The vacuum state is the environment that supports the operation of the vacuum coating machine, especially the equipment that needs high vacuum degree. Usually we need to reach high vacuum degree, and the function of the air extraction system is indispensable. But in addition to the air extraction system, in the process of the operation of the vacuum coating equipment, there is another point that is the degassing of the workpiece. There are many gases, water, etc. in some workpieces. These substances will be discharged into the vacuum chamber when the equipment is heated, reducing the vacuum degree. What's more, some gases have toxic components, which directly damage the mechanical structure in the vacuum chamber, causing the equipment to not operate normally.

In addition, during the coating process, due to the heating and expansion of the gas in the workpiece, it is easy to crack the coated film. Of course, the probability of this situation depends on the physical properties of the workpiece itself. The probability of this situation depends on the physical properties of the workpiece, such as plastic, which is easy to expand, is relatively high, and the probability of hard metal, which is relatively low, but can not be ignored. Therefore, degassing of the workpiece is very necessary.
Generally, the degassing method we use is baking. The gas and water in the workpiece are discharged by heating. Before coating, the workpiece is heated while the air is pumped. When the water and gas in the workpiece are discharged by heating, they are pumped out by the vacuum pump together with the gas in the vacuum coating machine. Different degassing measures are taken for different workpieces to effectively control the gas and water discharge inside the workpieces and improve the stability and uniformity of the coating.