Electronics > Projects, Designs, and Technical Stuff
copper pins to increase PCB heat sink capability?
OM222O:
Vias will have no airflow! Way too high of static pressure with even fans, let alone with passive negative pressure! They will be pointless and dumb. Filling them with copper or solder allows much better heat transfer to either a large plane or a real heat sink.
coppercone2:
yea I gather that you won't get good flow through the holes, but it will still be interesting to see how much extra performance you get if rods stick out from the PCB rather then just a flush cut fill solder copper bar. Without any air flow holes that are counterproductive towards cooling effort.
How do you calculate the pressure drop on an orifice like that without doing alot of work in solidworks, anyway? everyone seemed to know the figure would be counter productive with no math.. how is it so obvious?
OM222O:
as I mentioned, EVGA has done it. the effects are minimal at best! you need a ton of fins in order to get any meaningful difference and the airflow through the vias won't be just "not good flow" it will be zero! the static pressure behind fans is simply not high enough, unless you are using a delta fan and blasting air right through those vias which is a waste. this is just a matter of common sense as PC hardware has already proven these facts. even in radiators higher density can increase your temperatures despite the fact that it has more area. here the key is pressure, not area!
coppercone2:
so pin fin heatsinks (even if its say a solid cast or machined part) is going to be inferior to a blade heat sink?
How do they compare to bladed heat sinks when passively cooling vs forced air? highly inferior in both cases?
A pin fin heatsink is appealing to make from a machined part because you don't need much more then a drill press, braze, and your parts. You can pretty much slap it together with no clamps or anything with minimal work. Like drill holes, dunk it in acid, put some flux and braze in there and heat the whole thing red hot. Then lap it. It's brainless compared to bending a bunch fins.
I mean a dense pin fin like your first picture.
https://www.iarjset.com/upload/2016/november-16/IARJSET%2026.pdf
OM222O:
a dense array such as the one in the first picture can work well, but that requires a lot of manual work if not automated. and yes pin fins are inferior as opposed to the blade style in both cases. I agree that they are easier to make when you have something to press the fins into a sheet, but that comes with it's own disadvantages.
in water cooling equipment, they use skiving machines to create micro fins with crazy high density. that is much more complex to make but the pay off is much superior cooling compared to air cooling. the more complex a heat sink is, usually the better it performs as well (with exception of peltier cooling as it's useless for many reasons).
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