The metalworking lubricant will produce oil mist during the working process, and the droplet particles ≤ 5um will cause harm to human body and cause some occupational diseases. During metal processing such as turning, milling, drilling and grinding, a large number of oil mist particles will be formed in the air due to the use of metalworking fluid. Metalworking fluid is a very complex mixture. In addition to hydrocarbon composition, it may also contain sulfonates, fatty amines, nitrates, dyes, fungicides and other chemical substances.
Existing form of oil mist The metal cutting process can produce the following three types of oil mist: (1) Clean oil mist generated by jet impact, free of solid dust; (2) Smoke generated by evaporation or burning due to high temperature of heating or high-speed cutting; (3) Oil mist containing grinding dust generated by metal cutting fluid spray during grinding. The particle diameter range of oil mist is also greatly different due to different ways of producing oil mist. Medical research has proved that oil vapor and large particle droplets do relatively little harm to human lungs. The oil mist in the form of oil vapor is inhaled and exhaled in the lungs, and they will not be captured by the alveoli, while the large oil droplets cannot enter the lungs through the nose and bronchus. Only oil mist particles in the form of liquid droplets with a diameter of less than 5um can reach the alveoli smoothly and precipitate in the lungs, thus causing great harm to the human body. Hazards of oil mist 1. Fire hazard and environmental pollution The existence of oil mist in metalworking fluid greatly increases the potential fire hazard, and at the same time, the possibility of slipping on the floor with oil mist increases. The air with oil mist discharged from the workshop will also cause pollution to the environment. The greatest harm of metalworking fluid oil mist is also that it affects the health of workers exposed to it. Long-term exposure of workers to metalworking fluid oil mist will lead to diseases, allergic skin diseases, malignant tumors and other diseases, and may cause genetic effects. 2. Affecting human health Another major hazard of metalworking fluid oil mist is its carcinogenic potential. The carcinogenicity of metalworking fluid mainly depends on its additive concentration, pollution and use conditions. At present, there is no research on the carcinogenicity of metalworking fluid for human beings. Although there is still controversy about the carcinogenic tendency of metalworking fluid and its oil mist, experimental studies on animals have found that the oil mist of processing fluid can cause skin tumor/skin cancer stabbing, lung cancer and pancreatic cancer.
Control method There are two main methods to control the concentration of oil mist particles in the workshop atmosphere: mechanical and chemical. 1. Mechanical methods include installing exhaust fan, oil mist catcher, and installing protective cover or splash baffle around the machine tool. These methods are widely used because of their convenient implementation and obvious effects. But these methods have their own shortcomings. Although the exhaust fan is simple and effective, the simple exhaust device is not desirable. It only moves a large amount of oil mist from indoor to outdoor, which is an extremely irresponsible behavior for the environment. The discharged gas shall be filtered by oil mist. Oil mist filter is an important equipment to complete this task. The oil mist capture rate of equipment with good quality can reach more than 98%. At present, most of the processing workshops adopt the mechanical oil mist purification method. The exhaust hood is used to collect the oil mist in the processing center locally. The oil mist is pumped by the fan to the centralized or stand-alone oil mist purifier, and then discharged after the special Filter Material filtration treatment in the purifier. Benefits of doing so: (1) Reduce the impact on employees: 0.3~3.5UM oil mist particles will remain in the human body and pose a hazard to health. (2) Reduce industrial accidents: Oil mist deposition makes the working area, floor and walkway slippery, which is easy to cause falls. (3) Reduce fire hazard: The oil deposits on the wall, ceiling and equipment to form potential fire hazards. (4) Reduce coolant consumption: The recycled oil mist can be reused to reduce the economic cost of coolant for the factory. 2. The chemical method uses special low oil mist machining lubricant. From the perspective of cutting fluid, using Class III oil or ester oil and low viscosity oil as the Base Oil of cutting fluid can reduce the generation of oil mist to a certain extent. Oil-based cutting fluid with high viscosity is not easy to disperse and form oil mist. Cutting fluids containing macromolecular compounds such as polyepoxyethane, polyisobutylene and polymethacrylate are often used as antifogging agents because of their high cohesion and are not easy to be broken, and the larger the molecular particles are. The harm caused by the oil mist of the processing fluid in the machining workshop has attracted the full attention of the world. Although the installation of the oil mist purification system increases the project investment, it can significantly reduce the harm of the oil mist, improve the level of labor safety and health, and reduce the emission of air pollutants, which has become a development trend. China should also speed up the corresponding work, formulate the control standards for oil mist, guide the engineering design and implementation, and protect the health of workers.
