In general, the oil mist generated by the mechanical atomization process mainly exists in the form of droplets, and the diameter of the droplets is wide, usually 2-10 um. The oil vapor generated by evaporation also forms a very small diameter condensate suspension during the condensation process, and the particle size is usually less than 2 um.

The research shows that the maximum distribution of oil mist particle size in the atmosphere is 1um. The test results of oil mist particle size around the grinding machine show that 95% of the droplet diameter is less than 3um. The large amount of lubricant evaporation makes the total diameter in the air in the processing workshop. The content is much larger than the oil mist test value, but medical studies have shown that oil vapor and large particle droplets are relatively less harmful to human lungs. Oil mist in the form of oil vapor is inhaled into the lungs and exhaled. They are not captured by the alveoli, and large droplets of oil cannot enter the lungs through the nose and bronchi. Only in the form of droplets, oil mist particles with a diameter of less than 5um can reach the alveoli smoothly and precipitate in the lungs, thus causing harm to the human body.

Oil mist hazard

·The harm to the human body

During the processing of CNC machine tools, a large amount of oil mist containing PCB components is generally generated, which implicitly impairs the physical and mental health of the workers. Inhalation of 0.3-3.5 micron particles poses a health hazard to the human body. Work area, easy to cause work injuries and other accidents.

Known oil mists can cause occupational diseases with significantly increased morbidity including benign respiratory diseases (including asthma, pneumonia, etc.), allergic skin diseases, and malignant tumors. The results of the animal-based study showed that when the dog was exposed to 5-100 mg/m3 oil mist for more than 12 months, fat-containing alveolar and macrophage fatty granuloma appeared, and the respiratory tissue showed morphological changes. In 1996, an investigation was conducted on 166 workers in a ball bearing manufacturer in the United States. The results showed that when the oil mist concentration in the workshop was 0.65 mg/m3, workers who were exposed to metalworking fluid oil mist were among the workers. 4% had asthma; and among workers in the same factory who did not come into contact with oil mist in the processing fluid, the number of asthma patients was zero. The Occupational Dermatology Survey released by the US Department of Labor Statistics also showed that the average incidence of skin diseases in full-time workers in 1991 was 0.77‰; in the same year, the incidence rates of assembly screws and general machining industries were 3.33‰ and 2.22‰, respectively. These two industries are also the industries with the highest concentration of oil mist in the work environment.

The carcinogenicity of oil mist is the most concerned and controversial issue. Many epidemiological studies were conducted in 2001, and the American Association of Governmental Industrial Hygienists proposed a revised value for changing the oil mist control index of the workshop to 0.2 mg/m3.

· Impact on machine tools:

A large amount of oil mist generated by high-speed cutting is adsorbed on equipment and workpieces for a long time, which may be the cause of malfunctions in the machine tool and electrical systems. It brings no small trouble to the maintenance of the machine tool, and also greatly reduces the machining precision of the machine tool.

· Waste resources and damage the environment:

If the oil mist gas is discharged to the outside, it will damage the environment; if it can be effectively recycled, it can save resources.

· Impact on the fire:

Oil mist is deposited on the wall for a long time, and there are potential fire hazards on the equipment.