6 watt Nubm44 focus help

[DistortedDesigns]

Several of us are looking to use DTR's new 6 watt diode for full gray scale engraving. The issue is with the standard lenses G2, 3 element, and J-Tech lenses can't get it focused small enough. Right now it only gets to 0.3mm / 0.012" and we need it to focus to a minimum of half that to be usable but would be better if it would go down further like 0.12mm / 0.005".

What are our options? Are there any options? Is there a better or different lens we can use to make this happen?

 

[Isaac Clarke]

try using single mode optical fiber

 

[Cyparagon]

Try a shorter focus to the target. The closer the target is to the lens, the tighter the spot will be.

 

[DistortedDesigns]

I think the norm for engraving is around 2" from the work piece with a 3 element lens and a M140 laser or the 3 watt version. How close should we get then? At 1" i would be worried about build up on the lens even with a fan blowing the smoke away constantly. Are their any other lenses we could try?

 

[DistortedDesigns]

I think the norm for engraving is around 2" from the work piece with a 3 element lens and a M140 laser or the 3 watt version. How close should we get then? At 1" i would be worried about build up on the lens even with a fan blowing the smoke away constantly. Are their any other lenses we could try?

ANYONE? No one knows of some better optics to get?

 

[CDBEAM777]

ANYONE? No one knows of some better optics to get?

Yes....I do....but....you must read the original thread to find the secret answer...Read....learn.....I mean to educate...not scold !! See this thread !!!! http://laserpointerforums.com/f65/nubm44-6w-450nm-laser-diode-94119.html

Read....and appreciate how we slowly....and collectively.... arrive at the best answer !!!

We discover the solution....and share our collective results by making many mistakes....by spending our time, money and energy !!

 

[CDBEAM777]

Several of us are looking to use DTR's new 6 watt diode for full gray scale engraving. The issue is with the standard lenses G2, 3 element, and J-Tech lenses can't get it focused small enough. Right now it only gets to 0.3mm / 0.012" and we need it to focus to a minimum of half that to be usable but would be better if it would go down further like 0.12mm / 0.005".

What are our options? Are there any options? Is there a better or different lens we can use to make this happen?

Well...after re-reading this thread....perhaps I was a bit hasty in my sermon !!

The NUBM44 is just a nasty diode...very powerful, but hard to optically correct.

See post # 199 in the thread:

http://laserpointerforums.com/f65/nubm44-6w-450nm-laser-diode-94119-13.html

As Planters noted in this thread....perhaps the junction of this diode is just too large to allow much optical correction.

I think I would switch over to the NUBM07E as a diode to experiment with. Power levels of 5W can be achieved...but then.... what duty cycle does engraving demand. Heat management may be an issue. Possible the very compact water cooled heat exchangers used by the Computer Overclockers could be employed to move heat away from the LD at extended run times.

As to optics...the NUBM07E has much better raw output properties. We have arrived at an optical solution to correct this diode. See you now http://laserpointerforums.com/f65/nubm07e-465nm-2-9w-diode-test-hitting-470nm-94437.html

Contained in the thread is what the current optical solution has been determined to optically correct the astigmatism of this diode...a G2 collimation lens coupled to a set of Cylindrical optics. But...how to get the focal point down to a dimension of .005"....that is another story.

Perhaps it may be as simple as adding a single convex lens after the Cylindrical lenses to focus the beam down. Maybe I will try a little quick and rough experiment with a 50mm EFL lens I have to see what the effect is !! All things are worth doing if there is some learning involved.

 

[micheal rosen]

though it has much less power, you may want to look into a 900mW 405nm laser. they are single mode, so they can be focused to very, very small points, likely smaller than 0.1mm. plus, the short wavelength aids in engraving, it nearly burns everything.

 

[CDBEAM777]

Well....did a quick little set up with a 50mm Convex lens to focus the beam down. Best I could get was down to 0.0075"
Perhaps a different lens could obtain a smaller focus. This was using the NUBM07E / G2 collimation lens / 6X Cylindrical optics....then the 50mm EFL convex lens. Perhaps this is the best way to go ?? Dunno ?? My work here is done.

 

[DistortedDesigns]

Well...after re-reading this thread....perhaps I was a bit hasty in my sermon !!

The NUBM44 is just a nasty diode...very powerful, but hard to optically correct.

See post # 199 in the thread:

http://laserpointerforums.com/f65/nubm44-6w-450nm-laser-diode-94119-13.html

As Planters noted in this thread....perhaps the junction of this diode is just too large to allow much optical correction.

I think I would switch over to the NUBM07E as a diode to experiment with. Power levels of 5W can be achieved...but then.... what duty cycle does engraving demand. Heat management may be an issue. Possible the very compact water cooled heat exchangers used by the Computer Overclockers could be employed to move heat away from the LD at extended run times.

As to optics...the NUBM07E has much better raw output properties. We have arrived at an optical solution to correct this diode. See you now http://laserpointerforums.com/f65/nubm07e-465nm-2-9w-diode-test-hitting-470nm-94437.html

Contained in the thread is what the current optical solution has been determined to optically correct the astigmatism of this diode...a G2 collimation lens coupled to a set of Cylindrical optics. But...how to get the focal point down to a dimension of .005"....that is another story.

Perhaps it may be as simple as adding a single convex lens after the Cylindrical lenses to focus the beam down. Maybe I will try a little quick and rough experiment with a 50mm EFL lens I have to see what the effect is !! All things are worth doing if there is some learning involved.

I just don't know enough about focusing lasers or the different optics that can be used. I have been reading, I always do but everything is so scattered. I have been talking with the guys at picengrave about this. They are looking for a solution to this as well, but they are not having much luck either.

Engraving duty cycles are very long. My last engraving was more than 5 hours. It probably averages only 50% power but hard to say. It just depends on how dark the images is. I will look into the other laser you recommended. I need to upgrade lasers because my engraving times are so long. I would like to go to something over 4 watts with still being able to engrave images at full gray scale. Any help is appreciated.

Thanks

 

[DistortedDesigns]

Well....did a quick little set up with a 50mm Convex lens to focus the beam down. Best I could get was down to 0.0075"
Perhaps a different lens could obtain a smaller focus. This was using the NUBM07E / G2 collimation lens / 6X Cylindrical optics....then the 50mm EFL convex lens. Perhaps this is the best way to go ?? Dunno ?? My work here is done.

Thanks, I do have 1 question. How are you measuring your beam diameter?

 

[CDBEAM777]

Thanks, I do have 1 question. How are you measuring your beam diameter?

Crudely !!! Very bright beams are difficult to measure...in a standard diameter...3mm +.....005"....well....that is even more difficult..... I just used a white sheet of paper....and measured the burn mark....as best I could !

No Comparitor....no Beam Profile machine.....but just a white piece of paper and a jeweler's lope. Hmmmm....just a quick and simple test.

I am not at all sure the NUBM07E LD would focus down far enough....but....having experimented with the NUBM44.....IMNSHO...
the 07E would be a better choice for u to experiment with !

Perhaps a convex lens with a different focal length ? Dunno...Good luck....and do report back as to your discoveries !:wave:

 

[RYDorDIE278]

If you click here http://laserpointerforums.com/f39/f...andheld-lasers-2-5w-639nm-released-93166.html
and scroll to the bottom of the OP, there are what Podo calls G7 lens, buy one of these also for your tests, They have different characteristics than other single element lens, I have a couple and i find them very good instead of three element with similar beam
Anyway Worth a try at $10 a pop......

 

[marcuspeh]

Not sure if this help but try to focus the beam with 2 lense.

 

[DistortedDesigns]

I bought a usb 500x microscope off ebay for $20. It does a pretty good job of getting close. I have tried a couple of different things. Generally I use something very thin and black to cut out the glare or I shoot onto a small piece of OD4 protection glass with something black under it to get rid of the reflected dot. I am only doing this at it's lowest power where you get a full beam. I think 300ma for my m140. Usb micro comes with a clear transparency sheet with super fine measuring stuff on it. Very cool.