TECHNET Archives

July 2009

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:
"Stadem, Richard D." <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Stadem, Richard D.
Date:
Tue, 14 Jul 2009 09:37:23 -0500
Content-Type:
text/plain
Parts/Attachments:
text/plain (187 lines)
I am not sure what you mean by Post T/C?

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Victor Hernandez
Sent: Tuesday, July 14, 2009 9:31 AM
To: [log in to unmask]
Subject: [TN] Maximum Allowable Bow & Twist for Post T/C Reliability

Richard,

I did not receive any comments on my Post T/C Reliability inquiry so I
will post again.

What about Bow & Twist on Post reliability testing, T/C?
Does the 1.5% still applied for SMT/PTH assemblies?

The assembly is a rectangle, 10.5 x 8 inch, form factor.

Victor,

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D.
Sent: Monday, July 13, 2009 10:07 AM
To: [log in to unmask]
Subject: Re: [TN] Maximum Allowable Bow & Twist for PWB-PCB

Bev, I totally agree with you, but the point they are getting at in IPC
2221 is that no section of the PWB should have more than .75% per inch
as a rate of warpage, extending in both the X and Y directions, after
reflow. This is because if you have more warpage than that you are
putting a stress on the resultant solder joints that leads to a
reduction in reliability, especially with a lead-free joint and also
especially if you need to straighten the CCA when mounting it into a
chassis or frame.
I think this specification, like so many others that were based on
leaded solder, should be revisited for unleaded solders.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Bev Christian
Sent: Friday, July 10, 2009 3:24 PM
To: [log in to unmask]
Subject: Re: [TN] Maximum Allowable Bow & Twist for PWB-PCB

I contend this is old school and if you aren't measuring warpage at
reflow temperatures how do you know you aren't suffering from head on
pillow?

I suggest the term head in pillow be dropped because you don't actually
put your head IN a pillow.

Bev
RIM

PS Waiting for my Dewism.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Genny Gibbard
Sent: Friday, July 10, 2009 4:20 PM
To: [log in to unmask]
Subject: Re: [TN] Maximum Allowable Bow & Twist for PWB-PCB

IPC-2221 5.2.4 
...
Unless otherwise specified by master drawing, max bow and twist shall be
0.75% for boards that use surface mount components and 1.5% for all
other board technologies.
...
Values are measured as per IPC-TM-650 Method 2.4.22 


Genny Gibbard, P. Eng 
Manufacturing Engineer, Vecima
PTS dept. x.4229 

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Victor Hernandez
Sent: July 10, 2009 2:15 PM
To: [log in to unmask]
Subject: [TN] Maximum Allowable Bow & Twist for PWB-PCB

What is the maximum allowable Bow & Twist value?   Not able to locate in
IPC-2221, 2222, & 6012A

Victor,

---------------------------------------------------
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
-----------------------------------------------------

---------------------------------------------------------------------
This transmission (including any attachments) may contain confidential
information, privileged material (including material protected by the
solicitor-client or other applicable privileges), or constitute
non-public information. Any use of this information by anyone other than
the intended recipient is prohibited. If you have received this
transmission in error, please immediately reply to the sender and delete
this information from your system. Use, dissemination, distribution, or
reproduction of this transmission by unintended recipients is not
authorized and may be unlawful.

---------------------------------------------------
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
-----------------------------------------------------

---------------------------------------------------
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
-----------------------------------------------------

ATOM RSS1 RSS2