify workpieces for further testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If laser welding is performed on rotationally symmetrical workpieces with radial seams, then welding automation and productivity are improved, but seam position control precision deteriorates due to run-out, hysteresis, and mechanical disruptions
Solution Approach 1:
The patent implements a feedback mechanism where the actual position of the laser beam is continuously monitored during welding and compared with the nominal (planned) position. The deviation between actual and nominal positions is calculated and used to generate feedback signals that enable real-time correction of seam position control, compensating for run-out and hysteresis effects in automated welding of rotationally symmetrical workpieces
Solution Approach 2:
The patent replaces purely mechanical positioning methods with an optical-mechanical system. Instead of relying solely on mechanical precision of the positioning device, the system uses optical sensors to detect the actual laser beam position and joint location, converting mechanical position control into an optically-guided process that can compensate for mechanical imperfections like run-out and hysteresis
2Productivity
If threshold-based acceptability classification is used for seam position control, then productivity is improved by reducing manual inspection, but measurement precision requirements increase to accurately detect deviations
Solution Approach 1:
The patent changes the measurement parameters by not only detecting absolute positions but also calculating deviations from nominal positions, mean values, and amplitudes of positional variations. This multi-parameter approach enables more robust threshold-based classification that can distinguish between acceptable variations and actual defects, reducing false rejections and manual inspections while maintaining measurement precision
Data Source
AI summary
A course of a position of a positioning device is determined as a laser beam welds a workpiece at a focus area of the laser beam. The positioning device is configured to position the focus area of a laser beam on a workpiece such that a joint is formed on the workpiece. A course of the joint on the workpiece from the determined course of the position of the positioning device is estimated, and a deviation between the determined course of the position of the positioning device and the estimated course of the joint on the workpiece is calculated. The deviation represents a parameter related to the precision of the seam position control.