How does SMT Assembly Work?
Surface-mount technology or SMT means that electronic components are assembled with automated machines that place components on the surface of a PCB board. SMT is the most frequently used in the electronic assembly process.
Applying soldering paste is the first step in the SMT assembly process. Solder paste is printed on PCB boards using the screen printing method. Depending on the design of the board, various product-specific pastes are used. After printing the solder paste on boards, a 2D-soldering paste inspection is performed to ensure that the paste is evenly and correctly applied.
Component Soldering: During this process, boards are put on the conveyor of reflow oven machine and are gradually warmed up with heated air until the soldering paste melts and the flux vaporizes, which fuses the components to the PCB. The temperature profile should be made by setting the temperature of each zone.
AOI und Visual Check: Soldering is the second-to-last step of the SMT assembly process. In order to ensure the quality of the assembled boards, or to catch and correct a mistake, AOI visual inspections are performed for almost all series production orders. Using several cameras, the AOI system automatically checks each board and compares the appearance of each board with the correct, pre-defined reference image. If there are any deviations, the operator of the machine is informed of the potential problem, who then corrects the mistake or pulls the board from the machine for further inspection. The AOI visual check ensures consistency and accuracy in the SMT assembly production process.