5W FAC laser diode ( line output )

[RedCowboy]

Just testing one of the fac enhanced 5W multi mode blues ( line output ) the spec sheet looks identical to 7A75 raw divergence before the added fac of course, the raw output with it's fac is a bar but much smaller than it would be without the fac.

I set up a random lens from my collection of scavenged optics and got a nice spot @ 15 feet about 2/3 of a pencil eraser, it could be a lot tighter with a bigger/longer FL lens, this would be good for lighting the old campfire, thinking about putting one in a threaded zoom to focus head FL.

This one is doing 6W @ only 3.5A

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[RedCowboy]

I also tested one of the square output FAC blues since I have both, the output is square and does not focus as tightly at the same 5 meters with the same lens which was expected, but it cuts Popsicle sticks very well up close with even a 3 element lens and you get basically the same power reading with a 3 element as a G2 because with the reduced divergence there is zero clipping in the 3 element.

I purchased this square output about 6 months before the line output and I think they used the older model 7A75 or equivalent as
this one is doing a full watt less 5W @ 3.5A where the line output is doing 6W @ 3.5A

Makes a nice smokey fat beam.

 

[Dusty_Lenses]

Interesting diode. Hows the longevity on these custom units?

Im curious, any idea which diode offers the most power and lowest divergence outside of the a and m 5.6mm series and the custom FAC's? So many diodes out there but the beam specs appear to be dreadful on the highest power diodes.

 

[RedCowboy]

Of the common multi modes the sharp 2w is pretty good and the NDB7875 is the same divergence as the m-140 but can do about 3W @ 2.3A

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[Dusty_Lenses]

I have a 7875, and nubm08 in the mail. , minus the gball, which is next in line for lowest divergence? or are all the 5W(ish) the same?

 

[RedCowboy]

No they are not the same, use a G2 lens to compare because a longer FL lens will cause more clipping with the higher divergence diodes.

nubm08 and nubm44 are about the same as far as divergence, both produce about a 2 inch ( 50mm ) long line @ 5 meters when focused through a G2 lens. ( nubm08 with it's factory GBall lens removed )

7875 is same divergence as m-140

ndb7A75/nubm05/nubm06/nubm07 divergence falls between 7875 and nubm44

DTR has images on his page here.

 

[Dusty_Lenses]

I plan on upgrading my engraver and bought nubmo8's on ebay but the china seller sent near fully spent diodes, so im waiting on a block of new ones at the moment.

Hope this batch are within spec.

 

[RedCowboy]

The square output FAC diode in this thread is what you want, you get a tighter spot and it cuts the same speed on both axis, also it's under a window can with inert backfill so it will last.

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[Dusty_Lenses]

Yeah I looked at those, but I'm going to try a cylindrical pair first.

 

[RedCowboy]

Are you wanting to cut thicker material ?
If so you should consider CO2, your beam quality is much better and you are dealing with a round beam.
What kind of material are you working with ?
How thick will it be ?

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[Dusty_Lenses]

Im just using it for engravings on wood cutting boards etc. More experimenting with than anything, so i'll be trying some diy setups.

 

[RedCowboy]

Sounds like fun, just remember you can easily break what modern medicine can't yet fix, so safety 1st is a good policy, stick to your safety protocol, don't get complacent or allow familiarity to breed contempt.

 

[Dusty_Lenses]

I have proper certified eyewear, most importantly I know how to put them on

 

[RedCowboy]

Ah yes, but the having and knowing alone aren't enough, it's the doing that really counts.

 

[Dusty_Lenses]

Ah yes, but the having and knowing alone aren't enough, it's the doing that really counts.

This is very true.

 

[farbe2]

I build a cutter head that uses two NUBM44 diodes (i think the V1 variant, they are old).
I used cylindrical lenses to square up the beam near field and used a PBS to add a second diode.
The third diode is just a cheap 660nm diode that runs at low power. Its mixed with a dichroic.

This gives me the ability to line my workpiece up without taking the safety glasses off.
It also is perfectly aligned to the blue beam.

A changeable and adjustable focus (i tried F60 and F30) finishes the beam.
I also added air assist.

This thing is just a beast. I even cuts trough 8mm plywood (granted at multiple slow passes). I would need to get a longer focal length lens for a longer beam waist. F60 is not enough for 8mm plywood.
Fast engraving of anodized aluminum is a piece of cake.



This setup should give a smaller spot (i measured <0,05mm in both axies with a F30 lens) than FACed diodes with just one collimating lens.
The FACed diode would need two cylindrical (or more for tighter spaces) lenses to correct the astigmatism of the diode die.