1, SMT chip processing flow is: solder paste mixing → solder paste printing →SPI→ mounting → reflow soldering →AOI→ repair.
Stirring of solder paste: after the solder paste is taken out of the refrigerator and thawed, stir it by hand or machine until it is suitable for printing and welding.
Solder paste printing: place the solder paste on the steel screen and print the solder paste on the PCB pad with a scraper.
SPI:SPI is a solder paste thickness detector, which can detect the printing situation of solder paste and control the printing effect of solder paste.
Mounting: SMT components are placed on Feida, and the mounter head accurately mounts the components on Feida to PCB pads through identification.
Reflow soldering: reflow soldering the pasted PCB board, and the paste solder paste is heated by the high temperature inside to become liquid, and finally cooled and solidified to complete the soldering.
AOI:AOI is an automatic optical inspection, which can detect the welding effect and defects of PCB board through scanning.
Repair: Repair defects found by AOI or manual inspection.
2.DIP plug-ins handle links
The processing flow of DIP plug-in is: plug-in → wave soldering → foot cutting → after welding → board washing → quality inspection.
Plug-in: the plug-in material is processed into pins and inserted on the PCB.
Wave soldering: Wave soldering the inserted circuit board. In this process, liquid tin will be sprayed on the PCB, and finally cooled to complete the welding.
Foot cutting: The stitch of the welded board is too long and needs to be cut.
Post-welding treatment: welding parts by hand with electric soldering iron.
Wash the board: After wave soldering, the board will be very dirty, which needs to be cleaned by washing water and bath, or by machine.
Quality inspection: check the PCB board, and the unqualified products need to be repaired before the qualified products can enter the next process.
3.PCBA test
PCBA test can be divided into ICT test, FCT test, aging test and vibration test.
PCBA test is a big test. According to different products and different customer requirements, the testing methods adopted are different. ICT test is to detect the welding conditions of components and the on-off conditions of circuits, while FCT test is to detect the input and output parameters of PCBA board to see if it meets the requirements.
4, finished product assembly
Assemble the shell of PCBA board to be tested, then test it, and finally it can be shipped.
PCBA production is closely linked, and problems in any link will have a great impact on the overall quality, so we should strictly control each process.