Issue link: https://iconnect007.uberflip.com/i/831357
18 SMT Magazine • June 2017 your boards. We see that the return on invest- ment most of the time is very short at about two years, and sometimes even sooner. We do understand it's a big investment, especially be- cause inspection is not productive equipment in your line. It's an inspection, return on invest- ment is about reducing the cost of non-quality," explained Peallat. For McMeen, their rule of thumb is twofold. "One is this should pay for itself in less than 18 months, and if a human inspector can find something that the 3D cannot find, that's where the challenge is. That's what you'd want it to do. Everything that the human inspector finds goes back to our programming lab and they try to incorporate whatever escaped into the 3D AOI machine. Remember, human inspectors are only as good as about 70–75%, so the idea is that you really need to use AOI as a process tool because it never gets tired and it's not going to have misses, provided that you can program for it. For the EMS guys today, from my perspective, the 3D AOI is much needed, and the chal- lenge is the time that it takes to program those more diffi- cult components that take the burden off the human inspector. "Every time a human inspector finds something that should have been caught by the AOI, we are going back and forcing ourselves to figure out how it escaped. Was it poor lighting? Did we not come at the right angle? Did we have the parameters set too loose or too tight? It's a learning curve, just as Jean-Marc said before. It takes a lot of time to program these pieces of equipment, but you're better off in the long haul because you're taking a burden off the hu- man inspector and that's the main objective. It is a non-value added process, but it is one of those processes that you have to have to give assurances when you're producing hundreds, thousands, or millions of products." However, while inspection is a non-value add from the perspective of the end product, the value in the inspection data collected dur- ing the process is overwhelming. "The in-process data that you get is huge because that's going to be the data that allows you to make adjustments to your stencil or your placement accuracy, and then maybe you have to make adjustments to your reflow. All of those things go a long way to what your solder joint and reliability integrity is going to look like, but more importantly, its re- peatability from job to job or assembly to assembly. I was looking at it from a final standpoint, but from an in-process 3D: TOWARDS BETTER INSPECTION CAPABILITY