When many electronic engineers are doing product design, PCBA proofing only requires a small order, usually a sample order of about 10 pieces. If the processing cost is taken into consideration for this small amount of PCBA proofing orders, PCBA hand-attached processing can be used.
In hand patch processing and production, the splicing of ICs is relatively difficult. After all, ICs are generally ICs with a large number of pins. This requires our patch processing personnel to treat it carefully and patiently and operate in strict accordance with the processing requirements to obtain the desired result. A product of comparable quality to machine stickers. There are many things worth noting about hand soldering of wafers. For example, due to the high degree of internal integration, it is easily damaged by overheating, etc.
PCBA proofing
IC chip patch welding steps
SMD welding is an indispensable part of the PCBA prototyping process. If mistakes are made during this process, the circuit board processed by the SMD may be directly affected or discarded. Therefore, when welding, you must be familiar with the correct welding method and understand the relevant precautions. Avoid problems.
1. Before patch soldering, first apply additives on the solder and treat it with solder once so that the soldering plate will not suffer from poor plating or oxidation, and the chip generally does not need to be processed.
2. Use tweezers to carefully place the PQFP chip on the PCB board. Be careful not to damage the pins. Align the wafer with the backing plate so that the wafer is in the correct orientation. Control the temperature of the soldering iron at 300 degrees Celsius, apply a small amount of solder to the end of the soldering iron, use a tool to press down on the positioned wafer, put a small amount of flux on the two diagonal needles, and still press down on the wafer. , weld two diagonally positioned pins to fix the chip. After welding the diagonal lines, confirm again whether the position of the chip is aligned. If necessary, it can be adjusted or removed and rearranged on the PCB board.
3. When starting to solder all pins, insert solder at the end of the soldering iron and apply flux to all pins to keep the pins moist. Touch each pin end of the die with the soldering iron until you see the soldering annotation flowing into the pins. When welding, the end of the soldering iron should be parallel to the soldering needle to prevent excessive overlap of the soldering iron.
4. After soldering all the pins, use flux to clean the soldering notes. Pull unnecessary welding annotations where needed, eliminating shorts and overlaps. Finally, use tweezers to check whether there is virtual soldering. After the inspection is completed, apply flux to the circuit board. The chip resistor components are relatively easy to solder. You can first add comments on the solder joints, place one end of the component, use tweezers to clamp the component, solder one end, and then confirm whether it is upright. If it is already placed correctly, re-solder the other end. It takes a lot of practice to master welding technology.
Common precautions for PCBA proofing and processing of IC patches
1. The IC welding time should be as short as possible, generally no more than 3 seconds.
2. The soldering iron used is good and has a constant temperature of 230 degrees.
3. The PCBA proofing machine workbench should be treated with anti-static treatment.
4. Choose a soldering iron tip with a narrow tip so that it will not touch the adjacent endpoints during welding.
5. During PCBA prototyping and processing, do not remove the CMOS circuit before soldering.
PCBA