PCBA production process
2023-08-24
First, SMT patch processing
The process of SMT patch processing is: solder paste mixing → solder paste printing →SPI→ mounting → reflow welding →AOI→ repair
1. Stir the solder paste
After the solder paste is removed from the refrigerator and thawed, it is stirred by hand or machine for printing and welding.
2, solder paste printing
Place the solder paste on the steel mesh and print the solder paste onto the PCB pad with a scraper.
3. SPI
SPI is the solder paste thickness detector, which can detect the solder paste printing situation and control the solder paste printing effect.
4. SMT assembly
5. Reflow welding
The mounted PCB board is reflow welded, and through the high temperature inside, the paste-like solder paste is heated into a liquid, and
finally cooled and solidified to complete the welding.
6. AOI
AOI is automatic optical inspection, which can detect the welding effect of PCB board through scanning, and can detect the defects of the board.
7. Repair
Repair defects detected by AOI or manual.
Two, DIP plug-in processing
The process of DIP plug-in processing is: plug-in → wave soldering → cutting foot → post welding → washing board → quality inspection
1. Plug-in
The plug-in material is processed with pins and inserted on the PCB board
2, wave welding
The inserted board is welded over the wave crest, during which liquid tin is sprayed onto the PCB board, and finally cooled to complete
the welding.
3. Cut the feet
The pin of the welded board is too long and needs to be cut.
4, after welding processing
Manual welding of components using electric soldering iron.
5. Wash the board
After wave soldering, the board will be dirty, need to use washing water and washing tank for cleaning, or use a machine for cleaning.
6. Quality inspection
Check the PCB board, unqualified products need to be repaired, and qualified products can enter the next process.
Three. PCBA test
PCBA test can be divided into ICT test, FCT test, aging test, vibration test, etc
PCBA test is a big test, according to different products, different customer requirements, the test means used are different. ICT test is to
detect the welding condition of components and the on-off condition of lines, while FCT test is to detect the input and output parameters
of PCBA board to check whether they meet the requirements.
Four, PCBA conformal coating
PCBA conformal coating process steps are: brushing side A → surface dry → brushing side B → room temperature curing 5. Coating
thickness: Coating thickness: 0.1mm-0.3mm6. All coating operations should not be lower than 16℃ and relative humidity below 75%
conditions. PCBA three anti-coating is still a lot of, especially some temperature and humidity more harsh environment, PCBA coating
three anti-paint has superior insulation, moisture, leakage, shock, dust, corrosion, anti-aging, anti-mildew, anti-parts loose and insulation
corona resistance performance, can extend the storage time of PCBA, isolation of external erosion, pollution and so on. Spraying method
is the most commonly used coating method in the industry.
Five. Finished product assembly
The coated PCBA board with the test OK is assembled for the shell, and then tested, and finally it can be shipped.
PCBA production is a link to a link, any link of the problem will have a very big impact on the overall quality, the need for strict control of
each process.
