A Comprehensive Guide to PCB Inspection: Errors and Inspection Methods Analyzed

As the world progresses, the demand for smaller, faster, and more reliable circuit boards increases. The development of new technologies has allowed for the creation of smaller and more intricate devices. These devices are more likely to fail if the circuit board is not made correctly. To combat this, the manufacturing process of PCBs has become more reliable and efficient. A critical part of this process is inspection, which is performed at various stages to ensure the quality of a board. A wide variety of inspection methods are available to suit the needs of different manufacturing processes. If you would like to know more about the most popular types of PCB inspection techniques, then this post is for you.

 PCB inspection techniques

Types of Errors Detected during PCB Inspection

There are several reasons why thorough inspection is essential. First, it ensures that the board is free of manufacturing defects. Second, it allows for the detection of errors that may have occurred during the design process. Finally, it helps to ensure that the board will function correctly once it is assembled.

The following is a list of a few errors that can be detected using various PCB inspection techniques:

  • Delamination
  • Missing or damaged vias
  • Shorts between conductors
  • Opens in conductors
  • Misaligned or incorrect components
  • Incorrect component values
  • Spurious signals
  • Incomplete or inaccurate solder mask definition
  • Improper solder mask opening around vias
  • Excessively small solder fillets
  • Lifted or missing component leads
  • Insufficient solder paste coverage
  • Random component orientation
  • Incorrect component polarity
  • Improper thermal relief connections

3 Popular Methods for Effective PCB Inspection

Inspection is performed using a variety of methods, each with its own advantages and disadvantages. Keep reading to learn more about these popular types of PCB inspection methods.

  • Manual PCB Inspection: This is one of the most preliminary forms of PCB inspection where an expert looks at the PCB through naked eye. Many times, magnifying glasses may be used by experts to focus on some areas. The board is compared against the design document to ensure all specifications are met. In many cases, the visual inspection will help identify manufacturing defects such as broken sides or thick boards, loose solder bridges, and so on. This type of inspection works the best only when conducted by an expert.
  • Automated Optical Inspection (AOI): This is a form of quality control that uses optical technology to inspect circuit boards for defects. AOI systems use a variety of optical technologies to inspect circuit boards, including contact image sensors, structured light, and laser scanning. These systems are able to detect a wide range of defects, including missing or incorrect components, bad solder joints, shorts, and open circuits.
  • X-Ray Inspection: X-ray inspection is a process that uses high-energy X-rays to examine the internal components of printed circuit boards. During an X-ray inspection, a PCB is placed on an X-ray source and a series of X-ray images are taken. These images are then processed and analyzed to look for defects or deviations from the expected PCB design. X-ray inspection is a nondestructive testing (NDT) method, which means that it does not damage the PCB in any way. This makes it an ideal inspection method for preventing defects in PCB manufacturing.

Needless to say, inspection is a critical element in PCB manufacturing. The three main goals of inspection are to find, correct, and prevent defects. To meet these goals, the quality control experts in PCB assembly facilities use a various tools and methods, as listed above. By thoroughly inspecting each PCB, manufacturers can ensure that their products are of the highest quality. Realizing the importance of inspection, today’s leading manufacturers like Rigiflex ensure to keep a proper inspection system in place that includes trained inspectors and the latest techniques. This ensures that their PCBs are of the highest quality and meet all industry standards.

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