← Back to team overview

kicad-developers team mailing list archive

Re: Thermal spoke count


Keep in mind that the total width of all the spokes (assuming they’re all the same length) doesn’t control the current they’ll carry, only how hot they will get for a given current.  Most boards are designed with a huge margin of error here.

It’s correct that would could do all the calculations automatically (both for heat-transfer during soldering and heat-generation during use), but it would be glacially slow.


> On 8 Jul 2019, at 18:04, Eeli Kaikkonen <eeli.kaikkonen@xxxxxxxxx> wrote:
> ma 8. heinäk. 2019 klo 19.04 Evan Shultz (evan.shultz@xxxxxxxxx <mailto:evan.shultz@xxxxxxxxx>) kirjoitti:
> Because of varying pad shapes, sometimes "+" spokes are best and other times "x" may be preferred. So having a choice of those options, even though both have the same number of thermal spokes, may be desirable. I believe this is captured in the "initial angle" concept, but IMO having the choice of "+", "x", "8 way", and "solid" is more obvious that picking an initial angle. But perhaps I misunderstood.
> What I have felt need for is automatically finding locations for spokes so that when a pad isn't fully surrounded by a zone it would still be connected with 4 (or as many as possible) spokes. Sometimes changing the direction between x and + would be enough, sometimes adding spokes from x to spokes of +. For example N(orth), NW, W, SW instead of just N and W.  Because adding spokes is automatic anyways, exact positioning isn't important. There should be as much copper as possible (and preferably in many directions) while still having the thermal effect. Even the thicknesses of the individual spokes could be calculated automatically to meet the requirements. What counts is the total width of all the spokes together, or am I wrong?
> Eeli Kaikkonen
> _______________________________________________
> Mailing list: https://launchpad.net/~kicad-developers
> Post to     : kicad-developers@xxxxxxxxxxxxxxxxxxx
> Unsubscribe : https://launchpad.net/~kicad-developers
> More help   : https://help.launchpad.net/ListHelp

Follow ups