New Experimental Heat Sink

Krutz · Sep 5, 2009

well, 100mw wont be more than 500mw thermal energy.. with such ridiculously low powers (compared to about anything else), i dont think the heatsink's volume or surface will be the limiting factor, but the thermal resistance between the diode and heatsink. the heatsink you made should be absolutely adequate for this. so i agree, think about how to efficiently connect the diode, like press-in or screwing it in place.. with as few "boarders" between individual pieces as possible! (diode + aixiz + heatsink equal three pieces, two barriers in between them)
thats why i started to solder my aixiz modules into my hosts..

one more thing: i bet its really time- and moneyconsuming to do these. couldnt find any equivalent? i thought i saw a pic of such a "star" heatsink somewhere here, with a 12mm inner diameter..

manuel

Benm · Sep 6, 2009

Pre-fab heatsinks exist for TO-5 sized transistors. Aixiz modules a somehwat bigger in diameter, but such heatsinks are often made out of phosphor bronze, which is spriny enough to stretch and fit.

The look something like this: Heatsink for Case Style TO5/39 : Heatsinks : Maplin - but bigger ones are out there too. With some thermal grease they make nice heatsinks for the modules, but not very attractive to use in flashlight hosts.

Contacts from diode to aixiz and aixiz to heatsink to add to the total thermal resistance from diode to ambient, but if you get it even half right, the resistance from heatsink to ambient is the largest, unless you get ridicioulsy large heatsinks.

Tech_Junkie · Sep 6, 2009

I have a finned HS that is a little longer than yours and it gets way hot with a 120mW BR module. You almost cant touch it. Maybe you could add more mass to your finished design, because mine can defiantly use it and its larger than yours.

Is it me or have these heat sinks been offered/used already? They look familiar.

Benm · Sep 10, 2009

Heatsinks are more about surface area than about mass - unless you only work with very small pulses and use them for thermal capacity.

The design as posted in the first post is actually a pretty good one and commonly used for other electronics. One problem is that is it most effective with its fins vertical (such as when mounted on a transistor on a flat-lying circuit board).

For a horizontally mounted module, the ideal placement would be something like on this engine: http://www.pspmfg.com/images/graphics/mvc009s350.jpg
Your module would fit where the sparkplug sticks on the left. The leftmost fins should have been vertical, not horizontal, but i dont think you'd want fins there anyways...

Tymtravler · Sep 11, 2009

Thanks again for the possitive feedback and suggestions, the new design will hopefully be done today. The ID will be smaller for the Axi mod to sit tighter then the original post pics and it will enclose almost the whole mod. I have tested the original using a 405 BR that was left on for 10 min. I could still hold the heatsink in my hand. Hope to have pics buy next week.

Tymtravler · Sep 15, 2009

My universal finned heat sink is now finished and it works great. I tested it last night for 20 minutes and again the sink was just a little warm, but did not get hot to the touch. I had this made with 4 extra long fins so you can customize the sink for the opening of your host with just a little filing. As you can see in the pictures I show the dimensions except the length and that is 25.75mm. I only need 1 set screw to hold the AXI Mod in place since I got the hole diameter close to the AXI Mod, and that is in the middle of the sink. I drilled and tapped 2 other holes for mounting screws if you choose to mount the sink for a project instead of placing it in a flash light host. I made 10 of these but a couple is going out to some friends. And again your feedback is always appreciated. :beer:

Tech_Junkie · Sep 16, 2009

Hey Ty, you need to use the default text color because its to dark to read on the DarkShodow option.

Very cool. But how come it looks like its been sitting at the bottom of a drawer for a year?

larrball · Sep 16, 2009

Tech_Junkie said:
Very cool. But how come it looks like its been sitting at the bottom of a drawer for a year?

All most look's like it was cast alum.
or even bead blasted?

HumanSymphony · Sep 16, 2009

Shall you be mass producing this sir?

Tech_Junkie · Sep 16, 2009

larrball said:
All most look's like it was cast alum.
or even bead blasted?

You are right, or extruded in some way.

23308d1253077336-new-experimental-heat-sink-laser-003.jpg

Burner54 · Sep 16, 2009

finn direction will not matter when a fan is used and at these powers a pretty small fan at that, I have seen some that were less than 1" on the sides that might even fit inside of an MXDL...

Peace All...

Burner54 · Sep 16, 2009

I'll bet you it was water jetted...

Tech_Junkie said:
Hey Ty, you need to use the default text color because its to dark to read on the DarkShodow option.

Very cool. But how come it looks like its been sitting at the bottom of a drawer for a year?

Tymtravler · Sep 16, 2009

@ Burner, congrats you win the Qupee doll, yes I used a Flow water jet machine to cut the sink out, this gives the sink a kind of a glass beaded finish, that’s why it looks like cast aluminum in the pictures. These were cut out of a solid piece of aluminum. I was able to keep playing with the hole diameter until it fit just right. The AXI is 12mm and I was able to get the holes diameter to 12.14mm which is just loose enough to slide the mod in.
I tested it again last night for 20 minutes with the sink in a pipe I had to see if there was a temperature changein a closed in area and again the sink was just a little warm, but not hot to the touch using a 405 BRD. I am also toying around with the idea of trying copper or brass for the heat sink; I can cut up to 2” of Titanium with the Flow so brass and copper would be no problem, it’s just more expensive. Also, I am checking out prices to have them anodized, but I will only do one for now until I can test the sinks temperature with the anodized finish and also see what the cost is.
@ Human, I may mass produce these if people show an interest but only after I have some friends on the forum test these out.
Also sorry about the quality of the pictures, I know everyone on the forum wants to see the best details of whatever you make.
:beer: Tymtravler :beer:

Benm · Sep 16, 2009

That looks pretty good - if its still at decent temperature after 20 minutes i'd say its at equilibrium and big enough to operate indefinitely.

The material looks a bit rough, which is a good thing for the fins on the outside. Perhaps the inside should be smoother, but then again, this texture can probably be used with some heatsinking paste to make a very decent connection (you do have the whole module as contact surface).

I'd love a couple of these... could even be used effectively with flashlight hosts if you leave it sticking out the front for a fair portion of its length. No more worries about thermal contact with the host since this heatsink can do the job on its own... though this only works if it sticks out, enclosed within the head of a flashlight it will not be any good.

Tech_Junkie · Sep 16, 2009

I'd test one for you. I have a >220mW GGW module I could sick in. Man if you made these out of copper you would sell a ton.

Tymtravler · Sep 16, 2009

@ TJ, Well it all depends on how much a solid 1" piece of copper would cost. I can check with Speedy Metals on the price because I want to make it affordable to the forum members, and I would like feedback if alot of people would want copper.

@ Benm, I could only get a stock 1" thick piece at a resonable price. The AXI is, less the adjusting lens is 30.76mm which is a little less then a 1/4" longer and that would have put me in another price bracket. Check out the first picture on post 1 and you will see the AXI in the heat sink. ALso the roughness is what the Flow cutter does and like I said it is like glass beading, however it is not that bad when you look at, it's kind neat looking.

Hey If there is a great demand for copper, please let me know, I will price it out.

Tymtravler

New Experimental Heat Sink

Krutz

0

Benm

0

Tech_Junkie

0

Benm

0

Tymtravler

0

Tymtravler

0

Tech_Junkie

0

larrball

0

HumanSymphony

1

Tech_Junkie

0

Burner54

0

Burner54

0

Tymtravler

0

Benm

0

Tech_Junkie

0

Tymtravler

0

Online statistics

Forum statistics

Share this page