>      My preference is to have the land 2 to 5 mils wider than the lead to
>      allow for proper joint solderability.  The lead will also be 40/60 or
>      30/70 centered with respect to the land length.  This allows proper
>      solder forming to the toe and foot.  I see a lot of advantages to
>      adding additional width to the lands where real estate allows.  So why
>      do so many Designers opt for the 1:1 ratio, or am I generalizing?

Hi John --
In that (particularly on commercial specs) a lot of components are
not truely square and in that P&P equipment is (or may not be) 100%
calibrated at all times, a little tolerance in the way of a larger
pad to place the part on is appreciated w/ regard to
maufacturability (which increases quality by creating a more robust
design)... Maybe the argument is more space between pads decreases
the likelihood of shorting?  Personally, components are less than ideal
and the equipment is a pain in the neck to adjust, and I'd rather
have the tolerance on the placement area.  Of course, we don't have
much of a problem with the shorts (knock on wood)...so maybe I'm
biased...    Comments anyone?

Regards,
Lainie Loveless
General Atronics Corp
Wyndmoor, PA
(215) 242-7336

##############################################################
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
##############################################################