In the days of 2x master artwork and photographic reductions I included a note that specified an layer to layer registration. The tolerance required was either +/-0.005" or +/-0.003" accuracy for the 3 photographic alignment points, when one target (moiré) was perfectly aligned. This note was dropped from our requirements when we went to providing gerber data for photo-plotting in place of the photo reduced black-and-clear acetates.


Jeffrey McGlaughlin, CID 
Engineering Designer 
Battelle 
505 King Avenue 
Columbus Ohio 43201-2693 
(614)424-7582 Phone 
(614)458-7582 Fax 



-----Original Message-----
From: DesignerCouncil [mailto:[log in to unmask]] On Behalf Of Jack Olson
Sent: Monday, April 07, 2008 3:58 PM
To: [log in to unmask]
Subject: Re: [DC] specify layer to layer registration?

I've never specified layer registration.

Now that I think about it, I have been given a fairly large collection of
notes to collate into the new IPC-2614 publication on Documentation of Bare
Boards. Unless, I've had a mental lapse, NONE of those notes specify
registration either.

I'll go double-check just out of curiosity, but I don't think I have a
single note about that.

And I think you are on the right track with the annular ring,
because that's where any mis-registration would show up.

Jack

.
On 4/7/08, Murphy, John <[log in to unmask]> wrote:
>
> Greetings,
>
>                  Is it a good idea to specify layer to layer
> registration for Class II
>
> multi-layer PCB's?  My searching thus far indicates it is not directly
> contained
>
> in any IPC specification (other than annular ring requirements) but
> relegated to
>
> the Master Drawing.
>
>
>
>
>
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