The Xiris Blog

Monitoring Tube and Pipe Production to Find BEAD HEIGHT Defects

Posted by Cornelius Sawatzky on Tuesday, April 08, 2014 @ 11:01 AM

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: Tube Bead Height Defects. 

 

The Bead Height Defect (Raised or Sunken Welds)

The material in the bead area may rise on top of the tube parent material surface (known as a “raised weld”) or drop below it (known as a “sunken weld”), depending on the compression force applied, the metallurgy of the material and the welding process parameters.

A sunken weld defect is a visibly significant and quality critical defect that could create weakness in the tube along the bead.  While a raised weld defect may not be considered as an important a defect (as it can be ground off later), it can indicate quality problems in the setup of the welding process.

The bead measurement is defined as the largest absolute value of a raised or sunken weld.  Calculating the bead metric in this way helps to determine the height of the tube material that needs to be ground off to smooth the profile (and restore the cylindrical shape, as required).  In cases where there exists a mismatch defect at the same time, the bead metric will include the mismatch measurement and will report the total loss of the material thickness after grinding.

April 08.14 Blog Bead Height resized 600

The Bead Height Defect, where “h” = the height of the defect.

 

How the WI2000p System Measures the Bead Height Defects

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 Bead Height defects 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 Bead Height profile defects that often escape detection by other quality tools such as Eddy Current testing, or Ultrasonic Testing techniques

 

Conclusion

A new technique for detecting Bead Height defects 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 Height defects 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 height

Monitoring Tube and Pipe Production to Find UNDERCUT Defects

Posted by Cornelius Sawatzky on Tuesday, March 18, 2014 @ 12:10 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 mainly in Laser and Plasma welded Tube manufacturing: Weld Bead Undercut. 

 

The Undercut Defect

The undercut defect is primarily a result of laser or plasma welding processes.  It may form if the laser beam or plasma arc is too far off center of the ideal welding zone of the tube material.  Undercut is actually a non-melted, non-welded area of the bead that can occur on one or both sides of the bead.  It looks and behaves like a crack along the bead, creating a very weak point on the tube cross-section.  Undercuts are detected as sharp, narrow negative drops in the actual profile (where at least one side of the undercut must have a high deflection derivative, or near vertical slope) that happen close to the edges of the bead.  The absolute value of the biggest negative drop found is reported as the height of the undercut.

Mar 18.14 Blog Undercut

The Undercut Defect, where “h” = the height of the defect.


How the WI2000p System Measures the Undercut Defect

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 Undercut 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 Undercut profile defects that often escape detection by other quality tools such as Eddy Current testing, or Ultrasonic Testing techniques

 

Conclusion

A new technique for detecting Undercut on laser or plasma 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 Undercut defects 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, undercut

Monitoring Tube and Pipe Production to Find MISMATCH Defects

Posted by Cornelius Sawatzky on Tuesday, March 04, 2014 @ 12:55 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: Tube Mismatch. 

 

The Mismatch Defect

The Mismatch defect is caused by uneven joining of two edges of the tube material strip before welding. Mismatch is a vital parameter to monitor for all tube and pipe fabricators, regardless of which side is higher. This is because many mills employ a grinder or scarfing process to remove any excess bead that is out of round.  However, if mismatch occurs prior to welding, once the tube bead has been removed, part of the wall on the high side of the mismatch may get removed as well, causing significant thinning of the tube wall or leave a step on the lower side after grinding the weld area.

Sometimes the actual welded tube wall thickness in the area of the bead becomes smaller than the original tube wall thickness. This is a result of processing steps other than material removal, such as corrugation or bending of the tube, which can create additional potential failures if a Mismatch defect is also present.

Mismatch is calculated as the absolute value of the radial difference between the two reference points where the weld bead meets the parent material. The mismatch calculation uses the current roll angle to compensate for the bead roll, as such:

 Blog 140304 students resized 600

 

The Mismatch Defect, where “h” = the height of the defect.

 

How the System Measures the Mismatch Defect

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 Mismatch 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 Mismatch profile defects that often escape detection by other quality tools such as Eddy Current testing, or Ultrasonic Testing techniques

 

Conclusion

A new technique for detecting Mismatch 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 system that is capable of detecting Mismatch defects 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

Using Weld Cameras to Monitor Pipe Cladding

Posted by Cameron Serles on Friday, December 27, 2013 @ 02:57 PM

New developments in electronics and sensor technology offer fabricators the ability to use specially designed Weld Cameras to monitor the Pipe or Pressure Vessel Cladding process with better clarity than ever before.  A better quality image of the cladding process can provide numerous productivity, quality, and health and safety benefits to the Fabricator. 

A Xiris Weld Camera Configured to Monitor a Pipe Cladding Process

A Xiris Weld Camera Configured to Monitor a Pipe Cladding Process

(Courtesy LJ Automation Ltd.)

While there are many applications where a Weld Camera is an important component of an automated welding process, Pipe or Pressure Vessel Cladding stands out as an application where a Weld Camera is essential.  Often performed in difficult or dangerous working conditions, the cladding process greatly benefits from an operator being able to remotely monitor the process using a Weld Camera.  The environment of the cladding process is often complicated by restricted operating sizes (such as small diameter pipe or pressure vessels), elevated working temperatures (that could reach as high as 700°F) and the need to not only see the definition of the welding arc, but also the detail, position and quality of the weld bead that is generated during the cladding process.

By using a Weld Camera that is equipped with High Dynamic Range capability, the operator can improve the time to setup the welding equipment because adjustments to the welding process can be done while the camera is live.  In the same manner, troubleshooting of the weld process can be done faster as small tweaks in welding parameters can be monitored immediately using a camera.

In certain high value Pressure Vessel applications where precise cladding is essential (e.g. power generation), the ability to record video of the welding process using a Weld Camera helps the fabricator to perform a quality audit and review of their processes

In some inner diameter pipe cladding applications, a Weld Camera is the only way to see the function of the components of the weld process, namely the Weld Tip condition and position relative to the seam, the previous clad layer, the spacing between solidification waves, shielding gas, filler wire and other parameters.  Being able to see all these parameters provides the main benefit of using a Weld Camera:  as an early indicator of defects in the welding process that would not be visible to the operator otherwise.

A Welded Bead Viewed from a Xiris Weld Camera

A Welded Bead Viewed from a Xiris Weld Camera

Conclusion

Using a Weld Camera for Pipe Cladding applications provides fabricators a faster way to setup and troubleshoot their cladding process, as well as maximizes the arc “On-Time” during welding and provides the ability to adjust the weld parameters “on the fly”.  With the ability to record video, the welding operators can also monitor the recorded video of the cladding process offline for quality audits.

For more information on how Xiris Weld Cameras can help monitor your weld processes, visit Xiris.com 

Sign up to receive our Weld Video of the Month 

Topics: remote monitoring, weld camera, High Dynamic Range, Pipe Cladding

Latest Posts

Follow Me