The main reasons affecting the success of BGA rework can be divided into three kinds: mounting accuracy, precise temperature control, preventing PCB deformation, and of course, other factors. However, these three factors are difficult to grasp, so they are listed to be solved together. The following are the main reasons affecting the success rate of BGA rework.First, it is necessary to ensure a certain mounting accuracy when soldering BGA components, otherwise it will cause empty soldering. When soldering and heating, the solder ball has a certain self-centering effect, and a slight deviation is allowed. When mounting, the center of the shell during the period is approximately coincident with the center of the screen printing frame, which can be regarded as the correct mounting position.In the case of not using the optical grade BGA rework table, it is also possible to judge whether to touch or not according to the hand feeling when moving the BGA (this point is more subjective, and everyone's feeling is not necessarily the same). The optical-grade BGA rework station can directly see whether the BGA components are aligned with the bonding pads and automatically solder them.At present, the domestic BGA rework table basically adopts the way of upper and lower hot air and bottom infrared preheating, so it is necessary to use a reasonably designed tuyere to prevent the hot air from moving the BGA when heating.2. Reasonable and high-quality rework requires a corresponding rework temperature curve. The temperature and time should be well controlled within the range that BGA can bear. Under standard conditions, the temperature of lead is less than 260 ℃ and that of lead-free is less than 280 ℃. If the temperature control is not precise enough and the temperature fluctuation is large, it is easy to damage the BGA components. At the same time, the heating time should not be too long, the number of repair should not be too much, in the case of high temperature will cause the oxidation of BGA, a long time will shorten the life of BGA.