What is the PCB assembly process?
PCB assembly refers to the process of welding and assembling electronic components on prefabricated parts. Matting and manufacturing printed circuit boards (PCBs). Usually professional production machinery used for mass production, and the printed circuit board assembly process usually called PCBA.
1.So how is the PCB assembled? Let’s take a look at the PCB assembly process：
1.Application of solder paste: First, the solder paste (a small particle of solder paste mixed with flux) applied to the board.
For this application, most PCB manufacturers use templates (there are several sizes, shapes and specifications that are consistent with the specifications). These templates can only correctly apply the correct amount of solder paste to certain parts of the board.
2.Component placement: Unlike in the past, the PCB assembly process at this stage is now fully automate.
The picking and placing of parts (such as surface-mounted components) use to be done manually. But now it performe by a robot picking and placing machine. These machines accurately place components into the pre-planned area of the circuit board.
3.Reflow: The solder paste and all surface-mounted components are in place. And curing the solder paste to the correct specifications is essential to properly adhere the PCB components to it.
This is this related part of the PCB assembly process-reflow soldering. To this end, the components with solder paste and the components on them passed through a conveyor belt, which passes through an industrial-grade reflow oven. The heater in the oven melts the solder in the solder paste. Once the melting is complete, the components will move in the conveyor belt again and exposed to a series of colder heaters. The purpose of these coolers is to cool the molten solder and cure it.
4.Inspection: After the reflow process, the PCB should inspecte to check its function.
This stage can help determine poor-quality connections, misplaced components. And short circuits caused by the continuous movement of the circuit board during the reflow process. PCB manufacturers have adopted multiple inspection steps. Such as manual inspection, automatic optical inspection and X-ray inspection, to check the function of the circuit board, identify lower-quality solder and identify any potential hidden dangers. After the inspection completed, the assembly team will make a crucial decision. Circuit boards with several functional errors are usually scrappe. On the other hand, if there are smaller errors, the board sent again for rework.
5.Through-hole element insertion: Some types of PCBs need to inserte into the through-hole element together with conventional SMD components.
This stage dedicated to the insertion of such components. To this end, which PCB components use to transmit signals from one side of the board to the other to create plating through holes. PCB through-hole insertion usually uses manual or wave soldering to obtain results.
6.Final inspection: Now is the time for the second-level inspection.
Here, the assembled board functionally tested, or the PCB is thoroughly inspecte to monitor its electrical characteristics, including voltage, current, or signal output. Today’s manufacturers use a variety of advanced testing equipment to help determine the success or failure of finished boards.
7.Cleaning: Since the welding process will leave a lot of flux residues in the PCB. It is essential to thoroughly clean the components before delivering the final circuit board to the customer.
To this end, polychlorinated biphenyls cleaned in deionized water. After the cleaning process, use compressed air to dry the board thoroughly. The PCB components can now prepare for customer inspection.
2. What are the advantages of PCB assembly?
1.Save time
2.Help you find the problem from the beginning
The main advantage of using turnkey PCB assembly in the prototype stage is that any problems can detecte early.
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