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 utilizes 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.