The advantages and disadvantages of AOI （1）

Everyone in the industry knows that the AOI (Auto Optical Inspection) system has been widely used in SMT patch processing production lines to replace the previous manual visual operations. AOI uses imaging technology to determine whether the object to be tested meets the standard if there is too much difference between the object to be tested and the standard image.

In the early days, AOI was mostly used to detect defects in the surface printing after IC (integrated circuit) packaging. With the evolution of technology, it is now used to detect the assembly of parts on circuit boards (PCB) on SMT assembly lines or check whether the solder paste meets the standard after printing.

The biggest advantage of AOI is that it can replace the previous manual visual inspection work before and after the SMT process, and it can judge the shortcomings of SMT parts and can be more accurate than the human eye. But just like the human eye, AOI can basically only be surface inspection of the object, so as long as it is a shape that can be seen on the surface of the object, it can be checked correctly. But for hidden under the part or the edge of the part ,  AOI may not have enough power. Of course, many AOIs can already increase their ability to detect IC pin tilt, and increase the camera angle of some hidden components. But the effect is always not ideal, it is difficult to achieve 100% test rate.