Increase My Laser Knowledge

I have done the CNC milling and the 3D printing, now I will step into the laser cutting a bit more. I have done some laser etching with an Ortur laser but I crave more power… and yes I know that means more responsibility yadayadayada

I have ordered the NEJE E40. With some slight research I have determined it will be a pretty easy install on the Ortur system. Just take off the Ortur laser module and replace with the E40 using the small adapter board that comes with the E40. The E40 requires 12V 4A which I am already putting into the Ortur so I should be good there.

Next step is figuring out the air assist. I understand the use of it and why it is needed. But I need to figure out how I want to make it work. I would like to use my current shop air compressor but my brain tells me I will probably have to regulate that down from the air pressure that everything else in the shop runs off of. Is that right? Or can I go full blast? Also, for the machine to control the air on/off with gcode there will have to be some type of solenoid valve or something that I can actuate with 12v DC, correct?

Someone stop me or correct me before I go the wrong route here. Ideally I would like to not have an additional air pump just for the laser, but if I have to then I have to.

Well, you could run the air assist at full pressure, but that would have the probably unwanted effect of blowing your subject work around the table.

One of the nice things about a laser is that you usually do not need a hold-down solution. The laser itself exerts no force on the work piece. (Technically rhere is a little, but we can ignore it.)

What you want from the air assist is just enough pressure to keep any smoke from getting in the way. In the same way that re-cutting chips is a bad thing woth your endmill, the smoke reduces the efficiency of the laser.

I use a very small pump that provides very little pressure for ait assist. The pump I use is marketed for things like aquariom aeration. It’s on the larfer side for that, but makes it perfect for air assist. If I had my machine in the garage, I would definitely use the air compressor, with a regulator.

The target is to have a jet of air that you can feel with your fingertip at about 1cm away from the nozzle. The pump I ha e is advertised at a bit over 1000gph, but I expect that it will move maybe 600. That’s not a lot of pressure. You can get air compressor regulators that can be adjusted for flow. I would recommend one for airbrushes.

Hmmm. Let me ask, could I not just use a DC fan directly into a reducer (cone) connected to the 4mm air tubing on the E40? All I need is a concentrated air stream no?

Air assist serves three purposes:

  • Redirects the smoke away from the lens and the path of the beam
  • Cleans out soot and particles from cuts
  • Puts out fires.

The only serious fire I’ve had with my laser setup was when the air assist line got tangles and pulled out.

I’ve seen a few shootouts comparining the different air assist methods. Here is one of them. Personally, I went with, as labeled in the shootout article, a “deluxe aquarium pump,” and I’ve been very happy with the results. He got his best results from an air compressor running at 15 psi, so if you already have the air compressor, that might be the best way to go.

The articles take on a fan is, “…the radial fan is worse than no air assist. It blows the smoke back onto the workpiece and just makes a mess.”

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Yes definitely. Very new to lasers, but @dkj4linux may be able to help. He is how i got into it. I know many are using air pumps for fish tanks. Now i am not sure if that will be enough for your laser.

My air-assist setup consists of…

An aquarium air pump suspended on surgical tubing (greatly reduces the vibration and noise)… smallest unit (60 gph) is fine

1/4" ID clear vinyl tubing to ball valve (different machine shown, same air setup… also note the 1/4" tubing slips over a short length of 6mm OD tubing)

and 6mm tubing to a printed air-assist nozzle for Neje A40640 laser module

My workpiece support is passive CPU heat sinks … better than honeycomb IMO, easily cleaned soaked in dish soap and water, supports odd shapes, any size, etc

on a sheet steel bed from big-box store… and an assortment of magnets will come in handy for stops, etc

Oh… and a drafty old farmhouse for fume control :wink:

Also, I very scientifically judge the air assist pressure by using my finger and adjusting the ball valve…

My general rule for air-assist… for cutting, wide open (full flow), for engraving, just enough to keep positive pressure in the nozzle to prevent smoke from fouling the lens.

– David


I use this one on my ortur

Thanks for all the good info! This definitely helps to clear up what I want to do for my air source. I definitely want to go with my air compressor and I will regulate it down to 15psi just as done in the Shootout Robert posted.

Plumping in the air and regulating it would not be a challenge for me, but I still think there needs to be solenoid valve that I can actuate on/off from the control board/gcode. Am I right in thinking this?

Extra air won’t hurt. So the easiest thing to do is just turn it on before starting your gcode and remembering to turn it off later. A solenoid would work well too. I’m not sure it will pay off in effort. But it would be fun to try.

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See what did I tell you @dkj4linux has alot of knowledge, look at his postings here and in the lightburn forums. He does alot, and helps alot :slight_smile:

oh wow, those are not badly priced at all!