Last week I pointed your attention towards a set of "SHALL"s in the new
IPC-2610 series on Electronic Documentation
http://frontdoor.biz/PCBportal/ThouShaltDocument.pdf

Then, in a follow-up email "To Grid Or Not To Grid" several people responded

to the requirements in 6.4.7 and 6.5 about documenting grids.
To summarize
(I think this is a fair statement based on the contents of my mailbox),
many people provided good reasons for using grids DURING DESIGN,
but no one advocated DOCUMENTING the grid.

Now, in this email, I would just point out a few more shalls, give you a
chance
to respond, and then I'm done.
(I say I'm done because these comments have to get back to the group before
the committee meetings in Las Vegas)

-=-=-=-
What Do You Think Of These Requirements?

The drawing revision description block shall identify the specific changes
made.
It is not acceptable to just reference to the Engineering Change Proposal
(ECP)
or other engineering document that initiated the change

The initial release of a design will be given a (-) revision. Subsequent
revisions
will be assigned A,B,C,etc, leaving out I,O,Q,X,S,Z

Whenever the drawing, or computer transferrable media, requires a revision,
the
description shall identify whether the revision impacts form, fit, function

Three fiducials (or registration targets) shall be located on grid and on
each layer
of data pattern. Each additional layer or data pattern shall have fiducials
located
at the same points which, shall register with each other, layer to layer.

The method of excising individual boards shall be included in the assembly
pallet
description

Unplated through hole patterns, especially tooling and mounting holes (board

mounting holes, interface connector mounting holes, board top plate/mounting

bracket mounting holes, etc.) are generally drilled in separate drilling
operations
as one of the last fabrication operations. They shall be explicitly
dimensioned and
toleranced, even if they occur on grid.

The fabrication drawing shall specifically indicate the location for the
date code,
fabricator’s I.D. and UL marking, user’s cage code, ESD symbol and all other

required traceability markings

A note on the fabrication data set shall specify the acceptable bow and
twist
requirements
-=-=-=-

Anyone who writes back can say they helped a standards development
committee!
See how easy this stuff is?

If you are lucky enough to attend APEX/EXPO, wander into a real meeting.
Here are the choices:
http://www.ipcapexexpo.org/Std.aspx

Jack (aka "the new guy")

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