Laser Welding Safety - Earlbeck Gases & Technologies

All welders know that safety is top priority- but with new technology on the market like the handheld laser welder Theo from Maxphotonics, it's important to understand that this new tech calls for a new set of safety needs! So what are the differences between laser welding and traditional welding when it comes to considering safety? Read on to learn more about laser welding safety protocols and how you can create a safe laser welding workspace at your shop!  Traditional welding techniques require extensive personal protective equipment (PPE) such as helmets, gloves, jackets, long pants, and boots to shield against bright arcs and sparks. And while laser welding doesn't tend to produce a ton of sparks, it is still recommended that you take precautions to cover your extremities. However, the real danger when it comes to handheld laser welders, is actually invisible to the human eye!

What many people don't realize is that the 1.5-kW, 1-µm-wavelength fiber laser coming from your welder is the same class 4 laser that many fabricators use for cutting- the only difference is that the laser on the cutting machine operates within an enclosure, behind laser safe-glass. Just because you cannot see the beam, doesn't mean it won't impact your retina or the retinas of those around you. This invisibility calls for specialized laser-safe eyewear, like laser glasses and welding helmets equipped with laser-safe glass lenses, as well as barriers to protect those who are in the vicinity from exposure.  Safety in laser welding begins with designing a restricted-access area. Make sure you clearly mark the area, minimizing  unnecessary access and exposure. Appropriate warning signs are crucial at all entry points, clearly indicating that a laser is in use. These signs must comply with safety standards and include information about the type and class of laser, potential hazards, and required PPE. Regulations tend to vary by country and region, so check out your local regulations for guidance. 

• CURTAINS & COVERS
• BARRIERS
• WELDING BOOTHS
• ENCLOSURES & OTHERS

< > Looking for a higher level of protection? Give the portable rigid barriers a try! Built with versatility in mind, these panel systems have unique 360° hinges so you can move and position your barrier according to your needs! Then once you’re done, it’s easy to fold up and store taking up less space than most barrier systems! Ranging from 2-6 panels, these are made with materials that have a laser safety rating of up to 10,000 W/cm2 for 100 seconds. LaserVision USA's Welding Booths provide essential protection for laser welding jobs. These enclosed spaces protects outsiders from both reflected and direct stray laser beams. Built in windows can provides visibility without risk! Engineered by their top specialists, these welding booths are made from the highest quality laser rated materials on the market. We have one installed at our Baltimore location and we couldn't recommend it more! They come in either a portable, fold away option, or a heavy duty, floor anchored option in standard sizes. Plus, you can add on custom options like extra windows, a roofing kit, and an interlock system!  Laser Vision also offers enclosures that come in standard sizes or can be custom built, featuring M5P06 laser safe panels and sturdy aluminum framing.

Common small enclosures include table-top glove boxes, inline enclosures, and processing workstations. While their larger enclosurescan incorporate viewing windows, access points, and a variety of door styles- think room dividers, open top machine surrounds, and custom booths!
In addition to those, they offer cabinstyle fixtures.  These use their highest laser safety rated material with 3 inch thick walls and can incorporate laser safe windows & doors, interlock systems, LED signs and more, making them an ideal choice for permanent, high power laser protection. With worry-free on-site installation included!
So whether you're looking for something heavy duty with floor anchors, or portable and fold away- LaserVision USA has a solution. Plus their flexibility in standard sizes and customization means you’ll be happy with the outcome. 

We stand behind LaserVision USA's quality craftsmanship so much that we have our own laser enclosure from them-  you can check out Earlbeck’s custom built enclosure when you book your demo with Theo today!

PRO TIP: INTERLOCK SYSTEM

Once you figure out your barrier set up, there are still other considerations. Even though laser welding is different to traditional welding, effective fume extraction is still crucial for maintaining air quality since both methods still create harmful fumes. Check out our recommendations for PAPRs and other fume mitigating systems like portable fume extractors, booths, downdraft tables, and more!

Additionally, as discussed above, all welding requires appropriate PPE. This includes your standard gloves, jackets, long pants, and boots, plus laser safety glasses with the proper rating and a welding helmet with a laser safe lens. 
 
Fire safety is also an important requirement for any welding job, including laser welding. Make sure your space is equipped with suitable fire extinguishers and be sure that fire detection and suppression systems are in place! And as always, keep flammable materials away from the area you are welding in to minimize fire risks.

Another way to stay safe is to keep your equipment up to par with regular maintenance and inspections. This ensures that equipment functions correctly. Make regular inspections part of your routine to help identify potential issues before they become significant problems.
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And then lastly, and perhaps most important, proper training and awareness! If your staff doesn't know the dangers or can't physically see them, as is the case with laser beams, then how can they be expected to work safely? Shops must designate Laser Safety Officers (LSOs) who understand laser classifications, hazards, and safety protocols in depth. Training for LSOs can be conducted online or in-person, and it’s crucial that they have a full understanding. All operators of the laser welder should also receive safety training- keep your staff informed by investing in training BEFORE implementing laser welding at your business. Regularly reinforce the importance of following safety protocols with refresher training sessions.  Maintaining a safe welding environment requires both an understanding of the risks involved and the measures necessary to mitigate them. Thinking of incorporating laser welding into your practice but not sure where to start?

​Well, our team is here to assist! We have our very own laser welder, Theo by MaxPhotonics, and an enclosure by LaserVision, and we’re happy to show you firsthand!
Already have your laser welder but need help navigating the rest of it- just fill out the form below to reach out today! We’ll give you the rundown on what you need and help you find the perfect solution for your space!

Increased output from laser welding systems drives this need

WOUTER M. ZWEERS

Laser welding has become more popular in automotive body-in-white and component production because it is highly productive—a single laser welding robot can replace up to five conventional spot welding robots. High-power disk or fiber lasers, combined with a scanner welding head and an industrial robot for on-the-fly laser welding, can produce more than one hundred welds per minute.

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This causes a challenge: if the production is so high, how can one ensure that stable, good-quality welds are produced? Often, crash safety-relevant parts are produced in the automotive industry, making weld quality even more important. AWL-Techniek, as a specialized machine builder, supports its customers in tackling this challenge (FIGURE 1).

FIGURE 1. AWL-Techniek's laser welding machine. (Courtesy: AWL-Techniek)

This article will discuss the three aspects of a stable production machine: the machine itself, the limits of quality control by a human inspector, and automatic quality inspection.

The laser welding machine

Quality starts in the welding machine. The laser welding fixture must be able to clamp the parts in a stable manner even if the tolerances are rough, as is often the case in stamped metal parts.

The fixture must also be able to prevent errors by the operator. A good laser welding fixture detects if all single parts are loaded correctly before the laser welding process can be started. Poka yoke systems (a Japanese development of any mechanism in a lean manufacturing process that helps an equipment operator avoid [yokeru] mistakes [poka]), product detection sensors, and a well-designed tolerance chain are needed. Attention must be paid to clean air supply and fume exhaust, and the fixture must be easy to clean and to service (FIGURE 2).

FIGURE 5. This schematic illustrates the principle of photodiode-based laser quality monitoring [2].

Diode-based systems have the advantage of being quick and automatic. They evaluate weld quality during the actual welding, so no extra inspection station is needed in the production line. Of course, this is only valid if the system is reliable.

However, a disadvantage of diode-based systems is that they measure indirectly. The diode measures the process light, which is correlated to the weld quality—but is not the actual weld quality. This leads to errors that are not detected (false-negatives) and to good welds that are detected as errors (false-positives). AWL-Techniek experiments showed that the reliability of the diode-based automatic systems was not perfect, but when the error rate of automatic quality monitoring systems was compared to human visual inspection, it was clear that a well-adjusted automatic system performs significantly better.

It is important to realize that quality monitoring systems will need adjusting and fine-tuning not just at installation, but especially during full-scale production. A fine balance between sensitivity (no true errors missed) and no false-positive errors must be found. It is important to educate the maintenance team working with the installation so that they feel comfortable in performing these optimizations. Therefore, strong support and understanding by the factory management is needed.

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Error handling strategy

A challenge is to design a good error handling strategy that includes how to handle false-positives. A typical part can have several hundreds of welds. Therefore, even a low percentage of false-positives for a single weld can lead to a considerable number of positives for a complete part.

It is important to make rules for the part quality—for example, a rule that a defined percentage of welds can be defective before the part must be sorted out. A statistical analysis of the results, during production and fine-tuning the system, can be helpful. If the error handling strategy is not sufficiently robust, the user will not be satisfied with the quality control system.

Outlook

For the future, more reliable systems are expected on the market. An emerging trend—with several systems being brought to market—is optical coherence tomography (OCT), where the actual depth of a laser weld, as well as the profile of the surface, is measured. This enables direct evaluation of the features of a laser weld and thus promises more reliability. An ultimate step would be to use this measurement signal as an input for feedback control of the laser welding process. A further possibility is to use a laser triangulation-based system, which checks the quality of the surface of the weld. These systems are especially appropriate for edge welds.

Clearly, quality monitoring in laser welding is a theme that has grown more important over recent years, as output from laser welding machines has increased. Quality monitoring is not without challenges, but commercially available monitoring systems can be a great help.

Popular systems that are available are not plug-and-play. Optimization and fine-tuning during production are necessary, as well as training for the maintenance staff in doing this optimization. A robust quality strategy must be designed, which does take into account the reliability of the monitoring system as well as the danger of false-positive errors.

REFERENCES

1. C. G. Drury and J. Watson, "Good practices in visual inspection," FAA/Human Factors in Aviation Maintenance (); see https://goo.gl/w2X5qN.

2. M. Schmidt, "Process monitoring for laser materials processing - standstill or progress," Proc. EALA, Bad Nauheim, Germany ().

3. W. M. Zweers, "Process control in industrial applications," Proc. AKL'16, Aachen, Germany ().

WOUTER M. ZWEERS ([ protected]) is technology manager for AWL-Techniek, Harderwijk, Netherlands; www.awl.nl.

Contact us to discuss your requirements of Laser Vision Sensor for Special Welding Machine. Our experienced sales team can help you identify the options that best suit your needs.