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Low Cost Heat Sink Tests

BobDiaz

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My students are always impressed with my laser demos in class and some students want to build their own. After considering all sorts of options, I decided that the Mitsubishi 500mW 638 Diode (ML501P73-02) from DTR's Laser Shop was an ideal choice. This offered enough power to have fun, but even at full power, didn't produce too much heat.

https://sites.google.com/site/dtrslasershop/home/diodes/mitsubishi-635nm-500mw-diodes

The biggest problem was deciding on a heatsink that was reasonable cost, that worked well. I love the $20 Z-Bolt Heat Sink, but for the sake of my students, I do try to keep the cost down.

http://shop.z-bolt.com/Heat-Sink-fo...dftrk=gdfV25268_a_7c1640_a_7c6357_a_7cHS_d_1a


A search of Amazon showed the following:

$6.99 2pcs Aluminum Radiator Heatsink Heat Sink Holder Mount For 12mm Laser Modules Black (21.6 Grams)
https://www.amazon.com/Aluminum-Rad...=2025&creative=165953&creativeASIN=B07GP3C9PW

$8.99 2pcs Heat Sink for 12mm Laser Diode Module Aluminium Heatsink Holder Cool 20x27x50mm (31.6 Grams)
https://www.amazon.com/Module-Alumi...=2025&creative=165953&creativeASIN=B07BF7SW5C

$11.99 2pcs 12mm Aluminum Cooling Heat Sink Holder Mount for 12mm Laser Diode Modules 32x62mm (116.9 Grams)
https://www.amazon.com/Aluminum-Coo...3&creativeASIN=B07GPHWKH6#feature-bullets-btf


So I purchased all of the above and tested them with the red laser module. The supply current was 680mA going through the diode.

The $6.99 (2 pcs) heat sink: With a starting temperature of 70F (21C) after 5 minutes i measured 89F (31.6C) on the diode. I was surprised that such a small heat sink could do so well.

The $8.99 (2 pcs) heat sink: With a starting temperature of 70F (21C) after 5 minutes i measured 88F (31C) on the diode. I had hopped that this would do better than that, but it only did slightly better than the first.

The $11.99 (2 pcs) heat sink: With a starting temperature of 70F (21C) after 5 minutes i measured 82F (27.7C) on the diode. It did so well, that I let this run for 15 minutes and ended up with 87F (30.5C) before I got tired of testing. This is the heat sink that impresses the heck out of me, because I didn't expect it to do so well.


Next I'm re-building the power supply because I wanted to try some changes before I finish and write up the build for my students, but it looks like this is turning into one fun little project.


Bob Diaz
 

GSS

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Nice test:)
It show's size does matter.. So there was no fan involved i'm assuming. Wondering how much better the 2 finned sinks would be with one.
 

BowtieGuy

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Hey Bob, thanks for sharing your heatsink test results! :)

@Lifetime17, that's a very nice, compact, powered heatsink! :cool:
 

Lifetime17

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Hi, Thanks guys I use these myself and they stay cool for a long time while testing.
@ BOB,
Those Mitsu 500's can be ran pretty high and they are very durable compared to the Oclaro 700 .Here's a pic of one of the 500's build that sold. fullsizeoutput_911.jpeg fullsizeoutput_936.jpeg IMG_4231.JPG fullsizeoutput_798.jpeg

Rich:)
 
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GSS

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Rich, why the 2 9V's? Are they rated at that or you just like the extra fan speed?
 

Lifetime17

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Hi GSS,
I just thought to put 2 on the sink no problem. Plenty of run time compared to 1 - 9V

Rich:)
 

BowtieGuy

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Rich, why the 2 9V's? Are they rated at that or you just like the extra fan speed?
I was wondering about that also.

Hi GSS,
I just thought to put 2 on the sink no problem. Plenty of run time compared to 1 - 9V

Rich:)
Rich, do you have that fan blowing towards the diode, or pulling the air past it?
 

hakzaw1

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New At AixiZ (houston USA)
round finned Alley heat sinks.. w/standard 12 mm dia.
Review coming. at $4 each-- I will 'apply' at AixiZ for a discount on bulk orders (GB) and send a free one to the OP.
Not much mass but testing will tell us more.. These were added by Dr Chuck due to forum requests.

linkage
http://www.aixiz.com/store/product_info.php/cPath/43/products_id/476 < that is the BESTEST place to buy AixiZ(never at scamazon or Feebay)
and!!! they offer --speak to the 'MAN' weekdays 8 to 7PM central 1-713 240 4929 ask for Chuck-or leave mssg.
 

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Lifetime17

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Hi,
the fan blows directly onto the back of the diode. You can use one or two batteries , The fan can handle 18V easy or 9V's.
I just tested a NUBMOA diode from a bank that I have and I ran it for about 5 min. Once at 4.0A it hit 5400+ and once at 4.5A at this it hit 6500+ and has a G Ball ,and it stayed really cool .

Rich:)
 

paul1598419

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Bob, you should remember that the outside temperature of your heat sink is only part of the equation. The two best metals for heat sinking are aluminum and copper. Copper is by far superior to aluminum, but is more costly. Surface area is also very important. That is why many heat sinks have fins on them. If your heat sink will be stationary, a fan that moves air through the fins is also a good idea. That Mitsubishi diode can be run at 1.2 amps. I have one set there that outputs over 1 watt of optical power. It is in a copper host made by a machinist that is no longer active here.
 

BobDiaz

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Nice test:)
It show's size does matter.. So there was no fan involved i'm assuming. Wondering how much better the 2 finned sinks would be with one.
Sorry, I'm a little slow in getting back to people. I was going for the Keep it simple approach, so no fans are used. However, past tests with heatsinks always shows that fans always help to coll things. In the case of the biggest $11.99 (for 2) heatsinks, it won't matter too much, but the other two could work so much better with a fan. If I get a chance, I'll try it with fans, but this week is going to be very busy at the college with all the tests I need to give and grade.


EDIT: Sorry, but I meant to type $11.99, not $1.99
 
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hakzaw1

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TYPO??
'in the case of the biggest $1.99 (for 2) heatsinks,' did you mean $11.99 (2 pcs)

I have plans to visit AixiZ SOON..I try to go every two weeks .. I knew he and the Ms (& her daughter Zi) would be busy with the HUGE bike rally on Galvestion Island(50K+ bikes there) - They ride HDs (Xia's is all white 'Sporty' and Zi has a sweet Buell-)-Chuck's is a full dresser.
So PM me where to mail your free heat sink from AixiZ .

len
 

BobDiaz

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New At AixiZ (houston USA)
round finned Alley heat sinks.. w/standard 12 mm dia.
Review coming. at $4 each-- I will 'apply' at AixiZ for a discount on bulk orders (GB) and send a free one to the OP.
Not much mass but testing will tell us more.. These were added by Dr Chuck due to forum requests.

linkage
http://www.aixiz.com/store/product_info.php/cPath/43/products_id/476 < that is the BESTEST place to buy AixiZ(never at scamazon or Feebay)
and!!! they offer --speak to the 'MAN' weekdays 8 to 7PM central 1-713 240 4929 ask for Chuck-or leave mssg.

Thanks for the link, I just put in an order and it will be fun to test it against the best of the three heatsinks I've tried so far.


NOTE: To avoid a double posting, I moved the text from the lower thread up to this one.

My Red Laser Build in turning into one of the most interesting and fun builds I've done so far. I'm trying to keep it simple for the students, but at the same time, I'm exploring the different options to see what works the best.
 
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paul1598419

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Just received two lenses that DTR sent me to test. They are new long focal length single element glass lenses. They do reduce the output of the ML501P73 diodes horrible divergent line down to a nice round dot. The aperture at the diode side of the lens housing is smaller than other single element aspherics, so it could be cause by clipping. I will know more when I get a chance to measure the power difference between the short focal length lens I have and this lens. Even if it is caused by clipping, it still looks much better than that line with wings.
 




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