When the friction surface of the mechanical motion pair is in relative motion, because the surface directly contacts and generates frictional resistance, a part of the energy transferred by the machine is consumed by the friction and the surface heats up, and the parts are worn at the same time.

　　 Thin oil lubrication is to force the lubricating oil to the friction part of the machine to form a lubricating agent film that can withstand part or all of the load on the friction surface, and separate the friction surfaces of the two moving pairs to make the friction between the metal and the metal. It is converted into internal friction between oil film molecules with lower shear strength.

　　 Thin oil lubrication mainly plays the following important roles in the normal operation and maintenance of mechanical equipment: 1) reduce wear, 2) cool down, 3) wash and clean, 4) prevent corrosion, 5) save energy and reduce consumption.

　　 Thin oil lubrication is mainly used for the lubrication of reducers, dynamic and static pressure or sliding shoe bearings of mechanical equipment such as electric power, metallurgy, petrochemical, cement, etc.