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Staying safe with hand

Jun 16, 2023

In this setup, the laser welding operator wears gloves, long sleeves, long pants, a helmet with a lens that has laser-safe glass, and (for redundancy) laser safety glasses underneath. IPG Photonics

Online videos have been both a blessing and a curse for hand-held laser welding technology. The videos spread the word of just how well the fiber laser can weld, even when manipulated by hand. Some of the latest single-mode fiber lasers allow welders to keyhole weld 0.25-in. plate in record time. In many cases, postweld finishing can be a thing of the past.

On the other hand, some videos show laser welding guns being used on the shop floor next to MIG and TIG welding cells, sometimes behind welding curtains, other times completely out in the open. Welders don laser safety glasses, but that's about it. You’d never know they’re operating a 1.5-kW, 1-µm-wavelength fiber laser, the same Class 4 lasers fabricators everywhere have installed for cutting—only the laser beams within cutting machines work within an enclosure behind laser-safe glass.

Hand laser welding's quality is undeniable, as is its speed. Some systems even feature a pulse mode with lower average power, to slow the feed rate and sometimes replicate the stack-of-dimes TIG-weld look, if desired. For many, the technology's productivity and quality benefits are just too great to ignore, especially considering the seemingly never-ending skilled labor shortage.

But then there are those online videos from around the world demonstrating hand laser welding—out in the open, or just behind some welding curtains designed for arc welding. They’re fascinating to watch but, for those familiar with fiber laser safety protocols, it's all a little scary to see.

"They’re disregarding any concern for safety of operators and passersby," said Daniel Earley, LightWELD product manager at IPG Photonics Corp., Marlborough, Mass. "That's not good for the industry in general. We have a multipronged approach to safety. We train our sales partners and other subsidiaries and our end users about what's expected in terms of safety and the standards that apply. And we work with our commercial partners to provide a total safety solution."

A new market of hand laser welding safeguarding products is growing. As more who follow best safety practices adopt the technology, a good safety track record will in turn broaden hand-held laser welding's adoption. That's a goal both equipment vendors and metal fabricators share.

With hand laser welding, as with any manufacturing technology, the onus is on the fabricator to provide a safe working environment for employees. The goal is ensuring everyone can identify and respect the hazards, which requires education—especially for operations that haven't run industrial lasers of any kind before.

A weld shop knows arc welding safety, so it sets up the hand laser welding cell in a similar fashion. The hand laser welding operator pulls safety curtains aside (designed for arc welding, not 1-µm laser light), dons laser safety glasses, and gets to work. After all, the process isn't flashy, like an arc weld or plasma cut. The light seems contained, the sparks and fumes minimal. What's the worry?

"People cannot see 1-µm laser light," said Rich Greene, a laser safety specialist with Kentek Corp., Boscawen, N.H., adding that this invisibility introduces a host of hazards for the unaware and unprotected. "You never want to come in [to the laser welding cell] without any protective equipment on. The beam can especially impact the retina. Retinal injuries are some of the worst ones you can be exposed to. If your optic nerve or macula is hit, it's game over."

He added that some systems have certain protections engineered into the machine. IPG's LightWELD, for instance, has a part-contact electrical interlock that turns off the laser power if the welding head isn't in contact with the welded parts. It also has a fiber interlock that runs the length of the umbilical to the welding head; if that becomes damaged, the laser module shuts down.

This enclosure features laser-safe glass and a door with a safety interlock. If someone opens the door while the operator is welding, the system shuts down. Kentek Corp.

As David Fisher, IPG's senior director of global marketing, explained, "This is a new process for traditional welders. They’ve been doing MIG and TIG for years, and they know the safety precautions. They grew up doing it. [Transitioning to hand-held laser welding], the biggest issue is that many people don't understand the laser light used in the process is invisible to the human eye. Because they don't see it, they assume it's not there."

Safeguarding and personal protective equipment—from interlocked enclosures with laser-safe glass, laser safety eyewear, and specialized welding helmets—are being tailored for the hand-held laser welding market. All of it designed to allow fabricators to operate the systems safely and abide by ANSI Z136.1, Safe Use of Lasers, an OSHA-recognized standard.

Earley described hand laser welding safety mitigation using two scenarios, the best and the worst. "In the best-case scenario, the scattered or diffused light spreads out in hemisphere around the process. However, when performing your calculations for risk assessment and mitigation, we recommend considering the worst-case scenario, called specular reflection, which is a direct reflection of laser energy. So, the main mitigation for this is to create a laser-controlled area so you minimize the risk to passersby. You also need to ensure the operator is wearing the right personal protective equipment. The best way we can communicate this is to demonstrate what our recommendations are when we show the technology at an exhibition."

This included FABTECH 2022. At the Atlanta show in November, IPG demonstration booths showed not only the process in action but also what the company considers best safety practices. The booth floor had no carpeting or anything else flammable, and its four walls had laser-safe glass that protected onlookers. "We had a roof on the enclosure to mitigate any stray reflection," Earley said, "and the doors had interlocks. Opening them immediately disabled the laser."

Those laser welding wore gloves and a jacket that covered their extremities. They not only wore laser safety glasses but also a welding helmet with laser-safe glass used in the lens. "There's laser-safe glass in the safety glasses and helmet, but we recommend you use both," Earley said, adding that the arrangement provides redundant eye protection and guards against sparks and other hazards.

"We recommend leather gloves, long sleeves, long pants, and boots," Earley said, adding that although laser welding looks like a relatively "tame" weld, "you still have a chance for sparks to fly."

Like arc welding, hand laser welding also produces weld fumes, and local fume extraction is ideal. Fabricators can reach out to experts to assess the fumes generated in their specific shop, but as Greene explained, it's often easier to install local fume extraction by default, both for safety and worker comfort.

"If you don't have someone who knows exactly the kind of fumes and airborne contaminants you’re generating, then you really don't know," he said. "It's better to be safe than sorry, so we recommend using fume extraction by default."

Shops that employ laser cutting and perhaps even robotic laser welding know all about the need for trained laser safety officers (LSO), but the LSO concept might be new to a weld shop making its first industrial laser purchase. "The ANSI standard states that any organization operating a Class 3B or Class 4 laser must have a laser safety officer," Greene said, "and hand laser welders are Class 4 lasers."

Taking a training course, online or in the classroom, LSOs learn the different classes of lasers, the hazards, and mitigation and prevention methods, including required safeguards and signage.

An attendee tries laser welding at FABTECH 2022 in Atlanta. Everyone in the light-tight enclosure wears long sleeves, gloves, a special welding helmet with a laser-safe glass lens, as well as laser safety glasses underneath.

"The LSO is the admin person and oversees the laser safety program to ensure that control measures are in place," Greene said. "But end users also require training—not as in-depth as the LSO requires, but they need to understand what they’re working with and the safety implications. The training helps them show respect for a system that could damage their eyes or skin."

That training also includes safeguarding basics. As Greene explained, the ANSI standard describes three levels of entryway into a Class 4 laser use area. The goal is to separate the rest of the plant from the diffuse nominal hazard zone around the laser beam. The first is the undefeatable interlocked entryway. Again, when someone opens the door, the equipment shuts down immediately.

"Then there's the defeatable entryway," Greene said. "There is still an interlock, but you can bypass the interlock with a keypad code or swipe card to temporarily get into an area without interrupting the work."

The third scenario involves an entryway with no interlock on the door. "In this case, there are procedural controls," Greene said. "This involves training and can include a barrier to the entryway, PPE requirements, warning signs, and a light outside the door indicating there's a laser operating inside the area."

Greene added that safeguarding to meet minimum standards set by ANSI Z136.1 really shouldn't be the goal. Yes, OSHA inspectors knowledgeable of laser safety standards will refer to Z136.1. They’ll ask to see training records and ensure what they see satisfies the standard. But they also can resort to the general duty clause that states employers are responsible for protecting their employees of known hazards. "And lasers," Greene said, "are a known hazard."

Still, hazards, when managed properly, don't have to be unsafe. "It really is all about spreading the word and educating everyone, including distributors and end users, about the importance of hand-held laser welding safety," Greene said. "With the right training and safeguards, it's a very safe process."

Earley added that fabricators shouldn't set their safety bar at the minimum requirements but instead start with a study of the application, including the average size of workpieces and the welding positions operators are likely to use. "We’ve applied our recommended best practices using the standard Class 4 laser safety standard. And generally, that advises you to implement a fully controlled area in the facility for laser welding and appoint a laser safety officer who can help perform risk assessments and recommend mitigation of potential hazards."

It's a time of transition as early adopters bring hand laser welding onto the shop floor. Perceptions are wide ranging, yet no one can deny that the fiber laser has entered the manual realm and market acceptance is growing. Ideally, as the technology spreads, so should best practices in safety.

"We advise that, before purchasing a system, you have a plan for safety," Earley said. "Don't make the investment, take delivery, and then work on safety as an afterthought. Consider safety as part of your overall investment."