We always design using the Maximum Material Conditions (MMC).  In doing so,
I can just use the values of X, Y and C specified.  One note of caution,
always check that the mechanical dimensions specified by the supplier match
those that the land pattern was developed around.

At 12:40 2/28/96 EDT, Jeff Seeger wrote:
>
>
>	Pat,
>
>	Good to hear your endorsement of the IPC land patterns.  We have
>	found good acceptance of them in the general assembly community.
>
>	I'm always glad to hear of "paths to higher yield".  Given your
>	testimonial I'd be curious to hear more specifically how you've
>	implemented the spec, though.  In your interpretation of IPC 782
>	(I assume it's rev A), do you use the nominal values presented or
>	do you envelope broader tolerances?  Perhaps you start with the
>	nominals and adjust for your process within the broader tolerances?
>
>	I have found this particular version to be a bit subject to the
>	user.  Nominal values are aggressive compared to factory specific
>	specs that we also support, while the full envelope presented is
>	too conservative for complex products.  Is your interpretation
>	part of your success?
>
>	Long live TechNet!
>
>	Jeff Seeger				Applied CAD Knowlege Inc
>	Chief Technical Officer			      Tyngsboro MA 01879
>	[log in to unmask]				    508 649 9800
>
>
>

-Pat-

-------------
Patrick McGuine
Nicolet Instrument
[log in to unmask]
(608) 276-6334