In any manufacturing facility that performs welding, fume control and overall air quality are always concerns. All welding operations today need some sort of fume extraction, whether it’s general ventilation, local extraction with hoods and arms, or source extraction with a fume extraction gun, which is the answer for most welding operations and facilities and where larger equipment won’t work for hard-to-reach welding areas.
Fortunately, source capture fume extraction equipment has evolved from the cumbersome, ineffective designs of the past. Today’s systems have features and benefits that impact fume extraction performance in industrial settings – and so it’s worthwhile to explore those new offerings.
A good rep
For a variety of reasons, fume extraction MIG welding guns have a bit of a bad reputation. But, the bulkier, less comfortable fume guns from 10 years ago have been replaced with today’s technology.
The biggest complaint about fume extraction guns was that they were heavy. However, with an increased focus on ergonomics and lighter components, many of today’s fume guns weigh as much as if not less than comparable MIG guns.
“Fume guns used to be a lot heavier and harder to work with than MIG guns,” says Etienne Blouin, director, environmental systems group, Abicor Binzel. “Today, the weight is equivalent to a non-extraction gun. And the xFume fume gun is 15 to 30 percent lighter than our competitors because of the type of components and cables we use to build it.”
The lighter weight goes hand in hand with the ergonomics of the fume gun. This can include how much trigger pressure is needed to strike the arc, the diameter of the handle, the angle of the torch, how much range of motion on the wrist the welder has and even the rubber texture on the handle grip.
Another criticism of fume guns was about the tip. To collect the most weld fumes, gun makers made the nozzles big and bulky. The welder couldn’t access the area they were trying to weld or even see the weld. Today’s fume extraction guns, however, feature a tapered-style construction similar to standard MIG guns.
Weld quality issues, porosity specifically, are another common issue with fume guns. Older fume gun designs didn’t always take into account how fume extraction affects gas flow in a fume gun. The problem occurs when the fume shroud is positioned too close to the weld and, in turn, suctions the shielding gas.
“That’s a big concern about fume guns for most welders,” Blouin says. “With older guns, fume extraction was done extremely close to the arc where the metal is actually molten. If you extract the shielding gas, you might allow oxygen and moisture to go into the molten metal, affecting the properties of the metal. When it cools, you would have bubbles and other defects because you did not properly protect the metal with the shielding gas.”
Conversely, the design of the xFume fume gun creates enough distance between the weld and the extraction so porosity and other welding defects are not a factor. The torch operates like a traditional MIG torch in that it does not affect anything near the arc or the molten metal.
Welders might also be concerned about welding position with fume guns. But Blouin says it’s not an issue.
“There is an angle that is prescribed by the welding procedure and if you follow that angle, you’re often at the optimal angle for fume extraction, as well,” he says. “If you’re welding in the optimal position, you will reach near 100 percent fume capture. That position means you’re almost 90 degrees above your weld with a little angle to move forward, depending on the weld. Of course, some welding positions such as vertical are still not as efficient for fume extraction but we’ve compensated for position with our design by allowing a lot more airflow. It’s a little more permissive than some of the older designs.”
Vacuum suction strength is another factor to consider – for best results, it’s important to use a high-vacuum system when using a fume gun. These high-vacuum systems create a higher static pressure that allows a welder to overcome the restrictions of the weld gun, such as the smaller hose. Also, the cubic feet per minute (cfm) settings of the vacuum unit should match the specification of the fume gun.
With those considerations in mind, Abicor introduced a complete source capture system with its xFume fume gun and vacuum unit. “Using a good gun and vacuum is something that is oftentimes overlooked,” Blouin says. “We developed our own line so that we can be confident the user is applying the proper static pressure and flow so the gun and vacuum can work well together.
“If your fume gun needs up to 100 cfm, but your vacuum is only pulling 50 cfm, that result is not going to be sufficient,” he adds. “For an optimal setup, you will have 90 percent-plus fume extraction. But, if you have an underperforming vacuum, you may see a 30 or 40 percent extraction rate.”
The new line includes three portable units: the xFume Vac Flex, Advanced and Pro. The machines feature many benefits not found on all fume extraction vacuums. “The power of the motors and the static pressure that they can produce is at the high end of the spectrum for vacuum systems, all the way up to 3.2 kW and 20,000 pascals (80 in. of water column),” Blouin says.
Also, automatic filter cleaning lets the fume extraction system clean autonomously, independent of the welder. This means the welder doesn’t have to stop and initiate cleaning manually. “It’s actually quite unique for a portable system to have an automatic cleaning system like ours,” Blouin adds.
The xFume filter is rated to remove 99 percent of particles larger than 0.1 micron, which is above the typical MERV rating. Essentially, a MERV rating indicates how effective a filter is; Abicor’s xFume filter membrane features a Teflon-like coating that allows the filter to be cleaned better to achieve high efficiency for a long life.
The automatic start/stop function keeps operating costs low and reduces wear on the vacuum unit’s motor, filter and other components. It also stops the noise of the machine.
“With the auto start/stop function, along with the auto filter cleaning, we’re trying to make it easier for the welder to focus on welding,” Blouin says. “Welders are specialized and you want them to weld. That is what they are good at and that is what you pay them for. You don’t want them to have to stop and start the machine and change filters. And with fume extraction built into the MIG gun, the welder uses it automatically. They only have to focus on welding. They can’t even forget to turn it on.
“The overriding goal is and has always been to protect the welder,” he concludes. “Capturing the fumes for every welder is a safety and health issue, and it’s one that is best taken care of with an automatic process.”