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Date: | Sunday, January 12, 1997 3:40PMMon, 13 Jan 97 14:52 |
Content-Type: | text/plain |
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The address is a little different. It has the word "-request" after the
word TechNet to subscribe.
----------
From: Automata
To: dabonz; jasatt; mimall; 'Matthew Leary'
Cc: [log in to unmask]
Subject: RE: vias
Matt, If I understand your question correctly, the answer is quite =
elementary. Generally, a four layer board has circuitry on the two =
outerlayers and the internal cores are a power plane and a ground plane. =
To pass a conductor from the top to the bottom, the internal layers =
have a clearance etched in the copper larger than the=20
hole that is going through. When you laminate the layers together the =
clearance area fills in with epoxy.
At locations where you want a conductor to connect to the ground plane =
(or power plane) there is no clearance on the plane. =20
You can subscribe to the IPC technet by sending mail to the same address =
you sent your question to with the word subscribe in the subject field =
and no text in the body. I doubt you want an average twenty five or =
thirty messages per day from people who build or use boards listing all =
their travails.
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From: Matthew Leary[SMTP:[log in to unmask]]
Sent: Monday, January 13, 1997 4:51 PM
To: [log in to unmask]
Subject: vias
Hi guys,
I wound up here thanks to Yahoo and I do have aquestion for you,=20
although I do not know if I am in any position to ask you to answer me. =
If I need to sign up for something, could you fill me in. Anyway my=20
question is this:=20
A via passes through a four layer board, is a hole=20
drilled in the ground and the power layers. What is used to insulate =
the=20
ground and power layers from the solder that eventually will fill this=20
hole? Is it a form of mask? I thought mask prevented it from the top =
of=20
a layer (i.e. the top of the board), but not the width if a board is =
cut.=20
Anyway, please get back to me on this. Thanks.
Matt
[log in to unmask]
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* TechNet mail list is provided as a service by IPC using SmartList v3.05 *
***************************************************************************
* To unsubscribe from this list at any time, send a message to: *
* [log in to unmask] with <subject: unsubscribe> and no text. *
***************************************************************************
* If you are having a problem with the IPC TechNet forum please contact *
* Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] *
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