Generally, people who do not know much about pvd coating machines do not know that the components of pvd coating machines actually include three pumps, let alone what functions these pumps play. Today, I will show you about vacuum Each pump of the coating machine and understand its role in the coating machine. The three pumps of the pvd coating machine are divided into: mechanical pump (usually oil rotary pump), booster pump, also called roots pump, high vacuum pump (diffusion pump or molecular pump).

The first is the mechanical pump, which starts working from the atmosphere. The exhaust effect of the mechanical pump is also related to the speed of the motor and the tightness of the belt. When the belt of the motor is relatively loose and the motor speed is very slow, the exhaust of the mechanical pump will The air effect will also deteriorate, so it is necessary to maintain and check regularly. The sealing effect of the mechanical pump oil also needs to be checked frequently. If the oil is too small, the sealing effect will not be achieved, and the pump will leak air, and the oil will be too much. The hole is blocked, and it is impossible to inhale and exhaust. Generally, the oil level can be 0.5 cm below the line.
The second is the booster pump, which is a mechanical pump with a pair of double-lobed or multi-lobe rotors that rotate synchronously at high speed. Because its working principle is the same as that of a Roots blower, it can also be called a Roots vacuum pump. There is a large pumping speed in the pressure range of 100-1 Pa, which makes up for the shortcomings of the mechanical pump's insufficient exhaust capacity in this range. This pump cannot work from the atmosphere, nor can it directly discharge the atmosphere. Its function is only Increase the pressure difference between the intake and exhaust ports, and the rest requires a mechanical pump, so it must be paired with a mechanical pump as a backing pump.
The third is the oil diffusion pump. The ultimate vacuum of the mechanical pump is only 10-2 Pa. When it reaches 10-1 Pa, the actual pumping speed is only 1/10 of the theoretical value. If you want to obtain high vacuum, you must use an oil diffusion pump. . The application pressure range of the oil diffusion pump is 10-1 Pa-10-7 Pa. It uses the gas diffusion phenomenon to exhaust. It has the advantages of simple structure, convenient operation, high pumping speed (up to 105 liters/second), etc. Features. The oil diffusion pump is mainly composed of a pump casing, a nozzle, a guide tube and a heater. The diffusion pump oil is mainly added in it (the Japanese model is D-704#). According to the number of nozzles, it can be divided into single-stage pump and multi-stage pump.
 When the oil of the diffusion pump is heated by the electric furnace, the oil vapor produced provides the pre-pressure, and the mechanical pump acts as the pre-pump. When the diffusion pump oil is heated by the electric furnace, the generated oil vapor is sprayed down through the umbrella nozzle along the guide tube. Because there is a vacuum of 1-10-1 Pa provided by a mechanical pump outside the nozzle, the oil vapor can be ejected for a certain distance to form a jet that moves toward the air outlet. The jet finally hits the pump wall cooled by the cooling water, condenses into a liquid, and flows back to the evaporator, that is, by the evaporation of oil - spray - condensation, and repeated cycles to achieve air extraction.
 The three pumps of the pvd coating machine are indispensable for controlling the entire coating process, and each plays a vital role. Without any pump, the coating process cannot be completed. For those who want to work in this field, they can learn more about this knowledge, which is very helpful for future careers.