Sigh. You've missed the point again. You must read down through the
previous e-mails on the subject, especially Susan's that I first replied to.
Rather, let me copy the section (that Susan wrote) here, that I commented
on:
"1. Anne - line width and spacing is 15 mil traces on 25 mil centers. We
have a different supplier for our multi-layer boards who also uses Camtek
inspection stations. They have no problem with the annular ring. I did ask
them for input on our "other" supplier problems and they suggested that the
design rules needed to be changed. They also said the quality of the camera
would influence the results. Maybe this is part of the issue. This vendor
also uses LPI for our multi-layer boards.
2. Ed - yes, the finished hole size is .038. I know the potential for pad
break out is high but we have never had break out issues on these boards.
3. Franklin - you make a good point about whether AOI is worth it on older
boards and, Yu-Shan, I did not know that AOI is usually reserved for inner
layers. The reason we requested AOI and LPI is that we have had some
quality issues with this supplier and see these as a way to help eliminate
the problems. We have a good relationship with this supplier and really are
looking to improve the quality of our bare boards as well as improving the
assembly process in our own facility. This supplier is hand screening our
boards and doing visual inspection. We are seeing things like blown tracks,
shorted tracks, poor drilling, debris in holes, and sometimes dusty boards.
This doesn't happen a lot but we need to prevent it. It's hard for me to
talk to our assemblers about quality when we accept defective boards.
Unfortunately, I have no clout with respect to incoming inspection on
boards. I would like to work this out with the vendor. I'm sure they have
some valid points but I think we do, also. Yes, I agree that partnership is
important and we will be meeting with them next month to discuss all of
this."
Note what Susan says about the supplier's basic quality on the board in
section 3 - and we are talking a double-sided board with 15-mil lines and
38-mil holes. This is very basic stuff and the supplier is still shipping
some bad boards to their customer (with whom they have a "good
relationship"). Now really. Can you agree that AOI is not the answer in
this situation? Gosh, even I can see defects of this size with just an eye
loupe, while the young inspectors can probably see it with the naked eye.
So, why not fix the obvious process problems at hand and then the quality
issue becomes a non-issue.
I don't think I am being hard on board shop(s) to expect them to be able to
reliably make a 15-mil line/10-mil space board with 38-mil holes! (And to
not need AOI to "inspect in" quality?) Board shops out there, would you
agree?
p.s. - Want to get an idea how to fix the board shop's quality problems
(other than management issues)? Take a look at PE-740A, the IPC's
"Troubleshooting Guide for Printed Board Manufacture and Assembly". (How's
that for a little plug for our Process Effects subcommittee?)
Patty
Patricia J. Goldman
PPG Industries, Inc.
412-492-5516
[log in to unmask]
-----Original Message-----
From: Greysonne Jorgenson [mailto:[log in to unmask]]
Sent: Wednesday, August 18, 1999 3:44 PM
To: [log in to unmask]
Subject: Re: [TN] Board Layout for AOI and LPI -Reply
Wow Patricia,
You seem to really have a bug about board shops.
Care to explain why?
Thanks
G~
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