Focus the beam on Neje 30 w. Have I done it right?


Got nice help last time and now I have one more question / information combined thought.

I have managed to make my first cuts with different results, not completely satisfied than with a little thicker and harder material such as Plywood for example.

Fails to cut through, either it will be burnt and wide edge at the top or it will be fine lines but not depth.

Have not installed air assist yet but it seems that you need it.

Question: is it to blow away the smoke or blow clean in the cut, that you use air assist !?

Following all the rules of the art, I have used a magnifying glass X10 with ND filter to be able to set the point of intersection.

I get a sharp at the edges rectangular oblique 45 degree shape, which in IRL just looks like a little dot.

My laser is a Neje 30 w, Standard and regular I guess, belongs to the “Master 2S MAX” series, so we know which one we are talking about.

In the manual I can read that the “right” height to get the right focus is between 20 - 30 mm from the underside of the laser module to the work surface.

Now that I have set mine, I do not come below 42 mm from the underside of the laser module to the work surface.

Maybe this is customary and that the rest of you have had the same experience !?

Question: What is your height?

Would be interesting to hear what you have and done about it.

Related: I have cut in fomeboard, Black 5 mm with good results, but wonder why the fome is looks like it does, see picture.

It’s 1 pass, 80 power, Speed ​​500.

If you have any comments, I warmly welcome them!

Thanks in advance, Petter greets

I’m guessing, but I’ve seen similar.

During the cut, it heats the foam insides which retract. It’s probably the ‘stack’ of materials that are causing the issue. It would be different if there wasn’t paper mixed into it.

Make sense?

Maybe there are some other ideas…

Good luck


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Was the cut made focused into the center of the material as implied in the diagram? If so, here’s my take on what I think is happening.

You might want to read a previous post from me that describes what I’ve recently discovered about cutting foam:

  1. The center portion of the foam is sharp and vertical with the paper walls because that’s where you focused the beam. The center portion is vaporized and leaves a small kerf.
  2. The parts that are retracted are due to the unfocused beam not vaporizing but rather melting the foam. This causes those areas to retract.
  3. The top and bottom paper layers don’t retract in the same way so are cut relatively cleanly and with little kerf.
  4. I’m a little surprised that the bottom portion of the foam near the paper is not further retracted… as to have a wider kerf at bottom. I suspect what’s happening is that the paper below is somehow insulating the foam or perhaps acting as a heat sink to reduce melting. Or maybe just due to adhesion the foam doesn’t pull away as much.

Overall, I would have guessed this was a 2 pass cut but I think my explanation could work.

I was unclear with the image, focus was on the table surface, new image shows it and assume that you are right with the different materials density and heat the development between these creates the strange shape of the form.

Thanks for the reply

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