Hi community,
I’m trying to cut 3 mm MDF.
Settings I use: 400 mm/min, 100% power, 22 passes, additional air assist (a compressor with 250 l/h flow). It does not cut through all the times (I mean sometimes it does, sometimes there are uncut areas, sometimes it does not go through at all), on the same piece of the material.
Any ideas what could possibly go wrong?
You don’t say what power your laser head is. That is pretty important…
Thanks for pointing that out. It is 30 W (optical output 7.5 W).
Have you checked that you are focus correctly for cutting? Having the correct focus will make cutting easier.
I’ve been using a ‘Ramp technique’ for focusing (this one: Easy and precise Laser Focusing!! NEJE 30W laser Module - Ramp technique - YouTube) in a single pass. I fully screwed the lens in, then did five clicks to unscrew it, then found the best focal distance by engraving a single line on a ramp and finding the narrowest spot on it.
For that setting it turned to be 30.25 mm between the surface and the laser aluminum radiator.
For cutting purposes I try to focus the laser in the middle of the material, it turns to be 30.25 - 3 / 2 = 28.75 mm.
I 3D-printed a template for 3 mm thick material, so it wasn’t a measurement with a ruler or a caliper.
Sounds like you have the same issue with your machine as mine.
Don’t know how old your machine is, but I bought mine in March 2021 and 45 days later my laser module was dead. NEJE continues to ignore my emails, despite their claimed Customer Service 
and desire to make things right 
My one was bought in the early May 2021. I already regret choosing Neje vs. Ortur.
Was there ever a resolution for this issue??
Unfortunately not. I did some tweaks to the focusing tool equipment, but it did not fix the situation, only improved it a bit.
I too have the 30 watt. Haven’t tried MDF yet. Not to much into cutting but! I screwed my lens all the way in. Then ran the ramp test and checked for a thin line. I have cut some 3 mm plywood…i focus 1 mm pass the surface then second pass 2 mm…seems to work ok…might try that?
Still tuning mine. 150mm/m, 75%, 3 passes, air assist to reliably cut 3mm Baltic Birch plywood. Its a new lens and seems too short focal length for good cutting.
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For me the best distance between the aluminum part of the laser head and the surface is about 15 mm. If I put the head lower, the laser starts burning the edges of the cut instead of actually cutting. It leaves trail of 2-3 mm width. I user air assist (250 l/h).
i have the 30 watt (7.5w)too and cutting did not as good as seen online.
i did make air assist on it with tin tube close to burning point with 1 bar pressure.
wow did get better at 2 pass 100 mm/m.
no black side at burn line but not good everywhere good thrue the 3.2 mm thick multiplex.
change the standard lens with a g7 optick and now burns without problems all thrue the wood nice clean cut.
its important that the air assist good blows IN the cutting line.
even orange transparant perspex is good cutting now but without air assist.
You are not saying with 30 watt Neje has 2, an N and a A version
One cuts upto 7 mm the other upto 18 mm…
Keep pushing, took me half a year . And a lot of mail where not very friendly to saythe least.
N version is manual focus right?
A version is fixed focus I believe
I really don’t remember writing this one lol My cutting sucks even with air assist. The laser though is still running to date anyhow. I’m still trying to find a way to cut without resorting to the $260 “80” watt module. So far I can cut paper though! I did manage to cut some 2 mm ply…seems to matter a whole lot the type of ply though.
There is new payer in town with four diode’s so up to 160 watt. and offcourse the price also …
This is the neje comparison,
But whats the difference of turning the lens for focussing or the whole laser up and down?
Im also having some issues getting a good cut on 3mm plywood and mdf… I have a N40630, i’ve cleaned the lens, ive adjusted the focus and even made several 3d printed templates for the focusing (15mm from the radiator), cut 3mm wood (13.5mm from the radiator), cut 6mm wood ( 12mm from radiator) to ensure that the focal point is at the center point of the material but so far even at speeds lower than the recommended by Neje and at 100% i can’t get to cut trought in anywhere near the number of passes they claim and that you can see in lost of youtube videos!