I had a benchtop Yestech demo until for a couple weeks. It was a very good machine. I particularly liked the RGB light system which gave a good visual representation of solder fillets. There was software that allowed you to evaluate based on the presence of certain percentages of color (vs. the usual black/white binarization protocols) but I could never get a really good, repeatable formula to work. Keep in mind I did only have it for a couple weeks. The system was well built and the support from the company was great. It had a massive library and many cool and useful features that their competitors do not. The only real downside for me was the lack of a part specific bench made just for the unit, the opening for the boards was a bit small for our needs and last and most serious, the software seemed to crash a lot. But I was also running a beta version as they change their software a lot to incorporate customers needs and desires, so the crashing might have a been a by-product of that.
We currently have two YTV-M1 inline-systems from YesTech. I have been using them for around 3 years now. They are descent machines. If you decide to go with YesTech, go for the F1 system. This will give you the ability to upgrade with side cameras later on if you decide, something the M1 system doesn't have. Also, you can do single pass inspection with the F1. Normally, the number of light settings used indicates the number of passes the system will have to make during the inspection, decreasing your overall inspection time. The single-pass feature allows all light sources to activate during each inspection frame. For std white and red light inspections, you could see a 40-50% decrease in inspection time, but that's just a guesstimate. This is something the M1 doesn't have as well. I believe their new F1X systems has a high res option. So your not loosing anything there if you need higher resolution. The software is easy to use and user friendly for developing new recipes. Over-all, I have been happy with the systems. The only gripe I have is their lack of documentation. Their user manuals are good, but are not kept up-to-date like they should be. So a lot of new features that are added to new software releases go unnoticed, unless you pay attention to the release notes.
We are currently using the F1. We've had it for a couple of years now and overall we are happy with it. We did have some issues with the software crashing but after replacing the PC several times we seem to have found a stable platform. Also the conveyor system and control has had some headaches. Other than that it is reasonably user friendly and does a good job of finding defects if you stay on top of the templates. If we needed to add another AOI I think we would stick with Yestech.
What Derek means is, you will have to train new templates from time to time, something you have to do with every AOI. Because there is no established method for marking parts, these markings can change. For instance, the text on chip resistors could change to a different font, or perhaps the numbers are bolder, smaller, bigger, etc. Because of this, these changes will effect your pass score for these parts, and you may have to train an additional template into the system for that particular part in question. This is expected. Believe it or not, one of the hardest parts to test for are chip capacitors. Because they have no markings, I have to inspect the body of the part using GSC (pattern matching). Of course, if the color of the part changes, this is going to effect my score and a new template may be necessary. There are other algorithms that can be used such as binarized imaging, solder inspection (a trick I learned some time ago to test the presence/absence of the part using histogram inspection). The point is, the parts physically change: They change color, text, or even the method to which they are printed. That's why you have to "stay on top of the templates."
If you are looking for a solid AOI system that is simple to program and extremely accurate my recommendation is MIRTEC by far.
We checked out several machines and narrowed the selection down to two, YESTech and MIRTEC. We had an opportunity to work with both of these machines on our production floor. We found that the MIRTEC machine consistently provided better defect coverage than the competitive system, especially with regard to solder joint inspection. We also ran a very simple Gage R&R test on the two systems. The MIRTEC machine easily won.
The MIRTEC machine was about two and a half times faster with roughly 20% less false calls. Although this did help with my ROI, performance was my main concern. We cannot afford escapes... PERIOD! That's the reason why we needed AOI in the first place!
We now have a total of five MIRTEC machines in production including a new MV-7xi system configured with a total of five(5) 5 mega pixel cameras and a high resolution telecentric lens. Solder inpsection on 01005's is not a problem. You should also check out thier Intelli-Scan Laser system option. Totally worth the investment in my opinion.