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Multiple AOI systems

Anthony_B

#6546

Multiple AOI systems | 10 May, 2001

Can multiple AOI systems in a production line be cost effective or should I use a single tool?

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Eyal

#6547

Multiple AOI systems | 10 May, 2001

A configuration of a number of AOI tools located at different inspection stages along the SMT production line has, by its nature, the ability to provide a faster and closer response to possible process related fault occurrences.

Comparing with today�s common practice of a single AOI tool per line, we can consider two scenarios:

a. A fault that occurs before the inspection point

b. A fault that occurs after the single inspection point.

In both cases, adding inspection steps may result in reduced costs.

If the fault occurred before the inspection point (scenario a), the chances of detection may be reduced when additional process steps take place prior to the inspection. At the same time, the repair costs increase.

Having inspection points close to the processes enables real-time reporting of evolving trends and process drifts, even prior to actual defect occurrence. Thus, fault occurrences are minimized and may be prevented. Repair (when needed) gets cheaper and more effective, and overall costs are reduced.

If the fault occurred after a single inspection step (scenario b), inspection can�t detect the fault. In this case, the ICT or the functional tests are the only tests left available for the fault identification.

Some process faults, most of which are related to reliability, can be identified by AOI only. Therefore, field return ratios may get too high and costly.

Adding more inspection steps may solve this situation, and reduce costs.

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