First heatsink *build finally finished*

[qumefox]

I mostly finished my first laser related machining project. While it didn't come out spectacularly, I did manage to make it work. I got distracted when cutting the threads and got dragged away from the lathe. When I came back I forgot where I last had the carriage settings at, so the last thread cut ended up waay too deep, so the threads are pretty rough, since they ended up at the depth they needed to be, I couldn't recut them any to clean them up.

I had a few of the hosts from the $15 18650 50mw focalprice greens laying around from when I got a few to review and ended up destroying them heh.

Anyway.

Not the prettiest host around, but making a heatsink for this was fairly simple, so I figured it'd be the best 'starter'

The recess in the end will hold the PCB for the positive battery contact. Negative will be through the host body/heatsink.

Here it is screwed into the host, with an aixiz module installed. I still need to figure out what i'm going to put in it. I have a few more LPC-815's so it'll probably end up as a red, but I also have a few PHR's and a casio 445 left as well, and a couple of micro flexdrives and microboosts.

 

[Kevlar]

Re: First heatsink

Thats pretty good for your first heatsink qumefox!! I saw the lathe you have in a post a while back, similar to Jayrobs so I'll be expecting much more from you in the future!!

Nice job!!

 

[qumefox]

Re: First heatsink

Thanks. It was certainly a learning experience. Especially the thread cutting. Never done that before until now. This is actually my second attempt. The first one I actually cut the threads the wrong direction on. but I also figured out I had the gearing wrong as well, so the thread pitch was way off on that one too.

Here's a pic from the first try. Yeah I know my starter stock was way too big but 1.5" 5051 was what I had laying around.

I also finally learned how to grind tool bits that work worth a crap. heh

 

[Kevlar]

Re: First heatsink

Well I'll be looking forward to seeing some good things from you in the future that you can maybe offer us LPF members!! :beer:

There can never be enough people out there that can machine a good heatsink!

 

[qumefox]

Re: First heatsink

Heh. I'm not very fast though. the second one took me over 6 hours. Though the first was 20+. lol. But there was a lot of bit grinding and other experimentation in that 20 too.

 

[qumefox]

Re: First heatsink

About all I got accomplished tonight on this project was machining out a nylon spacer for the positive terminal, which is just a brass flat head screw I turned down. It's press fit, but not installed yet since pressing it in will pretty much be the last step to finishing the 'pill'.

I also dismantled the tailcap clicky completely, and soldered a spring to it, as well as shortening the aixiz module, since there's really no reason to have it enclosed inside the heatsink.

All I should have left to do now is drilling/tapping a hole for a set screw to make sure the aixiz module stays put, then pressing in a diode and wiring the driver.

 

[qumefox]

Re: First heatsink

Finally got around to finishing this tonight. I ended up putting one of my LPC-815 LOC diodes in it so I guess this can be moved to the 'red' section.

Here's the business end after pressing the module in the heatsink. And yes I know the aixiz module is beat to hell. I was going to use a new one but didn't feel like going back home to get a new one so I used the one I had laying around that had lived in the shop by the lathe for a while, since it was the only one available at the time. Since the aizix modules were press fit to this heatsink, I ended up not even adding a set screw. If it ever suffers shock strong enough to dislodge the module, then the laser is going to have far more issues than just a loose aixiz module. heh.

Here's the other end before I pressed the positive battery contact in. I used a flexdrive v5 set at 420mA (originally.. more on this in a bit) The white chunks are thermally conductive foam (relatively anyway. It tested better than air but not by much heh) that was holding the original driver in the host in place when it had the green module in it. I figured I'd reuse it to keep the flexdrive in place. The red wire is the positive, the black is stripped and goes to a groove I filed in the edge of the aixiz module. Since I used thermal grease around the aixiz module, I didn't really trust the case ground connection of the diode to supply the driver ground.

The positive soldered to the brass screw I used for the positive battery connector.

The whole thing pressed together now.

Testing.. though this discovered a slight problem..

This is the slight problem...

The best I can figure is that when I was putting the foam in, I accidentally bumped the pot. One of the first things I did when getting the diode pressed in was to run it off the bench supply at 420mA and it did 273mW with the best performing lens I could find in my collection. After wiring the flexdrive to the test load and setting it for 420mA, I attached it to the diode and measured it again. Running off the flexdrive it was putting out 267mW, so I bumped it up until it was doing 275mW. Well.. After I put the back of the aixiz module on and foamed the flexdrive in place, I forgot to test it again before I pressed everything together.. My best guesstimate is that it's running right around 500mA now. I know it's not going to have a long life at that current, but i'm not dismantling a working, pressed together, laser until it dies.

Anyway, Here's a couple of more shots of the completed host. The lens i'm not sure where I got. Off some ebay seller but I don't remember which. It performs marginally better than aixiz glass.

And lastly, the obligatory beamshot. 329mW of 660nm with no smoke. Yes I know it looks pink but I just had the camera on auto, and didn't really feel like screwing with manual white balance and exposures to make it red.

 

[Kevlar]

Sweet!! I like how you have the module AND driver all contained in the heatsink so when it gets screwed into the host, there is no worry about twisting wires, possibly pulling one of or snapping a diode pin.

Nice output!! Maybe you got a freak diode and it will last!! :beer:

 

[qumefox]

Thanks, but I doubt it's a freak. I bet it LED's within a couple of weeks. But i'm not really worried about it. I have a small mountain of scavenged 660nm diodes of various powers, and at least 6 more LPC-815 LOC's as well. The good side is the heatsinking seems to work fairly well. After keeping it on 5 minutes the host only gets moderately warm, and the heatsink doesn't seem to get any hotter than the host does.

 

[Mohrenberg]

nice work.
I think we share the same problem. projects take me FOREVER because it sit there and sand and turn stuff trying to get it just perfect.

Took me 3 attempts to make the focus adapter for my new kit. I kept drilling into the wrong size for the aixiz threading

 

[cd520]

Nice work qumefox. I envy you. I wish I could do this stuff. I have the mental pictures of hosts/heatsinks in my mind but no way to materialize them.

 

[qumefox]

nice work.
I think we share the same problem. projects take me FOREVER because it sit there and sand and turn stuff trying to get it just perfect.

Took me 3 attempts to make the focus adapter for my new kit. I kept drilling into the wrong size for the aixiz threading

Heh. I wasn't really trying for perfection though. More just trying to figure out what the hell i'm doing. lol. I've played with the lathe many times in the past, but that's all it was. Making random shapes just because. This was one of my first attempts at actual making *something*. So I got to learn all kinds of nifty things like how to cut threads, and exactly how worn out that old lathe really is. :yabbem: Needless to say a spindle bearing set and some miscellaneous carriage parts are fairly high on my 'to buy' list now after I get the 12x BR GB settled.

 

[qumefox]

Measured it again tonight and it's just as I was afraid of. Power output is down from 329mW to 315mW, and there is some banding starting to appear in the unfocused output that wasn't there initially. It's been run maybe a half hour so far. I'm trying to keep track of it. I know LPC-815's have been around for a long time, but hey.. One can't have too much data right? heh.

 

[qumefox]

This laser has about an hour on it now. Output is down to 291mW. 500mA drive current on an LPC-815 LOC definitely causes noticeably quick degradation.. If anyone was unsure before.

 

[Vaporizer]

Nice work. I like the way it all goes together. Sorry to hear abt the diode falloff. Good data for the cause though. I'm finishing up my 1st build and I'm down to finding the right resistor combo for 450ma on an LPC-815. Looks like I'll need abt 2.8ohms.
The one listing showed 420ma as a "good value" and 500ma as max.
I would have expected a more time than you got. Maybe just that particular diode?

 

[qumefox]

Judging by the power output, I think it's a fairly typical LOC, and my 500mA drive is just a guess. I don't have a way to test it without tearing it apart, which I don't want to do while it's still working. I arrived at that number from having tested this diode at first at 300mA (195mW), then at 420mA(275mW) originally, then assuming the ramp up was linear, plotting what current 329mW happened at.. which was 506mA.