1. Reasonable adjustment of preheating temperature: Before performing BGA welding, the motherboard must be fully preheated, which can effectively ensure that the motherboard does not deform during the heating process and can provide temperature compensation for later heating.
2. When the BGA is soldering the chip, the position should be adjusted reasonably to ensure that the chip is between the upper and lower air outlets, and the PCB must be tightened with clamps to both ends and fixed! The standard is to touch the motherboard with your hands and the motherboard will not shake.
3. Reasonably adjust the welding curve: Method: Find a motherboard with a flat PCB without deformation, use the welding station's own curve for welding, and insert the temperature measuring line that comes with the welding station between the chip and the PCB when the fourth curve is completed. , to obtain the temperature at this time. The ideal value can reach about 217 degrees without lead, and about 183 degrees with lead. These two temperatures are the theoretical melting points of the above two solder balls! But at this time, the solder balls at the bottom of the chip are not completely melted. From the perspective of maintenance, the ideal temperature is about 235 degrees without lead and about 200 degrees with lead. At this time, the chip solder balls are melted and then cooled to achieve the optimal strength.
4. The alignment must be precise during chip welding.
5. Use an appropriate amount of flux paste: When the chip is soldered, a small brush can be used to apply a thin layer on the cleaned pad, and try to apply it evenly. Do not brush too much, otherwise it will also affect the soldering. When repairing soldering, you can use a brush to dip a small amount of flux paste around the chip.
