1. Do not charge nitrogen.
2. In the bga reflow welding process, the welding area needs to be heated at high temperature, and nitrogen injection will increase the pressure of the welding area, which may lead to unstable welding or other problems.
3. In the bga reflow welding process, nitrogen is usually used for atmosphere control to reduce the influence of oxygen on the welding area and improve the welding quality.
However, it is not necessary to fill nitrogen directly in the specific welding operation.