Regulations are becoming more stringent in many countries with lower exposure limits for airborne metalworking mist and smoke. International health organizations recognize the importance of preventing health risks associated with mist and smoke generated during metal cutting and machining operations. In many countries, strict personal exposure regulations and standards such as ISO Limit Values, OSHA PEL and ACGIH TLV are heavily enforced to minimize worker exposure.
Containment and filtration are the primary solutions to mitigate employee oil mist and smoke exposure. Mist is primarily generated by coolant nozzles spraying metalworking fluid on the machine tools to lubricate the cutting surface, remove dust/swarf from the cutting surfaces and/or for cooling the cutting tool and part being machined. Smoke, which in most applications is actually thermally generated mist, is created when oil comes in contact with hot surfaces, vaporizes, and then condenses to form submicron mist particles which we see as smoke.
Containing the mist and smoke inside the CNC machine enclosure is essential to reducing employee exposure. Sizing the proper airflow to ensure containment of mist during machining and capture of any mist that will escape the enclosure when machining is finished and employees must open the door to remove parts or replace tools is critical to the success of the collection system and meeting the exposure level requirements.