NUBM44 6W+ 450nm Laser Diode

[jander6442]

Dutch, how will you retain that huge sink in the host with no lip to grab the bezel ring?

 

[DutchLaser]

I would call it a pocket. A slot is a narrow, shallow, and long feature

What is a diameter of your Al block? Looks like ~30-40 mm.

Diameter is slightly over 49mm
And thanks for improving my English a little bit

Dutch, how will you retain that huge sink in the host with no lip to grab the bezel ring?

I've cut the diameter of the heatsink just a little bit larger then the inner diameter of the flashlight.
I'm gonna press it together with a machine vise.
Once it is pressed it is pretty much impossible to remove unless of course, you use a press or vise.
This method is also one of the best possible ways for heat to transfer to the flashlight body. For this reason I also 'press-fitted' the copper module into the heatsink instead of using a oversized boring hole and set it with a screw which will always leave a small gap on one side of the copper module. You can try to fill the narrow gap with thermal compound but thermal compound does not work very well that way. But probably better then keeping an air space. But you know that.

It requires a little more effort yes, but hey, everything to move heat away from the laser diode right?
except a solid copper heatsink because that is too expensive :crackup:
Edit:
50x100mm Hmmm not that bad 37.69 + 12.5 euro shipping ...tempting...
Kupfer Rundstange Länge wählbar Rundstab E-Cu 57 CW 004 A Stab ziehhart CU-ETP | eBay

Just kidding, the one I have is plenty and heavy enough

ow, and I cut the inner diameter of the bezel ring also a little larger so that the heatsink can fit through.

 

[jander6442]

Diameter is slightly over 49mm
And thanks for improving my English a little bit



I've cut the diameter of the heatsink just a little bit larger then the inner diameter of the flashlight.
I'm gonna press it together with a machine vise.
Once it is pressed it is pretty much impossible to remove unless of course, you use a press or vise.
This method is also one of the best possible ways for heat to transfer to the flashlight body. For this reason I also 'press-fitted' the copper module into the heatsink instead of using a oversized boring hole and set it with a screw which will always leave a small gap on one side of the copper module. You can try to fill the narrow gap with thermal compound but thermal compound does not work very well that way. But probably better then keeping an air space. But you know that.

It requires a little more effort yes, but hey, everything to move heat away from the laser diode right?
except a solid copper heatsink because that is too expensive :crackup:
Edit:
50x100mm Hmmm not that bad 37.69 + 12.5 euro shipping ...tempting...
Kupfer Rundstange Länge wählbar Rundstab E-Cu 57 CW 004 A Stab ziehhart CU-ETP | eBay

Just kidding, the one I have is plenty and heavy enough

ow, and I cut the inner diameter of the bezel ring also a little larger so that the heatsink can fit through.

So how do you access the driver in case of future repairs or other things like maintenance? I do not disagree with the press fit, however I've been able to fine sand the diameter of the sink to be able to firmly press the module in while using thermal paste as a lube this has always been one of my focus points during a build.

 

[DutchLaser]

So how do you access the driver in case of future repairs or other things like maintenance? I do not disagree with the press fit, however I've been able to fine sand the diameter of the sink to be able to firmly press the module in while using thermal paste as a lube this has always been one of my focus points during a build.

How many times did you disassemble your lasers?
Maybe you did and you had to re-align some mirror or clean something. I see you have some nice builds
I have a few lasers and never opened one because mine are very simple, maintenance free and it is no effort to remove my lens as you can see.

however, I can remove the heatsink once it is placed
and by that I mean it is possible, not that I am planning to do that

That's why I milled a 'pocket' for the driver so I don't crush it when pushing out.
The driver might get heat issues and I don't want to keep fooling around by removing the heatsink once it is placed
That's why I need you guys. what is the maximum temperature for the inductor side of this driver? I THINK it is getting around 60-70 degrees celcius (140-158 fahrenheit) because I can barely touch the aluminium holder with the 2 bolts for more then a couple of seconds.

 

[jander6442]

I think you find it better to machine a lip so that the ring can tighten down (snugly) a much simple and better solution I'm not bashing just trying to help out here. Given the size of that sink the attention to flooding the host itself with heat after the sink has been saturated to be kinda extreme for all that trouble and perhaps scuffing the host one way or the other.

Just turn down a lip and polish the top portion. Your build will be fine what ever scenario you choose.:beer:

 

[DutchLaser]

I think you find it better to machine a lip so that the ring can tighten down (snugly) a much simple and better solution I'm not bashing just trying to help out here. Given the size of that sink the attention to flooding the host itself with heat after the sink has been saturated to be kinda extreme for all that trouble and perhaps scuffing the host one way or the other.

Just turn down a lip and polish the top portion. Your build will be fine what ever scenario you choose.:beer:

No offence taken

I don't need the mass of the body of the flashlight to store heat, I need the surface of it for greater surface/cooling area to air. Once that heatsink is warm it takes very long time to cool down. I think good conductivity with the flashlight body can definitely reduce that time.

besides, making a lip is not an option any more. There is no metal left to cut it from. It is ready to get pressed. I would like to know whether that driver is mounted good enough to keep delivering 4.5Amps without overheating. How heat-sensitive is that thing?

Edit:
Out of interest I just looked at an AMC7135 datasheet. That driver can handle +85 degrees celcius.
I know that my driver is a different one but I was hoping it can handle those temperatures as well. In that case I can press the hole thing together today.

 

[RedCowboy]

How many times did you disassemble your lasers?
Maybe you did and you had to re-align some mirror or clean something. I see you have some nice builds
I have a few lasers and never opened one because mine are very simple, maintenance free and it is no effort to remove my lens as you can see.

I like your driver mounting, it should be ok from what I see others do, I heat sink both sides of mine as well.
What lens are you going to use? G9 with cylindrical correction?
If you are not going to use any correction then the 3 element is more useful.

 

[DutchLaser]

I like your driver mounting, it should be ok from what I see others do, I heat sink both sides of mine as well.
What lens are you going to use? G9 with cylindrical correction?
If you are not going to use any correction then the 3 element is more useful.

Thank you

Yes I intend to use a G9 lens on this laser and I really like the idea of cylindrical correction but I have to admit I have zero experience with that.
It was in my mind to make some sort of rim on top of the heatsink with my lathe. So I could precisely press-fit a metal holder on top of it with a secondary optic in the future.
But because I don't have any concrete ideas or even an optic I skipped that part and made a flat top.

Beam divergence is horrible. But I like the burning capabilities of this laser. Therefore I am not planning to use a 3 element lens.

 

[RedCowboy]

@ DutchLaser WOW I just put in a G9.....at .5 meters yes it's still strong but at 7 meters the tightest line is 2 times as wide and 2 times as long as with the 3 element. That's .25 the energy density so even with a 25% loss up front....just try a 3 element, you will see the difference, even with the power loss you still have 4x the energy density and you will set fire to any wood up close with a 3 element faster. And your night time beam will look a lot better. It's a good idea to use a lens flare hider with these bright lasers, a tube 50mm long around your lens knob will help a lot.

Ok this will help, read post 192-200 page 13 I think. Also read about p73 correction.
http://www.ebay.com/itm/Cylindrical...20nm-diodes-/171849122285?hash=item28030181ed

I'm still learning about beam shaping lenses, but It will be done.

 

[Cyparagon]

one can see that the inductor is not 'heat sinked' very well and yes, it is getting hot fast. is that a problem?

Do NOT heat sink your inductors! Proximity to conductors changes the inductor's value, and can cause all kinds of problems in your circuit - one of which is overheating.

If the inductor is too hot, it means you've chosen the wrong inductor.

 

[Cyparagon]

I have been getting away with it for a long time

Sounds like something a drunk driver would say.

"I got away with it" doesn't mean it's a good idea.

 

[RedCowboy]

Do NOT heat sink your inductors! Proximity to conductors changes the inductor's value, and can cause all kinds of problems in your circuit - one of which is overheating.

If the inductor is too hot, it means you've chosen the wrong inductor.

I thank you for sharing your knowledge, I use mounting heat sink compound and fill the 12mm housing or install the driver inside a 12mm pill, as DTR has sold them inside the non-ferrous shells for some time I don't think my method could effect the inductor. Maybe Dutch Laser would rather use a plastic retaining bar?

 

[DutchLaser]

@ DutchLaser WOW I just put in a G9.....at .5 meters yes it's still strong but at 7 meters the tightest line is 2 times as wide and 2 times as long as with the 3 element.

Ok this will help, read post 192-200 page 13 I think. Also read about p73 correction.
Cylindrical Lens Pair to Suit Mitsubishi Red Diodes 445nm and 520nm Diodes | eBay

Thanks, I'll take a look at it

Do NOT heat sink your inductors! Proximity to conductors changes the inductor's value, and can cause all kinds of problems in your circuit - one of which is overheating.

If the inductor is too hot, it means you've chosen the wrong inductor.

Thank you for your response, I appreciate it
So you say I should get rid of the little piece aluminium that holds the driver in place and make one out of plastic?
I did not choose my inductor. Lazeerer did I think. His name is written on the PCB. Are you online Lazeerer?

I think this is the first diode that is letting the SXD driver run @ 4.5Amps so maybe some heat is expected and acceptable?

 

[RedCowboy]

Thanks, I'll take a look at it

Thank you for your response, I appreciate it
So you say I should get rid of the little piece aluminium that holds the driver in place and make one out of plastic?
I did not choose my inductor. Lazeerer did I think. His name is written on the PCB. Are you online Lazeerer?

I think this is the first diode that is letting the SXD driver run @ 4.5Amps so maybe some heat is expected and acceptable?

LOL I just said the same thing about a plastic bar then saw you already said it. DTR runs those drivers on the back of his CNC mounts with only the chip attached.

 

[Pi R Squared]

Let me take a moment to say something about inductors. This is basic electronics that anyone with a basic knowledge of electronics needs to know. To make this short and not too technical, the main purpose of an inductor is to delay or oppose changes in current. The way it does this is that when current begins to flow through the inductor, there is a delay while the inductor stores a small amount of energy in a magnetic field before current is allowed to flow, when current drops, the inductors magnetic field collapses maintaining the current for an instant. This is similar to the way capacitors reduce voltage fluctuations. Cyp is correct. An inductor never needs heat sinking, if it gets too hot then something is wrong. Attaching a piece of metal to the inductor will interfere with it, also with much larger inductors placing them in the wrong place can sometimes be a problem, these are because of the magnetic field the inductor creates. Hopefully this helps some people understand a little more.

Alan

 

[DutchLaser]

Thank you Alan, very helpful!

A few test results:

I bought the driver set @ 4500mA and it was already soldered to the diode when it arrived.

I was playing with the laser this afternoon and decided to add an ammeter (multimeter) between the driver and the diode.
Lab supply was set @ 8.0V and deliverd 2.4-2.5A (I set voltage, current is left unlimited.)
Surprisingly the multimeter reads 3.6xx mA to the laser diode.
I don't know why that is. I'm not accusing anyone, maybe I touched the potmeter with my fingers when handling it.
I soon realized that increased temperature on the driver gives a higher amperage to the laser.
With a little screwdriver I set the driver @ 4.1xx mA (and I realized how sensitive that potmeter is)
Amperage quickly ramps up. After ~5 minutes the driver delivers 4.620mA and the 445gram module is 51degree Celsius (123.8 degrees Fahrenheit). Measured with IR-thermometer gun pointed close to a piece of black tape that I added to the heatsink. Room temperature is 26 degree Celsius (78.8 degrees Fahrenheit, yes its a nice summer here )
Lab supply was of course still set @ 8.0V and delivered 3.0 Amps near the end

I disconnected power.
And reconnect after ~1 minute with the heatsink still quite warm and driver having the same temperature as the heatsink now.

It takes 1-2 minutes for the driver to start from 4.1xx mA and ramp up to +4.6xx mA.
Kind of a heat-sensitive driver, right?
I hope it's not that little aluminium holder that is causing it.
I will make one out of plastic tonight.

Any thoughts?