The automatic optical inspection (AOI) is one of the most effective and most important equipment to the quality assurance.
During automatic and manual mounting there exists the possibility that the components get missing, twisted, offset or are incorrectly assembled. During reflow soldering a component can float and be the reason for short circuits through solder bridges or solder spheres (balls). Therefore, it is necessary to identify and to correct these mistakes before the next processing step.
The automatic optical inspection (AOI)
During this procedure every single produced unit is photographed digitally by means of image processing and is compared to the recording of a flawless reference sample. A PCB identified as can be automatically sorted out, reworked by trained employees and checked again. Each cycle is captured by scan and pictures of the assembly are archived under the respective product-ID. Therefore, all production steps are retraceable and the use of unchecked modules in the next processing step are virtually ruled out.
AOI systems are versatile
During the AOI procedure colors and surface properties can also be checked, hence the automatic optical inspection has proven itself optimally in the everyday application, to recognize all color, position and solder mistakes, as they can appear during mounting and the subsequent reflow soldering or wave soldering step.