PCB Tech - What is the principle of pcb board repair?

Not all PCB factories can guarantee that every design and processing is without accident, sometimes due to various circumstances, the PCB board will have problems, which need to be reworked and repaired. However, the rework and repair of PCB board processing is not carried out casually, but has certain principles. What is the principle? Let's take a look.

1. The basis for the need to rework and repair the PCB board is that after the design and production personnel found inconsistent with the actual situation after the production according to the PCB design documents, they must be repaired, and this rework and repair also has a unified process specification, and can not be random. alley.

2. The number of times the solder joints are allowed to be reworked is limited each time during the PCB processing. Some novice PCB board processors think that as long as they are wrong, they can rework and repair them. It's no big deal. But in fact, according to the production principle, solder joint rework is limited to a certain number of times, basically no more than three times, otherwise it will cause damage to the soldering part, and then affect the performance of the PCB board. Therefore, once there are three rework situations, basically this PCB board will not be used again.

PCB board

3. In the case of disassembling components during PCB processing and repair, in principle, the disassembled components cannot be used again. Even if it is to be used, it must be screened and tested to confirm that it meets the requirements before it can be used again. Here, the editor will give you a small reminder. In order to save costs, some small workshops or small manufacturers of unprofessional PCB processing will re-use the components that have been reworked and repaired. This approach is not correct. Yes, although the cost is saved, the performance is actually affected. Therefore, the low price of some small workshop-type PCB board processing plants is because of this.

4. When the PCB board is processed, the number of desoldering on the pad is also specified. According to the designer of a regular PCB board processing manufacturer, each printed pad is basically a one-time operation, and only one component is allowed to be replaced, because a qualified solder joint will increase in thickness after remelting, causing the solder joint to change It is brittle and has reduced strength. In the event of vibration, it is extremely easy to bring safety hazards to electronic products. Therefore, regular PCB board processing manufacturers will not often de-soldering twice.

5. When remelting, the required temperature is higher, this temperature will have a certain impact on the manufacture of PCB plates, especially the IMC needs to be removed, so a certain high temperature must be maintained. The high temperature will cause the copper plating layer to break or deform, and eventually cause the pad to detach. In addition, in the case of lead-free, high temperature will also pull up the entire pad, and eventually heat up and delaminate, causing warping or separation.

The above is about the principle of rework and repair in PCB processing. Although it is troublesome, it can guarantee the quality of production and processing, so that customers can have no worries. Therefore, PCB processing manufacturers must strictly abide by it. Only in this way can they ensure their corporate image and attract more customers to cooperate.