Automated Optical Inspection (AOI) is the process why which a machine takes pictures of a board and compares it to what the machine has been programed to understand as passing. If in the comparison the image comes different a flag is raised and an operator will have to decide if it is a false call.
In the beginning, as any new technology is it was a buggy process with many false calls and even more dangerous no calls. However as technology has progressed the AOI process as become more streamlined. Another advancement in AOI is that of 3D AOI.
What is 3D AOI?
Three Dimensional Automated Optical Inspection (3D AOI) is where the images being compared get the added dimension to find defects that a traditional 2D AOI can never find. Things like Chamfers and Dimples are measured and found to check markings more accurately. Also Solder joints are measured to a 1 micron level to ensure that solder joints are passing of IPC Class 2 or 3. This inspection method in many cases eliminates the need for testing; this is especially beneficial in the prototype stage where there are only few boards to run, and it does not make sense to develop testing fixtures.
Amtech runs all boards end of line through the 3D AOI to ensure that the end product will be of excellent quality.