As we all know, any electronic product must go through PCBA processing. After the components are mounted and plugged into the bare PCB board, normal functional testing can be carried out before being released to the market. However, the production process of PCBA needs to go through a series of processes to complete the production. Today, Shelly will introduce to you the various processes of PCBA production.

The PCBA production process can be divided into several major processes: SMT → DIP→ PCBA testing → Coating Cover → Box Build.

A. SMT patch processing process 

The process of SMT patch processing is: solder paste mixing → solder paste printing → SPI → mounting → reflow soldering → AOI → repair 

1. Solder paste stirring Take the solder paste out of the refrigerator and thaw it before use Mix by hand or machine to suit printing and welding. 

2. Solder paste printing: Place the solder paste on the steel mesh, and use a scraper to print the solder paste onto the PCB pad. 

3. SPISPI, the solder paste thickness detector, can detect the solder paste printing situation and control the solder paste printing effect. 

4. Mounting 

5. Reflow soldering: Put the mounted PCB board through reflow soldering. After the high temperature inside, the paste-like solder paste is heated and turns into liquid. Finally, it cools and solidifies to complete the soldering. 

6. AOI is automatic optical inspection. It can detect the welding effect of the PCB board through scanning and detect defects in the board. 

7. Repair: Repair the defects detected by AOI or manual inspection.

B. DIP plug-in processing

The process of DIP plug-in processing is: plug-in→wave soldering→foot cutting→post-soldering processing→board washing→quality inspection

1. The plug-in process the plug-in material into pins and inserts it on the PCB board.

2. Wave soldering: Put the inserted board through wave soldering. During this process, liquid tin will be sprayed onto the PCB board and finally cooled to complete the soldering.

3. Trim the pins. The pins of the soldered board are too long and need to be trimmed.

4. Post-soldering processing uses a soldering iron to manually weld the components.

5. After washing the board and performing wave soldering, the board will be dirty and needs to be cleaned with washing water and a washing tank, or with a machine.

6. Quality inspection checks the PCB board. Unqualified products need to be repaired, and qualified products can enter the next process.

C. PCBA test

PCBA testing can be divided into ICT testing, FCT testing, aging testing, vibration testing, etc. PCBA testing is a big test. According to different products and different customer requirements, the testing methods used are different. The ICT test is to detect the welding conditions of components and the continuity of circuits, while the FCT test is to detect the input and output parameters of the PCBA board to see if they meet the requirements.

D. PCBA Coating Cover

The PCBA three-proof coating process steps are: Painting side A → Surface dry → Painting side B → Curing at room temperature 5. Spraying thickness: Spraying thickness: 0.1mm-0.3mm6. All coating operations should not be lower than 16℃ and Carry out under relative humidity lower than 75%. PCBA three-proof coating is still used a lot, especially in some environments with relatively harsh temperature and humidity. PCBA coating with three-proof paint has excellent insulation, moisture-proof, leakage-proof, shock-proof, dust-proof, corrosion-proof, anti-aging, and mildew-proof , prevent parts from loosening and insulate against corona, which can extend the storage time of PCBA and isolate external corrosion, pollution, etc. Among them, spraying is the most commonly used coating method in the industry.

E. Box Build

The PCBA board that tests OK after coating is assembled into the casing, then tested, and finally ready for shipment.