The Xiris Blog

Monitoring Tube and Pipe Production to Find SCARFING Defects

Posted by Cornelius Sawatzky on Tuesday, June 17, 2014 @ 12:53 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 Scarf defects.

 

The Scarfing Width

In certain situations on ERW/HF tube and pipe production lines, there is not enough space to perform the Non Destructive Inspection (NDI) measurements right after the weld box because the scarf tool (used to remove excessive bead from the tube) is placed directly after the weld box.  In such situations, the measurement process must be made after the scarfing tool, measuring the flat area of the tube where the scarf has occurred. On some production lines, this measurement is essential to identify the shape and profile of the tube, and to understand how it is travelling through its forming process.

Known as the scarf width, this measurement is defined as the length of the “flat” portion of the tube that appears after the weld bead has been removed by scarfing.  Scarf width measurement changes quickly during production, so it is best averaged over a number of inspections in order to make the measurement stable.

 June 17.14 Blog Scarfing resized 600

The Scarf Width, where “w” = the width of the defect.

How the WI2000p System Measures the Scarf Width

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 freeze line defect 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 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 And by measuring the outside contour of a weld, 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: quality control, weld camera, weld inspection, Laser welding, image processing, High Dynamic Range, Tube and Pipe welding, laser-based monitoring, Pipe Cladding, welding defect, scarfing

Monitoring Tube and Pipe Production to Find FREEZE LINE Defects

Posted by Cornelius Sawatzky on Tuesday, June 03, 2014 @ 03:09 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 ERW Tube manufacturing:  Freeze Line defects in the weld bead. 

 

The Freeze Line Defect

Particularly in Electric Resistance Welding (ERW) or High Frequency (HF) welding processes, incomplete heating of the faces of the parent material can sometimes occur, resulting in a potentially cold-welded joint, which manifests itself as a line or seam extending from the top surface of a weld down into the welded area, in the shape of a sharp valley. Such a defect could indicate major metallurgical or structural problems in a weld, such as cold welding or improper forming.  It can very often be a point of a major failure of a weld in high-stress applications because the freeze line acts as a crack initiator into the welded material.  The Freeze Line becomes a concern to weld operators when it goes below the surface of the parent material of the tube because once the weld bead has been removed through grinding or scarfing, there is a risk that a void of non-welded material could be left behind.

The freeze line is measured from the lowest point of any contour in the weld bead to the surface of the parent material as defined by the ideal circle scribed by the walls of material beyond the weld zone.  If the freeze line goes below a pre-defined height, then it is considered a defect.

June 3.14 Blog Freeze Line resized 600

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

 

How the WI2000p System Measures the Freeze Line 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 freeze line defect 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 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 And by measuring the outside contour of a weld, 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: quality control, weld camera, weld inspection, Laser welding, image processing, High Dynamic Range, Tube and Pipe welding, laser-based monitoring, Pipe Cladding, welding defect, freeze line

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

Monitoring Tube and Pipe Production to Find FORMING Defects

Posted by Cornelius Sawatzky on Tuesday, April 29, 2014 @ 01:19 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 Forming Defects, otherwise known as Deflection. 

 

The Deflection Defect

Defection is defined as the overall variance of the tube parent material from an ideal circle.  This defect moves the starting point of all other defects that the Xiris WI2000p measures, up or down. The deflection measurement detects the overall deflection from the ideal circle to the closest tube side within the bead area. The deflection metric is determined by measuring the distance between the sections of the parent material outside of the weld bead width and the ideal profile line. The deflection usually represents the overall offset of the tube walls before welding and is indicative of forming set up or variances in the parent material’s metallurgy.

The drawing below illustrates the defect:

 

 April 29.14 Blog Forming Defect resized 600

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


How the WI2000p System Measures the Deflection 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 tube deflection 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 Deflection 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 Deflection 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 Deflection 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.

 

Resource Library

More source and videos of tube and pipe weld monitoring available at our online library!

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, forming

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