Subject: | |
From: | |
Reply To: | |
Date: | Thu, 13 Jan 2005 10:03:48 -0800 |
Content-Type: | text/plain |
Parts/Attachments: |
|
|
Ryan: "Butter Coat" is an old term and probably a lousy one. It is not
butter and is not a true coating.
It is not applied by the board fabricator. It is actually part of the
laminate manufacturer's standard process. It typically is an epoxy resin
that is incorporated into the lay up process that among other things helps
seal the outer layer of glass weave in the laminate to prevent moisture
penetration.
The board fabricator can disturb this coating by over aggressive chemical
and mechanical processing, exposing the glass weave. Thus creating pathways
for moisture and chemical intrusion into the laminate.
Regards
Michael Barmuta
Staff Engineer
Fluke Corp.
Everett WA
425-446-6076
-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Ryan Grant
Sent: Thursday, January 13, 2005 8:52 AM
To: [log in to unmask]
Subject: [TN] Butter coat
Hi Technetters,
I just learned a new PCB fabrication term today..."butter coat". It's
supposed to be thin layer of resin between glass cloth bundles and
conductors to assure reliability. In the few shop audits I've been
through, I've never seen or heard of a "butter coat". What would the
process look like? Is the resin pressed and frozen into a sheet that
can be handled or would it be squeegy'd on? If it is squeegy'd, can
that be performed by hand or must a machine do it? If a machine must do
it, how do you lay up the brick for the press? Finally, is this a
standard process that I've just been unaware of?
Thanks,
Ryan
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to
[log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to
[log in to unmask]: SET Technet Digest
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
-----------------------------------------------------
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
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
-----------------------------------------------------
|
|
|