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Question about heat sinking a desktop laser

sopark4000

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Ok my original plan was to put a 445nm diode in a 12mm aixiz module in a CPU heat sink like this


but then I figured instead I could just use a brick of copper. Now my question is this. Which one will provide better heat sinking capability. I would assume the brick is better but I'm not sure that it would be as good as a radial CPU heat sink with a fan. So what are everyones thoughts on this?
:thanks:
 

ARG

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The purpose of the heat sink is to transfer the heat from the metal to the air, having more surface area means better heat sinking, so the CPU H/S would work better.
 

rocket689

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Definately the CPU sink, especially if it is fan cooled.
A brick of copper will transfer heat, but if the heat is not dispersed, the temperature of the whole assembly will rise.

I have a CPU sink that has a copper core and aluminum, fan-cooled fins.
Best of both worlds right there. It's like it was designed to do that... :rolleyes: :)
 

sinner

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Definately the CPU sink, especially if it is fan cooled.
A brick of copper will transfer heat, but if the heat is not dispersed, the temperature of the whole assembly will rise.

I have a CPU sink that has a copper core and aluminum, fan-cooled fins.
Best of both worlds right there. It's like it was designed to do that... :rolleyes: :)
Thanks man, i have the same h's from my pc.. It wasnt good enough for overclocking but i think i just found out a use for it ;)
Will i be able to run at max current with unlimited duty cycles ? i have a 660nm LPC diode, which is desperately in need of some power :p
 

rocket689

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Thanks man, i have the same h's from my pc.. It wasnt good enough for overclocking but i think i just found out a use for it ;)
Will i be able to run at max current with unlimited duty cycles ? i have a 660nm LPC diode, which is desperately in need of some power :p
The LPC 815 or LPC 826 both put out a small amount of heat at the 400-450 ma they usually max at.
So, the diode will be plenty good with a huge heatsink like that.

It's the driver that I would be concerned about overheating on long or unlimited duty cycles.
 

sinner

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Aluminum h's , and a good old lm317 (japan made) .. chinese ones overheat after 1minute, this one is worked for about 4minutes with a moderate heating up at 480mA,
so i guess it will work even better with those aluminum h's ;)
..and unlimited duty cycles like 10~15min , in my case.. after that i may get a bit ..cant say boring.. but less interesting :p
 

sopark4000

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Thanks for the feedback everyone. I assumed the finned heat sink would be better but I didn't know if a large enough brick would do a better job drawing heat from the module quickly. The heat sink i am planning on using is actually this one.
 
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rocket689

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Thanks for the feedback everyone. I assumed the finned heat sink would be better but I didn't know if a large enough brick would do a better job drawing heat from the module quickly. The heat sink i am planning on using is actually this one.
Yes, a brick of copper would draw the heat away more quickly.
BUT, once the brick became thermally saturated, it would hold the heat.
Surface area and air flow is just as important for long duty cycles.

It also depends on how much heat your setup is outputting....
 
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sopark4000

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Yes, a brick of copper would draw the heat away more quickly.
BUT, once the brick became thermally saturated, it would hold the heat.
Surface area and air flow is just as important for long duty cycles.

It also depends on how much heat your setup is outputting....
I'm planning on running a 445nm between 800-1,000mW with the hopes of having pretty much unlimited duty cycle while using the fan, although I don't see myself running it for more than 20 minutes at a time which it should handle.
 

Ablaze

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This sounds like an excellent application for a water cooling system.. although that may be overkill.;)
 

Ablaze

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But it sounds cool. Anything that is water cooled sounds cooler then its counterpart that is not.

That's why I water cooled my desktop when I was getting my computer degree. If you start talking about Mhz and dpi it goes over most people's heads... but just tell people your thing is water cooled and they are automatically impressed.
 
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sopark4000

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But it sounds cool. Anything that is water cooled sounds cooler then its counterpart that is not.

That's why I water cooled my desktop when I was getting my computer degree. If you start talking about Mhz and dpi it goes over most people's heads... but just tell people your thing is water cooled and they are automatically impressed.
Speaking of water cooled laser heat sinks I'm curious how this thing works.

HIGH POWER TO3 LASER DIODE WATER COOLED HEAT SINK on eBid United States

It's meant to be used with laser diodes but I don't quite understand how.

EDIT- Obviously I understand what the hoses are for, I just don't understand how you attach it to a diode.
 
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BShanahan14rulz

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CPU heatsinks, technically, are overkill as well. They are meant to dissipate what, 90W? 125W?

Our 445nm diodes use around 5-6W on average

Water cooling probably doesn't apply to to56. If you had a high power die, you'd mount it in something other than a to56 because other packages are better at dissipating heat.

Edit: I see in the link it is for TO-3 laser diodes.
Not my image, so I'm not hotlinking, but in the following image, there are the main types of diode packages: http://www.lasermate.com/cp-L081-1.jpg
TO-3 are the ones on the top. Big heat spreader and holes for bolts make it a good heat dissipating package.
TO-9 is a scaled up version of the TO-56, where the 5.6mm diameter is scaled up to 9mm and all other dimensions are scaled up by the same ratio, and is in the bottom-left of that picture.
C-mount is the bottom-right. Since the diode heat spreader is bolted down to the mounting plate with high pressure, it makes a better thermal contact than the TO-9 or TO-56.
 
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