Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers



NUBM44 problems. Please help.

DTR

Well-known member
LPF Site Supporter
Joined
Jun 24, 2010
Messages
5,771
Points
113
Yep that swirling pattern in the video is the window melting. All the power of the unit is not escaping the diode can causeing it to overheat quickly which is probably why you are getting dimming. This can also cause damage from either back reflections or if smoke is created inside the diode can. At the very least the diode needs to be decannec but depending on how long it was run like that it could have suffered damage. Looking at the top of the diode in the pictures looks like lots of particles on the diode can and window.

I suggest decanning the diode. I can do it if you want to send the module over(not the host).
 



CaliKirk

New member
Joined
Mar 30, 2016
Messages
376
Points
0
Yep that swirling pattern in the video is the window melting. All the power of the unit is not escaping the diode can causeing it to overheat quickly which is probably why you are getting dimming. This can also cause damage from either back reflections or if smoke is created inside the diode can. At the very least the diode needs to be decannec but depending on how long it was run like that it could have suffered damage. Looking at the top of the diode in the pictures looks like lots of particles on the diode can and window.

I suggest decanning the diode. I can do it if you want to send the module over(not the host).
That seems like that is my only option at this point as otherwise I spent good money for a aluminum paperweight.

I'd estimate less than a minute of ON time since it left its bar profile (in <10 second intervals). I'm very hopeful it is the can, but seeing as the diode is now lasing extremely dim and dims to almost nothing very fast.
 

astralist

Active member
Joined
Mar 27, 2011
Messages
505
Points
43
Remind me of my NUBM44 which the diode window got melted because of the reflection of three elements lens (in my theory).
That's because it was burned when i try to adjust the focus when using three elements lens. :cryyy:

My solution was to hack the diode window off as i don't have tools for decanning the diode, but it was quite risky IMO.
Simply smashing the diode window using hexagonal shaped screwdriver (or whatever you called it) and clean the glass pieces.

Here is the pics:






And after hacking the window off:

After this, the beam looks like a healthy beam :D

But unfortunately, after several days using it without the window, i accidentally adjusting the focus once again and burned off the die and now it's zombified :cryyy::cryyy:


 

Alaskan

Well-known member
LPF Site Supporter
Joined
Jan 29, 2014
Messages
12,247
Points
113
How did adjusting the focus cause that to happen?

I bought a diode from a member here some months ago and as soon as I started using it the window got a crack in it producing the same swirly blob pattern too, bought a de-canning tool, removed the can and then no problem but I never had a problem due to focusing the lens, did you accidentally hit the diode with it? If not that, didn't know this could happen of the lens was too close and out of focus at the same time.

Although the NUBM44 isn't exactly cheap and the loss a disappointment, members have destroyed far more expensive diodes than what that cost you, the NDG7475T 1.4 watt capable output 520nm diodes used to cost a thousand dollars, imagine ruining one of those.
 
Last edited:

CaliKirk

New member
Joined
Mar 30, 2016
Messages
376
Points
0
How did adjusting the focus cause that to happen?

I bought a diode from a member here some months ago and as soon as I started using it the window got a crack in it producing the same swirly blob pattern too, bought a decanning tool, removed the can and then no problem but I never had a problem due to focusing the lens, did you accidentally hit the diode with it?
At first it seemed like it was going to be a burnt can problem, which it is, but after hearing other members it seems that their diode still lased normally even though the output was affected by the window. The thing I haven't heard happen is that once turned on,the diode goes from very weak intensity (not just from the window, overall output is very weak, got weaker each quick use) to near off within 2-3 seconds of turning it on. I'm worried that decanning wont be the trick and I possibly had something go bad with the die.
 

Alaskan

Well-known member
LPF Site Supporter
Joined
Jan 29, 2014
Messages
12,247
Points
113
This diode has a reputation for being very robust, even at the outputs we run them at so I wouldn't be afraid of getting another one, there is a member selling them fairly inexpensively in the BST section (Edit: just learned he had a death in the family, is away now and not responding to PM's). I don't know the manufacturers rating for the diode to know how far over their recommended current we are pushing them to, but whenever we run our diodes far beyond design current and output we can have failures, even if only a few out of a large number it is disappointing when it happens to us. So far, I have only had a window problem and I'm not sure that wasn't just due to dirt getting on it. If a window fails like that, I imagine too much light can be reflected back on to the dye and cause it to overheat. If anyone has a window problem like that I would not power it up anymore, not until the damaged window is removed.
 
Last edited:

HydroSean

New member
Joined
Mar 25, 2016
Messages
529
Points
0
I noticed with my NUBM44 in a 25mm copper module it heats up very quickly. Since yours is in an S4 host it is probably in the 12mm copper heatsink which would heat up so fast I don't think it would even work... I just got the M462 2W diode in the 12mm module and that even heats up very quickly. I think your diode overheated and melted, a new can may work but if it were me I'd either get a new NUBM44 in at least a 25mm module or size down to the M462 in 12mm module.
 
Last edited:

GSS

Well-known member
Joined
Apr 28, 2015
Messages
5,061
Points
113
Cali, just giving you a kudo's for not placing blame and taking it in stride:beer:
I was getting so many laser packages at one point that the USPS must of got curious and ripped a hole in one and when it got delivered you could see Lifetime's build focus knob just about sticking out that hole. Not here to start a Post Office rant just giving you a heads up to you going the way of fixing the issue than blame.
Love it when members come together and yes believe a decanning is all thats needed:) Laser cutting off issue's aside.
 
Last edited:

Lifetime17

Well-known member
LPF Site Supporter
Joined
Dec 15, 2014
Messages
6,014
Points
113
Hi,
Like i said before check to see is the driver is properly heat sinked this causes the driver work intermittently . and if your worried about the beam profile cause of the can de-can the diode . Open cans are functional without the window , i have de-canned diodes and they are still running fine just have to be a little more careful that all when changing the lens. Get yourself a de=canning tool and do it your self. Its a great investment in this hobby you need tools ..

Rich:)
 

RedCowboy

Well-known member
Joined
Jul 10, 2015
Messages
9,125
Points
113
Watching that video I can clearly see that is plastic melting making that pattern on the wall, I bet you someone ran that with an acrylic lens and I bet it got some plastic/acrylic on the can's window and they will burn through and crack when obstructed, that's too much energy in a small spot, I popped one just like that myself by getting some trash on the window.

This is shining the beam through a plastic RX pill bottle. That melting pattern looks like plastic on your window, likely from a melted acrylic lens.



Here's your video again, see the tell tell melt pattern.

 
Last edited:

Alaskan

Well-known member
LPF Site Supporter
Joined
Jan 29, 2014
Messages
12,247
Points
113
Mine looked like that due to the way the glass window on the diode got so hot it fractured it in a pattern like that.
 

DTR

Well-known member
LPF Site Supporter
Joined
Jun 24, 2010
Messages
5,771
Points
113
This diode has a reputation for being very robust, even at the outputs we run them at so I wouldn't be afraid of getting another one, there is a member selling them fairly inexpensively in the BST section (Edit: just learned he had a death in the family, is away now and not responding to PM's). I don't know the manufacturers rating for the diode to know how far over their recommended current we are pushing them to, but whenever we run our diodes far beyond design current and output we can have failures, even if only a few out of a large number it is disappointing when it happens to us. So far, I have only had a window problem and I'm not sure that wasn't just due to dirt getting on it. If a window fails like that, I imagine too much light can be reflected back on to the dye and cause it to overheat. If anyone has a window problem like that I would not power it up anymore, not until the damaged window is removed.

From what I have seen I am pretty confident in the belief that the only thing that actually causes the window to melt is particles landing on and blocking the light path right at the window causing a runaway effect that will crack/burn a hole in the window due to the great heat. While it is true these diodes are the most powerful this is an issue with many other diodes especially the 1W+ diodes.

I know there was some speculation a while back about back reflection with the three element lenses but have not seen anything that actually shows it and from what I can surmise by the things I have read about it the light would just pass right through the window and the damage that can be caused is in the lasing cavity itself when hit by it. Mostly read about this being an issue using dicros or other beam combining optics and accidentally sending the beam directly back into the diode. Have not heard of it being able to pose a threat to the window as it has much less power density than the exiting light. I haven't seen any data showing any quicker degradation with the three element lenses vs other lenses like the G-2.

What I see the most is either from after a recent lens change or running a high power diode with an acrylic lens that melts getting smoke on the diode window during operation.
 
  • Like
Reactions: GSS

RedCowboy

Well-known member
Joined
Jul 10, 2015
Messages
9,125
Points
113
I have several NUBM44's that I work the heck out of most every day getting their big heat sinks hot after 5 minute runs, I have even gone to 3 x 26650's to keep the fun going between charging, they are super tough diodes, the one I burned through was after a lens change and I likely got something on the window because a dozen diodes later and they are all super tough.
 

Alaskan

Well-known member
LPF Site Supporter
Joined
Jan 29, 2014
Messages
12,247
Points
113
I ditto that, my window died after a lens change too, something must have gotten on it.
 

CaliKirk

New member
Joined
Mar 30, 2016
Messages
376
Points
0
I ditto that, my window died after a lens change too, something must have gotten on it.
The thing that is very confusing is that the laser worked upon shipment from seller, it turned on the first use but at ~10 seconds is where it started changing intensity and after letting it cool down (thinking it was a heat issue) I turned back on and again ~10 seconds is where the bar turned into a swirling blob.

I'm thinking that possibly shipment shook something loose and upon me receiving and turning the laser on, then trying to figure out what the hell (with pictures and video) I further put a nail in the coffin for this nubm44. I'm very hopeful since these diodes are robust and can take a beating. But since the diode won't stay on past a couple seconds, I'm more heartbroken than anything. :yabbmad:
 




Top