Re: gEDA-user: PCB thermal width

[Steve Meier <smeier@xxxxxxxxxxxxxxxxxxx>]

One issue we ran into was that certain plastic connector with pogo pins
had such a low melting temperature that heat applied for more then a
couple of seconds caused the plastic to melt enough to suck the pogo pin
down so that it no longer protruded above the plastic.

The amount of time that heat has to be applied to a pin is dependent on
the size of the effective heat sink.

Seems to me that a single formula for calculating thermals is to
restrictive.

Steve Meier


On Mon, 2009-03-16 at 07:58 -0400, Ethan Swint wrote:
> IIRC, it has to do with both the annulus width as well as the clearance 
> width.
> 
> -Ethan
> 
> Duncan Drennan wrote:
> > In the PCB manual it says,
> >
> > "Thermal [Scale]
> >  	
> > Scale Relative size of thermal fingers. A value of 1.0 makes the
> > finger width twice
> > the annulus width (copper diameter minus drill diameter). The normal value
> > is 0.5."
> >
> > So theoretically making the annulus larger (with "s") should make the
> > thermal spoke width larger, but when you do this the thermal width
> > stays constant. Has this definition changed? How is the thermal width
> > currently calculated?
> >
> > Thanks,
> > Duncan
> >
> >   
> 
> 
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