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3 ways that welding vision systems boost production efficiency

Camera technology keeps the welding operation moving along while minimizing rework

Figure 1a
The weld camera reveals a torch that is not properly aligned during a pass.

Early adopters of welding vision technology in the 2000s were motivated by the most basic of needs: They needed to see what was going on during the welding process.

For some operations with semi- or fully automated welding cells, the use of weld cameras was related to safety. Fabricators needed clearer views of the work area than a welding helmet allowed, but good safety practices obviously prevented someone from observing an active arc without such eye protection. In other instances, fabricators needed a way to see how the welding process was going in difficult-to-reach areas. In both instances, weld cameras proved to be beneficial.

Welding applications such as these still drive the market today, but fabricators are increasingly discovering other ways that powerful weld cameras are making a true difference in boosting production efficiency. Here are three applications that might be coming to a shop floor near you.

1. Keeping the Torch Aligned

One of the unexpected benefits of using a weld camera is the ability to quickly and remotely align the torch and seam. Traditionally, torch alignment with the seam is done manually with the eye, often from less than ideal angles in awkward positions. For example, a fabricator lying down on a weld seamer trying to peer into a small gap or climbing on a ladder to see the top of a large-diameter pipe simply doesn’t have a good view of what’s going on. By integrating weld cameras with the process, an operator is able to get a clear, bright view of the torch and seam, no matter the setup. Any operator is then able to use the weld camera system right away to achieve perfect alignment on a consistent basis.

Figures 1a and 1b show the alignment process. In these examples, the manufacturer installed a positioning sensor on a robotic arm, which was meant to ensure perfect torch alignment during each weld, with the operator simply verifying the alignment prior to welding. You see in the first image that the positioning sensor and the operator have misaligned the torch, which resulted in a poor weld. In the second image, the operator used the camera system to verify the alignment and made adjustments accordingly after the robot had been aligned. Ultimately, the magnified view of the weld head can reduce robotic touch-point programming time and increase accuracy because operators now are able to view existing misalignments on problematic sequences.

Not only do the cameras ensure accuracy, they also allow operators to perform the alignment quickly and make adjustments right from the console rather than bending, stretching, or climbing up onto the equipment. 

In addition to torch alignment, a filterless weld camera provides a clear view of the background material and seam, enabling the operator to steer (see Figure 2) and make fine adjustments to ensure the torch does not deviate from the seam. A skilled operator using a weld camera typically can ensure that complete penetration and equal tie-in take place during challenging welding applications.

2. Improving Pressure Vessel Fabrication

Because of the critical service that pressure vessels provide, fabricators must ensure that the welds be of the highest quality. As a result, pressure vessels are often inspected thoroughly using both X-ray and ultrasonic testing.

If a weld is considered a failure after nondestructive testing (NDT), the fabricator has to rework the weld, which translates into a substantial number of labor hours and production scheduling headaches. Fabricators spend a great deal of time and money on surface preparation tools and processes to mitigate the risk of weld defects, but some defects such as porosity and inclusions still occur.

Pressure vessel fabricators that use semi- and automated welding processes are investing in weld cameras so operators can observe the weld process in real time, catch defects as they occur, and stop the process if required.

Figure 1b
A robotic welding cell operator can rely on a weld camera to get an up-close view of the alignment to see if everything is OK. This is an example of good torch alignment.

Porosity, which is a common defect that occurs when gas is trapped in the molten weld pool, is more easily detected with the use of weld cameras. As the weld cools and solidifies, the gas forms bubbles that appear as voids in the weld material upon inspection. Numerous issues can cause porosity in a weld. In some processes, porosity can be seen forming only with a high-frame-rate weld camera (see Figure 3).

Weld cameras are also useful in identifying inclusions. These weld defects often result from surface contaminants that become mixed into the weld pool and are trapped during solidification. In multipass welding applications, slag that is not completely removed between passes can be a source of inclusions. Thorough cleaning with a suitable wire brush before welding and between passes is a very effective means of eliminating this type of defect. Even then, though, the naked eye behind a welding helmet is sometimes blind to these small contaminants that aren’t cleaned up. That’s where a weld camera can make a difference (see Figure 4).

For critical welds, a weld camera system provides the ability to record the complete weld process for archiving purposes and offline review if needed. With the help of software, operators are able to embed production information, such as welder position, welding parameters, part number, and materials, into a file with the weld video.

Why is such documentation important? Should an NDT inspection raise questions about the integrity of the weld, the weld video record can be immediately reviewed for any anomalies and process improvements can be made.

3. Turning a Fabricator Into a Manufacturing Expert

For the longest time, metal fabricators have been able to remain competitive just by building parts to the submitted specifications and delivering those parts by deadlines. It was good business, and jobs were plentiful. Today, however, many large OEMs are expecting more from their metal fabricating service providers. They want more than parts. They want manufacturing expertise that can help to improve production efficiency and drive down manufacturing costs.

Some metal fabricating companies are boosting their manufacturing credentials by investing in high-dynamic-range, high-frame-rate weld cameras for R&D purposes. (High-dynamic-range weld cameras with a signal range of more than 140 dB are able to display a clear image of the background parent materials and the arc before, during, and after the weld. Older weld camera technology relied on spot filters over the arc, which had to be manually aligned prior to each weld; neutral density filters, which provided an image only while the arc was on; or an adjustable iris, which had to be manually adjusted before turning the arc on and again when the arc turned off.)

A high-resolution, high-dynamic-range camera allows manufacturing and welding personnel to see the weld process in great detail (see Figure 5). Small changes in weld parameters can be observed and documented. Suggestions aimed at improving weld strength, such as a change in wire materials, for example, can then be offered to the customer.

With the weld camera, cause and effect are no longer limited to theory and can be supported with recorded video. In many cases, an issue can be isolated, and recorded video can be viewed in slow motion or frame by frame to show exactly what is occurring in the process. A weld camera can reduce process development and troubleshooting time, allowing manufacturing and R&D personnel to make informed decisions in a shorter amount of time. Once a new process has been defined and established, the weld camera serves as a tremendous marketing and teaching tool to sell interested parties on the new process.

Recorded video also can be sent to weld technology developers and equipment makers, which can be useful for those fabricating companies that don’t have in-house welding expertise. The video can be helpful in discussions with vendors as a company’s welding department attempts to fine-tune welding parameters for a job and troubleshoot equipment failure.

Clear images of the weld process also can show impurities and additives in parent materials if present. That’s very useful when a fabricator has to go back to a metal supplier to have a discussion about the quality of supplied material. Recorded video represents hard evidence to support any concern of questionable material.

A weld camera doesn’t make a fabricator smarter, but it does provide a valuable tool to help improve processes (see Figure 6) and quality. It enables the fabricator to collect critical manufacturing knowledge to discuss with subject matter experts and make any recommended changes or enhancements to improve quality in a timely fashion. That makes the fabricator a smart and useful supply chain partner to its customers.