The principle and process of evaporation of vacuum coating equipment

1. The principle of resistive evaporation plating

The principle of resistance evaporation coating of vacuum coating equipment: It is the process of sublimation (evaporation) when the solid material becomes liquid and then reaches the boiling point by the resistance heat generated by the current passing through the tungsten twisted wire.

2. Adjustment method

The resistance evaporation coating of vacuum coating machine is divided into three steps: preheating section, premelting section and linear evaporation section. However, these three steps are closely related to the length of time and the size of the current. I think that the method of medium current in a short time, small current for a long time, and linear rise in evaporation current should be used as the usual adjustment method to adjust the process, such as the same current time It will turn yellow if it is one-half longer, and turn black if it is longer. The thickness of the film of the vacuum coating equipment is too thick, it will bring a little black, but the metal color is black. Thin film is white silver.

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① Phenomenon in the preheating section: The tungsten wire in the preheating section is basically the same, but the tungsten wire is heated first with a certain ampere current. The usual process current is between 600A-1000A and the time is 10-30 seconds.

② Phenomenon in the pre-melting section: At this time, the tungsten wire in the furnace body will be bright, and then the aluminum wire will behave like an explosion, and then it will gradually change from a solid state to a liquid state. The usual process current is between 800A-1200A and the time is 5-15 seconds.

③. Linear evaporation section: This stage is the most important. The blackening and yellowing of the vacuum coating machine's film occurs at this stage. During the evaporation, all the tungsten filaments are as bright as a 60-watt light bulb. ), as the current increases, the aluminum wire becomes brighter and brighter. At the beginning, the aluminum wire hangs upside down on the tungsten wire like a water droplet, and as the current increases, it will slowly be completely evaporated. (The temperature in the tungsten twisted wire ring also rises continuously as the current rises. The usual process current rises linearly between 1200A-2700A, and the time is within 10 seconds.

Zunhua Baorui Titanium Technology Co., Ltd. is a well-known vacuum coating manufacturer, specializing in the manufacture of various vacuum coating equipment, providing industry customers with customized process solutions and coating equipment.