Analysis of PCB PAD falling and De-laminating

1. CCL quality problems. If the adhesion of the resin glue between the copper foil and epoxy resin is relatively poor, even if the copper foil of the large-area copper is slightly heated or under mechanical external force, it is very easy to cause problems such as peeling of the pad and peeling of the copper foil.

2. The influence of storage conditions of the circuit board. If influenced by the weather or stored in a damp place for a long time, the moisture absorption of the circuit board will be high.
In order to achieve the desired soldering effect, the heat of the volatilization of moisture must be compensated, so the temperature and time of the soldering are both to be extended. Such soldering conditions tend to cause the PCB board copper foil to be separated with the epoxy resin.

3. Soldering iron welding problem, the general circuit board adhesion can meet the ordinary welding, there will be no peeling off of the pad. Sometime, PCBA need to be repaired during components assembly.
If the repair is done with a soldering iron or hot air gun, the local high temperature of often reaches a temperature of 300-400 degrees, causing the local temperature of the pad to be too high, and the resin glue under the copper foil is detached at a high temperature. Also, when the soldering iron is used to remove components, it is easy to cause the physical force to the pad, which is also the cause of the falling off of the pad.