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Laser & Plasma Cutting, Weld Fume &
Thermal Spray

Arc Welding uses an electric arc between a consumable or non-consumable electrode and the base material to melt the metals at the welding point. The welding region is sometimes protected by inert or semi-inert gases (shielding gas), and/or an evaporating filler material. Arc welding is widely used because of its low capital and running costs.

Developed in the 1950's, Plasma (Arc) Cutting allows cutting of metals that could not be flame cut, such as stainless steel, aluminum and copper. Plasma cutting uses electrically conductive gas to transfer energy through the plasma torch to the material being cut. Plasma gases include argon, hydrogen, nitrogen and mixtures, plus air and oxygen.

Laser Cutting is typical in industrial manufacturing applications, but is starting to be popular with schools, small businesses and hobbyists. Laser cutting directs the output of a high-power laser at the material. The material then melts or burns, and a gas blows the residue away from the cut, leaving an edge with a high-quality surface finish. Industrial lasers cut flat-sheet material as well as structural and piping materials. When compared to plasma or flame cutting, laser cutting utilises a much more focused or smaller cut, so it puts much less heat into the workpiece and removes a narrower path of material. This allows the laser to cut precise parts to a higher tolerance and with less taper on the cut edge.

Are There Hazards Involved with Welding, Plasma Cutting & Laser Cutting?

Welding often generates gases and smoke containing particles of various types of oxides. The size of the particles can influence the toxicity of the fumes, with smaller particles presenting a greater danger. Additionally, many processes produce gases (most commonly carbon dioxide and ozone, but others as well) that can prove dangerous if ventilation is inadequate.

The generation rate of fumes and gases varies with the composition of the base metal, fluxes, and fillers, and with the rate and depth of welding or cutting. Exposure to the operator varies with the generation rate, duration and frequency of operations, work practices (particularly distance of the plume from the breathing zone), and the effectiveness of ventilation.

Ventilation Recommendations:
Choose a hood design in the following descending order of effectiveness:

  • Enclosing hoods are by far the most effective in controlling welding contaminants; however, they restrict access and force reconsideration of material and product handling.
  • Capturing hoods are less effective than enclosures but can be adequate if properly used.


General ventilation filters the air in the entire room to reduce the airborne fume concentration. Consider this method only if source capture is not possible and/or practical. Because general ventilation does not remove fume at the source, it does not limit exposure at the worker’s breathing zone.

Dust Collectors for Welding, Plasma Cutting & Laser Cutting Applications
Because of the variation in welding, plasma cutting and laser cutting applications (airflow, loading, fume properties), multiple dust collectors can be suitable. The Donaldson® PowerCore® TG collector series is the latest breakthrough product to revolutionise the approach to dust collectors for welding, plasma cutting & laser cutting. It combines an ultra-high efficient filter with a “smaller and smarter” footprint and the lowest maintenance cost in the industry. Traditionally, cartridge collectors are a traditional type of collector due to the small nature of the particulate size in fume. The Donaldson Downflo® Oval Cartridge Collector is the recognised leader in this category, and is the proud winner of Filtration Products “Product of the Year”.

Thermal Spray

Thermal Spray or Metalising is a group of coating processes which deposits finely divided metallic or non-metallic materials in a molten or semi-molten condition on a surface/substrate to form a coating. The coating material may start out in the form of a powder, ceramic rod, wires, or even molten materials. The process has the potential to generate very small particulate often referred to as “fume”. This thermally generated fume can be smaller than one micron in diameter, and uniform in size making collection a challenge.

Thermal Spray Coating Process

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Donaldson® dust collectors are in hundreds of thermal spray applications worldwide. Our advanced Ultra-Web® nano-fibre filtration technology is supremely suited for applications involving thermally generated fume, especially when installed in a Donaldson dust collector selected for your application.

Processes Involving Thermal Spray
The thermal spray processes involves such heat that the process produces a very fine dust (fume), typically sub micron in size and very uniform. Some of the materials used in thermal spray applications have associated adverse health effects, and defined minimum exposure limits set for them, which necessitates effective dust collection.

Following are terms for typical thermal spray processes that produce fumes needing to be controlled;

​Flame Spray

​Powder Flame Spray

​Wire Flame Spray

High Velocity Oxy/Fuel Spraying (HVOF)

​Cold Spray

​Plasma Arc Spray

​Electric Arc Spray

Related processes producing contaminants - surface preparation and finishing operations

  • Abrasive blasting
  • Grinding
  • Wet machining 

 

Special Considerations

Many metal fume dusts are combustible and those operations generating or handling metal fumes can require special mitigation efforts to minimise fire and explosion risks. Standards such as NFPA 654 can provide guidance for those who generate and handle these types of dusts. See the Donaldson Dust Collectors and Combustible Dust Strategies brochure.

Metal fume dusts may also have identified adverse health impacts, and special mitigation strategies may be required to limit occupational exposure below levels OSHA or other health organisations have established for these materials.