Pcb Manufacturing Assembly

The PCB fabrication process begins by creating the board’s layers. Each layer gets its own sheet of film, and a special hole, known as a registration hole, is punched through each of the films. The holes are used as a guide when aligning the boards later on in the assembly process. Each of these steps are done by the contract manufacturer to ensure that the final product meets your precise technical specifications and PCB quality standards.

Once the board has successfully passed through fabrication, it moves to the assembly process. During this phase, your pcb manufacturing assembly company will insert all of the necessary components, both SMT and through-hole. Depending on the complexity of your design, your circuit board may have two or more layers. It will also have a silk screen layer for reference designators, pin-one indicators, polarity markers and other essential callouts that make the assembly process much easier.

SMT assembly is a critical part of the process, and it requires an extremely high level of precision to avoid problems such as soldering paste residue and misaligned component footprints. These problems can lead to poor connection quality over time, or even short circuits on the finished PCB. SMT assembly is typically accomplished by using automated machines. However, manual inspection is still used, especially for small batches. These inspections must be conducted by a trained technician to avoid errors caused by eye fatigue.

Different Methods For Pcb Manufacturing Assembly

In order to allow these machines to accurately place SMD components, the circuit board must contain a series of rounded copper shapes called fiducials. These are placed on the edges of the board so that automated equipment can recognize the orientation of a component and place it in the correct position. Fiducials can be divided into two classes, global fiducials and local fiducials. Global fiducials are placed on the edge of the PCB so that automated equipment can easily detect its location on a board, and local fiducials are placed close to the corners of SMD components to help identify their footprints.

Once all SMD components have been properly inserted, the board will be subjected to a reflow soldering process. This involves applying liquid flux to the component leads, then heating them to a specific temperature range in order to melt solder paste so that it can adhere to the newly placed components. The board will then be moved through a cooler to allow the solder to solidify and create a permanent connection between the components and the board.

Once the reflow soldering process is complete, the PCB will be subjected to an automatic optical inspection (AOI) machine. This machine uses a series of high-powered cameras that are positioned at different angles in order to “see” the solder connections on the board. The AOI inspection can check large batches of PCBs quickly and with a high level of accuracy. The results of the AOI inspection can then be compared to the original Gerber file from which the board was fabricated in order to verify that the final products have no defects.