The vacuum state is the environment that supports the operation of the vacuum coating machine, especially the equipment requiring high degree of vacuum. Usually, we need to achieve high vacuum, the function of the pumping system is indispensable. But in addition to the exhaust system, degassing of the workpiece is also required during the operation of the vacuum coating apparatus.
Some workpieces have a lot of gases, moisture, etc. inside. These substances will be discharged into the vacuum chamber when the equipment is heated, reducing the vacuum degree and even some gases with toxic components, which will directly damage the mechanical structure of the vacuum chamber and cause the equipment to not operate normally.
In addition, in the process of coating, because of the gas heating and expansion in the workpiece, it is easy to crack the film that has already been plated. Of course, the probability of this situation is related to the physical properties of the workpiece itself. Such plastics, which are easily inflated, the probability is relatively high. Like hard materials such as metals, the probability is relatively low, but they cannot be ignored. Therefore, degassing of workpieces is very necessary.
The commonly used method of degassing the workpiece is baking. The gas and moisture in the workpiece are discharged by heating, and heating the workpiece at the same time before the coating is. When the moisture and gas in the workpiece are released due to heating, they are pumped out together with the gas in the vacuum chamber.
Different gassing measures are taken for different workpieces to effectively control the internal gas and moisture emissions of the workpiece and improve the stability and uniformity of the coating.