9mm 445nm heatsinking question

So I recently bought a 9mm module from DTR, with a 405-G-2 lens and 2.2A flexdrive attached. I love his modules and how easy he makes things. I'll run through my build quickly before getting to the problem.

Here is the host provided by Survival Laser, it's beautiful and has a nice weight to it.


I also ordered a blank driver board to use as a battery contact.


It took me connecting the wires and mounting it before I noticed that the wires were not connected to the positive and negative contacts on the other side. Additionally I realized I had no springs laying around so I fashioned one out of an earring I found laying around.






Here comes the problematic part...


I also bought a stainless steel host from survival laser with the NON tapered heatsink. I didn't like the way the tapered one looks with the focus ring basically sticking off the end of the laser. I thought the non extended one would look much nicer. This came back to haunt me. With the driver module attached to the diode directly I discovered that I couldn't fit the heatsink inside the host properly. So I decided to remove the aluminum part of the diode module which protects the driver circuit. With the extra 1/4 inch and a little gentle bending of the driver board it fit.



I put it all together and it works fine, here's one of the "finished" product.


The thing I don't like is having that aluminum part of the diode module essentially wasted (as well as exposed). Additionally, the duty cycle for this is pretty atrocious (30 sec on 2-5 minutes off). I didn't realize just how poor stainless steel is at conducting heat compared to aluminum or copper.

All that to say, I have an extra aluminum heatsink laying around. By attaching the aluminum part of the diode module over the driver, it causes the actual diode part of the aixiz module to not be in contact with the copper host heatsink. My question is whether I would gain any advantage by attaching this extra heatsink over the part of the diode module that hangs out the front like so:


My hesitation is due to the fact that the actual diode would then have just the copper aixiz module around it and the aluminum heatsink on top of that. The copper host heatsink would be in contact with the aluminum part of the diode module rather than directly on the diode. Between the two of these, will I have adequate heatsinking? Is this dangerous since I'm using such a powerful diode? Please let me know any thoughts or suggestions!

Hey looking good for a 1st build. Nice and clean. Good idea on the spring... that is a microboost driver however other than that +rep.

I cannot see any advantage, whatsoever, in your proposed fix. You need as much sinking around that module as possible. Why don't you remove the driver and put it in the pill, where it belongs? That way, you can fit the module into the heatsink properly.

jander6442 said:

Hey looking good for a 1st build. Nice and clean. Good idea on the spring... that is a microboost driver however other than that +rep.

Click to expand...

Actually it's an X-drive since I am using two 18650 batteries with it.

Anyway, new update is I have mounted the additional heatsink on the module.



This has upped the duty cycle from 30 seconds on, 5 min off to about 60 seconds on and 2 minutes off. I attribute it to the fact that part of the heatsinking is now done by the large copper module in the host, and the excess is done through the aluminum fins. They really help cool the whole thing off much more quickly now.

I measured the power with a Thor labs thermopile and came up with an average power between 2.6-2.7 Watts. Not the 3+ W I was hoping for, but you all know how it goes.



Here is the thermopile (sorry couldn't get the thermopile and gauge in the same picture due to the table setup)





Anyway. I call this a successful build. It's a bit of a frankenstein's monster with the extra heat sink on top, but I really like it. I've gotten a few lightsaber comments from people as well.

Thanks for reading, and special thanks to DTR and Survival Laser who both shipped me parts within 20 hours of ordering. Spectacular service!