1. Disassemble the BGA and turn on the power switch of the BGA rework station, install the PCB board to be reworked and the corresponding air hood, check whether the hot air nozzle has cold air blowing out, and the lower temperature setting temperature curve is correct. When the BGA is repaired, the BGA is different. Yes. The programming temperature control table needs to set different temperature curves, and the actual temperature of each segment is generally the highest. Generally, it is not copied to search and send to the mobile phone translation Jun BGA solder ball welding temperature curve reference setting. First set the cooling fan switch to gear 0, press the start button to start the set program, after the temperature curve runs, after hearing the prompt sound, at this time use a vacuum suction pen to quickly suck the BGA away from the PCB board. Then switch the cold air switch to manual or automatic to cool the PCB, and then remove it from the PCB pallet when the PCB board can be directly touched by hand. 2. Moisture removal treatment. As PBGA is sensitive to moisture, it is necessary to check whether the device is damp before assembling, and bake the damp device. 3. Because other components are already installed on the surface assembly board, the printed solder paste must use a special small template for BGA. The thickness and opening size of the template should be determined according to the ball diameter and ball distance. After printing, the printing quality must be checked, if it is unqualified , PCB pads must be cleaned and dried before reprinting. 4. Cleaning the pads Use a soldering iron to clean and level the remaining solder on the PCB pads. Use desoldering tape and flat spade-shaped soldering iron heads to clean them. Be careful not to damage the pads and solder mask during operation. 5. Choose a template that matches the BGA pad. The opening size of the template should be 0.05-0.1mm larger than the diameter of the solder ball. Sprinkle the solder balls evenly on the template, shake the ball planter, and remove the excess solder balls. Roll from the template to the solder ball collection groove of the ball planter, so that exactly one solder ball remains in each leak hole on the surface of the template. Place the ball implanter on the workbench, suck the BGA device printed with flux or solder paste on the suction nozzle, align it according to the method of mounting BGA, move the suction nozzle down, and mount the BGA device to On the solder balls on the surface of the ball planter template, the BGA device is sucked up, and the solder balls are stuck on the corresponding pads of the BGA device with the help of the viscosity of the flux or solder paste. Use tweezers to clamp the outer frame of the BGA device, turn off the vacuum pump, place the solder ball of the BGA device on the workbench, check whether there is any missing solder ball, if any, use tweezers to fill it up. 6. If the mounting BGA is a new BGA, it must be checked whether it is damp, if it has been damp, it should be baked before mounting. The removed BGA device can be reused in general, but it must be used after ball planting. The steps for mounting BGA devices are as follows: A: Place the surface assembly board with solder paste printed on the workbench. B: Select the appropriate nozzle and turn on the vacuum pump. Suction the BGA device, observe the picture of the computer monitor, adjust the positioning mode and camera alignment on the device to fine-tune the Y-direction, so that the bottom of the BGA device and the PCB pad are completely overlapped, and then move the suction nozzle down, and mount the BGA device on the PCB , And then turn off the vacuum pump. Setting the soldering temperature curve can be set according to the size of the device, the thickness of the PCB and other specific conditions. Compared with the traditional SMD, the soldering temperature of BGA is about 15 degrees higher. 7. Inspection of the welding quality of BGA requires light or ultrasonic inspection equipment. In the absence of inspection equipment, the welding quality can be judged through functional testing, or the inspection can be carried out based on experience. Lift up the surface assembly board of the soldered BGA, look at the BGA around the light, observe whether the light is transmitted, the distance between the BGA and the PCB2 is the same, observe whether the solder paste is completely melted, whether the shape of the solder ball is correct, and the solder ball collapses. Degree etc. One-if there is no light, it means there is a bridge or there is a solder ball between the solder balls; one if the shape of the solder ball is not correct, there is a distortion phenomenon, it means that the temperature is not enough, the soldering is not enough, and the solder does not fully perform self-positioning when it flows again The effect of the effect; a degree of solder ball collapse: the degree of collapse is related to the soldering temperature, the amount of solder paste, and the size of the pad. When the pad design is reasonable, it is normal that the distance between the bottom of the BGA and the PCBA after reflow soldering is 1/5-1/3 collapsed than before soldering. If the solder ball collapses too much, the temperature is too high.