News Center

Learn about the latest company information





After PCBA welding processing, how to properly clean the solder on the circuit board?

After the PCBA soldering process, some of the slag left by the solder is usually left on the circuit board. These welding slag should be cleaned before not affecting the use of the circuit board. With the development of science and technology and the improvement of the level of technical personnel, there are many ways to remove welding slag. Today, the method of cleaning the solder on the circuit board will be introduced.


There are two ways to clean the solder on the circuit board. One is to clean the solder on the original circuit board, and the other is to remove the excess solder slag after the soldering process is completed. A tin absorber is recommended for operation as follows:

1. cleaning the solder on the original circuit board

1. First shake off the solder on the soldering iron, and then melt the solder joint again. Just repeat it a few times.

2. Find a small piece of multi-strand thread, eat rosin, and melt it with a solder joint. Pull out the wire while it is hot to remove excess solder.

3. If the solder area is large, you can use a special hot air gun or tin furnace.

Remove excess welding slag after 2. welding

1. Use absolute ethanol (or more than 95% ethanol). If it is too dirty, use a soft brush dipped in alcohol.

2. Then dry with cotton wool.

3. The use of tin suction device and double panel is more troublesome. After the soldering iron is heated, a medical needle is inserted and rotary welded to process the hole. Or take a special thread (cord) to melt and take it out.

4. No tin absorber, after heating, the printing plate can be shaken quickly to remove tin slag. Be safe and don't move too much. When soldering the soldering iron, remove excess solder from the tip of the soldering iron and throw away the tin.

The pores produced by the welding of PCBA plates are the bubbles we often call. Generally, during PCBA processing, reflow soldering and wave soldering will produce porosity. So how to improve the porosity problem in PCBA board welding?

1. Baking

Expose the PCB and components to the air for a long time to bake to prevent moisture.

2. Control of solder paste

Solder paste contains water, also easy to produce pores and solder beads. First, choose a good quality solder paste. The return temperature and mixing of solder paste shall be carried out strictly according to the operation. The solder paste should be exposed to air for as short a time as possible. After the solder paste is printed, reflow soldering should be carried out in time.

3. Workshop humidity control

It is planned to monitor the workshop humidity and control it between 40-60%.

4. Set reasonable furnace temperature curve

Test the furnace temperature twice a day to optimize the furnace temperature curve, and the heating speed should not be too fast.

5. Flux spraying

During wave soldering, the amount of flux sprayed shall not be too much, and the spraying shall be reasonable.

6. Optimized furnace temperature curve

The temperature of the preheating zone shall meet the requirements and shall not be too low to make the flux fully volatilize, and the speed of passing through the furnace shall not be too fast.

There are many factors that may affect PCBA welding process bubbles. It can be analyzed from PCB design, PCB humidity, furnace temperature, flux (spraying size), chain speed, tin wave height, solder composition, etc. After many tests, it is possible to get a better process.