Nichia NDG7475 1W 520nm Laser Diode

[ARG]

Aluminium and copper are both great conductors though. In a handheld laser system it doesn't much matter because the heat generated is a very small amount.

I doubt you would see an appreciable difference between the two.

 

[sinner]

One more considerable fact is that 1lbs of aluminium is 1ft* (12") long and Copper being 3x in density shares equal mass in a 0.3ft* (3.75")
So the only thing that is even more advantageous is in the same host with a 1lbs copper sink, you can only stuff a 300g of aluminium.


*both numbers are based on 1" diameter bar stock.

 

[LarryDFW]

I've got a little over one pound of copper in a sink Flamingpyro built for me for a Frankenstein host. It's a direct press 5.6 and I am thinking it is time to pull my 2.1w 445 out of it and have it re-machined to accept this. How would 1.1 pounds of copper compare to the 2/3 pounds of aluminum you estimated it would require?

Good question for a durable build.

I think the dissipation of your host would be fine.

The copper conducts heat to the body faster due to higher conductivity.

The heat capacity of copper is less than aluminum, but the extra aluminum in the host should help in the capacity area.

LarryDFW

 

[numquamretro]

Good question for a durable build.
The heat capacity of copper is less than aluminum, but the extra aluminum in the host should help in that area.

LarryDFW

That is only true compared to weight. But if you compare the heat capacity of the two materials in volume, copper is 3,3times better then aluminum.

 

[LarryDFW]

The numbers I have for Volumetric Heat Capacity are:

Aluminum - 2.4

Copper - 3.45

So aluminum by volume is about 70% of the heat capacity of copper.

Volumetric Heat capacity is heat energy required to change the temperature of a given volume of a material.

Each heatsink would normally have the same volume.

LarryDFW

 

[numquamretro]

The numbers I have for Volumetric Heat Capacity are:

Aluminum - 2.4

Copper - 3.45

So aluminum by volume is about 70% of the heat capacity of copper.

Volumetric Heat capacity is heat energy required to change the temperature of a given volume of a material.

Each heatsink would normally have the same volume.

LarryDFW

Hmmm... i have the following numbers:

Alumium: 2,7 g/cm3 and 897 J/(kg · K)

Copper: 8,92 g/cm3 and 385 J/(kg · K)

I mixed something up. Copper is 3,3times the weight of Aluminum.

And then we get (3,3*385)/897=1,416 times more heat capcity.

Thats exactly what you wrote. Aluminum has only 70% heat capacity of copper compared to same volume. :beer:

 

[TheDukeAnumber1]

Or copper has 40% more, however you want to look at it.

 

[ARG]

Oh boy, this has become a full fledged copper vs aluminium debate.

Time to abandon ship.

 

[DTR]

Oh boy, this has become a full fledged copper vs aluminium debate.

Time to abandon ship.

Wait come back looks like it is still twitching.

 

[Jmillerdoc]

So, to be clear......you think my 1.1 pound copper Frankenstein heat sink won't float on water? Crap, that won't work, I needed it to be compact, good looking, able to handle the heat of this new diode, and float just in case I slip next to some water and it falls in. What shall I do now.....

What about styrofoam? How does it compare to both copper and aluminum?

 

[Jmillerdoc]

Ok, to change the subject up a little. Recently I bought a few diodes of a forum member and he forgot to mail them off when he said he would. Feeling bad about it, he sent a few extra "goodies" along with my diodes. One of the was the pump diode assembly from what appears to be one of those TEK B&W 473nm units that were selling as malfunctioning on ebay a while back. It appears to have a tiny TEC attached to the diode mounting block. Has anyone ever tried to use one of these in a handheld unit? I've never played with a TEC before but I would assume they require some sort of current source as well. I think I've read 12v somewhere as the usual voltage these operate on. My second question is, either maybe link me to a thread that has some tutorial on using a TEC, or can someone quickly explain what is required to make a TEC work properly. Current source or simple voltage supply? Any regulation required at all? Or can you just supply the proper voltage and put it between your diode sink and another sink for transfer to? I've always wondered if this could be done effectively but haven't given much thought to it until I saw this tiny one in the B&W unit. I doubt this one I have would be adequate for this diode but maybe two or three would prove to be helpful. One last thing, it appears to have a temp probe on the sink as well leading me to the idea there may be a miniaturized TEC circuit that both powers and regulates the TEC through a feedback loop with this probe. Anyone know if a small circuit like this exists somewhere that could be incorporated into a handheld?

I realize this is not the best way to skin this cat. That's really not the point, it would clearly be easier to just use enough of the proper materials as a sink for a handheld you might want to run 5-6 mins or longer. The only reason I would attempt it was just to see if I could do it. No other reason, curiosity wins over reason on this one for me.

As usual, thanks in advance for all the great input around here!
JM

 

[rhd]

JM -
It strikes me that assuming the temp probe is a thermister, you could probably feed that resistance into a ZXCT1009 and then scale the output to run the FB pin of any regulator IC (whether linear, bucking, etc) that is configured to provide a constant current to the TEC.

It would really just be a matter of math to figure out all the resistors involved to set the upper and lower bounds of the TEC.

 

[BShanahan14rulz]

Don't forget about dissipation. harder to calc for, but does introduce quite a bit of wiggle room, in many cases, hence the reason many folks use a fitted heatsink and dark anodized aluminum hosts.

Oh, and I think that rectangle is simply a projection of the front face of the laser "chip." Only the active region between waveguides shows output.

Also, DTR did us all a favor by buying these to share the information with us! He probably HAD to buy them in a batch, otherwise no sale. I feel kinda bad for being able to see this testing info, while not having any financial stake in this purchase, nor plans to purchase one of these diodes off of him even at cost. If I had the money, would be different. All I can do is give you stupid green bars and say, "Thanks for the awesome info, DTR!"

So, thanks for the awesome info, DTR!!!

 

[ricktrent4]

I got one from him /DTR and love it got 1.5W 520nm hand held for sell

Don't forget about dissipation. harder to calc for, but does introduce quite a bit of wiggle room, in many cases, hence the reason many folks use a fitted heatsink and dark anodized aluminum hosts.

Oh, and I think that rectangle is simply a projection of the front face of the laser "chip." Only the active region between waveguides shows output.

Also, DTR did us all a favor by buying these to share the information with us! He probably HAD to buy them in a batch, otherwise no sale. I feel kinda bad for being able to see this testing info, while not having any financial stake in this purchase, nor plans to purchase one of these diodes off of him even at cost. If I had the money, would be different. All I can do is give you stupid green bars and say, "Thanks for the awesome info, DTR!"

So, thanks for the awesome info, DTR!!!

 

[Shakenawake]

that picture DTR has of the diodes he got, not sure what kind of bulk discount he got but I'm counting over $10,000 worth of just diodes. I imagine he hopes to sell some pretty fast to recoup investment

why not the new 3.5W 9mm 445nm nichias too? I'm actually personally just as interested in those

 

[paul1598419]

Thanks, Jordan. These truly are awesome! Unfortunately, it will be awhile before I can justify the price. Excellent tutorial! Paul