1, the first step: BGA disassembly using a professional BGA repair table, or a large hot air duct, with the gentle touch of tweezers, carefully separate the BGA material from the PCBA.
2, the specific method: use the hot sol gun in the chip between the four sides and the motherboard to pour a layer of slightly thick hot sol, so that the four sides of the chip and the bottom plate adhesion, the best adhesion surface is slightly larger, if necessary, the hot sol can be covered on the surface of the chip.
3, the necessary tools are: wind gun, constant temperature soldering iron, easy to use flux, tin wire (can be replaced by wire), tin paste, washSound welding properties.
2, void specifications: According to the BGA device manufacturer's recommendations or industry standards, also need to consider the size of the void specifications. The void refers to the gap between the BGA ball and the pad, which is usually used to contain the thermal expansion and contraction of the solder paste or during the welding process. This specification can be found in the specifications of the BGA device.
3, for skilled maintenance personnel, even stickers do not need to be used, IC alignment after planting the tin plate with the hand or tweezers to press firmly, and then the other hand to scrape the tin blow welding into a ball. If the tin paste is too thin, it is easy to boil and lead to ball formation during blow weldingDifficult, so the more dry the tin slurry, the better, as long as it is not dry hard into a lump.
1, generally, the common BGA welding material is lead-free solder. The melting point of lead-free solder is about 220 to 240 degrees Celsius, so it is generally believed that the BGA welding temperature should be controlled between 220 and 240 degrees Celsius. Exceeding this temperature range may lead to excessive melting or scorching of the welding material, thus affecting the quality of the welding.
2, the peak temperature of no leadThe degree is generally set at about 250, with a lead of 230. The chip itself has a peak temperature of 260 degrees. Check with parts suppliers.
3, lead: molten tin temperature is low 180-220 degrees, not environmentally friendly! Lead-free: high melting tin temperature 240-260 degrees, environmental protection. bga chip welding should pay attention to temperature, time, anti-static measures, Zhuohui core technology bga welding program.