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Low Cost Heat Sink Tests

Benm

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Heatsinking certainly is interesting stuff - and as you found from the amazon models larger generally works better.

It also has to do with the purpose they are designed for though: The cheapest one doesn't seem to be intended as a heatsink on it's on, just to provide thermal coupling to a baseplate or other flat heatsink, which can be fine depending on application. The middle one is a bit disappointing in performance, but it also looks very flimsy so that might be a reason. The best performing one has the most surface area and also seems pretty solid - a well designed heatsink overall.

When you start using fans things obviously change, as you now control airflow instead of relying on convection. Also airflow rate is generally much higher, making it attractive to sometimes make fins thinner so that they impede the airflow less and perform better with a fan, while they would be worse without one.
 

BobDiaz

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699_Heatsink.jpg

I agree the $6.99 heatsink struck me as something that I should attach to a larger heatsink. The flat surface should have a good heat transfer.


1199_Heatsink.jpg

The $11.99 heatsink is the winner, BUT I can't wait to put it up against the one from Aixiz. I'm not sure which will win here...

AIXIZ.JPG
 

paul1598419

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I've used all of these heat sinks at one point in the past. Mostly for low power stuff. The ones you paid $6.99 for I got for about $3.00 each for five of them. I used them in an aluminum enclosure and applied Arctic Alumina thermal adhesive to the bottom of the heat sinks to transfer heat to the entire enclosure. That way I could use them with 1 watt pump diodes in solid state lasers. It actually worked pretty well.
 

hakzaw1

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Great stuff and needed. You say you have one (heat sink)coming from AixiZ?
I am still offering to send one to you...AND so glad you are a teacher as I suspect we have many more teachers here but we do not who they are.
I had some crazy ideas about forum members getting in touch with local science teachers.
I wondered what they are currently learning about lasers and MORE on working towards the goal of reducing the incidents of young people getting into big time trouble (& of course we want less injuries).

Its no longer 'just a felony'... it is a federal case(THAT means you serve 'EVERY 'day...no early outs) when aircraft is involved and there is a $10, 000 reward for info leading to arrest and conviction'

We can all agree that peer pressure is often involved... we need (positive)peer pressure to stop the laser 'pranks' that can lead to prison.. please check LPS.org out and share w/ your students.
laserpointersafety.org-- my friend Pat Murphy (ILDA pres) runs it--pretty much on his own. (IIRC)
IT is full of stories (some very sad) and I hope students can learn a lot about lasers w/o risking jail and fines.

It has a lot of safety info. It has a LOT of info on arrests -and the outcome plus quotes from the convicted which include a husband /wife both arrested --both getting jail time and fines. -- latest stats say incidents are becoming less common.. but afaik pilots are required to report any lasing in their direction..
Some offenders.. not having learned any different, have ideas like-" I could see the end of the beam.. so the plane/heli etc was not close enough for any danger''...tell it to the judge.
SO good friends PLEASE reach out to your kid's teachers and find out if they need more laser info..offer to come and demo some of your lasers.. and speak on safety.
it seems what is being taught now, is just not enough
ITS THE RIGHT THING TO DO. :Len
 
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Benm

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I think the $11.99 ones will be the winners here, they look a lot like z-bolt heatsinks to me. Not only do they have a nice black anodized coating, they could also be bolted down to a larger heatsink or baseplate - afaik there are some threaded holes on the bottom to do so.

The aixiz star design may work well if you have a lot of airflow back to front or front to back, but the tooling on them just looks aweful. I guess there are some tapped holes on the bottom so you could mount them to something else, but it all looks very rough, probably not making any good thermal contact.

It may look worse than it actually is, but from the photo it looks like the two smaller holes haven't even be deburred at all.
 

RedCowboy

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Some of those may be ok for low output lasers, but for any multi watt you need COPPER, it makes a big difference as to how much you get out and how well you can maintain output, waste heat is the enemy, respect it and handle it or it will handle you and your laser will suffer.
 

Cyparagon

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I never cared for the set-screw type. The contact area is pretty bad with that method. These are my go-to these days. 50 cents shipped when you buy 3 (sk12):

https://www.ebay.com/itm/113307812293

I bolt them to whatever Al block or heat sink I have on hand. They'll run a nubm44 for hours no problem.
 

RedCowboy

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I was thinking about modules as some of those black aluminum housings have brass modules inside that are not very good, but yes the linear rail aluminum brackets work well when paired with the copper modules and screwed down to a thick aluminum case.
 
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GSS

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I never cared for the set-screw type. The contact area is pretty bad with that method. These are my go-to these days. 50 cents shipped when you buy 3 (sk12):

https://www.ebay.com/itm/113307812293

I bolt them to whatever Al block or heat sink I have on hand. They'll run a nubm44 for hours no problem.
Nice, they more or less wrap around the the module the way the screw is set up top and for only $1.49 you can stack a couple together if needed :)
 

CurtisOliver

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I have done this with some of my modules, I got the idea from Jordan when he shipped out the NUBM44's with the larger type.
 

BobDiaz

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I never cared for the set-screw type. The contact area is pretty bad with that method. These are my go-to these days. 50 cents shipped when you buy 3 (sk12):

https://www.ebay.com/itm/113307812293

I bolt them to whatever Al block or heat sink I have on hand. They'll run a nubm44 for hours no problem.

Thanks for the link, I just ordered several of them for testing. However, it will be a while before I get them and can test them.
 

Benm

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Those aren't that bad at coupling heat down to a baseplate at all.

Just remember they are not (any good) heatsinks themselves, but despite being fairly small can conduct quite a bit of heat to a baseplate or heatsink if made from proper aluminium. The set-screw design also allows you to get a decent contact area between these modules and the round laser module, though you will need to use heat conductive paste here to get any good results regardless.
 

hakzaw1

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OP
david- AixiZ was about to ship but I got an extra one added..
I will be doing some tests myself..
and then we will know if it is worth the extra $$ and get good results using these round bored out to 14mm (penpointer size)
so calling for 'murder' testing.

Long ago these was a ebay seller listing penpointer black (Alley) heat sinks... but none now..
Results will not be very valid... even when using 9 pointers (3 of each RGV) .
 

BobDiaz

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I'm really excited, the AixiZ shipment just arrived today. The following photo shows the size differences. I included the red laser diode for comparison.

Heat_Sinks.jpg

The AixiZ weighs in at 19.8G (0.69oz), compared to the largest at 116.9G (4.12oz).

If all goes well, I'll run the tests tomorrow and report back... If not, I'll have to wait until Thursday for the tests.

The one from ebay may take a while to arrive: SK12 Bearing Linear Rail Shaft Support
https://www.ebay.com/itm/113307812293
SK12.png
 




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