hello,

this has been enlightening.  i really appreciate everyone's post here.
let me repeat that i'm not the one who's actually supposed to perform
this operation.  another facility here on base already does it.  but it is
my job to make sure that we get good work out of them for our boards, 
and have my eyes open to the pitfalls.  

it appears to me from all your posts that if you rely upon a totally
automated process, the results are going to be questionable.  and if
you just snap a picture of it and lay traces over the top of it using some-
thing like protel, you gain some but not a lot.

so when i go over to talk to this other facility, i'll be looking at how
much of the process is automated and how much they do by hand,
and i'll be looking with a critical eye at the quality of the end result.

thanks,  miker

> -----Original Message-----
> From: Ralf GŁtlein [SMTP:[EMAIL PROTECTED]]
> Sent: Thursday, October 18, 2001 11:01 AM
> To:   Protel EDA Forum
> Subject:      Re: [PEDA] gerbers from a scan ??
> 
> Hi Michael,
> 
> some kind of semi-automatic procedure for rebuilding legacy
> hardware would be a nice option. Here's what you need to do:
> 
> 1. Take a picture of your board using a flatbed scanner.
> 2. Chance the color of the board plane to white and of the
>    traces to black; save as BMP file.
> 3. Use one of those converters mentioned in the
>    "BMP-to-gerber" threads.
> 
> This was the good news. Now back to the real life.
> 
> I think the problems getting this into operation are so big
> that (almost?) noone takes this procedure into consideration:
> 
> 1. Depending on the board pattern it is hard or even impossible
>    to get a sharp, high-contrast image.
> 2. You will have a hard work post-processing your picture to
>    a black/white bitmap.
> 3. Dimensions (and maybe the aspect ratio) gets lost when saving
>    it as a bitmap file (it depends on the bitmap resolution).
>    Rescaling it back to the original outline may drive you nuts
> 4. With big, detailled bitmaps you will spend a hard time in
>    converting them to gerber or pdb data. The conversion will
>    bring myriads of tiny tracks and artefacts into the pcb,
>    which you have to remove/redraw in post-processing.
> 5. Double-sided boards are a crap if you want both sides to match.
> 5. No matter what you do, you will not get a re-editable artwork
>    file, which you can cross-check with a schematic.
> 
> Maybe with small, crude, single-sided boards and with some
> effort you will have some success, but those boards are
> easily to be redrawn in the "old-fashioned" way anyhow ;-)
> 
> I will not say that it is impossible to get useful results
> from such kind of reengineering. But you will need highly
> sophisticated tools to hit the jackpot. I disbelieve you
> will find them.
> 
> Regards, Ralf
> 
> 
> 
> 
>            .....
>            Ű Ű )
> -----oOOo--(_)---oOOo------
> 
> Ralf Guetlein
> Biotest Medizintechnik GmbH
> Industriestrasse 19
> D-63755 Alzenau
> Germany
> ---------------------------
> Tel. +49 6023 9487-42
> Fax. +49 6023 9487-33
> [EMAIL PROTECTED]
> ---------------------------
> 
> ----- Original Message -----
> From: "Robison Michael R CNIN" <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Thursday, October 18, 2001 3:33 PM
> Subject: [PEDA] gerbers from a scan ??
> 
> 
> > hello,
> >
> > i guess our customer on this board rebuild job is happy with us
> > and has given us a bunch more boards to do.  over half of them
> > are simple two-sided boards.  with no existing gerbers, up til
> > now i've been recreating these in protel with a stripped board and
> > a set of calipers.
> >
> > this issue has been sitting on the backburner for me a while, but
> > bob wolfe mentioned something close to it and now my interest
> > is piqued.  there is another facility here on base that can take an
> > existing board that's stripped and somehow scan or photograph
> > the surface and generate gerbers from that.  they want me to go
> > over and check it out and give them an idea of whether this is a
> > good idea and what kind of problems might be involved with this
> > process.
> >
> > my question:  what am i likely to find when i go over there?  i'm
> > going to assume that there is some scanning or photographic
> > hardware thats associated with some software program that
> > converts a raster image into the vectorized gerber files.  are you
> > guys familiar with this kind of setup?  what are some of the software/
> > hardware setups employed for this?  surely its better than me sitting
> > here re-creating the boards by hand.
> >
> > any comments will be appreciated.
> >
> > thanks, miker
> >
> >
> >
> >
> 

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