Build thread: 4.4W 445nm dual diode laser

[Seoul_lasers]

Re: Concept: 4W corrected 445nm handheld

Copper isn't that much better than aluminium, it's not a huge difference; the modules are copper though. I also despise the brown look of copper, and the front part of the heat-sink will be seen. I wont be pushing the diodes either, I changed the plan up some more. I'm probably going to run each diode @ 1.9A so there wont be as much heat.

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Thanks!

Aluminum works but for stability sake Copper is 62.3% better than Aluminum at removing heat. k - W/(m.K) Aluminum 250W/(m.K) Copper 401W/(m.K)
Even better than Copper is Silver at 429W/(m.K)

I was just thinking from a thermal standpoint, you will be transferring quite a bit of waste heat from those diodes and the divers as well. best to go with something to remove the heat as fast as possible. You have a really nice build there.
@ ~5v 1.9A per diode which is nearly 10W per diode, how much of that input gets turned into waste heat/loss? You're inputting nearly 20W between those diodes. That host will need some decent cooling if you want any kind of life out of it.

 

[Multimode]

Re: Build: 4W 445nm handheld

Hasn't the Cu / Al thing been flogged to death enough in other threads. ????
I'm more interested on his build, once it's complete we'll see how good Al performs.

 

[rhd]

Re: Build: 4W 445nm handheld

On a finned heatsink with a fan, sure the difference between aluminum and copper isnt that pronounced, but in a closed host copper is far superior. It has a much larger thermal capacity which means much longer duty cycles. Aluminum is just too light.

No it doesn't.

Sure, copper has 3.3x the mass (per unit of volume) that Aluminum does. But aluminum has around 2.3x the thermal capacity per unit of mass that copper does. So the actual specific heat capacity of copper is only very minimally higher than aluminum's on a volume basis (which is the basis you'd compare if building a specifically sized heatsink from one of the two metals).

In a build like this, it is all about specific heat capacity of the metal. The benefits of copper for the heatsink would be relatively small. The benefits of copper for the modules as heat transfer conduits TO the heatsink, would be huge (and it sounds like you've already come to that conclusion - so you're set).

 

[Mrcrouse]

Re: Build: 4W 445nm handheld

Wouldn't it be... If you are constrained by volume, copper will offer more heat capacity, while if constrained by mass, aluminum will offer more heat capacity.

 

[grainde]

Re: Build: 4W 445nm handheld

Wouldn't it be... If you are constrained by volume, copper will offer more heat capacity, while if constrained by mass, aluminum will offer more heat capacity.

Exactly, in a build the host generally limits the size of the heatsink. So, unless you go for an elaborate larger custom HS for the Al, both an Al and a Cu heatsink for the same host will have the same volume. As RHD said Al has a higher specific heat capacity than Cu, but due to the fact that Cu has a higher density than Al, you would need to build a larger Al heatsink to account for it. Cu would thus have a smaller temp increase per joule of heat for the same volume HS, than Al.

Hasn't the Cu / Al thing been flogged to death enough in other threads. ????
I'm more interested on his build, once it's complete we'll see how good Al performs.

I agree! :beer:

 

[kaunak]

Re: Build: 4W 445nm handheld

wow cant wait to see this thing in completed. Should be really awesome if it works out !

 

[ARG]

Re: Build: 4W 445nm handheld

wow cant wait to see this thing in completed. Should be really awesome if it works out !

I'll make it work, have already invested to much to not have it work

Host should be here any day now.

 

[ARG]

Re: Build: 4W 445nm handheld

The host arrived from Ehgemus today! It's a piece of art! :drool:

[Redacted]

Now the building can commence

 

[ARG]

Re: Build: 4W 445nm handheld

My apologies for the above photos, it had just came in the mail and I was exited. I had somewhere to be so I couldn't spend a lot of time to take quality photo's or resize them so that I could embed them.

Here's some better ones!

The head of the laser

Drop in Heatsink
Front
A piece will be added onto the tray so that the optics don't move when the aluminium warps in the heat.

Back

The driver pocket with two wires for the two drivers

Battery tube for 2x 32600

Tailcap

Front side all together

I am in awe of how good this all looks! The pictures don't do it justice. Ehgemus polished it up real well, it's a mirror finish




Now... On to the build :yh:

I wrapped the lens threads with some teflon tape, almost two full wraps so that the fit was really tight. I focused them to infinity and I put some silicon on the top to hold it in place; even though it was already really tight with the teflon tape. The silicon is easy to remove if I need to change the diode. It's just an extra measure to make sure the lens don't wiggle or move at all.

I put them in the aixiz heatsinks temporarily to hold them while they cure. Now to wait 24h for it to dry. :tired:

 

[lazeerer]

Re: Build: 4W 445nm handheld



How did i miss this thread.

 

[ARG]

Re: Build: 4W 445nm handheld

Well, the 445nm section is a hot topic Other threads keep bumping this one down

Can't wait to get those x-drives! This is what they are for Hopefully they will arrive next week.

 

[lazeerer]

Re: Build: 4W 445nm handheld

Thats awesome.


Looking forward to watching this build.
op:

 

[ARG]

Re: Build: 4W 445nm handheld

Thanks Lazeerer!

I borrowed a Power Supply so I could get some reading before I put the diodes in. The silicon has cured for the most part, so it's safe to fire them up.

Readings taken after 10 seconds on the sensor, to get an average reading. Rounded to the nearest multiple of 5. Small testing heatsink used, numbers will be higher once they are in the host's heatsink

Diode #1:
2070mW at 1.6A
2440mW at 2A
Diode #2:
2155mW at 1.6A
2590mW at 2A

Combined is 5W Leaves room for 20% optics loss on each diode! The loss should only be 10% on the better diode so 2331mW from that, and I expect 25% loss on the worse diode so 1830mW. Total 4161mW estimated. My optics loss estimates are fairly high, so it will likely be more than that!

This may even hit a 4.5W peak once this is all built!

 

[lazeerer]

Re: Build: 4W 445nm handheld

Looks like you got some efficient diodes there.:beer:

 

[ARG]

Re: Build: 4W 445nm handheld

Got the X-drives from lazeerer in the post today

I've got to install the modules before the drivers and I'm waiting on some quality thermal grease to put around the modules for the better heat transfer. I could use a dab of thermal adhesive, but it would be a pain to remove the modules if need be, and I need to be able to rotate the modules to get both of the lines to be perfectly perpendicular to the optics tray.

The silicon has set completely and the lens barrels don't move at all It's easy to peel off to if I ever need to realign.

 

[lazeerer]

Re: Build: 4W 445nm handheld

Nice. Yeah your better off not using Thermal Adhesive. Like you said if you have to remove them or hell even make adjustments which iam sure your going to have to make quite a few to get it just right you would not want to have to chip away thermal adhesive.

How come you decided to go with Grease rather then paste.?

Is it better performing in your Opinion.?