Homebrew PCBs

Stefan,

I appreciate your comments, and the posts prior to this. I've snipped 
them to get us back on track...

Okay, there's more info in those "short lines" than you think. For 
instance they have location obviously, but also a layer, and a 
filetype. And a width.

From this filetype, layer, and width info we can give our macro the 
info it needs to do the required dispensing. It is simply a matter of 
deciding WHAT a layer, or filetype, or width "means", and then USING 
that when we create the solder paste layer...

And the macro is a subroutine, so each time it's called it does the 
same thing, at the locations which are easily pulled from the drawing.

See, the thing is, you see a drawing. But the drawing is "described" 
by its file. It's that DESCRIPTION which has the "extra" info you're 
not "seeing"...

Your question about milling is answered by Eagle with the use of a 
ULP designed to create mill-able traces from the gerber files.

The SAME method can be used to make a "dispensing" ULP.

ULP is a user written program. In this case the "user" is the WRITER 
of the program; and the true end user might have NO IDEA how it's 
done; but it works just the same. No different than pressing "output 
gerber files" in your ecad once you've finished the board layout...
The conversion program uses the details provided (or "mined") to 
create the information the machine needs to mill, or drill, or 
dispense, etc.

Hope this helps,

Ballendo

P.S. Can someone please post a link to the step by step use of a ULP 
to make milling traces possible. I've only very recently begun using 
Eagle, and I have some high end--and older/outdated programs I use 
which most wouldn't be likely to use with the inexpensive machine I'm 
offering (VHF, Ztrace, and Contact2). But I'll know how to do it with 
Eagle inside and out before they ship next month<G>  FWIW, the 
excellon file is used directly for the drilling.


--- In Homebrew_PCBs@yahoogroups.com, Stefan Trethan > I mean i have 
a drawing of my solder paste layer, nothing more.
> It contains short lines where the paste must go, that's it.
> This file does know nothing about how deep the dispenser has to be 
> lowered, or anything.
> It is like a plotter file, just 2 dimensional.
<snip>
 Would be really, really helpful if someone could (maybe again) 
explain how this is done.
> Please assume a two-and-a-half D Milling project for explanation, 
as it seems the same to me.
> Assume one has a 2D gerber line-art and wants to mill it. how does 
he process the 2D file to get the machine to move.
> 
> 
> 
> Thanks a lot.
> 
> ST