Hi Bob,

 Machining part of a PCB that way, makes it asymmetrical. Depending on subsequent processes, and the size of this milling of curse, you may get warping at soldering temperatures. Also, you have two different set of properties, the laminate layers and the perpreg layers.
Werner


 

 

-----Original Message-----
From: bob wettermann <[log in to unmask]>
To: [log in to unmask]
Sent: Tue, Feb 2, 2010 7:04 pm
Subject: [TN] FR-4 Mechanical Properties


Technetters:

We are working on a project where we have to mill down 0.005" on each side of a 
populated FR-4 board which is 0.062" in thickness making the nominal thickness 
0.052" +/- 0.002".

The question for you mech-e's out there is :

"How will the mechanical properties of the board change with 0.010" being shved 
off of the thickness?" 

<The thickness is reduced by this amount near a mounting hole>

Thanks

Bob Wettermann
BEST Inc


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