New addition - neje A40640 w air assit; working well

I added a neje A40640 dual diode laser to my MillRight Mega V XL Router/Plasma CNC. I love it !
Install was relatively easy as my system has Arduino mega2560 board so Spindle PWM pin is ready and waiting for hookup.

Once working, I spent time getting the focal length dialed in, I started at 22mm from the bottom of the heat sink as neje diagram shows. However, that was not very accurate, the focal length was only 17mm. So I adjusted the brass lens ring, a full 1.5 turns in (towards the diodes), in fact it is fully adjusted to full stop inward when finished. I now have 22mm focal length from the bottom of the heat sink. The beam kerf is about 0.005 in. or 0.1mm, which I believe is excellent. Surprisingly the beam is square. Then I proceeded to cut some 5mm luan plywood. It cut perfect, in only 2 passes, at 350mm/min @ 95% power with air assist, 40PSI at the supply, and I had 50ft. of 3/8" ID hose, then 15ft of 1/8" ID hose, and then a beam concentric nozzle with a 2.5mm dia. exit port. The focal length from bottom of nozzle is 5mm, tight but OK given the results it produces. The cut shapes fell right out of the base sheet. The cuts I made were 3-5 mins in duration and the temperature of the unit ran a consistent 33-36 deg C.

Thanks to @ dkj4linux for providing the design and stl files for the beam concentric air nozzle. NEJE 30W/40W air-assist nozzle by dkj4linux - Thingiverse

And shout out thanks to @ TomWS for printing the nozzle for me.

Here are some pics.
After cutting the test circle, I proceeded to make some laser/router hold down clamps and a circle template for plasma hand torch use. The laser is magnetically mounted to my Z plate, using same Z/X registration points as my router and plasma torch. Its an easy switchover between processes.



I would think you should be able to do better, I can do a 0.1mm dot with my co2. I thought the led made a smaller spot…

Here’s one of Russ’s files that may be of benefit to your testing…

It’s a group of dots that are 0.1mm grouped. You need to use the zoom-to-frame-selection to see it after you load it. :slight_smile:

dotSize.lbrn2 (4.9 KB)

Good luck



just an ot question… can i see your plasma torch? you use it like laser module?
brand and model of the plasma?
sorry for questions and ot :slight_smile:

Lou has posted most of his plasma work here. Search for “plasma cutter @bLouChip

ok there is also plasma at work?

@killrob, the search @TomWS recommended will resolve to all my postings for ‘plasma at work’, including the torch. Let me know if you have other questions, I’m happy to help.

You’ll also find it on my youtube channel bLouChip Consulting - YouTube

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i wanna try to build a plasma cutter and any help will be appreciated :wink:

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@jkwilborn, thanks for the test pattern, I ran it yesterday on a sheet of white 20# paper, which was my original test and calibration material. It was a hurried test so I have more review and double check of measurements, but as I recall the 0.1mm dashes where easily discernible without magnification, and with a 6x loupe I could see easily that the ‘dashes’ were effectively dots slightly smaller than the spacing between them, which were also 0.1mm in the drawing. And considering that the burn of the paper makes the effective dot larger, I’d say I’m at or very close to the neje specification dot resolution of 0.04mm at my focal distance of 20mm (not 22) from bottom of heat sink and 5mm from bottom of nozzle. I even varied the power on 3 runs of the test pattern to mitigate the paper burn as best I could. I’m going to get a few squares of white tile and try it again, certainly the material matters.

Thanks again for the clever test pattern.

I’ve found it useful, glad it has helped you.

Take care


Hey Lou, im looking to add this laser to my mega v, I’m curious about the wiring. I understand the laser needs to connect to the millright board via the PWN port & GND. How did you pull the 12v power to the laser without plugging in the 12v wall plug adapter?

@Arctic_Laser , I did use a 12VDC power brick plugged into 120VAC.

If you are referencing photos or videos I have posted, from the 12VDC lead off the power brick I connected to shielded 18 ga. 2 wire cable and ran that through the drag chains to the Z carriage, then connected it to a 4 pin aircraft connector along with the PWM signal and Arduino GND ran in on a separate shielded 22 ga. 2 wire cable. An 8 inch 2 cable pig tail is connected to the laser LED/mode switch module, which then connects to the aircraft connector. I run both pig tail cables through an RF choke for EMI/RFI mitigation.

Photo library here 2022-Jun Pics - Google Drive
I had another request of similar info and will post a short video on Monday.


laser install video for MillRight Mega V series CNC is posted in my shared folder 2022-Jun Pics - Google Drive

see the video ‘MVP bC NejeA40640 install.mp4’

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Great info Lou, thanks for taking the time to do that. I’m still learning electrical so this helps me a ton. Great work!

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