Assembly reliability, also known as process reliability. It usually means that the normal operation will not be damaged when PCBA is assembled and soldered. Therefore, if you want to ensure the reliability of PCBA assembly, you have to start from two aspects, one is the design, and the other is the assembly process. Let's take a look at the following Sanjing:

(1) From the design perspective: If the design is improper, the solder joints or components are easily damaged or damaged. Therefore, when designing, ①BGA, chip capacitors, crystal oscillators and other stress-sensitive devices should be placed where the PCB is not easily deformed, or reinforced design, or appropriate circumvention measures should be adopted, otherwise these sensitive devices are prone to mechanical or thermal stress. been destroyed.

②The stress-sensitive components should be placed as far away as possible from the places that are prone to bending during PCB assembly. In order to avoid bending and deformation when the daughter board is assembled, the connector that connects the daughter board and the mother board should be placed on the edge of the daughter board as much as possible, and the distance from the screws should not exceed 10mm.

At the same time, in order to prevent stress fracture of the BGA solder joints, avoid placing the BGA layout in a place that is prone to bending during PCB assembly. If the BGA design is poor, it is easy to cause its solder joints to crack when holding the board with one hand.

(2) Improve the assembly process to reduce stress, such as avoiding holding the board with one hand. At the same time, the four corners of the large-size BGA should be reinforced.

When the PCB is bent, the solder joints at the four corners of the BGA receive the greatest force and are most likely to crack or break. Therefore, strengthening the four corners of the BGA is very effective in preventing cracks in the corner solder joints. Special glue should be used for reinforcement, or patch glue can be used for reinforcement. This requires space for component layout, and the reinforcement requirements and methods should be indicated on the process documents.

Therefore, the design of assembly reliability should not be limited to the improvement of the layout of the components. The more important thing should be to reduce the stress of the assembly, adopt appropriate methods and tools, strengthen the training of the operators, and standardize the operation actions. Only in this way can the assembly stage be resolved. The problem of solder joint failure.

The above is about the reliability of PCBA assembly, I hope it can be helpful to everyone!