The Xiris Blog

Monitoring Tube and Pipe Production to Find the TOE ANGLE

Posted by Cameron Serles on Tuesday, September 02, 2014 @ 04:30 PM

 Recent advancements in machine vision technology have made a new type of inspection, capable of finding defects related to the forming and welding area of a tube or pipe.  The result is improved quality assurance and process control on the production line.  The new inspection device is a laser-based triangulation system that measures the outside contour of a tube or pipe in the vicinity of its weld. 

Typically NDT (non-destructive testing) systems are placed at the end of a production as a final check.  However, the laser inspection system can be placed directly after the weld box.  This system can let operators know what is changing in their welding process, allowing them to perform corrective action before significant scrap occurs. This capacity is especially helpful for a closely monitored measurement on ERW/HFI production mills:  the Toe Angle.

The Bead Slop Angle

The Left and Right Bead Slope Angles are measured in degrees at either edge of the weld bead, and represent the angle subtended by a line that follows the contour of the weld bead on either side and a horizontal line.  Also referred to as the Toe Angle, it can indicate the strength of the weld, and the correct forming of the parent material during the creation of the weld, particularly on an ERW/HF process.  A forming problem could be detected because of a larger or smaller than normal slope angle.  It is important to measure both the left and right slope angles separately. This is because the forming of the parent material could be asymmetric on a pipe mill, causing the slope angles to be different on either side of the weld bead, and thereby indicating a forming problem.

als;kdgjdsa;lghfdag resized 600The Bead Slope Angle or Toe Angle, measured in degrees from the horizontal.

 

How the WI2000p System Measures the Bead Slope, or Toe Angle

Xiris Automation Inc. has developed a non-destructive inspection system called the WI2000p Weld Inspection System. The WI2000p includes a laser line, and a camera with an optical axis that is offset to the axis of the laser line by an “offset angle”.  The WI2000p creates a visible cross-section of the tube by projecting the laser line on to the tube, and capturing an image of the line using the camera.  The resulting image shows a profile of the tube surface as if it were cut in cross section.  If a tube is the ideal round, the laser image will represent a section of an ellipse and any anomaly such as the bead can be mathematically detected and the bead slope, measured. 

The WI2000p bases all of its measurements on the differences between the actual laser profile line (seen by the camera), and the ideal mathematical profile based on the tube parameters.  By knowing the position of the actual laser profile, the ideal profile, and the size of the pixels in the image, the WI2000p can detect weld bead profile defects that often escape detection by other quality tools such as Eddy Current testing, or Ultrasonic Testing techniques.

Conclusion

Overall, laser-based 3D imaging systems, such as the WI2000p from Xiris, offer an excellent measurement option for tube mill owners/operators who want additional, real-time monitoring of weld features. They can be used in a proactive manner, warning operators what is changing in their welding process so that they can perform corrective action before significant scrap occurs. Laser--based 3D imaging systems can operate on any type of material, regardless of its reflectance or magnetic properties, using a single head to perform the measurement.

Topics: camera placement, welding instruction, Tube and Pipe welding, bead height, bead roll

Monitoring Tube and Pipe Production to Detect BEAD ROLL

Posted by Cornelius Sawatzky on Tuesday, May 13, 2014 @ 02:29 PM

Recent advancements in machine vision technology have made a new type of inspection able to see defects related to the forming and welding area of a tube or pipe.  The result is improved quality assurance and process control on the production line.  The new type of inspection device is a laser-based triangulation system that measures the outside contour of a tube or pipe in the vicinity of its weld. 

Typically NDT systems are placed at the end of a production as a final check.  However, the laser inspection system can be placed directly after the weld box.  This system can let operators know what is changing in their welding process, allowing them to perform corrective action before significant scrap occurs. This capacity is especially helpful for one of the most common defects found across all types of Tube manufacturing:  excessive Bead Roll. 

 

The Bead Roll Measurement

The nature of some welding processes such as Laser Beam Welding (LBW) or GTAW (TIG) require that the weld bead remains within narrow range around the centerline of the tube to ensure the best quality weld.  Any small deviation from the centerline can cause a variety of welding defects mentioned earlier in this blog.  With such precision welding processes, the bead position cannot change even momentarily or a bad weld will result.  Bead roll could indicate setup problems in a mill where there are uneven forces on the tube that causes a gradual twisting.  Often, this is avoided by placing the weld box as close as possible to the forming rollers.  However, if a roll still exists in the tube beyond the weld box, the tube may be later rejected as downstream processes will not be able to process a twisted tube properly. In extreme cases, it could cause problems with bead removal later down the mill.

The Bead Roll angle is measured based on the midpoint between the left edge and right edge of the bead width.  The difference between the midpoint position and a vertical axis through the center of the tube defines the angle of the bead roll.  The actual angle also relies on using the ideal diameter of the parent material for calculation. 

May 13.14 Blog Bead roll resized 600 

The Bead Roll Measurement, where “θ” = the measured angle.

 

How the WI2000p System Measures the Bead Roll

Xiris Automation Inc. has developed a non-destructive inspection system called the WI2000p Weld Inspection System. The WI2000p  includes  a laser line and a camera whose optical axis is offset to the axis of the laser line by an “offset angle”.  The WI2000p creates a visible cross-section of the tube by projecting the laser line on to the tube and capturing an image of the line using the camera. The resulting image shows a  profile of the tube surface as if it were cut in cross section.  If a tube is ideally round, the laser image will represent a section of an ellipse and any anomaly such as a bead roll can be mathematically detected. 

The WI2000p bases all of its measurements on the differences between the actual laser profile line seen by the camera, and the ideal mathematical profile based on the tube parameters.  By knowing the position of the actual laser profile, the ideal profile, and the size of the pixels in the image, the WI2000p can detect subtle bead rolling that often escape detection by other quality tools such as Eddy Current testing, or Ultrasonic Testing techniques.

 

Conclusion

A new technique for detecting bead roll on welded Tube and Pipe has been developed by Xiris and is known as the WI2000p weld inspection system.  The WI2000p system is a laser based inspection system that is capable of detecting bead roll immediately after welding to alert the operator of a defect in time to minimize rejects.  The result is improved quality, fewer field defects and a more reliable method for the operator to optimize the welding process.

Topics: quality control, weld camera, weld inspection, Laser welding, image processing, High Dynamic Range, Tube and Pipe welding, laser-based monitoring, Pipe Cladding, welding defect, bead roll

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