What are the reasons for soldering blistering of circuit boards
PCB circuit board soldering and blistering means that the circuit board is separated from the board or copper foil in a high temperature environment (above 250 °C), so that the solder resist and the flow blocking effect are lost. The occurrence of solder mask blistering on the PCB circuit board not only affects the appearance of the circuit board, but also reduces the aesthetics and affects the performance of the circuit board. So what is the cause of soldering and soldering of PCB boards?
1. Poor surface treatment: Since the surface of the PCB circuit board is not well treated, such as uneven brushing, residual water stains, oil stains, etc., it is easy to cause soldering and soldering of the circuit board.
PCB circuit board soldering and blistering means that the circuit board is separated from the board or copper foil in a high temperature environment (above 250 °C),
so that the solder resist and the flow blocking effect are lost. The occurrence of solder mask blistering on the PCB circuit board not only affects the appearance of the circuit board, but also reduces the aesthetics and affects the performance of the circuit board. So what is the cause of soldering and soldering of PCB boards?
1. Poor surface treatment: Since the surface of the PCB circuit board is not well treated, such as uneven brushing, residual water stains, oil stains, etc., it is easy to cause soldering and soldering of the circuit board.
2, the thickness of the ink is uneven: when the printed circuit board is soldered, especially when it is hand-printed, the thickness of the solder resist is often different. Therefore, in the place where the solder resist is thick, the drying time is insufficient, which leads to the solder joint. The force is reduced, causing the soldering to blister.
3, multiple times tin orb tin pot temperature is too high: general circuit board soldering resistance has a certain degree of high temperature resistance, once it exceeds its range will affect the adhesion of solder mask, resulting in solder joint blistering. Usually, multiple times of spraying tin or excessive temperature will affect the adhesion of the circuit board soldering.
4. Copper surface depression: There are many kinds of plates on the circuit board. Generally, the international plate will not have the phenomenon of copper foil depression. Some manufacturers use PCB board manufacturers to use low-priced circuit board plates to reduce the cost. When printing to a concave position, the adhesion is lowered and the solder resist is peeled off.
when the printed circuit board is soldered, especially when it is hand-printed, the thickness of the solder resist is often different. Therefore, in the place where the solder resist is thick, the drying time is insufficient, which leads to the solder joint. The force is reduced, causing the soldering to blister.
3, multiple times tin or tin pot temperature is too high: general circuit board soldering resistance has a certain degree of high temperature resistance, once it exceeds its range will affect the adhesion of solder mask, resulting in solder joint blistering. Usually, multiple times of spraying tin or excessive temperature will affect the adhesion of the circuit board soldering.
4. Copper surface depression: There are many kinds of plates on the circuit board. Generally, the international plate will not have the phenomenon of copper foil depression. Some manufacturers use PCB board manufacturers to use low-priced circuit board plates to reduce the cost. When printing to a concave position, the adhesion is lowered and the solder resist is peeled off.
PCB circuit board common problems and solutions
1. Dark and granular contacts appear on the PCB circuit board
PCB boards have dark or small grain joints. Most of them are caused by solder contamination and excessive oxides in the tin. The solder joint structure is too brittle. Be careful not to use low tin content. The dark color caused by solder is confused.
Another reason is that the composition of the solder used in the PCB manufacturing process changes, the impurity content is too much, and it is necessary to add pure tin or replace the solder. Physical changes in the layered glass fiber layer, such as separation between layers, but this situation is not a bad solder joint, because the substrate is too hot, need to reduce the preheating and soldering temperature or no judgment and substrate speed.
Second, the PCB circuit board solder joint turns golden yellow
In general, the solder of the PCB board is silver-gray, but occasionally there are golden solder joints. The main reason for this problem is that the temperature is too high, and only the temperature of the tin furnace needs to be lowered.
Third, PCB circuit board short circuit:
PCB circuit board short circuit is one of the common faults that cause the PCB board to work, and the biggest cause of this problem is improper solder pad design. Solution: The circular pad can be changed to an elliptical shape to increase the distance between the point and the point to prevent short circuit.
The design of the PCB board part is not appropriate,
and it will also cause the board to be short-circuited and unable to work. If the foot of SOIC is parallel to the tin wave, it will easily cause a short circuit accident. Solution: It can be modified if the part is removed, so it is easy to cause a short circuit. The solder joint needs to be more than 2mm away from the line.
In addition, there are some reasons that may cause short-circuit failure of the PCB board, such as too large substrate hole, too low tin furnace temperature, poor solderability of the board surface, solder mask failure, board surface contamination, etc., which are common faults. the reason. Engineers can eliminate and check the above reasons and faults one by one.
The design and production of PCB circuit boards is a simple and cumbersome task. It is inevitable that some problems will arise. The production personnel need to understand the causes and solutions of the problems, in order to better avoid the PCB board problems.
