As circuit boards have become progressively complex, PCB inspection has evolved quickly. Though off-line manual visual inspection (MVI) using microscopes and magnifiers is still needed, because of the microscopic number and size of components on a circuit board, that approach is greatly limited. As a result of the tiny size of pieces and the even smaller size of solder joints, automated optical inspection (AOI) is essential for excellent procedure control and error detection. The majority of AOI systems have an angled camera and a top down camera to acquire solder joint details and prevent shadowing generated by parts that are placed very close together.

Absence / presence, skew, rotational variations, polarity, tombstoning, and solder joint analysis should all be detectable by excellent AOI software. These machines should all be able to perform both 2D (camera) and 3D (or structured lighting) evaluations.

AOI equipment can be manual load or in-line. Manual loading necessitates the operator to load each board individually, whilst in-line inspects each board as it exits the reflow oven on the conveyor. A real inspection just takes a matter of seconds. Many PCBs can be inspected to 100% inside 30 seconds (and generally in 15 seconds).

To program, one of two methodologies is commonly used: the data-driven approach or the golden board approach. Usually, the Golden Board technique is more prone to "false failures" when the PCB being examined contains pieces that were not accurately arranged as the Golden Board. When this occurs, the board does not pass; this is known as a false failure. Programs that use data understand where components should be placed on the PCB, and everything is contrasted to where the component should really be. These data driven systems are generally more accurate.

AOI solutions must be competent at pinpointing defects in component placement and solder joint formation automatically, so that manufacturing system faults can be detected before they approach the next manufacturing step.

Restronics Northern California's salespeople have extensive expertise in selecting the best AOI technology for unique client needs.