Re: gEDA-user: PCB lib.

[Chad Robinson <crj@lucubration.com>]

Steve Meier wrote:
> Chad Robinson wrote:
>
> > Xtian Xultz wrote:
> >
> > > yes, you are. What I think is, if the footprints you designed have a 
> > > standard definition, the name of the footprint must agree with the 
> > > standard. Then, you can contribute with these design to the project. 
> > > The problem is to contribute with a footprint named 
> > > "little_connector_with_32_pins_with_shine_bubbles", this will make 
> > > the design a nightmare...
> > > IF the footprint doenst have any standard, then it can have any name...
> >
> >
> > I completely agree, and unfortunately many of the footprints in the 
> > library are just like this. There's also a lot of crossover - there 
> > are like 6-7 different 0805 resistor footprints. It would be nice to 
> > consolidate these.
> >
> > Somebody needs to "own" the libraries and force quality control. In my 
> > experience that's the only way to make this happen. Is there a 
> > maintainer just for the libs?
> Be carefull some pattern variation can be do to the assembly process. 
> Different patterns may be needed.
>
> Bellow is a note from the standard document.
>
> *Note: If a more robust pattern is desired for wave soldering devices 
> larger than 1608 [0603], add 0.2 mm to the
> Y-dimension, and consider reducing the X-dimension by 30%. Add a ``W'' 
> suffix to the number; e.g., 103W.
Yes, my current product basically does what the chip manufacturers do. They 
add an A, AB, B, etc. to the end of the name. So the standard part is TO263AA 
or just TO263, but I can specify TO263AB to get slightly larger pads (good for 
some Maxim parts with stouter legs). There is an alias (or just copy, not 
sure) from TO263AA to TO263 so I can specify either if I don't know or care. 
Before I put a board out to proto I usually double-check all the pad 
measurements but it's a lot of work on a dense board so I usually only do it 
for critical parts like ICs and fine-pitch items like Hirose connectors. 
(Actually, I print them on laser and hold the part on the paper, make sure 
it's just right.)