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445nm Heat Sink Requirements

LarryDFW

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These high-power 445nm laser diodes require substantial heat sinks to operate @ 500 ma and higher.

This is the heat sink design on my new 445nm build:
finhx.jpg

The top cap tightens down on the aluminum disc and finned heat sink.
It has 2.5 oz. of finned aluminum in good thermal contact with the diode.
I think it can handle the full output of this diode.

It must dissipate about 1.5 watts of power @ 500ma,
and about 3 watts of heat @ 1 amp.

I plan on doing some temperature measurements with my IR thermometer at various power levels to verify the temperature rise of the diode.

I think this host has a nice appearance.

The power is provided by a 2600mah Samsung Li-Ion with a single resistor direct-drive.

LarryDFW
 
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designedfor1

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how are you calculating the heat dissipation? Have you made the heatsink yet? That looks pretty nice too.
 

LarryDFW

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designedfor1;

The power input @ 1 amp is 4.2 Volts * 1 amp = 4.2 Watts.

The laser power output is ~ 1.1 Watt.

That leaves ~3 Watts of heat to dissipate to keep the diode at a reasonable temperature.

LarryDFW
 

Hemlock_Mike

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I'm running an old 18650 driver on my portable. I'm only getting about 300 mW using that simple driver circuit because of switch and connection losses.
OH, I added more aluminum mass to my heat sink ass'y today. They do get really warm at 1 Amp.
HMike
 

designedfor1

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@Larry
How do you know your heatsink is going to dissipate that amount of heat? Just a guesstimate or actual test?
 
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With DX "temporarily sold out" mean they ain't coming back.

Backordered mean they will get some in.
 

jbtm

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Damn...The Silver, Gold, And black models are gone then :( They seem so nice! The only ones with heatsinks on the actual head :( Besides the $111 one posted at top...
 

LarryDFW

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jbtm;

The contact between the diode and the outer body is usually poor.

I've had to wrap stranded copper on some of them just to make contact.

designedfor1,

I've built a few hundred UV flashlights with 3 watt and 5 watt LED's for practice.

It has 2.5 oz. of finned aluminum in good thermal contact with the diode.

LarryDFW
 
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heruursciences

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I made a portable with a cheap c-cell flashlight, and screwed the axiz module head into a disk of aluminum and then to the flashlight, it gets warm after running for a few minutes but not hot. The power is 600mw at the diode.

The diodes need VERY substantial heat sinking if running at a full watt, as in a 3x2x7 aluminum project box gets quite warm after 15 minutes of use. The bright side is these diodes were meant to run hot in the projector so a little heat isn't an issue.

The bottom line is the axiz module or even the nicer black modules are NOWHERE CLOSE to enough heat sinking by itself!
 

Flaminpyro

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Howdy Larry Here is my first 445 I picked a host that would let me get two 18650 end to end so 8.40 volts with plenty of current.
I built my own linear driver for this diode and strapped the regulator to the back of the heatsink ;) I am feeding it 630ma and with a LarryDFW lens it's putting out 547mW :)
With this HS I could take it all the way though :D I think this would be good to offer in a kit :)
28i3sci.jpg
 




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