Possible risk 3 elements with high power lasers!

[grainde]

Re: Do not use 3 element lenses with high power lasers!

I had that same diode die on me too, but using a G2 lens and it did the same thing, went down to low output but with a dark slice in the middle of the beam after that. I believe we cannot drive them at 4 amps, probably better at 3 amps. Mine died at 3.5 amps.

Yep similar here, the raw output is missing quite a few lines and the output looks like a single mode with the 3 element. Interestingly the power went back up to around 500 mW with the 3 element. So it's now a 500 mW single mode 465...

As mentioned I didn't think that 4 A was too much, but perhaps we should start collecting data, it may very well be possible that 3.5 A is the max.:beer:

I have seen several NUBM07E diodes get weaker and weaker, every single one was run at 3.5 amps and had the GBall/can removed, I think the problem is oxygen, but I have not done a comparative study with a GBall intact diode, but I speculate that they would retain brightness longer with the GBall/can left intact.

-----edit-----

Ha, I remember looking at the raw output of the last 07 I had while the GBall was intact and it was mounted in a heatsinked HH of course, then not a day after removing the GBall/can I pulled the G7 lens I was using and noticed a dark line in the raw output. That diode also got weak in short order after the GBall/can was removed.

My NUBM08 lasted 6 weeks to about half brightness ( estimated ) , it lost it's burning ability over the weeks as I burn at a 20-30 foot distance often and I remember it got harder and harder to make it light a paper bag, but when I put a NUBM44 unit on the task " poof " up in flames no problem.

Well it's either heat from run times that are too long, the diode which isn't able to handle the current, oxygen killing them or all of the above. In my case the diode was on for max 1 min during current setting, focusing and one "on moment" to enjoy the beam out of the window. In all cases, I never ran it constantly for more than 10 secs. So I don't think oxygen was the case here, due to the limited time factor. If some one wanted to test this they could remove the GBall flush the lens area with Argon or Nitrogen and whilst flushing screw in a lens barrel wrapped with teflon tape to help seal it. They would have to screw in the lens barrel to set the focus and not move it to avoid sucking in air. Two diodes could be compared in identical builds; one with the inert gas and the other with air and tested to see if there is any degradation over time. A third build with a GBall could be used as a control.:beer:

Wish I knew if the manufacturer fills them with inert gas, but for that to work the GBall lens would need to have an air tight seal. If we knew that, we would know if oxygen is the problem or these diodes just don't like to be run so hard.

See above, my guess would be that they are. :beer:

 

[RedCowboy]

Re: Do not use 3 element lenses with high power lasers!

I bet I can put a NUBM06 in a jar of water for a week and then take it out and power it up and there won't be a drop of water inside. They would run under water until the lens shattered from heat differential.

 

[BobMc]

Re: Do not use 3 element lenses with high power lasers!

The "oxygen" question is something that is quite interesting. Did some searching on the question awhile back and the best I came up with was the "jury is still out". Would like to know, have a few de-canned builds. Guessing it a "wait and see" sort of thing. Not much consolation for you, your out the price of a diode. Sorry for your loss, its got to sting.

 

[Alaskan]

Re: Do not use 3 element lenses with high power lasers!

I was running my diode for about 30 seconds when it failed and it was in a host with a very large heat sink, should not have failed from heat. I am trying to remember the output after it failed, but I think it as 300-400 mw, somewhere about that.

 

[dden4012]

Re: Do not use 3 element lenses with high power lasers!

Yep similar here, the raw output is missing quite a few lines and the output looks like a single mode with the 3 element. Interestingly the power went back up to around 500 mW with the 3 element. So it's now a 500 mW single mode 465...

As mentioned I didn't think that 4 A was too much, but perhaps we should start collecting data, it may very well be possible that 3.5 A is the max.:beer:



Well it's either heat from run times that are too long, the diode which isn't able to handle the current, oxygen killing them or all of the above. In my case the diode was on for max 1 min during current setting, focusing and one "on moment" to enjoy the beam out of the window. In all cases, I never ran it constantly for more than 10 secs. So I don't think oxygen was the case here, due to the limited time factor. If some one wanted to test this they could remove the GBall flush the lens area with Argon or Nitrogen and whilst flushing screw in a lens barrel wrapped with teflon tape to help seal it. They would have to screw in the lens barrel to set the focus and not move it to avoid sucking in air. Two diodes could be compared in identical builds; one with the inert gas and the other with air and tested to see if there is any degradation over time. A third build with a GBall could be used as a control.:beer:




See above, my guess would be that they are. :beer:

Yahoo 465 sm diode. Glass half full right? No not really. I have been rather rough with my 07E and its still going strong. Ill LPM it sometime soon just to confirm. If I see + 3.5w ill be happy. I might need to get another one to compare.

 

[RedCowboy]

Re: Do not use 3 element lenses with high power lasers!

I like the NUBM06 because they are strong, at 4.0 amps they put out about 5 - 5.5 watts which is only about 1 watt less than a NUBM44 but they have better natural divergence and the factory GBalls are useable in the 5 foot range for producing an open flame on wood, no 30 dollar lens to buy and with the addition of a 3X BE from sanwu you can ignite brown bags outside at 20 feet, now if you pop out the GBall which is easy after it's mounted in a full copper module you have a nice laser with our off the shelf lenses, but it will lose brightness faster over the weeks of use ahead than the 44, ( my personal experience and opinion ) but I bought one from Techhood for 39 dollars ( at auction ) and that's not bad, if they get down a bit more they will be less than just a G2 lens and a lot of fun on the desktop, or just pop the can off and plan on replacing them more often, I am thinking a black buck driver mounted an inch away and just change out 30 dollar diodes every so often until I can find a good lens set up to use with the GBall intact, a cyl pair and larger expander set ( double concave and PCX )

That said the NUBM44 is still my favorite, but 30 some odd dollar powerhouse diodes have an appeal....until they wear out....again, LOL.

 

[Razako]

Re: Do not use 3 element lenses with high power lasers!

I can't really see it all being the lens. 3-element is the default lens sanwu uses with their higher powered lasers.

 

[Cyparagon]

Re: Do not use 3 element lenses with high power lasers!

I had that same diode die on me too, but using a G2 lens and it did the same thing

On no! That can only mean G2 lens will ALSO kill high power laser diodes!

"After this, therefore because of this" is a fallacy, Mr. Grainde.

 

[Alaskan]

Re: Do not use 3 element lenses with high power lasers!

My point is it is not the lens that is the problem.

 

[RedCowboy]

Re: Do not use 3 element lenses with high power lasers!

Alaskan, I think you, Cyparagon and myself as well as some others are all saying it's not the 3 element lens.

The 3 element clips the edges into it's black threaded lock ring and the inner lens barrel threads, also black non reflective looking coated brass.

 

[Alaskan]

Re: Do not use 3 element lenses with high power lasers!

OK, I agree with that.

 

[grainde]

Re: Do not use 3 element lenses with high power lasers!

Sorry I didnt get round to replying all day, I was slaving away building lasers and taking pics for a planned build info thread...Anyway guys I was just reporting what I saw. I won't be using 3 element lenses with high power diodes, but you of course are free to. :beer:

 

[Crazlaser]

Re: Do not use 3 element lenses with high power lasers!

I don't think it's the 3 element lens. I've run a three watt diode and several m140 with success with this lens.

I don't know about the oxygen, I have an open diode Mitsubishi 500 from sanwu that stopped working so they sent another. This one has been fine. I think the first one was only the driver though. It would turn off and on at random in different temperatures.

 

[Alien Laser]

i had the same problem when using a 3element lens on the 44 the (3e) lens cracked must be from heat no idea was long time ago, seen it happen again on the G7 lens strange thing happen the lens has a burn in the middle and a tiny crack after using it on the 44, no idea what cause it could be dust on the lens or something ! :thinking: