The Xiris Blog

How Weld Inspection Helps Tube Producers Meet Weight Reduction for Automotive Sector

Posted by Emily Blackborow on Tuesday, May 14, 2019 @ 01:00 PM

The Automotive Sector is constantly trying to reduce the weight of cars. Part of that effort is to approach their suppliers to see what they can do to reduce the weight of their components. Fabricators of tubes for the automotive sector are constantly being asked to meet more difficult weight limitations of their tubes.   

In order to achieve the desired weight reduction of a tube, tube fabricators need to use:

  • Lighter materials;
  • Thinner Wall Thicknesses; and
  • Higher Yield strength materials.

These are only possible if tighter manufacturing specifications and process tolerances are established.

Tubes fabricated from higher yield strength material are more susceptible to mismatch during fabrication. Traditionally; fabricators used a common practice of allowing mismatch on a longitudinal welded tubes of up to 5% of the wall thickness. 5% becomes a very small number very quickly when wall thickness is reduced. 

Experience has shown that for higher yield strength materials a mismatch of 5% will result in a higher weld split failure. In these applications tube producers need to maintain a mismatch tolerance in the 2% to 3% range, well below common practice on milder materials. These tight tolerances make it difficult for mill operators to see or detect using traditional means of looking at the scarf material, the finger nail scratch without stopping the mill interrupting production.

High resolution geometrical measurements are required in the weld zone making this an ideal application for laser based technologies such as Xiris’ Weld Inspection Solutions. The WI2000 or WI3000 makes continuous measurements providing the operator with a clear visual of the weld zone form process while also being able to set tolerance limits to alarm when an unexpected variation occurs.

WI2000 SystemWI2000

WI3000 System

 WI3000

Better Images. Better Decisions. Better Process Control.

Follow Xiris on social media for regular updates and welding videos!

Instagram LinkedIn FacebookTwitter

Topics: quality control, weld inspection, High Dynamic Range, pipe, tube, HDR, weld seam, tubedefects, consistent, WI-2000, inspection system, WI-3000

Color or Not? Five Questions to Consider When Choosing a Weld Camera

Posted by Cameron Serles on Thursday, May 02, 2019 @ 11:00 AM

Welding is not a very colorful operation. The metal, torch and other materials are usually varying shades of grey. The arc is bright white. The background is almost black. To accurately monitor and inspect welds, being able to see a massive tonal range, from the brightest to the darkest, is essential.

 Color and Monochrome images of a TIG Welding Proces

Standard cameras, and even the human eye, are incapable of distinguishing all features when faced with such a range of brightness. However, Xiris’ high dynamic range weld cameras can, either in color (the 1100 and 1100e) or black and white (the 1000 and 1000e).
As humans, we often think that color is better. But in weld cameras, that is not always the case. Determining whether a color or monochrome weld camera will work best depends on a company’s operations. Here are five questions to consider when choosing between color and monochrome weld camera:


1. What kind of welding process are you using?
TIG (GTAW) or Plasma welding benefit most from being viewed in color, simply because there is more color present in those welding processes. Evaluating the color of the torch tip, shielding gas, melt pool and even the Heat Affected Zone can help operators to assess the quality of the weld.

2. What do you want to monitor during welding?
For example, do you want to see certain features, such as the boundary between the end of the torch and the shielding gas and arc? That might help you closely monitor the integrity of the torch tip and avoid contamination.

Or, are you concerned about the amount or type of shielding gas in the process? The shielding gas can sometimes take on a unique color as it is consumed by the welding arc. Changes in the color can signify a change in the gas chemistry and alert operators to the possibility of impurities.

Or is the Heat Affected Zone (HAZ) of interest? The leading edge of the HAZ may become visible as the parent material colorizes at elevated temperatures. This can indicate the amount of heat penetration and energy transfer made during the welding process. Discoloration of the metal can signify the presence of excess heat.

3. Is color more important than resolution?
To generate a color image, the image sensor in the weld camera is “painted” with color filters. Each pixel becomes filtered with red, green or blue light in a standard pattern known as a Bayer pattern. The imaging software then mathematically recombines the pixels into a color image. One drawback of this process is that the resolution of a color image is decreased by approximately half compared to that of a monochrome image.

With higher resolution, monochrome cameras generate images with sharper detail than color cameras. In monochrome images, edges appear crisper and subtle details are more visible—important for assessing the texture of the melt pool, for example. However, the hues in a color image give the human eye the ability to better evaluate boundaries between various weld components, like the melt pool, torch tip and shielding gas.

4. Is camera speed important for your operation?
Despite being lower resolution, color image files are larger than monochrome because each pixel is described by 3 bytes of data, whereas in monochrome images, only 1 byte of data is required. As a result, a color camera often will transmit data slightly slower than a monochrome camera to its output device.

5. Does color provide additional information that can help your welding process?
Everyone’s welding operation is unique. You may have additional features such as guiding markers on your parent material, or wire being fed into the welding process that might be best suited to monochrome or color cameras. Our team can help you to assess your needs and advise whether color or monochrome will work best for your application.

Whatever the operational needs, Xiris’ weld cameras, in either monochrome or color, provide high contrast, clear images of the welding process, allowing manufacturers to quickly and easily monitor their welds for better process control.

Better Images. Better Decisions. Better Process Control.

Follow Xiris on social media for regular updates and welding videos!

Instagram LinkedIn FacebookTwitter

Topics: weld inspection, manufacturing, defects, weld monitoring, XVC Weld Camera, HDR, color weld camera, color imaging, weld camera system, welding education, consistent

LASIMM project goes live with Xiris Automation

Posted by Emily Blackborow on Wednesday, February 27, 2019 @ 01:00 PM

Lasimm Machine

 

The Large Additive Subtractive Integrated Modular Machine (LASIMM) project is now live and ready to build large 3D printed metal structures for construction. The machine is the first of its kind and is predicted to keep Europe's manufacturing industry as a leading competitor in the global market. The project highlights a milling robot – the first for additive manufacturing of aluminum and steel - to integrate seamlessly additive, subtractive, metrology and cold work applications into a single machine. 

LASIMM will enable the creation of mixed-material structures by using similar and incompatible substances along with  software to generate tool paths and machine sequences. The machine will ensure the component's structural integrity by allowing in-process, non-destructive testing and restoration of defects. 

Xiris partnered with Cranfield University, a defining member of the project, and delivered the XVC-1000 HDR Weld Camera as an inspection solution for LASIMM. We are honoured to contribute to this project and are excited to see the results of the project and the impact LASIMM will have on Europe's additive manufacturing industry. 

Topics: weld camera, Education, High Dynamic Range, manufacturing, applications, XVC Weld Camera, HDR, weld camera system, consistent, inspection

Triggering Weld Cameras from a MIG Process

Posted by Cameron Serles on Thursday, February 07, 2019 @ 11:00 AM

MIG processes, particularly short circuit MIG, will generate a huge range in brightness during their metal transfer cycle:  when the arc is extinguished as the wire makes contact with the parent material prior to expulsion, the image can be quite dark. However, after an explusion occurs and the arc is re-established, the image may be very bright as the arc intensifies to its maximum.

Using a camera to acquire images of a MIG weld process in free running mode can be problematic when the amount of light present in the image varies considerably. The variation in light is based on when during the metal transfer process the image exposure takes place: when the arc is extinguished, the image will be dark; when there is a full arc, there will be a bright image. However, if the camera acquisition is triggered by an electrical pulse generated by the camera power supply, the result will be a consistent image of the weld process that is repeatable because it is at the same point of the weld cycle.

Image4

(courtesy ESAB Group, Inc.)

A few words about how Short Circuit MIG and certain other kinds of MIG welding function:

  • Wire is fed continuously and makes contact with the workpiece to complete the electrical circuit.
  • At the point of contact, a short circuit occurs, resulting in a huge spike of current moving through the wire between the torch and the workpiece.
  • At point of wire contacting the workpiece, arc gets extinguished.
  • Segment of wire rapidly vaporizes under high current and an arc gets re-established.
  • Current falls as there is no short circuit.
  • Process repeats.

In a constant voltage welding power supply, the current being fed to the torch can rise and fall based on the metal transfer process. When there is a gap between the wire and the workpiece, the conducting current is low, and increases as the wire begins to touch the workpiece and create a short circuit. Then, once the wire tip explodes, the current falls as there is no conducting circuit. The plot of the current levels look something like this:

 Image3

(courtesy ESAB Group, Inc.)

While capturing the welding process to see certain features, it is sometimes interesting to only take images at a certain point in the metal transfer cycle. Rather than using a weld camera in free running mode where image acquisition is based on the clock cycles inside the camera, an efficient alternative is to use an external trigger that is based on the current levels present in the welding power supply.  If a circuit can be designed to generate a trigger signal based on the rising edge of the current level, then the trigger could be used to initiate image acquisition, resulting in video with an increased consistentency in brightness and quality because each frame will be acquired at precisely the same point in the metal transfer process. 

Further enhancement to the performance of the imaging process is possible by tweaking exactly when the images are acquired through adding a delay.  A delay can be added after the trigger signal is generated so that the exact imaging characteristic can be seen.

For example, imagine wanting to see only images of the metal transfer process after the weld arc is extinguished.  To do this, a trigger signal should be generated based on the current pulses coming from the weld power supply.  It may not be possible to receive the trigger at the ideal point in the metal transfer process, so a programmable delay can be added to make sure that the image acquisition occurs at exactly the right point.

With Triggering:

Image2Image1

Successive Snapshots of a MIG Welding Process Triggered from the Rising Edge of Welding Power Supply’s Current Pulse

The above two successive images show a MiG process at roughly the same point of the metal transfer process over different cycles of the metal transfer.  In this case, the imaging was tuned to see exactly what the viewer wanted to see: the melt pool fully visible with the welding arc present.

In Summary

Imaging a MIG welding process can be fairly difficult if using a weld camera in free running mode.  However, if a circuit can be designed to clamp on the rising edge of the current pulse, it can provide an excellent trigger to use to acquire consistent images at similar points in the metal transfer cycle.  The result is much more uniform images with similar brightness levels, allowing for better analysis and increased efficiency of the welding process. 

Better Images. Better Decisions. Better Process Control.

Follow Xiris on social media for regular updates and welding videos!

Instagram LinkedIn FacebookTwitter

Topics: quality control, image processing, HDR, mig welding, reduced costs, weld camera system, consistent, MIG process

Latest Posts

Follow Me