Cheap PCBs

From: Peter C. Wallace <pcw_at_mesanet.com>
Date: Thu Nov 21 18:43:00 2002

On Thu, 21 Nov 2002, Dwight K. Elvey wrote:

> >From: "Peter C. Wallace" <pcw_at_mesanet.com>
> >
> >On Thu, 21 Nov 2002, Jim Kearney wrote:
> >
> >> >From: "Dwight K. Elvey" <dwightk.elvey_at_amd.com>
> >> > Gerber format is not all that complicated. It seems that someone
> >>
> >> No, it's not. It doesn't seem like there's an off-the-shelf way to go from
> >> raster (PDF or TIFF) to vector (Gerber), though, or at least nothing jumps
> >> out from Google. In principle it would be easy to load a raster and write
> >> it out as a set of lines in Gerber format.
> >>
> >> Actually I have a vague recollection that one of the board houses charged
> >> extra for "very large Gerber files caused by rasterized plots".
> >>
> >>
> >>
> >
> >Plus its pretty hard to extract the drill info from a 'vectorized' raster
> >plot...
> >
> >
> >Peter Wallace
> >
>
> Hi
> That is why I didn't say that one should write a program
> that reads scanned files, I said that one should have a tool
> that worked from a mouse ( with human attached ). Most tools
> that would look at scanned data would tend to make a lot
> of small rectangles instead of correctly grouping the information
> as a single large rectangle. We are talking about something that
> a human can easily do but a program has issues because it
> requires judgement.
> The fact is that Gerber files are quite simple. They are
> about as simple as one can get. Although I don't recall the
> exact syntax, it is thing like goto to x,y; with aperture
> wheel position 2 draw relative xx,yy; goto to u,v; with
> aperture wheel postion 3 flash; and so on and so on.
> I don't think one could describe a PC board any simpler than
> that. I never said that an automatic tool should be easy to
> write. I said that one could make a useful tool that would use
> a mouse to locate and draw( snap would be nice ). One would
> simply trace the pdf or what ever with the mouse.
> Dwight
>
>
>

Gerber files are very simple vector commands (the earliest plotters had very
little brains - all hardwired logic...)


D14* C{ Chose aperture 14 }
X10038Y9785D02* { moveto x=10038,y=9785 }
X10063Y9810D01* { drawto x=10063,y=9810 }
Y9860* { drawto x=10063 y=9860 }
X10263* { drawto x=10263 y=9860 }
Y9810*
X10238*
X10213Y9785*
X10038*
X10043Y9790D02* { moveto x=10043 y=9790 }
D51* { Chose aperture 51 }
X8913Y10341D03* { flash pad at x=8913 y=10341}
Y6160D03*
X11113Y9860D03*
Y6160D03*
...

Peter Wallace
Received on Thu Nov 21 2002 - 18:43:00 GMT