Mime-Version: |
1.0 |
Sender: |
|
Subject: |
|
From: |
|
Date: |
Thu, 4 Dec 1997 10:32:50 -0500 |
Content-Type: |
text/plain; charset="US-ASCII" |
Organization: |
MTCC/Panasonic |
Reply-To: |
|
Parts/Attachments: |
|
|
There can be many possibilties. Check the vendor recommendations for oven
profiles and land pattern. Are you breaking the board out of the panels
by hand or using a post assembly score finishing machine (after-score)?
Try testing the boards before you break them out. The part is being
stressed, but where?
Scott
----------
From: DesignerCouncil Mail Forum.
Sent: Thursday, December 04, 1997 10:21 AM
To: DesignerCouncil
Subject: [DC] SMD Capacitor Cracking
We are a company new to SMT and are working on a design in which a 500V
Ceramic capacitor with a 1206 pkg. size has an initial 115VAC input
voltage applied to it. On 50% (5 of 10) units tested, the capacitor "blew
up" (The design works on the 5 that didn't "blow up"). We are no where
near the limits of the device and believe that the capacitors are
cracking at some point in the assembly process. What I am looking for is
all the possibilities for this occurrence.
Some additional info: the board size is .407"x2.075", FR4, .031 thick,
single sided. Assembled in a 7x4 array (28up), scored, panel size
3.5"x8.9". Placed in the reflow oven, the capacitor goes in last (at end
of PCB). Thank You in advance!
##############################################################
IPC Designers Council Mail List provided as a free service by IPC using
LISTSERV 1.8c
##############################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with
following
text in the body:
To subscribe: SUBSCRIBE DESIGNERCOUNCIL <your full name>
To unsubscribe: SIGNOFF DESIGNERCOUNCIL
##############################################################
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for
additional
information.
For the technical support contact Dmitriy Sklyar at [log in to unmask] or
847-509-9700 ext.311
##############################################################
##############################################################
IPC Designers Council Mail List provided as a free service by IPC using LISTSERV 1.8c
##############################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe: SUBSCRIBE DESIGNERCOUNCIL <your full name>
To unsubscribe: SIGNOFF DESIGNERCOUNCIL
##############################################################
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information.
For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311
##############################################################
|
|
|