The majority of the shops on MLC have very poor controls in process and
spend an amazing amount of people hours to salvage material affected by
poor processing practices.  Other areas in Asia have better controls
that have been driven by their customers.  The perception of quality and
acceptability in Asia is quite different than the west.  It is evident
to me from reviewing fabrication house in Asia that the main objective
is to rework/repair the units at any cost to allow for shipment.  We
generally take the view of field reliability over supporting shipments.


I think it is important the companies choosing the off-shore procurement
model take the time and resources to audit suppliers in Asia under the
standard guidelines established.  I am sure this would be an eye opener
for those companies that have matured to the level of handling the PCB
as an customer made interconnect devices rather than a commodity.  I am
always surprised at the number of companies who have never audited shops
they are dealing with either direct or with brokers. 
  

Jeffrey Bush
Director, Quality Assurance and Technical Support

VERMONT CIRCUITS INCORPORATED
  76 Technology Drive - POB 1890
    Brattleboro, Vermont 05302
      Voice: 802.257.4571.21 Fax: 802.257.0011
           http://www.vtcircuits.com
 

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Jack C. Olson
Sent: Friday, September 16, 2005 8:49 AM
To: [log in to unmask]
Subject: [TN] Bare-Board Inner-Layer Fab Quality

This is a question for anyone who is intimately familiar with bare-board
fabrication.

I've recently returned from a trip to China and Taiwan to visit five fab
vendors.
During one of the tours, I noticed people doing a lot of rework on inner
layers,
scraping metal flecks off with screwdrivers and scrubbing crud off of
conductors
with this black (alcohol?) stuff. I asked the tour guide what their
inner-layer
yield was, and he said 99.5%

huh?

Is that how people do it? I've only been on maybe two board tours in the
states
in the last couple of years, and that issue never came up. So maybe
that's
just the
way it is done, but what BUGS me about it is they don't record how many
repairs
they are doing on each layer, and it looked like different operators had
different
criteria for what constitutes a reject, and by claming such a high yield
no one
ever looks at the process right before it that is putting all the crud
and
metal flecks
on the layers to begin with!

Jack (the "I thought I'd seen everything" guy)



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Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
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