What is automated optical inspection?

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Automated optical inspection is a visual inspection methodology PCB assemblers implement to test PCBAs for defects.


It’s usually abbreviated as AOI. 


The methodology uses a machine with cameras to detect 


1. Major assembly failures, such as missing components.

2. Quality failures, such as misshapen fillets or misplaced components


This is what an Automated optical inspection machine looks like.


automated optical inspection machine for pcba what is it

Image from: Circuits DIY

When is it recommended to use an Automated Optical inspection machine?


  • A high volume of PCBAs
  • Low component variability


The configuration of an automated optical inspection process is complex and expensive, and engineers must set it up for a specific PCBA design.


Its purpose is to verify that the PCBA components are placed correctly as per the design.


Advantages of automated optical inspection


  • Highly accurate in detecting flaws in a PCBA

Disadvantages of automated optical inspection


  • It’s not a flexible testing method; engineers must configure each new run.


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