About 2 years ago our company tried to go with a post reflow AOI inspection. This AOI was suppose to be able to inspect to a level class 3 product. **It is impossible** You cannot inspect for a heel fillet and inspecting for poor wetting is a very fine line. Alot of it also depends on the component quality. We had some components that had degraded plating but was still acceptable, well this plating mixed with good solder paste would give dull solder joints, this in turn would call a false defect. This went on and on. We had a very bad experience. I am 100% for AOI if your inspecting placement, presence, or even component type if possible. But when it comes to solder joint quality expecially to class 3, sorry, theres nothing more reliable than the human eye. If your going to inspect to class 3 with AOI you need to make sure your going to have a very consistant parts supplier and not have your purchasing department buy bulk parts from different suppliers. What I ran into was that because of this I was having to reprogram part sizes, colors, as well as solder joint inspection changes if your parts are tinned more or less. Keep these things in mind if your going to go the AOI way. You will probably never eliminate reflow inspection to class 3 product expecially on complex assemblies. Also keep in mind that if your running BGA's that your will need something like AXI.
Just thought I would give my input..
Thanks, Paul
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