Analysis of the reason why the pad is easy to fall off when the circuit board is soldered
During the use of the circuit board, the pads often fall off, especially when the circuit board is repaired. When using an electric soldering iron, the phenomenon of the pads falling off is very easy. Analyze and take corresponding countermeasures against the causes.
Reasons for the pads to fall off easily when the circuit board is soldered:
1. Plate quality problems. Due to the poor adhesion of the resin glue between the copper foil of the copper clad sheet and the epoxy resin, even if the copper foil of the circuit board with a large area of copper foil is slightly heated or under mechanical external force, it is very easy to bond with the epoxy resin. Separation leads to problems such as pad peeling and copper foil peeling.
2. Influence of storage conditions of circuit boards. Affected by weather or stored in a humid place for a long time, the moisture absorption of the circuit board is too high. In order to achieve the ideal soldering effect, the patch must be compensated for the heat carried by the volatilization of the moisture during soldering. extend. Such soldering conditions easily cause delamination of the copper foil of the circuit board and the epoxy resin.
3. Soldering iron soldering problems, the adhesion of general circuit boards can meet ordinary soldering, and there will be no pad peeling off, but electronic products generally may be repaired. Repairs are generally repaired with soldering irons, due to the local high temperature of the soldering iron. It often reaches a temperature of 300-400 degrees, which causes the instantaneous local temperature of the pad to be too high, and the resin adhesive under the copper foil of the pad is exfoliated at high temperatures, and the pad falls off. When the electric soldering iron is removed, it is also easy to attach the physical force of the electric soldering iron head to the pad, which is also the cause of the pad falling off.
In view of the fact that the pads are easy to fall off under the conditions of use, the circuit board factory adopts the following aspects to increase the soldering resistance of the circuit board pads as much as possible to meet the needs of customers.
1: The copper-clad board is made of genuine substrates produced by quality assurance manufacturers. The selection of fiberglass cloth and lamination process for general genuine copper-clad laminates can ensure that the manufactured circuit boards have solder resistance that meets customer requirements.
2: The circuit board is packed in a vacuum before leaving the factory, and a desiccant is placed to keep the circuit board always dry. In order to reduce false soldering and improve solderability, create conditions.
3: In view of the thermal shock to the pad during the repair of the electric soldering iron, we increase the thickness of the copper foil of the pad by electroplating as much as possible. In this way, when the electric soldering iron heats the pad, the thermal conductivity of the copper foil is significantly enhanced and effective. The reduced local high temperature of the pads, meanwhile, the rapid heat conduction makes the pads easier to remove. Reach the solder resistance of the pad.