The visual inspection, Manual Optical Inspection (MOI), is used for the simple optical inspection oftraces, solder joints, components and assemblies on a printed circuit board. With this test method, visible defects can be detected directly or through a magnifying glass or microscope.
MOI testing can detect placement defects, including missing or incorrect components, components installed upside down or twisted. In addition, the quality of solder connections can bechecked and solder defects such as short circuits or interruptions can be detected. The manual visual inspection is one of the simplest inspections used after production and requires only a small amount of effort. A further development of the visual inspection is the automatic optical inspection, the Automatic Optical Inspection( AOI).
With visual inspection, various defects cannot be detected: For example, the correct component value of unlabeled components such as SMD components, defective components, bad solder joints of chips whose connections are underneath the component, cold solder joints and interruptions in conductor tracks.