| | I had someone suggest that they weren't really necessary as long as your process is good. Is this just a way to help you keep an eye on your process? | | | | I was thinking, as we set up our line, our money would be more well spent with controlling the process such as on UPC system. | | | | Have an opinion? | | | | Nancy | | | I am inclined to agree with Nancy here. Far better to invest the time and cash ensuring that processes are running properly than spending it on kit which, at the end of the day, doesn't add any value to the finished product. | | I would be interested to hear from any of you using this kind of equipment, what sort of payback periods did you work with when you originally put tohether a justification for the expenditure? And do you also perform In Circuit/Functional electrical testing on your finished boards? | | Thanks | Scott
We are a contract shop doing high mix work, job sizes can range from 20 to 800 pieces, typical is 200 pcs. Many of our customers are in a state of continuous change regarding their designs.
The AOI is one way to 'keep an eye on the process' as Nancy mentioned. We use the AOI as an audit of the surface mount process. We ICT and functional test many products, but the job is completed in surface mount before any of them reach electrical test. An AOI gives us quicker response, so we can correct reversed 'sticks' of IC's and wrong reels loaded on a PaP.
I was not involved with the initial AOI purchase, so I can't speak to the payback used for justification. The AOI we have costs less than 100K and programs very quickly. Management actually ASKED for the PO for a second machine when we reached capacity constraints.
An AOI does not "add any value to the finished product", very true. It is much like ICT and Functional tests, which are for the most part, just process process verifiction tools also. Compared to electrical tests, we find the AOI to require no test heads, faster to program, more flexible, and can be linked closer to our key assembly process (surface mount). However, it has reduced capability to find some defects because it is only an optical system but we think it has its place.
An AOI would not be first on my list for a new startup shop, of course equipment that assembles product comes first (that value added thing). But with increased complexity due to job sizes, customer mix, or even product challenges, an AOI may be a useful tool for line setup verification and process auditing.
Thanks
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