2D and 3D AOI inspect optically visible appearance, placement and surface height. Solder joints hidden beneath packages, internal solder voids and concealed bridges require a suitable X-ray, AXI or CT inspection method. Optical 3D reconstruction cannot see through a package. A visible QFN side fillet does not establish the condition of its underside pad.
How to validate
Map visible and occluded regions by package type, then define separate optical and X-ray acceptance criteria. Connect results by board ID, component reference and repair record. Electrical function and connection reliability require their own tests.
Project evaluation checklist
- Define the item, visible inspection surfaces and minimum defects; separate appearance, internal structure and electrical or functional checks.
- Prepare verified good, defective and borderline samples across lots; separate training and acceptance sets.
- Report escapes and false calls by defect class, with review workload, complete cycle time and repeatability.
- Confirm program versions, permissions, retention and traceability fields; approve production only after trials pass.
Continue with
2D AOI machines
Visible appearance, components and markings.
→3D AOI machines
Visible surface height and coplanarity.
→AOI software
Programming, review, model management and traceability.
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