Lasers are now an essential tool in industry for cutting, marking, engraving and welding a vast range of materials.
Metals are commonly worked substrate but organic materials (plastics, paper, wood) are also widely used.
In virtually all the above operations some form of fume is given off as the laser thermally decomposes the substrate to a greater or lesser degree. This fume is a mixture of particulate and gaseous matter.
Fume from materials such as metals and glass is mainly particulate, the majority of which is less than 5µm (microns) in diameter.
Organic materials, particularly plastics, produce much more complex fumes which are investigated below.
In tests conducted by BOFA, laser fume consisted of spherical particulate, the majority of which were between 0.5 and 10 microns. These particles fall within the respirable range (HSE, RR878). Understanding this can be key to assessing the risks from your process.
Particle size distribution of a sample taken from a BOFA filter connected to a process laser coding onto PET.
Respirable particle sizes taken from HSE, RR878
The gaseous organic compounds produced are known as Volatile Organic Compounds (VOCs).
VOCs emitted from lasered organic materials:
benzene, toluene, xylene
Acrylic acid, Lactic acid, Butyric acid
Methyl methacrylate, Butylacrylate
Additionally some materials have other specific groups e.g. PVC polymers generate HCl, 2 component epoxy polymers yield amines and PET generates THF.
A considerable number of the above have occupational exposure limits set for them. As with the particulate element these gases need removing from the workplace.