Blue Katana, a 70 watt handheld project!

[Minamoto Kobayashi]

Hello forum.
I started another ambitious crazy project called "Blue Katana", a "portable" laser with 9x NUBM44-81/NUBM47-A1 450nm diodes.
Since the beam diodes angles cannot be tilted, this will be a build suitable only for short focusing. I plan to reach a focusing range from 1/2 meter to 10 meters max.
I will use 75mm Aspheric Condensor lenses from Thorlabs inside a lenses tube.
The system will have two lenses, one fixed and another movable back and forth like a beam expander.
The head will be massive, 100mm diameter!
Every diode will be pressed on a 20mm copper barrel, and every copper barrell will be pressed into an hole made in the aluminum head with extremely perfect fit.
I will use 12x18650 VT5 hi-drain cells, 4 cells in parallel every battery holder and three battery holder in series, so I will obtain high current and high voltage at the same time.
For the momment I have already prepped some pieces .. take a look:

This is a preliminary handmade pic of the head:

This time I will create the build alone, without the help of the big guru CDBEAM777. :na:
This will be a very pricey and time-consuming project .. stay tuned and follow me in this odyssey :wave:

 

[paul1598419]

That is a very ambitious build you got there. But, I doubt you'll get 72 watts out as that 8 watt is not something every diode can achieve even at 5 amps. Plus you will have losses. But, it will be quite a huge build with a lot of waste heat, so you will likely have a very limited run time. Can't wait to see it finished.

 

[Minamoto Kobayashi]

Hmm the new NUBM44-81/NUBM47-A1 diodes have 10% more power compared to the previous model and yes, I will have <5% of total power loss, so the real output should be around 65 watt.
Enough to cut a cutter LOL

 

[RedCowboy]

That's an awesome concept, but the waste heat is going to be enormous, I assume that's just your battery tube, your head will need to be substantial.

Are you planning to use some kind of active cooling ?

Also with just a primary lens....well you said 10 feet max, it will be interesting to see how well you can get the power into one area, and are you using 9 x 18650's in 3 x 3 series parallel ?

Those batteries are going to be taking a heck of a load, you may need more.

I have been thinking about converging 3 or 5 nubm44's by using cylindrical correction on each so the focus is fixed, it's actually a pretty good beam for 2 - 40 foot burning, I was thinking the center laser would be stationary and the left and right would articulate to converge via mechanical linkage or servos, possibly mirrors and all would be positioned so that the spot/bar would run vertically and all would be on the same plane.

Good luck with your build, I hope it's a success. It sure looks like a lot of fun. :beer:

 

[trinh hong phuoc]

I see on YouTube have a video about 7xm44 laser (50w),it made by you?

 

[BobMc]

Love to see this project given life. Best wishes with your build. Looking forward to reading/seeing your progress.

 

[CurtisOliver]

This is madness. I like it.
Won't be 70W but with no doubt will be serious in power.
What is you plan to burn with this thing? Everything including Padova?

 

[lasersbee]

Interesting project...
Good luck with the build.

Jerry

 

[BowtieGuy]

That's an ambitious project, Minamoto; I'll be following your progress, good luck! :beer:

@RCB - I think he's planning on using 12 x 18650 batteries: "I will use 12x18650 VT5 hi-drain cells, 4 cells in parallel every battery holder and three battery holder in series, so I will obtain high current and high voltage at the same time."

 

[Minamoto Kobayashi]

x RedCowboy: this build is not intended to be used for more than 10 seconds,
but I have plenty of space inside the battery compartment to add a fan in the future!
I will use this kind of lens:

https://www.thorlabs.de/thorproduct.cfm?partnumber=ACL7560U-A

I could use only one lens to move the focus back and forth, but probably I will be very
limited, so I will add a second lens before the aspheric one to change the focal point.
I will use this nice and cheap adjustable lens tube:

https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=3393&pn=SM2V10#5522

And Yes, I will use 3x4 cells, but I'm thinking to switch to 3S LiPo drone cells,
because they are cheaper and they can supply all the amperes that I need.

x trinh hong phuoc: I suppose You mean this video, right?



x Alaskan: Ok If You want I can build another head for You, so the price will be lower making two of them.
But I must wait until the big CNC can be disposable again.
But are You sure that the diameter of the head and the diameter of the holes will be ok
for Your purpose?
Since the focusing point of this build will be short, the purpose will be to achieve the max power reachable.
Please have in mind that the focused spot will be NEVER seen at naked eye .. too much dangerous!

 

[trinh hong phuoc]

@kobayasy &#55357;&#56832;That is the video I mentioned, very impressive with size, they have been active for more than 10 s

 

[paul1598419]

Do you have a means by where you can measure the output power? I would be interested in what it actually measures once finished. Even with 12 high drain 18650s you will put quite a strain on those poor batteries. :crackup:

 

[RedCowboy]

x RedCowboy: this build is not intended to be used for more than 10 seconds,

And Yes, I will use 3x4 cells, but I'm thinking to switch to 3S LiPo drone cells,
because they are cheaper and they can supply all the amperes that I need.

I read somewhere that hobby/drone cells can cause the driver to overshoot because the internal resistance is so low, maybe it was the blackbuck, I will try to find the info.

 

[deadshadow]

very impressive thoughts for that build,you should definitely use some active cooling because those diodes are running very hot,today i was building a pocket 2x18350 batteries laser and set a nubm05 at 4A,it makes my 20mm copper module hot in 20s and consider that you will use aluminum after the 20mm copper modules and stronger diodes

 

[Minamoto Kobayashi]

x paul1598419: the only method will be to measure one diode at a time. My sensor cannot sustain more than 20w and my Laserbee can read max 7 watts ...

xRedCowboy: I'm interested about this LiPo issue. I do not want to fry 9 diodes all together!
I will use the classic SXD driver mounted on the back of every copper heatsink like this:

 

[Gazen]

Good luck on the project.. cooling will be tough. I look forward to seeing your results!