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Why does the pvd coating machine need to install a cryogenic capture pump?

2024-03-28

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The pvd coating machinee coats high-precision film layers. To achieve a high vacuum environment, the air in the cavity of the pvd coating machine must be removed. Therefore, it is often not enough to use a vacuum pump to remove the gas, because there are not only gases in the air, but also There is moisture, so it is essential to use a cryogenic capture pump


pvd coating machine


In the vacuum process, the molecular weight of water is smaller than the molecular weight of the main components of air such as oxygen and nitrogen. Therefore, neither the oil diffusion pump nor the molecular pump can extract it quickly and effectively, so it accumulates more and more, and finally becomes a waste. Residual gas: 65% to 95% or more of residual gas;
At the same time, since the pump oil will inevitably evaporate during use of the vacuum pump, a small amount of oil vapor will enter the vacuum system.
Due to the presence of water vapor and oil vapor, the vacuum system cannot quickly reach the vacuum required by the customer, resulting in longer vacuuming time and reduced production efficiency. The higher the required vacuum and the greater the ambient humidity, the more obvious the impact.
At the same time, the presence of water vapor and oil vapor will lead to a decrease in film firmness, inability to multi-layer coating, uneven color, etc.
Water vapor will also ionize under certain conditions to produce oxygen, which oxidizes the target and causes the color of the coating to change. The greater the ambient humidity, the higher the temperature, the higher the vacuum required, and the greater the impact. Therefore, water vapor and oil vapor are the main hazardous gases in the field of vacuum coating and high vacuum acquisition.

The pvd coating machine coats high-precision film layers, and the performance characteristics of the cryogenic capture pump used
1. Quickly absorb water and oil vapor, which can shorten the exhaust time by 60-90%;
2. Improve the coating quality, prevent oil return, not fall off, and have pure color;
3. Rapid cooling, cooling to -120℃ within 3 minutes, and the lowest temperature can reach -150℃;
4. Defrost with hot air in 2 minutes, quickly return to temperature, and cool again in 5 minutes;
5. Touch screen + PLC = perfect automation control;
6. One device can be designed with two load outputs;
7. Imported compressor, environmentally friendly mixed refrigerant;
8. It has two-way load inlet and outlet temperature display and local temperature display;
9. Defrost temperature can be set freely;
10. It has water temperature and exhaust temperature display;
11. Alarm for water shortage and high water temperature;
12. Protection against excessive compressor exhaust and excessive pressure;
13. Can be freely converted between local and remote control;
14. RS485 computer data interface, the computer can read temperature data and control.
Daily conventional pvd coating machine may only need a vacuum pump to coat conventional products. However, for coating high-precision coatings, such as optical coatings, flexible material coatings, etc., many pvd coating machine require cryogenic trapping. Pump.