TPT September 2023

TUBE MILLS & ROLLFORMING LINES

Camera-based seam monitoring to help prevent issues with TIG tube mills

MANY fabricators of metal tubes have chosen TIG welding as their welding process because it is a versatile, efficient process able to join most types of materials in a high-quality weld with clean edges and minimal weld bead. Like all welding processes, TIG welding relies on precise alignment of the welding torch to the welding seam to get a good weld and produce high quality tubes. The seam location can change over time as the various tensions in the tube can cause it to twist as it is pulled through the weld head. The twisting tube can mean that the weld seam can rotate in and out of position with respect to the TIG welding torch. The traditional solution to tracking the seam is an attempt to locate it using a mechanical feeler/wheel or a non-contact laser triangulation system. The problem with these is that they find the weld seam only and assume the measurement datum on which they are based is always in the same position. Such traditional measurement tools face challenges such as challenges using mechanical feeler/wheel: debris on or near the seam may cause a mechanical system that relies on physical contact with the seam edges to read incorrectly; if equipment gets knocked or the torch is moved, the seam position measured by the device will not be an accurate measurement relative to the torch tip. Challenges using non

Xiris SeamMonitor software detects the out-of-alignment condition

contact laser triangulation: typically mounted further upstream on a TIG mill so as to not measure the seam edge position close enough to the weld head; looks for edges of the seam by measuring a single point on each edge, which can lead to inconsistent data due to variable edge preparation. In comparison, a camera-based measurement tool, that can see the seam and the TIG torch tip in the same image, is able to measure the relative offset of the seam and its edges in a more robust manner. Should the camera be somehow knocked during production, it will still be able to see the weld seam position relative to the TIG torch tip, as long as both remain visible in the image. This approach allows multiple measurement points to be used to find the edges of a weld seam with a best-fit edge detection algorithm that removes any localised discrepancies. The resulting measurement is more precise and less prone to localised variations than other traditional measurement methods. Camera-based measurement tools like the Xiris SeamMonitor™ system have been developed to measure the seam alignment and weld seam width on TIG welded tube mills. Combining a High Dynamic Range (HDR) weld camera with sophisticated machine vision measurement software, SeamMonitor™ enables real-time monitoring of the weld seam size, the torch tip location, and the relative offset between the torch tip and its seam. Because it is a camera-based solution, the SeamMonitor™ can be used either as a standalone visual solution to provide image feedback to the operator, or it can be integrated with the mill’s controller for closed loop feedback control. Threshold warning and alarm limits of all the measured parameters can be set by the operator and the results can be output to an external device if required. All parameters and images can be recorded and exported for quality assurance of the tubes. SeamMonitor™ addresses one of the most pressing needs facing TIG tube fabricators: how to ensure that the seam being presented to the weld box is in the right position and prepared for a weld. By being able to see the TIG torch and weld seam, and detecting the alignment between the two, SeamMonitor™ can provide mill operators with objective, data-based tools that can precisely monitor the quality of the welding process.

ARRIVALs Landing at an exhibition near you…

EMO Hannover 18th-23rd September 2023 Hannover, Germany

Stand: Press Stand

Tube Southeast Asia 20th-22nd September 2023 Bangkok, Thailand

Stand: K15

MTM Expo 29th Nov - 1st Dec 2023 Shanghai, China

Stand: Press Stand

SteelFab 2024 8th-11th January 2024 Sharjah, United Arab Emirates

Stand: TBC

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Xiris Automation www.xiris.com

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SEPTEMBER 2023