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Laser machining

Danger posed by laser machining side products is often underestimated

Due to their versatility and high performance, lasers are often used for processing metals, wood, plastics and other organic and inorganic materials. They are, for example, used for welding, cutting and engraving. Usage of laser technology renders possible efficient and largely automated implementation of these processes.

Even so, users are often unaware of the risks of laser usage. Laser processes generate, dependent on laser type and performance, processed material and other factors, hazardous side products. These are, for example, hazardous vapours, gases, particulate matter or aerosols. A wide range of them does already pose a health risk because of their chemical composition, but even seemingly nontoxic substances affect workplace quality by dust and odour nuisance. Furthermore, nontoxic particulate matter is inhaled similar to cigarette smoke and can penetrate deep into the lungs. Hence, effective air purification is vital for quality of workplace conditions and health protection.

Airborn particles are especially damaging to health

Particulate matter is classified by particle size (or rather: by aerodynamic diameter). Dust with a particle size of 10μm is respirable. These particles reach the bronchial tubes. Smaller particles are even more hazardous, as they may penetrate deeper into the lung. Very fine dust will penetrate into the alveoli and block them, posing an unnecessary health risk.

Laser processes often produce particles and aerosols smaller than 1μm. These particles are especially hazardous as they penetrate deep into the respiratory tract and should not be inhaled! Dependent on their chemical composition, they have other health-damaging effects.

According to new analyses, there is no threshold beneath of which health-damaging effects by dust exposition is impossible, but health risks rise linear with dust exposition. EC clean air plans allow a maximum particle concentration of 40-50μg/m³, whereas, by contrast, laser processes generate particle concentrations of sometimes 100μg/m³ and more.

More detailed information is provided by the German Laser Zentrum Hannover by their database lasersafety (http://www.laser-zentrum-hannover.de/en/publications/db_lasersafety/index.php) As you can learn from the table above, the threshold of 50µg/m³ is often exceeded dramatically. In addition, the generated particles are small enough to penetrate deep into the respiratory tract. They will mostly reach the alveoli which will be blocked by this foreign material.

Laser machining generates hazardous side products

Apart from that, other hazardous substances than particles and aerosols are released. They partly consist of alloy material in case metals are being machined; machining of organic material will generate a number of new substances by means of chemical reactions that are initiated by the laser beam's energy. Additionally, additives such as colourants or flame retardants are released and will undergo chemical reactions. This way, a number of new hazardous material is being created, including some especially toxic substances.

To put it altogether, efficient and well-adapted air filtration is absolutely necessary. Some emissions are dangerous to water and environment, whereas most of them will directly or indirectly impair health and workplace quality.

Professional pollutant extraction protects man, environment and machinery

An appropriate extraction and filtration system has to offer some basic features to meet the specific requirements of laser machining of different materials:

	Well-fitting intake elements and sufficient suction lines for best possible intake of all pollutants.
	Speed adjustment for optimal air speed dependent on intake diameter, filter configuration and pollutant generation. Noise can be optimised by speed adjustment.
	Effective pre-filtration to protect downstream-connected finer air filters. Usage of HEPA filters to collect even finest particles.
	Sufficient filter surface for high filter capacity and longer filter lifetime, reducing consequential costs.
	Dependent on pollutant generation, usage of an activated carbon filter becomes necessary to adsorb gases and odours to provide for pollutant-free working conditions without odour nuisance.
	Simple filter change procedure that should preclude contamination to keep pollutants away from ambience and staff.
	Modular construction for optimal adaption of filter configuration to the process . initially as well as in case of later process adaptions or alterations.