bikeNomad
Newly Enlightened
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Duggg:
I've always used heatsink compound (aka thermal grease) when mating parts to heatsinks, but this thermal design document by Luxeon makes absolutely no mention of it, instead recommending just simple mechanical fastening.
I'm wondering what others here think?<HR></BLOCKQUOTE>
Thermal grease or epoxy has considerably worse thermal transfer than two perfectly flat metal surfaces clamped together tightly. Where the thermal grease might help is when the surfaces aren't all that flat, or when they can't be clamped together very tightly (as, for instance, with CPU heatsinks).
I've always used heatsink compound (aka thermal grease) when mating parts to heatsinks, but this thermal design document by Luxeon makes absolutely no mention of it, instead recommending just simple mechanical fastening.
I'm wondering what others here think?<HR></BLOCKQUOTE>
Thermal grease or epoxy has considerably worse thermal transfer than two perfectly flat metal surfaces clamped together tightly. Where the thermal grease might help is when the surfaces aren't all that flat, or when they can't be clamped together very tightly (as, for instance, with CPU heatsinks).
Sorry, I keep changing my post. I think they are recommeding to permanently attach it to the heatsink.
If you mounted it with thermal grease how would you keep it from swimming around over time?
I think thermal grease is fine. I've used it and was thinking about using it. But, now that I think about just attaching the LED to a heat sink, I'm not sure how to mechanically keep if from moving. Maybe you already have yours mechanicall fashioned and just need the thermal transfer.
If you mounted it with thermal grease how would you keep it from swimming around over time?
I think thermal grease is fine. I've used it and was thinking about using it. But, now that I think about just attaching the LED to a heat sink, I'm not sure how to mechanically keep if from moving. Maybe you already have yours mechanicall fashioned and just need the thermal transfer.
Unless the two surfaces have been polished like glass smooth, and prefectly flat, always use thermal grease, or thermal epoxy. It can increase heat transfer significantly. I would recommend Artic Silver epoxy, or Devcon 2 hour setting epoxy mixed with Artic Silver paste.
I've got several lights that run Luxeons in the 700ma range without any heat problems; they propably don't even reach 110F after an hour of operation.
I've got several lights that run Luxeons in the 700ma range without any heat problems; they propably don't even reach 110F after an hour of operation.
remuen
Enlightened
When I earlier had to do with audio power amps we always used thermal grease. We more than once measured temperature differencies of 10 and more degrees before and after use of this thermal grease.
