TECHNET Archives

March 2002

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
Earl Moon <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Mon, 25 Mar 2002 10:56:24 -0600
Content-Type:
text/plain
Parts/Attachments:
text/plain (34 lines)
Depends on what is meant by balanced glass styles. I have commented before
on this and prefer unbalanced constructions within each dielectric thickness
requiring multiple plies. The caveat is using homogeneous styles to promote
dimensional stability.

As an example when 5 mil thickness is required it is advantageous, instead
of using 2 plies of 1080, to use a single ply of 106 and one of 2113 to
acheive the same result. This allows a high resin to glass ratio, as the
106, for better bond characteristics and lower resin content, as the 2113,
for higher dimensional stability. Plus, the two ply 1080 is very "juicy" and
tends to slip about too much.

If you are talking about using, say, a balanced construction on one board
side, as several two ply 2113 styles per dielectric thickness, and another
on the other side, this too has merit. I recently used a construcion, when
the copper foil was heavier on one side than the other, consisting of
several plies of 7628, sandwiched between two plies of 2113, to counter the
copper imbalance to minimize bow and twist.

This is a good question and has many answers depending on design requirements.

MoonMan

---------------------------------------------------------------------------------
Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
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 delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives
Please visit IPC web site http://www.ipc.org/html/forum.htm for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
---------------------------------------------------------------------------------

ATOM RSS1 RSS2