The suggestion below seems like a good idea.  From a fabricators perspective
I can say that we have also on occasion messed up a stack but more often
than not it has been as a result of either cryptic layer/file naming
convention or a discrepancy between the file naming and the
readme/fabrication drawing, or, as I recall on at least one occasion, what
seemed like a straight forward board but with the customer intending the
stack direction to be from bottom to top and of course we laid it up, top to
bottom (sometimes you just can't win!).

When you have received a board with an error in lay-up what was the reason
given by the board shop.  If it was that the layer naming was not clear,
them maybe, even though you think it is understandable, your format needs to
be reviewed.  If it was simply an error on the part of the shop then some of
the suggestions provided, including that below are viable options which
should not only allow your inspectors to verify but also the fab shop.


> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]]On Behalf Of Eddie Rocha
> Sent: July 11, 2003 10:05 AM
> To: [log in to unmask]
> Subject: Re: [TN] Board Stackup fabrication errors
>
>
> The layer window idea can work very well if for each core (or layer pair)
> to the left of the layer number a solid copper block is to remain after
> etch. This makes it extremely easy to see if the PCB is layed up out of
> sequence. The out of sequence layer pair will not be visible (viewing
> form the top) because of the copper block. See example below, you
> won't be able to see layers 4 and 5 when viewing from the top, if it's in
> the wrong sequence
> correct sequence        wrong sequence
> 2 3                                2 3
> __ 4 5                           ______ 6 7
> _____ 6 7                     ___ 4 5
>
> ---------------------------------------------------

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