Pat,
We have only one SM device on our PWB's, so we haven't taken on the full
SM spec's yet.
Our current specs are wider than what you quote, but not out of line of
what I have seen in my exploration of branching into SM. We use our
equipment mfgr's spec for board handling as our spec. This relates to
.010" per inch of PWB length with a max of .125".
As I said, this is wider than what you are quoting, so this info may not
be too helpful. Good Luck.
Richard Hamilton
Clemar Mfg. / Rain Bird
[log in to unmask]
> -----Original Message-----
> From: Pat Bailey [SMTP:[log in to unmask]]
> Sent: Monday, December 15, 1997 2:48 PM
> To: [log in to unmask]
> Subject: [TN] Board Flatness
>
> Hello, TechNetters,
>
> I was wondering what others are calling out for flatness requirements
> on
> double sided boards with surface mount components. IPC-A-600 calls
> out
> 1.5% but with a caveat that automated assembly and surface mount may
> require more stringent requirements, and refers to IPC-D-275. The
> most
> stringent callout in D-275 for a 0.062" double sided board is 0.9%,
> and
> this is classed "reduced producibility". If we have, say, an 8.5"x11"
> board with 0.9% bow or twist, I know we'll have difficulty running it
> down
> our lines. What are others calling out, and how have your fabricators
> responded? Some of mine are balking at 0.7%, saying it can't be held
> (would have to be sorted, possibly increasing cost) because of
> variability
> in the base material. I think 0.7% is met most of the time, but every
> once
> in a while...
>
> Thanks for any input.
>
> *****************************
> * Pat Bailey *
> * Supplier Quality Engineer *
> * Zytec Corporation *
> * 1425 E. Bridge Street *
> * Redwood Falls, MN 56283 *
> * *
> * phone 507 637-2966 x355 *
> * fax 507 644-3720 *
> * e-mail [log in to unmask] *
> *****************************
>
> ##############################################################
> TechNet 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 TECHNET <your full name>
> To unsubscribe: SIGNOFF TECHNET
> ##############################################################
> 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
> ##############################################################
##############################################################
TechNet 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 TECHNET <your full name>
To unsubscribe: SIGNOFF TECHNET
##############################################################
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
##############################################################
|
