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CPU heatsink for phr.. little help..

ofekgg

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i have a cpu heatsink that i got from an old computer.
i want to cut is to 2 pieces and to drill 12mm hole in one and place the aixiz module. so where to drill, in spot 1 or 2? (see in the last pic)
[what is recommended, to put the rkcstr driver in the module or out of it?]
here some pics:
 

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chipdouglas

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i'm not sure about drill hole placement. but a 12mm hole will not give you the best thermal conductiveness, unless you use a set screw. as for the driver. a phr doesn't pull enough current to worry about heat. hope this helps
 
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I recommend buying one of these. Look at the fourth item in the list (the green module heatsink). They fit Aixiz modules perfectly, and they work great for higher-powered diodes. I know it's not quite as DIY as your original idea, but I have several of these heatsinks and I recommend them highly.
 
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Definitely hole #2. You should never drill along the lamelles, you'll end up f.cking up the module and having an ugly hole. Just drill through them, using little force, so as not to bend them (unless they're thick enough no to bend, test it on one half), and you'll have a lovely large area to dissipate heat.
Then mount a fan on it, just to make it work even better :D

Now that you mention it, I have a spare CPU heatsink, with the fan, and a copper conducting core. I was planning to use it as a cooler for my 1TB external HDD, but it might end up hosting my next laser project...
 

ofekgg

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If I`ll not use heatsink for my phr @120ma what is the recommended duty circle?
thanks for all the answers!
 
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I'd say something like 30s on, 60s off. But I'm just guessing, based on power and current.
I usually run my diodes (red) until I feel the module getting warm, then turn them off for at least a minute to allow them to cool off. Since it's fed 350mA, that usually happens in around 45secs... :)
 
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Looking at what I see here, the lamelles should be strong enough no to bend when drilling, provided you use high speed. Good luck!
 

ofekgg

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thank, tomorrow i`ll drill the hole..
and more question, it will be better to use thermal paste between the module and heatsink?
and when i drill, I think that i can put cardboard between the stripes. good idea?
 
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Cardboard won't help much, if you could put plywood, or something similar, that would be better. As for thermal paste, you can't go wrong with it, although frankly, there isn't a lot of surface where it can help the conduction...
 

Meatball

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Yes, there isn't much surface area for the paste to conduct to and from. It might look like a pasty mess if you aren't particular about where it is.
 
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Come to think of it, I might be able to help out...: one copper-core CPU heatsink with fan attacked for extra cooling, up for grabs! :)
 
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Just one piece of advice in connection with the electronics: the fan should be running all the time, so the button should only switch the laser. If it only blows while the laser is running, it won't cool as efficiently, as thermal conduction is not instantaneous.
 

ofekgg

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you right! I didnt thought about it.. thanks!
So I will use momentary switch for the laser and ON/OFF switch for the fan..
 
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That would be a way to do it, yes. Or use a common negative line for both, but the laser's positive is interrupted by a push-button(NO).

As for power source, a 9V battery, while it will drive the fan, won't make it full-powered. I'm testing my fan to see how much it can handle, being made for 12V, and so far, I'm at 18, with no ill effects :D
Also, I do hope you're using a RckStar, the Flex will fry with 9V!
 




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