Agree with Steve. I have a lot to do with a plant that solders about 500
metal boards per day. Like Steve said, these boards do not differ much
from common FR4 boards, except for the bigger mass, that needs more time
to maximum temperature. Remember one important thing: the recommended
soldering profile from the paste maker is still valid, which means that
you ought to run some boards with thermocouples on (MOLE) and make
necessary adjustments after the MOLE curve is read. Usually, you need to
accelerate the cooling because of the bigger mass.
Inge
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory
Sent: den 16 mars 2007 15:00
To: [log in to unmask]
Subject: Re: [TN] Metal-core PCBs
Hi Grant!
I don't know if the boards I've had experience with are like yours, but
the ones I've had experience with have had a great deal of copper in
them.
Below is a cross-section of one:
http://www.stevezeva.homestead.com/files/Rough_Cross_Section.jpg
The copper core on that one was .055" thick. Here's another:
http://www.stevezeva.homestead.com/HeavyMetal.jpg
This board didn't have a copper core per-se, but layers 2 and 11 were
40-oz copper layers..
When I first learned that we were going to build the first board I had
all kinds of questions. I didn't think our reflow oven was going to be
able to handle it. I thought that we were going to need vapor phase to
reflow it. But actually, it was a piece of cake. We were using
Electrovert Omniflo-10's at the time, and all I really did was slow the
belt-speed down to give the board some time to absorb the heat. I
normally ran most boards at 32 inches per minute, I ran the heavy metal
boards anywhere from 26-28 inches per minute and they did fine.
The heavy copper actually made the heat very even across the board,
there was very little delta across the assembly. One caution; when a
board with that kind of mass comes out of the oven, it is going to be
VERY HOT and stay hot for a lot longer than most assemblies! Depending
on the mass, the solder on the board may still be liquidous just as it
comes out of the oven.
-Steve Gregory-
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Grant Emandien
Sent: Friday, March 16, 2007 5:42 AM
To: [log in to unmask]
Subject: [TN] Metal-core PCBs
'netters, has anyone advice/guidelines to offer on the reflow of
metal-core PCBs? We are running for the first time and would appreciate
any insight.
Regards
Grant
**********************************************************************
Relevant company disclaimers are available at the following addresses:
Tellumat (Pty) Ltd e-mail:
mailto:[log in to unmask]
Web: http://www.tellumat.com/email.aspx
**********************************************************************
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 15.0 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 15.0
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
-----------------------------------------------------
|
