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Years of Business

PCB Assembly Optical Inspection

PCB Assembly Optical Inspection

Surface mount components are crucial parts of any electronic and electromechanical device in terms of the overall functioning. Hence, using thorough testing and inspection methods to check the design, functioning, and mounting of components is crucial. There are many testing processes and techniques we perform, including manual as well as automated ones. Automated optical inspection of PCBAs is a widely used technique. Suntronic Inc. being focused on the quality aspect performs various PCBA tests including automated optical inspection or AOI and ensures the design and functioning of PCB assembly.

An Overview of Automated Optical Inspection of PCBAs by Suntronic, Inc.

What is automated visual inspection? AOI is a rapid testing technique which gives highly accurate outputs pertaining to errors in boards and assemblies, and helps fix them before the boards leave the assembly line.

AOI makes a comparison of the required parameters of boards and assembly with the captured image of the PCB surface. The equipment comprises HD cameras and LED lights as well as UV lighting. The board surface is scanned and an image is captured with the help of the HD camera and various lights. Upon comparing the requirements with the image, various algorithms such as pixel counting are applied for identifying the differences or errors if any.

While manual and optical visual inspection are key to analyze and check the basic characteristics of PCBs and assemblies, we have significantly invested in technology and advanced testing techniques. We perform PCB optical inspection for boards as well as assemblies. AOI is typically done after visual inspection. It can identify a lot of surface level defects such as scratches, incorrect component mounting, stains, shorts, soldering issues, and so on. While some of these are also identified in visual inspection, AOI is faster and identifies bugs skipped by manual errors.

We, at Suntronic, use diverse algorithms of AOI for not only identifying errors but also categorizing and fixing them. This enables us to fix the most challenging errors with ease and meet the exact client requirement.

Our AOI Capabilities

Here are some of the capabilities we have in terms of automated optical inspection of PCBs and assemblies:

  • Pixel counting algorithm: We use this algorithm for identifying a number of surface defects, and various methods are used along with this.
  • Blob analysis: We use blob analysis, which is a process, wherein the object under scrutiny is separated. A group of pixels is formed to create a blob which is used for inspecting issues in PCBs.
  • Template: A small template is used to inspect a large area of an image, and this is done through a sliding template window. A normalized cross section correlation is calculated comparing the difference between the inspection image and the template. We have been using this template matching method from many years.
  • Statistical data: In this method, we store results for various types of boards as well as errors. The tolerance limits are set so that they are ignored in the results. After this, we perform statistical pattern matching to differentiate and identify errors.
  • 3D AOI: We can perform 2D as well as 3D AOI; the latter certainly has advantages in terms of clarity and a better view. The machines with 3D AOI have a very low defect escape rate and hence offer accurate output. However, our research team is still working on this segment for further improvements.

Benefits of Partnering with Us

There are many advantages of partnering with a full service electronic manufacturing services provider applying robust testing techniques. Here are some of them:

  • We are in a mode of continual improvement through our research and innovation and a policy to follow the best practices.
  • Our experience of having worked with clients from diverse industries comes handy, especially when customizing.
  • Offering end-to-end customized solutions has been our expertise for many years.
  • In terms of AOI, we are capable of identifying defects in the thinnest of boards and analyze each joint and component.

With over two decades of market experience, we have developed expertise in offering end-to-end and customized PCB assembly solutions, and AOI and automated visual inspection among various other forms of testing are an integral part of our process. We have fully equipped manufacturing facilities in Dallas and Houston which enable us to use advanced testing techniques. Please feel free to get in touch with us to discuss any questions you may have regarding our PCB optical inspection capabilities.