The blowhole caused by PCBA plate welding, which is commonly referred to as bubble, is generally caused by reflow welding and wave welding during PCBA processing. So how to prevent blowhole caused by PCBA production and processing welding?
1. baking
Bake PCB and electronic devices exposed to air for a long time to avoid moisture.
2. Supervision of solder paste
The moisture in the paste is also very easy to cause pores and tin beads. First, solder paste with high cost performance is adopted. The heating and mixing of solder paste shall be strictly observed according to actual operation, and the time of solder paste exposure to the air shall be as short as possible. After packaging and printing the solder paste, reflow soldering must be carried out immediately.
3. Supervision of environmental humidity in the workshop
The environmental humidity of the workshop with the scheme monitor is controlled between 40-60%.
4. Set an effective furnace temperature curve.
Carry out temperature control inspection once or twice a day, and raise the furnace temperature curve. The temperature raising speed should not be too fast.
5. Flux spraying
When passing through the wave soldering machine, the spraying amount of flux should not be excessive, and the spraying is effective.
6. Improve the furnace temperature curve.
The temperature of the heating zone should be regulated, and it should not be too low, so that the flux can be fully evaporated, and the furnace passing rate should not be too fast.
There are many factors that will harm PCBA welding bubbles, which can be analyzed from the aspects of PCB design, PCB environmental humidity, temperature control, flux (sprayer size), chain speed, aspect ratio of tin wave, solder wire composition, etc. Only after several adjustments can it be manufactured well.