Re: gEDA-user: Windows version of gerbv

[Rick Collins <gnuarm.2007@xxxxxxxxx>]

At 11:56 AM 4/23/2008, Stuart Brorson wrote:
> >> Maybe an XYRS configuration pop-up, including setting the orentation,
> >> also some type of pull-down selectors which allow you to specify which
> >> column (column number) holds each of the X, Y, R, and S data.  Maybe
> >> also a pattern to match for board side (TOP, FRONT, vs. BOTTOM, REAR,
> >> BACK).
> >>
> >> Some simple settable parsing parameters might help with situations
> >> like this.
> >
> > Except that the real problem is knowing *how to set* the
> > parameters!  So far, from what I have found, the convention is for a
> > part with pin 1 in the lower left quadrant to be at angle 0 and the
> > rotation specified to be CCW.  It certainly won't hurt to allow other
> > settings, but I wonder if they will just create confusion and ways
> > for the user to goof up.  I would not suggest adding that until more
> > information is available on what is used.  But if it is added, a
> > rotation direction should also be selectable, CW vs CCW.
>
>What I'd do is make the PCB generated file the default config, for
>compatibility within gEDA/PCB, but allow the user to change it if need
>be.
>
>The real issue with pick-place however, is that you need to agree with
>your vendor what their desired file format is.  Us gerbv guys can't
>know this info up fromnt since there is no standard.

I have stated what I have found as the convention.  There are still a 
lot of holes, but that is covered by the machine operator adjusting 
things to make them fit correctly.  I now believe my problem was due 
to a poorly trained machine operator.  I am going to see if that can 
be corrected.


>Actually, if I was the world's dictator, I'd mandate the IPC to come
>up with a pick-place machine file format, and I'd make all the
>pick-place machine vendors stick to it.  I wonder why the IPC hasn't
>tried to standardize this format?

Durn good question.  I still think Gerber formats are antiquated, but 
it is a lot better than what was used before the X version of the 
spec with separate aperture files.  However, these days they should 
be using other formats like PS or nearly *anything* else.  There are 
a few advantages of the Gerber format.  The board vendors typically 
can pull out pads from the file by looking at what is flashed as 
opposed to drawn.  These days most of that is not needed since the 
CAD software generates all the necessary files.  But the guys who use 
this stuff are used to the current format and don't want to change 
since they see it as dis-improvement.  Certainly the XYRS thing could 
be standardized in some manner, evne if that still leaves open a lot 
with respect to the PnP machine setup.

Rick 



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