(Laser Generated Air Contaminants).

Effects of Fume

There are three main areas of consideration associated with the fume

Health issues
- the effects it may have on the workforce coming into contact with it

Laser efficiency
- the effects on the laser optics

Product contamination
- the effects on the products being lasered

Health issues

Particulate
The particulate generated in most laser applications is sub micron in size and as such almost all is respirable. This gives rise to two separate concerns.

The quantity of dust being inhaled.

• Dust of any kind can also become a substance hazardous to health under COSHH when it is present at concentrations in the air equal to or greater than 10 mg/m3 (as a time weighted average over an 8-hour period) of inhalable dust or 4 mg/m3 (as a time weighted average over an 8 hour period ) of respirable dust. Marking applications typically generate up to 1mg/s of fume and Cutting applications in excess of 10 mg/s.
  
  
  
  
• The second is a reaction to the actual material of the particulate which may cause allergic, carcinogenic or toxic effects e.g. chrome and nickel compounds released from stainless steel are thought to be carcinogens.
  
  

Gases

Potential problems are usually associated with plastics which give off Volatile Organic Compound's when lasered, most of which have associated Occupational Exposure Limits (OEL). The table below covers a range of common plastics and lists the VOC's given off together with their OEL. PVC is worth a special mention in this context since it releases hydrogen chloride and small amounts of phosgene both of which are extremely toxic.

Laser efficiency

The optical system of the laser is susceptible to damage from particulate getting burnt onto the lens which reduces the laser efficiency and on marking applications can effect the quality of the code.

Additionally particulate in the laser beam can refract/reflect the light which diffuses the beam (see animation opposite).

Product contamination

Marking applications on open containers are vulnerable to particulate settling in the container which contaminates the product being filled.