Hello, Ioan Tempea said:

>Yes, we bought an AOI machine and have it up and running. The problem is
>that with each reel changed on the p'n'p machines, the writing on the
>components changes and the templates have to be readjusted. Is it natural?
>
>The component engineer cannot impose font and alignment requirements so
>we're stuck with tweaking the programs intensively.
>
>Is this a problem that everybody has? Is this machine dependent and we chose
>the wrong one? Are we not knowledgeable enough to do the right programming?
>Any tricks to get better results?

About seven years ago, a previous employer operated an assembly AOI machine
made by Omron. At that time, the Omron equipment was not sold in the US
market, but since our parent (Japanese) company had several of these
machines, we were honored by having one here in Texas. I have since seen
this equipment shown at NEPCON.

This machine was amazing to watch, it could "inspect" for missing, wrong,
reversed, solder shorts, and even insufficient solder. The reflection of
polarized (I think) light could be resolved to color gradients, and even
shallow fillets could be detected.

This equipment was about $250K at that time, and we put it in-line,
magazine load/unload conveyors, the whole 9 yards.

The Test Engineering section was managed by a very competent, hard working
Japanese engineer with whom I worked closely. He had one full time tech
assigned to keeping the machine programmed, largely a matter of telling it
to ignore variations in component markings, leadframes, and plastic
moldings. This manager and I kept up a steady running banter about the
(f)utility of the big automated inspection machine.

The inside joke (my original line) was that the machine was like having a
Lear Jet in your driveway - very good for impressing your neighbors (the
ISO auditors and customer visits) but not too useful for getting back and
forth to work (i.e., sorting our real defects). I was told that our home
plant production engineering staff thought that the "Lear Jet in the
driveway" line was the funniest thing they ever heard.

Our equipment produced a steady stream of false negatives, mostly for
changes in mold compound, lead finish, and predominantly in component
marking. When alternative component suppliers multiply (or perhaps raise
exponents of) these variations - it does seem to me a collosal cause of
problems with this technology.

Since the experience above is so dated, and since optical inspection
continues to advance rapidly - I suspect my critical comments are subject
to ridicule by new technology. Logic tells me that it ought to work - on
the other hand, I have not seen or heard any large groundswell of
testimonials for AOI by assemblers.


cheers,


Jerry Cupples
Interphase Corporation
Dallas, TX USA
http://www.iphase.com

##############################################################
TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c
##############################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in
the body:
To subscribe:   SUBSCRIBE TECHNET <your full name>
To unsubscribe:   SIGNOFF TECHNET
##############################################################
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information.
If you need assistance - contact Keach Sasamori at [log in to unmask] or
847-509-9700 ext.5315
##############################################################