Hi Marletta,

Now that I have seen a couple of answers, let me see how much trouble I
can get into.

1. Oblong lands are easier to route around
2. Stencils for oblong lands are cleaner, no corners (remembering that
it is easier to clean a square opening (0805 or 0603 or whatever) than a
rectangle)
3. Solder fillets are round (nature of the material) so a fair argument
has been made on the value (or lack of) of squared corners.
4. I agree with the last 8 mil trace statement, if your technology is
still requiring outer layer tracks than you can pick up considerable
routing room with oblong lands.

Now to really try and answer your questions:

The deciding factors for SMT land development should be (not necessarily
in order):
        A. Density of PWB (layer count, components per mm2, etc.)
        B. Company standards for design (if you don't have one, make
one)
        C. Assembly processes (beside yourself, these are the people
effected)

Should all SMD have oblong pads? NO! Some geometeries need to be square.
Should all SMD lands have filleted corners? I think so. This allows for
less paste build up in the stencil.

So now that you have mine and a few other answers digested, go talk to
your assemblers.
They should be a part of your design team and their input will make your
design a better one.
Call me if you would like to discuss further.
Best Regards
FNK


Frank N Kimmey
EM Designer
C&K Systems, Inc
(916) 353-5366
[log in to unmask]
> ----------
> From:         Marletta Tucker[SMTP:[log in to unmask]]
> Reply To:     TechNet E-Mail Forum.;Marletta Tucker
> Sent:         Tuesday, March 31, 1998 12:13 PM
> To:   [log in to unmask]
> Subject:      [TN] oblong lands
>
> What is the deciding factor on whether or not an SMD parts land is
> squared off
> or oblong?  Could/should all SMD parts have oblong lands?
>
>
>   @ @ @                 Thanks,
> @ @ @ ///
>  @    *                 Marletta Tucker
> @ @    >                1921 Hurd Dr. M/S 2-21
> @@|\ _                  Irving, Tx. 75038
> @ |                     972-518-7619
>   #                     [log in to unmask]
>
> We have enough youth, how about a fountain of SMART?
>
> The above views are my own, and do not represent those
> of Abbott Laboratories.
>
> ################################################################
> TechNet E-Mail Forum 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://jefry.ipc.org/forum.htm) for
> additional information.
> For the technical support contact Dmitriy Sklyar at [log in to unmask] or
> 847-509-9700 ext.311
> ################################################################
>

################################################################
TechNet E-Mail Forum 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://jefry.ipc.org/forum.htm) for additional information.
For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311
################################################################