The WELD Shop

As handheld laser welding continues to grow in popularity, welders and shop managers have experienced its benefits first-hand: faster, cleaner welds, less grinding, reduced distortion, and surprisingly high weld strength. However, some questions surrounding safety – such as proper PPE, barriers, and welding fumes – persist.

In this article, we’ll take a closer look at what we have learned about laser welding fumes, how they compare to arc welding fumes, and how to best protect yourself and your team.

What Are Welding Fumes?

Welding fumes are a complex mixture of gases and particulates that appear when metal is heated above its boiling point and the vapors condense into fine particles. In the case of laser welding, fumes are created when materials are vaporized by a high-energy laser beam.

The exact composition of these fumes depends on the materials – including base metals, welding wire, coatings, and contaminants – involved in the welding process. For example, galvanized coatings produce fumes with high levels of zinc particles, while stainless steel can emit fumes with nickel, manganese, and hexavalent chromium.

Regardless of their composition, welding fume particles are typically microscopic, ranging from 0.005 to 20 micrometers, allowing them to penetrate deep into the respiratory system. These fumes, if ingested consistently and in high enough volumes, can pose a risk to respiratory health.

Does Laser Welding Really Produce Fumes?

Laser welding is, in many ways, a milder process than arc welding. It’s quieter, creates less spatter, and can seem like it generates less weld smoke.

It’s hard not to notice the absence of plumes of smoke when laser welding. Experienced MIG or TIG welders are often surprised to see “basically no fumes” when welding with a laser for the first time.

Laser welding generating no visible fumes (left) versus MIG/GMAW welding generating highly visible fumes (right).

But laser welding does indeed produce fumes – they are just less visible. This reduced visibility can lead to the assumption that laser welding is inherently safer, at least when it comes to fume exposure.

However, this is a dangerous misconception, as early research has shown that even though laser welding tends to produce fewer fumes by mass compared to arc welding, it’s not safe to take fewer precautions.

What the Laser Welding Fume Research Shows

A study presented by the University of Alberta at the International Society of Exposure Science (ISES) 2024 Conference examined emission factors and fume generation rates across different welding processes. Here is a summary of some relevant findings:

• Laser welding generally produces a lower total fume mass compared to MIG welding.
• Laser welding exhibited higher emission factors but lower fume generation rates in some tests.
• Both fume generation rates and emission factors increased with higher voltage/power settings for both laser welding and MIG welding processes across all consumables tested.
• Although laser welding typically consumes less wire, the chosen wire material has a big impact on fume generation for both laser and arc welding processes.

For a detailed overview, you can view a PDF summary of the study here.

For context, fume mass refers to the total weight of fume particulates. Fume generation rate refers to the fume mass produced per unit of time during the welding process, whereas emission factor refers to the fume mass produced relative to impacted material (such as wire consumed in the welding process).

While laser welding (right) produces more fumes relative to the wire consumed and the size of its molten pool, it also tends to vaporize less material than arc welding (left) overall.

It is important to note that even though the study above sheds light on the potential for reduced fume-related hazards associated with laser welding, the fact that the emission factor is higher in some cases implies that the standard referenced may not capture the whole picture.

This may be because laser welding’s energy density – which is approximately 100 times higher than that of arc welding – tends to result in smaller vapor particles that are not always entirely captured by traditional testing standards and equipment.

Smaller fume particles, which are not as visible to the naked eye, can stay airborne longer and may potentially penetrate deeper into the respiratory system.

Particle Size Comparison, PPE, and Ventilation

So how exactly do arc welding and laser welding fume particles compare?

Arc Welding: Produces particles ranging from 0.005 to 20 micrometers, with a significant portion being respirable and capable of reaching the alveolar regions of the lungs.

Laser Welding: Produces particles that fall within the same 0.005 to 20 micrometer range as arc welding, but which tend to be smaller on average (typically between 50 and 100 nanometers). However, some theories suggest that the energy density of laser welding may create even smaller particles that are not accurately captured by current test methods.

The particles that make up laser welding fumes are consistently extremely small. The particles that make up arc welding fumes can range from extremely small to relatively large.

Considering these differences, an important question remains: when it comes to fumes, is laser welding more safe or less safe? Providing a definitive answer is difficult, and potentially a little irresponsible. The simple answer is that we do not know. Research does point towards lower fume generation rates, but also towards a higher percentage of small particles.

The most important thing to keep in mind is that laser welding isn’t uniformly better or worse than arc welding when it comes to welding fumes; it’s just different. And, while the particulate mechanics are complex, staying safe doesn’t have to be.

Given the potential risks associated with both visible and non-visible welding fumes, we recommend the following safety measures:

• Ventilation: At the bare minimum, laser welding work areas should be ventilated, with some amount of ambient air flow providing a way for fumes to escape.
• Fume Extraction Systems: Use local exhaust ventilation systems to capture fumes at the source. If possible, use adjustable extraction arms to keep the intake close to the weld zone without interfering with the work.
• Respiratory Protection: For laser welding, safety experts generally consider respirators to be optional, unless there aren’t sufficient environmental controls. If there is sufficient air flow, ventilation, or a fume extraction system, then a personal respirator may not be necessary. In cases when this is not possible, the OSHA 1910.34 standard regulates the type of respirators that may be used.
• Regular Monitoring: Conduct air quality assessments to ensure fume concentrations remain within safe limits.

Getting Started with Laser Welding

Laser welding offers many advantages, but a successful implementation requires a solid understanding of laser safety. Whether you’re tackling an advanced application or simply looking to add another tool to your kit, our LightWELD experts are here to guide you—from best practices for safety to hands-on support.

Click here to get started. We’ll take it from there.

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