Fiber Laser Cutting

Clean Air Matrix

RoboVent engineers are experts in every category of air filtration and ventilation. The four categories below represent the major options for treating your contaminated air. RoboVent has designed solutions for each of these categories and has manufactured air filtration systems of unrivaled quality.

For more information about these categories, see Indoor Air Quality 101.

Ambient_Filtration

Large blowers and air filtration equipment draw contaminated air from the plant (typically at the ceiling level), filter it and return it to the plant. This is a proven solution in plants welding large parts with overhead cranes. It reduces the haze in the air, resulting in a cleaner working environment, with no negative pressure or heat loss.

SourceCapture_Filtration

Air in the immediate area of the welding activity is captured in a hood system, then filtered and returned to the plant. This is the best solution whenever possible. It allows for a more flexible system and removes the smoke directly from the operator's breathing zone. There are many types of source capture, including overhead hoods, crossflow hoods, fume arms and fume guns, some of which work better than others.

Ambient_Exhaust

Large exhaust fans draw contaminated air from the plant and exhaust it directly into the environment, typically through the roof or walls. This is a traditional method and often results in negative air pressure. Also, it is very difficult to climate-control your plant and the system may not work well in the winter.

SourceCapture_Exhaust
Air in the immediate area of the welding activity is captured in a hood, sent through ductwork, and exhausted directly into the environment. This is a lower capital cost alternative to filtration, but tends to result in high operating costs and large, unsightly ducting systems that work less efficiently with modifications. It also results in negative pressure problems.

Dust Control Considerations for Fiber Laser Cutting

Fiber laser cutting has surpassed the popularity of CO2 laser cutting for many applications—and for good reason! Fiber laser cutting has significant benefits in terms of cutting speed, energy efficiency and operating costs. And over the last few years, fiber lasers have become more powerful than ever. High-wattage fiber lasers are now available that are capable of cutting even thick metals with high speed and accuracy.

But if you are considering making the switch from CO2 to fiber—or upgrading from a lower-wattage fiber laser to a higher-wattage laser—you may also need to upgrade your dust collection system. Here’s what you need to know about dust control for fiber laser cutting.

Why Manufacturers are Switching to Fiber Laser Cutting

Fiber lasers and CO2 lasers are both used for high-speed cutting, but they have some important differences.

  • CO2 lasers produce the laser by running electricity through a tube filled with carbon dioxide gas (often mixed with hydrogen, helium and nitrogen gases). Mirrors at the end of the tube focus the light into a powerful beam capable of cutting through metals, wood, paper, cloth and many other materials.
  • Fiber lasers produce the laser beam by channeling light created by a bank of diodes through a fiber optic cable. The fiber cable is similar to the cables used to transfer data in computing and telecommunications. The light is amplified by the fiber optic cable and focused using a lens.

CO2 machines remain widely used for non-metallic materials, including wood, paper, textiles and leather. But faster cut speeds and lower energy and operating costs make fiber laser cutting machines hard to beat for high-volume metal cutting applications. Here’s why more manufacturers are making the switch:

  • Lower energy costs: Fiber lasers are much more energy efficient, which results in lower operating costs. A 3kW fiber laser uses only 1/3 of the energy consumed by a 4 kW CO2 machine. This is because fiber produces a narrower, more concentrated beam, so the energy stays focused on the cut line and less energy is lost to heating the surrounding material.
  • Faster cutting speeds: Fiber lasers can cut thin materials much faster than a CO2 laser—3x faster for 1 mm galvanized or stainless steel and 2x faster for 2 mm steel. (CO2 still has an advantage for very thick metals, but those advantages are eroding with the newest generation of high-wattage fiber lasers.)
  • More uptime: There are fewer moving parts and no mirrors on a fiber laser machines, which reduces maintenance requirements and the need for frequent servicing and recalibration commonly required for CO2 lasers. Fiber laser machines are also less vulnerable to unexpected production downtime, as there are no mirrors that can be knocked out of alignment.
  • Lower maintenance costs: Servicing costs for fiber lasers can be half of the costs for a comparable CO2 machine.
  • Ability to cut reflective materials: Fiber lasers can cut reflective materials such as copper, brass and aluminum without the risk of back reflections damaging the machine.
  • Less material waste: Fiber lasers generate a thinner beam than CO2 machines, which translates to a thinner kerf (the portion of the material burned away by the laser). The difference may not be noticeable to human senses, but when processing large volumes of material, it can add up. A thinner kerf also allows fiber lasers to be used for more detailed and delicate work on thin materials.

Fiber Laser Cutting Machine

The Dangers of Fiber Laser Cutting Dust

Fiber laser cutting machines produce large volumes of dust when cutting materials at high speed. This dust must be collected and disposed of. Uncontrolled laser cutting dust presents several dangers.

  • Damage to laser cutting equipment: When dust is allowed to build up inside the laser enclosure, it can damage expensive laser equipment. Dust can accumulate on sensors, linear actuators and optical lenses, resulting in increased wear and tear, higher chances of a crash, and poorer cut quality.
  • Human health implications: If laser cutting dust escapes the laser enclosure, tiny particles can be inhaled deeply into the lungs, causing serious health concerns. Stainless steel and other metalworking dusts contain toxic substances such as cadmium, beryllium, hexavalent chromium and manganese. Other materials may also produce toxic, carcinogenic or irritating dusts when cut with a laser. OSHA requires facilities to reduce human exposure to these dusts.
  • Combustion risk: Many of the dusts produced by laser cutting are combustible. If they are allowed to accumulate in the air in an enclosed environment, it can result in a dangerous explosion.
  • Part Quality: If the airflow isn’t adequate, soot may accumulate on the bottom of the parts. This necessitates additional cleaning and could affect part quality.

Controlling High-Volume Fiber Laser Dust

Many manufacturers upgrade their laser cutting equipment without considering the implications for dust collection. This is a mistake. Dust collection systems designed for lower-wattage fiber lasers or CO2 lasers may not be adequate for new high-wattage fiber lasers.

Fiber laser cutting dust is more challenging than CO2 laser cutting dust for a few reasons.

  • Dust volume: While fiber lasers have a thinner kerf, and thus remove less material per inch as they cut, they are usually cutting many more inches per minute. The increased cutting speed results in more dust production per minute compared to a similar CO2 laser.
  • Dust characteristics: When cutting metal, fiber laser cutting produces very fine (often microscopic), jagged particles that can be inhaled deeply into the lungs or embed themselves deep within the fibers of the filter media in the dust collector. That makes this kind of dust especially dangerous if it is allowed to escape the laser cutting enclosure. It also creates challenges for dust collection.
  • Dust velocity: The high energies and speeds inherent to fiber laser cutting results in these tiny particles moving at high velocities within the enclosure. This means that they tend to hit the filter at high speed, further embedding dust particles into filter media. Static forces also attract tiny particles to the filter media. This makes it difficult to pulse dust off of the filter.

These characteristics can result in rapid clogging of filter media and inadequate dust collection. With the newest high-wattage fiber lasers, these problems are amplified even more.

What to Look for in Dust Collectors for Fiber Laser Cutting

When switching from CO2 to fiber laser cutting, or when upgrading to a higher wattage laser, it is important to evaluate your current dust collection system and determine whether it is up to the job. Typically, when upgrading to a new laser, the manufacturer will also recommend or require that you purchase a new dust collector. We recommend that you listen to their advice and follow it. In most cases, a more powerful dust collection system will be required.

There are a few considerations to keep in mind when evaluating a dust collector for fiber laser cutting.

  • CFM: Dust collectors are rated by CFM (cubic feet per minute). This is the volume of air they are able to move per minute. The higher the CFM of your collector, the more air it will move, and the more filter media you will need.
  • Filter media: Make sure you have enough filter media to collect the volume of dust you are producing each minute. The ratio of CFM to filter media (measured in square feet) is known as the air-to-cloth ratio. Applications that produce high volumes of dust, like fiber laser cutting, require more filter media per CFM (or a lower air-to-cloth ratio).
  • Pulsing: Dust collector filters are periodically pulsed with short, intense bursts of air to blow off excess dust, which is collected in a bin or tray. This extends the life of the filter media. Without pulsing, the filter rapidly becomes clogged, which prevents the dust collector from doing its job. As we explained above, the tiny, jagged, fast-moving particulates produced by fiber laser cutting are especially prone to becoming deeply embedded in the filter media, making them resistant to pulsing. Keeping your filters clean may require more frequent pulsing or a more aggressive pulsing system that is able to dislodge particulates from the media more effectively.

RoboVent has designed a dust collection system specifically for fiber laser cutting of metals. Senturion is a powerful laser dust collector with a pulsing system that reduces clogging of the filters with fiber dust. Senturion comes in a range of sizes for all kinds of fiber laser cutting applications. An experienced RoboVent air quality engineer can help you evaluate your processes and determine the right size collector for your facility.

Senturion Sizing & Configuration

Inside or Outside

Motor blower combinations can be adjusted to suit your application requirements. Senturion can also be modified and built with explosion-proofing for applications that may have combustible dust and need extra safety features with the system.

Visit our Combustible Dust resource center or check out the webinar to see if your application may require explosion proofing.