The evaporation system of the evaporation pvd coating machine mainly refers to the film forming device. There are many film forming devices in the coating machine, including resistance heating, electron gun evaporation, magnetron sputtering, radio frequency sputtering, ion plating and other methods. I will introduce two methods of evaporation, because I use these two methods a lot.

 According to its structure and working principle, resistance evaporation is by far the most widely used evaporation method, and it is also the evaporation method with the longest application time. Its working method is to make a tungsten sheet into a boat shape, then install it in the middle of two electrodes, add medicinal materials to the center of the tungsten boat, and then slowly energize the electrodes. , the high current makes the high melting point tungsten boat generate heat, and then the heat is transferred to the coating material. When the heat of the tungsten boat is higher than the melting point of the coating material, the material sublimates or evaporates. This method is easy to operate, simple in structure and low in cost. Therefore, it is used by many devices, but the evaporated film has certain limitations due to its poor compactness, and many materials cannot be evaporated in this way. When the tungsten boat evaporates the coating material, the melting point of the material must be lower than the melting point of the tungsten boat, otherwise there is no way to proceed.
Electron gun evaporation is the most widely used evaporation method so far. It can evaporate any kind of coating material. Its working method is: put the coating material in the crucible, make the evaporation source into a filament shape, and use a special control Cabinet, apply a strong current and high voltage to the filament, because the material of the filament is tungsten, so it will heat up, and eventually will emit electrons, and then use a certain magnetic field to gather it into a certain shape, and pull it to the crucible, so that An electron beam is formed. Because the electron beam temperature is very high, it can melt any coated medicinal material. When the coated medicinal material is melted by the electron beam (some materials are directly sublimated), the molecules (atoms or ions) of the medicinal material move in a straight line in a vacuum. , and then when it encounters the substrate, it condenses and grows in this way to form a thin film! The most commonly used ones are the electron beam deflection angle of 270 degrees, or the e-line electron gun with an e-type trajectory, or the c-type electron gun with an electron beam deflection angle of 180 degrees and a c-type trajectory.
The biggest advantage of electron beam evaporation of pvd coating machine is that the spot of electron beam can be adjusted at will, one gun can be used for multiple purposes, the filament can be hidden to avoid pollution, any coating material can be evaporated, maintenance is convenient, the evaporation speed can be controlled at will, and the material decomposition is small. Film density is high. Good mechanical strength. The sputtering method is to bombard the surface of the target with high-speed positive ions, and through the transmission of kinetic energy, the molecules (atoms) of the target have enough energy to escape from the surface of the target and condense to form a thin film on the surface of the product. The film prepared by sputtering has strong adhesion and high purity, and can sputter a variety of materials with different components at the same time, but it has high requirements on the target material and cannot save resources like an electron gun. At present, magnetron sputtering is the most widely used. Magnetron sputtering refers to applying a strong electric field parallel to the surface of the cathode to confine electrons near the surface of the cathode target to improve the ionization efficiency. It is the easiest one to operate, so it is very widely used.