Ball park G-Ball focal lengths

[charleslowryengineering]

Ball park G-Ball focal lengths

I've looked far and wide for an answer to this, and have yet not found one.

I'm simply looking for ball-park focal lengths with the G-Ball installed for the NUBM06, NUBM07, and NUBM08.

Looking specifically for one which has smallest diode image (that is to say, least rectangular) at somewhere between 30mm and 130mm.

I have already had good success using an NUBM44 and M140 with a G2 lens and I would like to find out if using the G-Ball is good enough instead. It would be tons more convenient if the G-Ball would work.

 

[RedCowboy]

They very a lot from block to block, I expect that it depends on how the OEM orders them.

I have seen prints ( the projected spot ) anywhere from 25mm x 50mm @ 15 feet to 5mm x 25mm @ 15 feet.

 

[lasersbee]

Ball park G-Ball focal lengths

I've looked far and wide for an answer to this, and have yet not found one.

I'm simply looking for ball-park focal lengths with the G-Ball installed for the NUBM06, NUBM07, and NUBM08.

Looking specifically for one which has smallest diode image (that is to say, least rectangular) at somewhere between 30mm and 130mm.

I have already had good success using an NUBM44 and M140 with a G2 lens and I would like to find out if using the G-Ball is good enough instead. It would be tons more convenient if the G-Ball would work.

It would be nice if you introduced yourself
in the Welcome section for new members and
told us a little about your self. It would also be
helpful to the Forum members if you included
your Global location in your Member Profile.

Jerry

 

[Lifetime17]

hi,
Maybe there should be a banner posted when you open up LPF to go to the welcome section before making a thread if your a new member. In nice bright bold letters for the seeing impaired. Then there are no questions needed to be presented. Just my little opinion..

Rich

 

[RedCowboy]

We will all get into the habit of directing new members to post a welcome thread, I usually notice a new member but today I didn't because this question was not a " How do I build a laser can opener " kind of question, so I didn't look at the name when I responded.
I am making a mental note to refer all laser/eye questions to the disclaimer and I usually mention safety to a new posters, really that's good welcome thread reply material.

 

[paul1598419]

This should not be your first post as others have said. It is highly recommended to introduce yourself before asking questions here. It takes very little time to do it and gives the forum a chance to learn something about you.

 

[charleslowryengineering]

Yes you're quite right. I have updated my profile and am very happy to make your acquaintance. As a brief overview I am out of Salt Lake City and have spent much of my career doing product development for those on a budget. I have my own design studio and fairly complete machine shop including anodizing equipment, 3D printers, industrial CNC mill, lathe, etc.. and a home brewed - pretty nice laser cutter/etcher.
I'm currently working on updating this Diode based laser etcher/cutter. My current design uses a NUBM44 diode with a G2 lens, both from DTR. It also uses vacuum extraction through a carbon activated filter and dual air assist. One air assist pumps directly onto the cutting surface while the other pushes filtered air past the diode/heatsink and over the lens, keeping the diode cool and the lens clear.
This system works so well that I regularly cut 3/4" MDF, as well as fine paper, etch anodized metal, and so on.
I'm updating the design because my current design is a full on/ full off design, no PWM. Also my earlier laser used an M140 which produced a finer point at focus. I like the power of the NUBm44 but I like the finer point of the M140.
I also would rather have a simple lens design. Not looking for the complicated setup of cylindrical lenses, nor would they work on a fast moving 3D gantry.
Hence the question about the G-ball lens on the NUBM06, NUBM07, and NUBM08.
Ideally a G-ball lens on a good diode will give a good enough point with acceptable power.
Question is, does a G-ball lens converge to a point at all? It should given it's characteristics. I need the diode emitter image to converge to a point between 30mm and 130mm with 60mm - 90mm being ideal.
I know there will be some compromises between power and point size, and that the point itself might be a little "wonky", but I don't want to let perfection be the enemy of good enough. Anvil reliability is critical.

Thanks for your help. As I get more answers and know where to go I'll blog the build and design.
Thanks again!

 

[steve001]

Ball park G-Ball focal lengths

I've looked far and wide for an answer to this, and have yet not found one.

I'm simply looking for ball-park focal lengths with the G-Ball installed for the NUBM06, NUBM07, and NUBM08.

Looking specifically for one which has smallest diode image (that is to say, least rectangular) at somewhere between 30mm and 130mm.

I have already had good success using an NUBM44 and M140 with a G2 lens and I would like to find out if using the G-Ball is good enough instead. It would be tons more convenient if the G-Ball would work.

Assuming this is a ball shaped lens you're not going to get anywhere near that focal length. Ball lens necessarily have very short focal lengths and are generally used to couple a beam to one end of a fiber optic.

 

[charleslowryengineering]

And therein lies the question. Is it a full ball, half ball, or something else? I think you're right that it has a very short focal length, but i'm hoping someone here knows for sure.

 

[RedCowboy]

Assuming this is a ball shaped lens you're not going to get anywhere near that focal length. Ball lens necessarily have very short focal lengths and are generally used to couple a beam to one end of a fiber optic.

That seems to be the case, maybe they are meant to be able to work coupled to fiber, this has me thinking..... could we fiber couple these diodes and merge the fibers, they would have to be the wider multi mode fiber, but then several fibers could be merged via biconic coupling ?

They are interesting lenses, and I have taken them off before and attempted to adjust the placement ( distance ) from the emitter in order to get a better far field and it seems they need to sit closer, so I cut some off the tail of the can and still it won't really focus far field, it's as if it's meant to focus tight right out of the lens and then what we get far field is after the crossover.

You can judge from the one I cut how thick the lens is, there is maybe a 1mm worth of lip on each end but the lens has a spherical shape, double convex at the least.

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And therein lies the question. Is it a full ball, half ball, or something else? I think you're right that it has a very short focal length, but i'm hoping someone here knows for sure.

I have not been able to get one out without it shattering, they are pinched in the can's end and there looks to be a roll formed lip, but they are air tight it seems and any tension when peeling the can away causes them to shatter. They could be multi element sandwiched together.

They are not a perfect ball but are ball like being slightly wider than deep it seems.

 

[deadshadow]

can we find those can-lenses somewhere without decanning a good diodes?i don't currently have any dead canned diodes but i would like to get 1 or 2 for testing

 

[steve001]

And therein lies the question. Is it a full ball, half ball, or something else? I think you're right that it has a very short focal length, but i'm hoping someone here knows for sure.

Half ball lenses are no different.

 

[steve001]

That seems to be the case, maybe they are meant to be able to work coupled to fiber, this has me thinking..... could we fiber couple these diodes and merge the fibers, they would have to be the wider multi mode fiber, but then several fibers could be merged via biconic coupling ?

They are interesting lenses, and I have taken them off before and attempted to adjust the placement ( distance ) from the emitter in order to get a better far field and it seems they need to sit closer, so I cut some off the tail of the can and still it won't really focus far field, it's as if it's meant to focus tight right out of the lens and then what we get far field is after the crossover.

You can judge from the one I cut how thick the lens is, there is maybe a 1mm worth of lip on each end but the lens has a spherical shape, double convex at the least.

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I have not been able to get one out without it shattering, they are pinched in the can's end and there looks to be a roll formed lip, but they are air tight it seems and any tension when peeling the can away causes them to shatter. They could be multi element sandwiched together.

They are not a perfect ball but are ball like being slightly wider than deep it seems.

Your photos need to be in profile. No one can tell their shape otherwise.

Any positive lens needs to be a distance equal to its focal length from the diode on order to achieve the best far field infinite focus.

 

[charleslowryengineering]

It looks like the G-ball has too short a focal length. It seems my choice of the NUBM44 with the G2 lens was not too far off.

I'm going to look around at other laser diodes which might hit my sweet spot, possibly the Nichia NDB7K75 since the Nichia NDB7875 has been discontinued. The Nichia NDB7K75 is pretty pricey at the moment so I will be looking for alternatives or see if DTR has any sources (preferred). It's pretty obvious the NDB7K75 is an updated NDB7875 anyhow.

Once I get this sorted out and the driver ready, I'll blog the build.

Thanks!