Production of vacuum chamber
Welding is one of the important aspects in the manufacture of vacuum chambers. In order to avoid chemical reaction between molten metal and oxygen in the atmosphere and affect the quality of welding, argon arc welding is usually used to complete the welding.
Argon arc welding means that a protective gas argon gas is sprayed around the tungsten electrode during the welding process to prevent oxidation of the high temperature metal after melting.
In the argon arc welding of the ultra-high vacuum chamber, in principle, internal welding must be used, that is, the welding surface is on the vacuum side, so as to avoid the occurrence of a virtual leak. The vacuum chamber does not allow double welding and double sealing inside and outside.
The inner wall surface of the vacuum chamber adsorbs a large amount of gas molecules or other organic substances, and becomes a deflation source that affects the degree of vacuum. In order to achieve ultra-high vacuum, the cavity should be baked at a high temperature of 150-250 ° C to promote the gas release on the surface and inside of the material as soon as possible. The baking method comprises winding a heating belt on the outer wall of the cavity, fixing the armored heating wire on the outer wall of the cavity or directly placing the cavity in the baking tent. A relatively economical and simple baking method is to use a heating belt, and the outside of the heating belt is wrapped with aluminum foil to prevent heat loss and uniform heating of the cavity.