The basic process of the SMT production as bellow: Printing (red glue / solder paste) -> Detection (optional AOI automatic or visual inspection) -> Components Mounting (mount the small components and then the larger ones:high speed mounting and integrated circuit mounting) > Inspection (optional AOI optical / visual inspection) -> Soldering (with hot air reflow soldering) -> Detection (can be divided into AOI optical detection appearance and functional test) -> Reparation(using tools: soldering station and hot air desoldering station, etc.) ->Board V cutting (manual cutting or V cutting machine)
The process is simplified as follows: printing-mounting-soldering-reparation-V cutting (each process can add detection and inspection to control the quality)
Solder paste printing
The solder paste is was printed to the PCB through the printing stencil sreen by 45 degrees angle placed printing scraper, for solder paste printing, semi-automatic or full automatic solder paste printer can be used, it deponds on the capacity, printing is first process in SMT production.
Mount the electronics components onto the surface of the PCB. The equipment used for the process is mounting machine,another name is pick and place machine,this process is after the solder pring, generally high-speed mounting machines and general-purpose mounting machine will matched together in accordance with the production requirements.
This process is to melt the solder paste by hot air reflow oven, so the components and PCB board firmly soldered together thorugh solder paste. The equipment used here is a reflow soldering oven,the machine is next to pick and place machine,connected by linking conveyor, for reflow soldering quality, the temperature requirements are very strict, especially the real-time temperature measurement,
AOI optical detection
AOI means automatic optic inspection, AOI is for checking soldering quality of the PCBA, the location of the machine is according to the needs of detection, can be configured in the production line where appropriate. Some is before the reflow soldering oven, some is after the reflow soldering oven.
The process is for sort the OK PCBA, and take out the defective PCBA,and repaire the defective parts, The main tools used are soldering iron, rework station and so on. Configured after AOI optical inspection
PCB V cutting
The PCB sometimes joined together on one board, so need to separate them into a separate individual, the general use of V-cutting machine,also called PCB separator