Extraction methods, how important are they?
Creating enough vacuum around the source of the laser can be achieved via a range of methods, commonly, tip extraction, extract cowlings, downwards vacuum (flat bed) and full enclosures. Each technique greatly affects the amount of air volume required to meet the minimum 0.5 m/s as set out by COSHH (LEV guidance notes)
Cutting example:
A 120cm x 120cm flat bed laser cutter will probably come with built in extract connections for the entire flat bed area. This will have a recommended volume extract rate of say 350 m3 per hour (estimate). This enables 0.5m/s of vacuum to be created across the entire flat bed. However for a system of this size it is feasible to fit an extract inlet direct to the laser head, thus significantly reducing the required airflow (40-50%). Allowing a smaller system to be specified, saving capital costs, energy costs and dramtically improving fume containment. This is not to say the volumetric rate is not applicable, but if the correct flow rate is acheived, naturally the volumetric rate will be also. We are expanding the issue and invite discussion.
