What is Automatic Optical Inspection?

Automatic Optical Inspection in the Populated PCB Industry is a process of visually inspecting a board for defects in the placed components, the way they are placed and usually the solder quality of those components. Typically using a stored image against which a comparision is made to spot differences, or using algortihms (especially for solder inspection) to calculate the measured value against a rule set.

Generally scanner systems have poor solder inspection capability, particularly for small surface mount components, where as more sophisticated units will provide a wider selection of options to not only spot solder defects but to use this and other information to highlight potential faults such as lifted legs on IC's.

With the complexity of modern PCB's it is extremely difficult to have a reliable and consistent manual inspection process that can run non-stop 24 hours per day. AOI provides this capability either as an in-line solution needing minimum operator involvement, or as a desktop unit manually loaded and unloaded. The consistent repeatability of this process is the real key to AOI's success with a level of improvement in quality that sets users of AOI above their competition, and saves them money.

The key to AOI's success in a business is the quality of programming, so it is important that any system is easy to use and flexible enough to cope with changes that may occur. So it may be that a company uses three different suppliers for their resistors, and each of these suppliers uses a diferent marking style to identify them. The AOI has to be able to pass components from all 3 suppliers as good without operator intervention.

Reducing false calls from Automatic Optical Inspection is essential to keep the process running smoothly, but it is important to ensure that all defects are picked up and stoppped for re-work. Again the quality and flexibility of the programming software is critical here. Constant false calls will reduce the operators confidence in the system, thus reducing the benefits that can be gained from the system.

For a full description of AOI and it's capabilities with a more detailed discussion of the different aspects involved please download our new guide “Introduction to AOI”. We have also produced a document to help people study the financial benefits of AOI more closely, “AOI – Cost of ownership”. The FAQ on this website has answers to some of the most commonly asked questions.

Copies of these guides can be obtained by email using the request form here, or to get a printed copy please request this using any of the methods noted on our contact page.

To discuss the Automatic Optical Inspection systems available from DCB Automation please contact us and we will be deilghted to help guide you though the evaluation process.

Automated Optical Inspection from DCB Automation
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