1. Improper use of auxiliary gas: When using air as an auxiliary gas, because the air contains water and possible oil vapor, especially in the compressed air system, if there is no effective oil-water separation device, the lubricating oil in the air compressor may enter the laser cutting head with the air flow and deposit on the lens to form oil.

2. Cooling system problems: If the cooling system of the laser cutting machine uses lubricating oil or coolant, and there is leakage or poor circulation of the system, it may also cause the oil to evaporate or leak into the cutting area, and then pollute the lens.

3. External environmental factors: oil mist or oil and gas in the working environment, such as other mechanical equipment nearby using oily lubricants, may also be inhaled inside the laser cutting machine, and eventually deposited on the lens.

4. Improper maintenance: lack of regular equipment maintenance, such as not timely replacement of the air filter, oil-water separator filter element, may also make the oil with the air flow to the lens.

Therefore, to solve the problem of lens oil pollution not only requires daily cleaning and maintenance, but more importantly, it is necessary to improve the quality of auxiliary gases from the source and strengthen the maintenance and management of equipment to ensure the normal operation of various systems and reduce the possibility of oil pollution.