Subject: | |
From: | |
Reply To: | TechNet E-Mail Forum. |
Date: | Mon, 13 Nov 2000 11:02:46 -0500 |
Content-Type: | text/plain |
Parts/Attachments: |
|
|
There are several potential root-causes of board warpage:
1. Incomplete cure of epoxy resin
2. Asymmetrical stackup of board layers
3. Unbalanced circuitry layers
4. Excessive bowing during board fabrication
Non-parallel lamination fixturing/press platens
Inadequate post-lamination stress relief
5. Absorption of moisture before assembly
6. Excessive temperatures during assembly
7. Rapid heating or rapid cooling during assembly
8. Bad fixturing during wave soldering
-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Malewicz Wesley
Sent: Monday, November 13, 2000 10:08 AM
To: [log in to unmask]
Subject: [TN] Warp/Bow after reflow
Importance: High
Hi,
What are some of the contributors that would cause a .040 thick PCB in a 12
up panel, routed and scored, with components mounted on both sides, to
warp/bow after reflow.
Thanking you in advance for your suggestions.
Wes Malewicz
Printed Circuit Development Supervisor
Siemens Medical EM-PCS
email: [log in to unmask]
----------------------------------------------------------------------------
-----
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
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
----------------------------------------------------------------------------
-----
---------------------------------------------------------------------------------
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
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
---------------------------------------------------------------------------------
|
|
|