PCBA refers to the process of mounting components, plug-in and welding of PCB bare board. PCBA production process needs to go through a series of processes to complete the production, this paper introduces the various processes of PCBA production.
PCBA production process can be divided into several major processes, SMT chip processing rarr; Dip plug-in processing rarr; PCBA test rarr; Assembly of finished products
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1、 SMT chip processing
SMT chip processing process is: solder paste mixing rarr; Solder paste printing & rarr; SPI→ Mount & rarr; Reflow soldering & rarr; AOI→ Rework
1. Solder paste mixing
After the solder paste is taken out of the refrigerator and thawed, it is stirred by hand or machine to be suitable for printing and welding.
2. Solder paste printing
The solder paste is placed on the steel net, and the solder paste is missing printed on the PCB pad by the scraper.
3、SPI
SPI is the solder paste thickness detector, which can detect the solder paste printing and control the solder paste printing effect.
4. Mounting
The SMD components are placed on Feida, and the SMD head can accurately mount the components on Feida on PCB pad through identification.
5. Reflow soldering
After reflow soldering, the pasted solder paste is heated into liquid by the high temperature inside, and finally the solder paste is cooled and solidified to complete the soldering.
6、AOI
AOI is automatic optical detection, which can detect the welding effect of PCB by scanning and detect the defects of PCB.
7. Rework
Repair the defects detected by AOI or manual inspection
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2、 Dip plug in processing
The process of dip plug-in processing is: plug-in rarr; Wave soldering rarr; Cutting foot & rarr; Post welding & rarr; Washing plate & rarr; Quality control
1. Plug in
The plug-in material is processed and inserted on the PCB board
2. Wave soldering
Solder the inserted board through the wave crest. In this process, liquid tin will be sprayed onto the PCB board, and finally the soldering is completed by cooling.
3. Cutting feet
The pins of the welded board are too long and need to be cut.
4. Post welding processing
Use electric soldering iron to weld components by hand.
5. Washing board
After wave soldering, the board will be dirty, need to use washing water and washing tank for cleaning, or use machine for cleaning.
6. Quality control
PCB board inspection, unqualified products need to be repaired, qualified products can enter the next process.
3、 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 methods are different. ICT test is to detect the welding condition of components and the on-off condition of circuit, while FCT test is to detect the input and output parameters of PCBA board to see whether they meet the requirements.
4、 Finished product assembly
The PCBA board tested OK is assembled into the shell, then tested, and finally shipped.
PCBA production is closely linked to each other. Any problem in any link will have a great impact on the overall quality, so it is necessary to strictly control each process.
