PCB Tech - Brief analysis of PCBA process flow and terminology learning

Usually, the word PCBA is often heard in the SMT industry. Today, I will learn the related terms and PCBA production process with you.

PCBA is the abbreviation of Printed Circuit Board + Assembly in English. Simply put, the empty PCB board passes through the SMT assembly, and then goes through the entire process of DIP plug-in, referred to as PCBA. In layman's terms, PCB is a circuit board with no upper components, and PCBA is a circuit board with soldered electronic components.

PCBA process is the combination of SMT process and DIP process. According to the requirements of different production technologies, it can be divided into single-sided SMT placement process, single-sided DIP insertion process, single-sided mixed packaging process, single-sided placement and insertion mixed process, double-sided SMT placement process and double-sided mixed process Installation process and so on. The PCBA process involves processes such as carrier board, printing, patching, reflow soldering, plug-in, wave soldering, testing and quality inspection. See the PCBA process flow chart below for details.

Brief analysis of PCBA production process and terminology learning

Different types of PCB boards have many different processes. The following is a brief description of various situations. The simple processing process of PCBA:

1. PCBA processing single-sided SMT mounting: solder paste printing-patch-reflow soldering. The solder paste is added to the component pad, after the solder paste printing of the bare PCB is completed, the relevant electronic components are mounted through reflow soldering, and then reflow soldering is performed.

2, PCBA processing double-sided SMT mounting: A side printed solder paste-patch-reflow soldering-flipping-B side printed solder paste-patch-reflow soldering. In order to ensure the aesthetics and functionality of the PCB board, some PCB board design engineers will adopt a double-sided mounting method. IC components are arranged on side A and chip components are mounted on side B. Make full use of the PCB board space to minimize the PCB board area.

3, PCBA processing single-sided mixed assembly (SMD and THC are on the same side): solder paste printing-patch-reflow soldering-manual plug-in (THC)-wave soldering;

4, single-sided mixed (SMD and THC are on both sides of the PCB): B-side printing red glue-patch-red glue curing-flap-A side plug-in-B side wave soldering;

5. Double-sided mixing device (THC has SMD on side A, and SMD on both sides of A and B): Printed solder paste on side A-patch-reflow soldering-flipping board-printed red glue on side B-patch-red glue curing-flipping Board-A side plug-in-B side wave soldering;

6. Double-sided mixed packaging (SMD and THC on both sides of A and B): Printed solder paste on side A-patch-reflow soldering-flip board-printed red glue on side B-patch-red glue curing-flip board-A Surface plug-in-B-side wave soldering-B-side plug-in is attached. The following two methods are mixed on both sides. The first method is PCBA assembly three times heating, which is low in efficiency, and the pass rate of wave soldering using the red glue process is low. It is not recommended. The second method is suitable for cases where there are many double-sided SMD components and few THT components. Manual welding is recommended. If there are many THT components, wave soldering is recommended.

In the soldering process, the smallest variables should belong to the machinery and equipment, so they are the first to be checked. In order to achieve the correctness of the inspection, an independent electronic device can be used to assist, such as using a thermometer to detect various temperatures and using an electric meter to accurately calibrate machine parameters. .

PCBA is to process an empty PCB board through a process, and finally process it into an electronic product that can be used by the user. In the production process, there are links to each link, and which link has quality problems will have a great impact on the quality of the product.