Detect defects with 2D and 3D automatic optical inspection

Detect defects with 2D and 3D automatic optical inspection

As the circuit board is more complex, the possibility of defects on the finished PCB is higher. Automatic optical inspection can scan the PCB to check for catastrophic failures and quality defects. It is mainly used after reflow soldering or post-production. The AOI system after reflow soldering inspects for many defects, including component placement problems, solder shorts or missing solder.

Use Automatic Optical Inspection system to detect defects

Some automatic optical inspection systems check specific tasks, such as pasting, before or after reflow. If the manufacturer spends a lot of time on inspection, the AOI cost is reasonable. AOI machines are fast and reliable. They can notify of recurring problems. They can track major issues and help improve the manufacturing process.

Automatic Optical Inspection checks the following:
Area defects, component deviation, component presence, component deflection, excessive solder joints, flipped components, insufficient solder joints, presence of foreign objects, severe component damage

The AOI industry has long relied on 2D inspection principles to test process quality. This technique is suitable for detecting many defects. But ultra-miniature chips, leaded devices and LED packages make 3D inspection technology necessary.

2D Automatic Optical Inspection system

2D inspection technology is the most commonly used solution. The most advanced system has multiple high-resolution cameras, 10 to 15 MP resolution and precision lenses.

Advantages of 2D system
Mature technology; high cost performance; high speed; less prone to shadow problems; able to inspect higher equipment larger than 5mm

Limitations of 2D system
Unable to perform true coplanar inspection; unable to provide volume measurement data; increased false call rate

3D Automatic Optical Inspection system

The 3D inspection technique is usually only used to inspect the solder paste deposit on the PCD after the screen printing process. Laser measurement is used to provide 3D measurement of highly sensitive equipment.

Advantages of 3D system
True coplanar inspection capability; volume inspection data; reduce false alarm rate

Limitations of 3D system
Emerging technology; unable to check 2D elements; cost increased significantly; speed reduced significantly; height limitation, maximum about 5mm; shadow problem; no color check

For a long time, it has been relying on 2D Automated Inspection Machine for defect testing and inspection. However, 3D inspection technology is also necessary due to the unique inspection requirements of ultra-microchips, lead equipment, and LED packages.