Steve;

Don't know if this would work but here goes with a thought. Why not process
the whole board a 4 layer board and those areas that are required to be 2
layer just etch off all the copper and have bare laminate. Wouldn't this be
similar to having a two layer board especially if the board is FR-4? Any
comments from board vendors or EE out there listening in today.

Steve Collins
PCB Design Supervisor

----------
> From: Stephen R. Gregory <[log in to unmask]>
> To: [log in to unmask]
> Subject: [TN] Assy: Strange new PCB Technology?
> Date: Wednesday, February 10, 1999 10:56 AM
>
> Hi everybody!
>
>      We've got a series of boards that we build for a customer who's
product
> is a WEB/CATV sort of system. The main board is what they call their
home-box,
> or set-top board. It's got a little of everything on it...a digital
section
> around the CPU, some RF circuitry with the metal sheilding, and analog
areas.
> The system is working and they've got customers, so the next logical step
in
> the product life cycle is cost cutting, figuring out how to do the same
thing
> only cheaper.
>
>       Yesterday my contact at our customer (the materials manager) asked
me if
> I have ever built a board that had two complete and distinct sections,
one a
> 4-layer section, and the other a 2-layer section, that was joined by some
sort
> of "staple" (that was the best way he could describe it to me) and I
would
> process it as one single board. He said he wasn't sure if the "staple"
was
> pressed into the PCB somehow, or soldered in. But he said he was sure
that it
> was said the assemblers would put it together as if it was one board.
>
>       I told him lordy no, I have never heard of such a thing. I've done
> boards that are different layers connected by a flex circuit or a ribbon
> cable, and that was a completely separate operation towards the end of
the
> process, but never processing two different layer boards at the same time
as
> one board...have any of you heard of such a thing? My customer said that
this
> was something that a fab house down in southern California had told to
one of
> their engineers in their efforts to reduce costs...says that they can
save on
> their PCB cost by doing something like that since the only section of the
> board that needs to be 4-layer is a small area right around the CPU.
>
>       My first reaction was holy-taco shell batman, how in the world is
> something like that gonna stay flat? I can't visualize something like
> that...is the materials manager just trying to mess with me or does
something
> like that really exist?
>
> -Steve Gregory-
>
> ################################################################
> TechNet E-Mail Forum 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's web site (http://www.ipc.org) "On-Line Services"
section for additional information.
> For technical support contact Hugo Scaramuzza at [log in to unmask] or
847-509-9700 ext.312
> ################################################################

################################################################
TechNet E-Mail Forum 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's web site (http://www.ipc.org) "On-Line Services" section for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################