kicad-lib-committers team mailing list archive

[Lorenzo Marcantonio <l.marcantonio@xxxxxxxxxxxx>]

On Mon, Jun 02, 2014 at 10:24:22PM +0100, John Beard wrote:
> But if it were, it wouldn't be part of the actual board, or have I
> misunderstood? So it wouldn't increase the actual cost of a unit, but is
> rather used for having a reference document to hand (presumably
> partnered with the BOM)?

Yes, it's only for assembly documentation (for checking the pick and
place machine and/or manual assembly reworking)

> PicoBlades. I think a lot of people using KiCad (like me) are not using
> very advanced fabrication technologies!

Seems a good starting point to me. Also advanced fabrication requires
often custom-made modules anyway.

> >There is another reason for courtyard excess, namely reworking
> >clearance. BGAs have extra courtyard because the desoldering nozzle is
> >big!
> 
> I was thinking more of last time I tried to manually hot-air reflow a
> joint that was too close to a plastic header and melted it out of shape.
> Why make those out of such low-melting-temperature and combustible
> material, I ask! ;-)

Because it's designed to run on a wave solder, usually (and anyway peak
reflow in the oven is 260°C, while hot air is usually in the 300-380°C
range)... also you can lower the needed hot air temperature preheating the
board to about 100-120°C (aoyue makes good stuff for that :P)
and/or heat shield the delicate parts (there is special tape for that
but scrap FR4 pieces are good enough).

-- 
Lorenzo Marcantonio
Logos Srl