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Anyone tried air cooling a heatsink/host with a tiny fan?




goninanbl00d

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I'd say go for the 10x10x3 at the very least- anything smaller and it won't move enough air to have a noticeable effect, unless you're using a heatsink that's too small to begin with.
 

boscoj

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yeah wondering what "0.17 l/min" . . . oh, paste reveals the true formatting of the airflow spec, .17 L/min unless small L = micro/milli liter

be cool to have a separate switch . . .
 
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Greenmechanic

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The short answer to your question is:
YES! It will help, with a proper heat-sink, but not much.

I'm using (2) 20X20mm fans (1.2CFM) on mine at the moment- LD@1A +/-
One on the heat-sink and one on the driver.
The heat sink (9 oz. T6061 AL finned and thru. drilled) remains fairly stable with a temp. rise of 20 degrees after 5 minutes using fan, 25 degrees without fan.
The driver one the other hand (Flex V5) gets very hot (no heat-sink)
I think I'm going to have to heat-sink the Flex. also (not easy to do, efficiently), or use a bigger CFM fan.
My general rule (after 15 years of electronic experience) is, if it gets too hot to touch, it is probably harming or shortening the life of the component.

Unless you have a custom made H/S (finned and drilled out, so air can move directly through the H/S, across the fins 4-5mm away from the module)
With a standard H/S, IE: solid block of metal, you will need a much larger CFM fan.

And as stated before, With a good H/S, I would worry more about the driver then the diode module.
Every driver I have tried (LM317, Rckstr, Flex.) has produced massive amounts of heat at >1A
 

Kevlar

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No big deal. :) We just think alike ;-) Thats what makes this forum great, the sharing of ideas!!!

You changed some of my plans (still in my head). The barrell lof the D mag light is at leat 1&1/2" so it would easily fit a 18mm fan. I had mine blowing throught the fins. The thought of dust going through there dose worry me...

I'd like to see someone implement this though. Making that heatsink with the fins going parallel to aixiz module is going to be the hard part IMO. I hope someone gets this made, I'd like to see the duty cycles on a 2A 445nm with this. :beer:
 
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qumefox

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I'd like to see someone implement this though. Making that heatsink with the fins going parallel to aixiz module is going to be the hard part IMO. I hope someone gets this made, I'd like to see the duty cycles on a 2A 445nm with this. :beer:
It wouldn't be hard, at least from a mechanical standpoint. Merely time consuming. If the fins were down the full length of the heatsink. They could be cut using a jig to hold the heatsink, and a saw(band, table, whatever. I've even cut AL with a circular saw with wood blades in a pinch), providing you were using aluminum or C145 copper. Pure copper would be bad about gumming up blades though. Having longitudinal fins only partway down the sink would require either a very small diameter saw (think dremel), or a mill though.

Another method would be to simply bore lots of small holes through the heatsink 'slug', parallel with the aixiz module for the air to move through. This method would actually probably be best and easiest to do for a heatsink that was to still be housed inside the host, and all it would take to do it would be a drill press, providing you were dealing with an existing heatsink, anyway.
 
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Kevlar

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Another method would be to simply bore lots of small holes through the heatsink 'slug', parallel with the aixiz module for the air to move through. This method would actually probably be best and easiest to do for a heatsink that was to still be housed inside the host, and all it would take to do it would be a drill press, providing you were dealing with an existing heatsink, anyway.
That sounds like a good idea, much easier to machine too.
 

goninanbl00d

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Copper has less resistance to heat but is much less efficient at dissipating this heat into the surrounding air, hence the composite copper-aluminum heatsink design.

The copper wicks the heat from the diode, and the aluminum dissipates it into the air.

From a thermal viewpoint fins would be more efficient than holes bored through a solid block.

Only problem is, I've neither the resources or the money to pursue this project. :( I'm hoping someone out there would be able to build one of these things.

Also- I don't know how well an axial fan would stand up to the back-pressure, especially with those small holes. Those small yet cute centrifugal fans just may be the way to go.
 

Kevlar

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I hope to start my project next month. I might even have a member from LPF that I know has fantastic machining skill do the heatsink for me.
 

Fonduman

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make a mold from the surface of the small intestine. thats a huge surface area :D
 

qumefox

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Copper has less resistance to heat but is much less efficient at dissipating this heat into the surrounding air, hence the composite copper-aluminum heatsink design.

The copper wicks the heat from the diode, and the aluminum dissipates it into the air.

From a thermal viewpoint fins would be more efficient than holes bored through a solid block.

Only problem is, I've neither the resources or the money to pursue this project. :( I'm hoping someone out there would be able to build one of these things.

Also- I don't know how well an axial fan would stand up to the back-pressure, especially with those small holes. Those small yet cute centrifugal fans just may be the way to go.
Actually this is incorrect. Copper's better heat transfer allows it to dissipate heat faster than aluminum for the same surface area. There are really two main reasons why copper isn't used entirely for most heatsink applications.

Cost and manufacturing limitations.

Copper in general costs about six times what aluminum does. Plus copper can't be extruded like aluminum, so fins either have to be machined, soldered on, etc.

I also know if you need high dissipation heatsinks for small enclosures (say, a 1U server chassis) They will be 100% copper.

If you really want to get technical, the best thermal conductor is diamond, which is about five times better than copper. :D You probably already have a little in your LD itself. heh
 
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