How to degas the workpiece of PVD vacuum coating equipment

The vacuum condition is the environment that supports the operation of the PVD vacuum coating machine, especially the equipment that requires high vacuum. Usually, we need to achieve a high vacuum, and the role of the pumping system is indispensable. However, in addition to the air extraction system, there is another point in the operation of the vacuum coating equipment, that is, the degassing of the workpiece.

There are a lot of gas and moisture in some workpieces. When the equipment is heated, these substances will be discharged into the vacuum chamber, reducing the vacuum degree. In addition, some gases contain toxic components, which directly damage the mechanical structure of the vacuum chamber and cause the equipment to fail to operate normally. In addition, during the coating process, the heating and expansion of the gas in the workpiece will crack the coating film. Of course, the possibility of this situation depends on the physical characteristics of the workpiece itself. The probability of simple expansion such as plastics is relatively high, while the mechanical expansion rate of hard metals is relatively low, but it cannot be ignored. Therefore, it is very necessary to degas the workpiece.

Under normal circumstances, the method of degassing the workpiece we use is baking. After heating, the gas and water in the workpiece are discharged. Before coating, air is drawn together to heat the workpiece. When the water and gas in the workpiece are released due to heating, they are pumped out by the vacuum pump together with the gas in the vacuum chamber.