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Tag Archive: x-ray evaluation

  1. 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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  2. 6 Common Design Concerns with PCBAs

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    Before PGF, There’s the Design

    Designing a Printed Circuit Board Assembly (PCBA) can be a complex task, and engineers must take into account many concerns to ensure that the assembly functions correctly and meets all the requirements. These concerns include everything from the layout and routing of the circuits to the selection of components and materials. Before starting with the PGF partnership, a company must first solidify its design for the assembly process. 


    1. Proper Routing

    One of the most important design concerns in PCB Assembly is ensuring the proper routing of the circuits. This means that the pathways for electrical current are clear and free of any obstacles that could cause a short circuit or other problems. The routing of the circuits must also take into account the power requirements of the components, as well as any potential electromagnetic interference (EMI) that could affect the functioning of the assembly.


    2. Layout of Components

    Another important design concern is the layout of the components on the PCBA. Engineers must carefully consider the placement of the components to ensure easy assembly and enough space for them to function properly. The layout must also take into account the thermal characteristics of the components, as some components may generate more heat than others, and the layout should dissipate this heat effectively.


    3. Component Selection

    Component selection is also an important design concern. Chosen components must be appropriate for the application and compatible with the PCBA. This designation includes not only electronic components but also the materials used on PCBAs such as the substrate, copper thickness, solder mask, etc. Engineers should select them based on their specifications and characteristics, such as power dissipation and operating temperature range, and should be of good quality to ensure that they function correctly and have a long service life.


    4. Safety and Compliance Requirements

    The PCB Assembly must meet any necessary safety and compliance requirements. PCBAs in medical devices, for example, must meet stringent safety and performance standards set by certifications such as ISO 13485:2016. This includes ensuring that the materials and components in the assembly are safe for use in a medical environment and that the assembly is properly shielded to protect against electromagnetic interference. Similarly, PCBAs used in other applications such as industrial or aerospace must meet relevant compliance and safety standards.


    5. Testing and Validation

    Another important design concern is testing and validation of the PCB Assembly. The functionality of the PCB Assembly must be verified through various testing methods such as visual inspection, continuity testing, in-circuit testing, and functional testing to ensure that it meets the specifications and requirements of the application. Some machines to assist with the testing process include X-ray and AOI Inspection. This testing must happen at different stages of the assembly process to ensure the early detection and correction of any problems.


    6. Cost

    Finally, the cost is always a concern when designing a PCB Assembly. PCBAs can be expensive to manufacture, and the cost of components and materials can add up quickly. To minimize costs, the designer must consider the most cost-effective components and materials and use them in the assembly. Additionally, the design should be optimized to minimize the number of components and the size of the PCBA, while still meeting all the requirements.



    In conclusion, designing a Printed Circuit Board Assembly involves many design concerns that need to be taken into account. Proper routing and layout of circuits, component selection, safety and compliance, testing and validation, and cost are key design concerns that engineers need to address to ensure that the PCB assembly functions correctly and meets all requirements. Skilled engineers and designers with experience in PCBA design and assembly can help to confirm functionality and feasibility before starting with your contract manufacturer. At PGF, you design it, and we’ll build it! 

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