Automated optical inspection (AOI) is an automated visual inspection of printed circuit board (PCBA)Assembly where a camera autonomously scans the device under test for both catastrophic failure (e.g. missing component) and quality defects (e.g. fillet size or shape or component skew). It is commonly used in the manufacturing process because it is a non-contact test method. It is implemented at solder paste inspection (SPI), post-reflow and pre wave.

AOI will detect the following defects on the line 

  • Billboarding
  • Component offset
  • Component polarity
  • Component presence or absence
  • Component Skew
  • Excessive Solder Joints
  • Flipped component
  • Height Defects
  • Insufficient Paste around Leads
  • Insufficient Solder Joints
  • Lifted Leads
  • No Population tests
  • Paste Registration
  • Severely Damaged Components
  • Solder Bridges
  • Tomb stoning
  • Volume Defects
  • Wrong Part
  • Bridging

These are common defects in SMT and wave process.