Use this Thermal Compound

[matrixcs]

Hi guys i recently configured a BOBLASER 405nm Pen, using a PHR 803T HD diode, and after days of testing it, i was wondering if i can put a better heat sink on its module, (just for diode portection) so what i did, i encoutered this Non - electric conductive Thermal compound

Ck4800 (Nano Diamond) price is about $$

and when i put it on the base side of the module and between the diode and the module, the results are awesome

duty cycle now is at 1 min constant ON and 10 secs off

at 150mW (Phr diode)

not to mention if i will put a good HeatSink like jayrob's could probably put more like 40% do the heatsink capability....

 

[k1kb0t]

Looks good Matrixcs, I'll have to try that out.

Jon

 

[Flaminpyro]

Thanks Matrixcs I just purchased a tube of this and will post some thermal results after testing, the one test I read about was pretty promising.

Peace All Pyro... :eg:

 

[Benm]

Good that it works, but what where your duty cycles before applying it?

More importantly, if you recommend this particular compound, do you have less good experiences with other thermal compounds?

As far as i know the differences in real world performance between such compounds are only marginal. The actual thermal conductivity does vary, but since its usually applied in a very thin layer, this doesnt affect the results that much. The main principle of action is filling air gaps. Air has a thermal conductivity in the order of 0.02 W/mK, while the most basic thermal compounds achieve 20 W/mK. In comparison, aluminium and copper alloys usually achieve 200 and 400 W/mK respectively.

For general application i would say there is no noticable difference between using a $2 and a $50 thermal conductive paste. Filling a 0.1 mm gap with basic compounds adds as much temperature to the diode as the next 1 mm of aluminium - its a minor effect.

 

[Flaminpyro]

I believe every thing you said here Benm I make my own heat sinks and plan on making one that is deeper behind the diode if this material is truely non conductive it can be applied on the back of the die and around the leads to sink heat to the surounding alum or copper heat sink, if this allows me to get 10 or 20 more Mw's outa my diode safely well then cool ! at present I don't know of any one cooling the back of the die in this manner so there my be some good power gains. if nothing else maby just a little extra power.
EDIT: yes I have thought of stuff thinning after it gets warm thats where the silicone plug comes in...
Peace All Pyro... :eg:

The main principle of action is filling air gaps. Air has a thermal conductivity in the order of 0.02 W/mK, while the most basic thermal compounds achieve 20 W/mK. In comparison, aluminium and copper alloys usually achieve 200 and 400 W/mK respectively.
For general application i would say there is no noticable difference between using a $2 and a $50 thermal conductive paste. Filling a 0.1 mm gap with basic compounds adds as much temperature to the diode as the next 1 mm of aluminium - its a minor effect.

 

[Benm]

Ceramic based thermal pastes are often very good electrical insulators. The consist of fine alumina or zinc oxide powder suspended in a silicone or mineral oil matrix. It would not be of concent to get this between the laser diode leads, it insulates well enough not to cause shorts.

It does, however, never insulate a component from the heatsink its mounted on, since there will be areas of direct metal-to-metal contact.

If you were to make a slightly 'to deep' mounting hole for the diode, you could fill up the remaining depth with such a thermal compound. I doubt it would add much to the overal thermal connection, but it would be electrically safe.

One problem is that most of these compounds become more liquid when warm, so if you use too much is might run out causing a mess.