Mike,
Basically, this boils down to 2 issues : what the user really want/must have
and what your HASL machine can give.
So, pls consider the following suggestions :
a) where is the point of measurement - center of pad, crest of solder, XX%
from pad edges, etc..
b) what MUST be measured, should be measured, nice to be measured, nice to
have, etc..
c) what are the user's conditions like - long storage, multi-reflows, board
make-up and density, etc..
With one HASL setting, there will alway be compromise. Generally, we
measured both 'large' areas (eg: PLCC, gnd, ....) and 'small' pads (QFBs, ...
.). Solder basically will range from 70 - 1000 umil, so getting 90-100 on
larger areas is pretty impossible all the time (unless you turn off the air !
). Small pads, on the other hand, hit above 100-200-300 easily but may tend
towards the higher end which can be a concern with customers. However, 1000
umil should be a very comfortable limit (BUT.....there didn't seems an end
to this issue).
Likewises, I would be happy to heard from anyone on HASL woes & fixes,
realistic specs., etc...
Season Greetings to you and all.
Joseph Yip
_____________________________________________________________________________
__
To: [log in to unmask]@INTERNET
From: [log in to unmask]@INTERNET on Mon, Dec 23, 1996 11:42 PM
Subject: HASL Surface Tolerence
Can anyone tell me what is the specs for the surface of pads after
HASL. I know that it will not be perfectly flat but what is the spec.
Merry Xmas to all
Mike Lopez
***************************************************************************
* TechNet mail list is provided as a service by IPC using SmartList v3.05 *
***************************************************************************
* To unsubscribe from this list at any time, send a message to: *
* [log in to unmask] with <subject: unsubscribe> and no text. *
***************************************************************************
* If you are having a problem with the IPC TechNet forum please contact *
* Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] *
***************************************************************************
***************************************************************************
* TechNet mail list is provided as a service by IPC using SmartList v3.05 *
***************************************************************************
* To unsubscribe from this list at any time, send a message to: *
* [log in to unmask] with <subject: unsubscribe> and no text. *
***************************************************************************
* If you are having a problem with the IPC TechNet forum please contact *
* Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] *
***************************************************************************
|
