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Tag Archive: pick and place

  1. Selective Soldering Process

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    The Selective Soldering Process

    Selective soldering is a key step in the electronics manufacturing process that requires specialized equipment, skilled operators, and careful control of the soldering process. As a leading electronics manufacturing service provider, PGF Technology Group has extensive experience in selective soldering and a commitment to quality, reliability, and efficiency in every aspect of our operations.


    Why Use Selective Soldering?

    Selective soldering joins components to the printed circuit board (PCB), creating a finished assembly. The process is “selective” because it involves the application of soldering only to specific areas of the PCB, rather than to all connections. This is important because not all components can withstand the high temperatures for reflow soldering. Reflow soldering is the standard process in the manufacturing of most electronic assemblies. Selective soldering allows us to protect delicate components and ensure that they are secure to the PCB, while also providing a reliable and consistent connection.


    What are the steps of the Selective Soldering Process?

    The selective soldering process typically begins with the application of flux to the pads and leads of the components. The flux helps to prepare the surface for soldering and to promote good wetting of the solder to the pads. Next, the machine places the components on the PCB, and the selective soldering equipment applies the solder. The equipment uses a combination of heat and pressure to melt the solder and join the components to the PCB. The machine carefully controls the temperature and duration of the soldering process to ensure consistent results.  The operator monitors the soldering process to ensure that each joint is soldered to the correct specifications. Here is the step-by-step explanation:

    1. Preparation: Selective Soldering Process Infographic

    Before the selective soldering process can begin, the machine and operator prepare the PCB by applying solder paste to the appropriate areas of the board. Prep work includes a stencil or a screen printing process.

    2. Component placement:

    Once the solder paste has been applied, the surface-mounted components are placed on the PCB using pick-and-place machines or other automated equipment. The components are typically held in place by a temporary adhesive or vacuum.

    3. Flux application:

    The machine applies flux to the areas of the PCB where it will apply the solder. Flux is a chemical that helps the solder flow and adheres to the PCB and component leads.

    4. Preheating:

    The machine preheats the PCB to activate the flux and remove any moisture from the PCB and components. The preheating temperature is typically between 120-150°C.

    5. Selective soldering:

    The selective soldering machine applies molten solder to the areas of the PCB that require soldering. The machine uses a solder nozzle to apply the solder in a precise and controlled manner.

    6. Cooling:

    After the soldering is complete, the machine cools the PCB to solidify the solder and ensure a strong bond between the components and the PCB.

    7. Cleaning:

    The machine then cleans the PCB to remove any excess flux or residue from the soldering process. This cleaning uses solvents, ultrasonic cleaning, or other methods.

    8. Inspection:

    Finally, the machine inspects the PCB to ensure that all components are secure and that there are no defects in the soldering process. This may involve visual inspection, automated optical inspection (AOI), or other testing methods.

    What Does PGF Offer?

    At PGF Technology Group, we use a variety of selective soldering techniques. This includes wave soldering, laser soldering, and selective spray soldering, to ensure that we have the right equipment and process for each project. Our flexible approach allows us to tailor our processes to meet the specific requirements of each customer.

    In conclusion, selective soldering is a critical step in the electronics manufacturing process. It requires specialized equipment, skilled operators, and careful control of the soldering process. As a leading electronics manufacturing service provider, PGF Technology Group has extensive experience in selective soldering. We are committed to providing quality, reliable, and cost-effective solutions to our customers. Our flexible approach and commitment to excellence ensure that we deliver the highest quality products and services to our customers, every time.

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  2. Deep Dive: AOI Inspection

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    AOI Inspect the Circuit Boards

    Automated Optical Inspection (AOI) is an important process in the assembly of Printed Circuit Board Assemblies (PCBAs). It is a non-destructive method of inspecting the surface of a PCB for defects such as missing components, misplaced components, incorrect component values, and shorts. AOI inspection is highly accurate, fast, and efficient, making it an essential tool for ensuring high quality in the production of PCBAs.

    Reference the OG

    The AOI process begins by capturing images of the PCB using high-resolution cameras. Technicians compare these images to a reference image, which is a pre-programmed image of what the PCB should look like. Any differences between the two images are defects. The AOI system can also check for specific defects such as missing components, incorrect component values, or shorts.


    One of the main benefits of AOI inspection is that it is fast and efficient. The inspection process can be completed in a matter of minutes, even for complex PCBs with many components. This allows for quick detection of defects, which can then be corrected before they cause problems in the final product.

    AOI inspection is also highly accurate. The system uses high-resolution cameras and advanced algorithms to detect even the smallest defects. This accuracy helps to reduce the number of false alarms and improves the overall quality of the final product.

    Another benefit of AOI inspection is that it is non-destructive. Unlike other inspection methods, such as X-ray inspection, AOI does not damage the PCB or its components. This makes it ideal for use on sensitive components and PCBs that are difficult to repair or replace.


    AOI inspection integrates with other processes in the PCB assembly process. For example, it can conjuncture with automated pick-and-place machines, which place the components onto the PCB. This allows for real-time inspection of the components, ensuring that they are correctly placed before they are soldered onto the PCB.

    AOI can also integrate with other quality control measures such as manual inspection, X-Ray inspection, and functional test to provide a comprehensive and robust quality control system. This can help to detect defects that may have been missed by other inspection methods and provide an overall high-quality assurance.


    In conclusion, AOI inspection is an essential process in the assembly of Printed Circuit Board Assemblies (PCBAs) due to its speed, accuracy, and non-destructive nature. This technology can provide several benefits to the manufacturing process, including detecting defects, ensuring quality, avoiding rework, and minimizing the risk of field failures.

    Additionally, there can be integration with other inspection methods and assembly processes, providing a comprehensive quality control system that can ensure high-quality final products and customer satisfaction.


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  3. SMT Assembly Process

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    Surface Mount Technology (SMT) Process

    Printed Circuit Board Assembly (PCBA) is the process of producing circuit boards with electronic components attached to them. One of the most popular techniques for PCBA is Surface Mount Technology (SMT), which is universal in the electronic industry today. The SMT process involves placing electronic components directly onto the surface of the PCB, rather than inserting them into drilled holes, as is the case with through-hole technology. This process is faster, more efficient, and allows for the use of smaller and more densely packed components.

    Trace the Lines

    The SMT assembly process begins with the PCB itself, which is a thin board of a non-conductive material, such as fiberglass or plastic. Copper traces on the board serve as the pathways for electrical current. A photolithography process etches these traces onto the board, which involves exposing the board to light through a stencil called a mask to create the desired trace pattern.

    Pick & Place

    Once the PCB is ready, the next step is to place the electronic components onto the board. Automated pick-and-place machines quickly and accurately place small components, such as transistors and resistors, onto the board.

    AO-I Must Inspect

    After the component placement, the PCB goes through an Automatic Optical Inspection (AOI) process to ensure that the correct components end up in the correct locations and that there are no missing or incorrectly placed components. AOI uses high-resolution cameras to capture images of the PCB and compares them to a pre-defined image of the PCB, allowing it to detect any discrepancies.

    Leave the Oven On!

    The next step is soldering the components to the board to make electrical connections. A reflow oven melts a small amount of solder on the bottom of each component, allowing the machine to securely attach them to the board. In some cases, selective soldering comes into play, which involves selectively applying solder to specific areas of the PCB, rather than applying it to the entire board. This technique is particularly useful when working with complex or sensitive PCBs that require more precise soldering.

    Test, Test, & Test

    After the reflow process, the PCB goes through another round of AOI inspection to check the quality of the soldering. If there are any defects, the assembler will rework the PCB to correct the problem.

    In some cases, the manufacturing process also includes X-ray evaluation, which is an additional step of quality control to ensure that the solder joints are properly formed. It also allows for checks for hidden defects, such as solder bridges or voids, that would not be visible in a visual inspection. X-ray inspection is particularly useful when working with dense or complex PCBs where it is difficult to visually inspect all the solder joints.

    Cleaned & Packaged

    After the AOI and X-ray inspection, the assembler may use the washer to clean the PCBA and then package it for shipping to the customer. If the PCBA is part of a larger product, the manufacturer will then integrate it into the final product, such as a computer or a mobile phone.


    In summary, the PCB assembly process using Surface Mount Technology (SMT) includes several steps: PCB preparation, component placement, Automatic Optical Inspection (AOI), soldering, selective soldering, AOI inspection, X-ray evaluation, cleaning, and packaging. This process is efficient, and reliable, and allows for the use of smaller and more densely packed components. By including inspection steps such as AOI and X-ray evaluation, it ensures that the final product is of high quality and meets all the necessary requirements. With the advancement of technology, the SMT assembly process has become more efficient, accurate, and reliable; however, it still requires skilled labor and attention to detail to produce high-quality circuit boards.

    It is important to use an experienced printed circuit board assembly (PCBA) manufacturer like PGF Technology Group to ensure that your PCBs are made to the highest quality standards and meet your specific requirements. With years of experience and state-of-the-art machinery, PGF Technology Group is well-equipped to handle all your PCBA needs. They have a team of experts who are knowledgeable in all aspects of the PCB assembly process, from design to manufacturing.


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