Afternoon All,
Isn't the Tg requirement design driven? Why not spec as a "minimum"
(dictated by the design) to allow the most flexibility to the fabbers?
MarkH
-----Original Message-----
From: James Hofer [SMTP:[log in to unmask]]
Sent: Monday, March 21, 2005 1:40 PM
To: [log in to unmask]
Subject: Re: [TN] Most common version of FR4?
Most of our thick core laminates are high Tg due to the industry
moving away
from low Tg products.
Our off-shore partners use only high Tg and High Td lead free
laminates as
is the case with 'most' off-shore manufacturers.
I see no problem calling out a higher Tg material for double-sided
parts.
Just my $0.02
James Hofer
Director of Operations
Accurate Circuit Engineering
3019 S. Kilson Dr.
Santa Ana Ca. 92707-4202
714-546-2162 work
714-473-6127 cell
[log in to unmask]
----- Original Message -----
From: "Jeffrey Bush" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Monday, March 21, 2005 6:52 AM
Subject: Re: [TN] Most common version of FR4?
4101/24-26 material is fine for multilayer PCB and is readily
available.
When looking at materials over .028" in thickness the /24-26
materials
become special order and are fairly costly. Much of the
manufacturing
for rigid laminates has moved off-shore and this also makes it more
difficult to procure thicker materials in higher Tg epoxies.
Double Sided boards should be 4101/21 materials unless .028" and
thinner.
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: Brooks,Bill [mailto:[log in to unmask]]
Sent: Friday, March 18, 2005 8:59 PM
To: [log in to unmask]
Subject: [TN] Most common version of FR4?
I'm looking for a reading on the most common version of FR4 material
for
2
sided boards and for multilayer boards... based upon usage in the
board
manufacturers shops...
I want to specify per IPC-4101/??
The best choices would have better Tg characteristics... so I was
leaning
toward IPC-4101/26 as my choice but there may be a suitable
alternative
that
is more commonly used that someone can point me to.
I have some old board designs that were originally build back when
MIL-P-13949 was the spec and GFN FR4 was all we had to specify...
It's time to update the notes...
Any help appreciated... :)
Best regards,
Bill Brooks - KG6VVP
PCB Design Engineer , C.I.D.+, C.I.I.
Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510
e-mail:[log in to unmask]
http://www.dtwc.com
http://pcbwizards.com
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