I am new to CNC.
I am using a CNC 3018 PRO with a 5.5 watt laser (driver GRBL)
What (and which) are the best parameters to choose, what should I mark to cut 3mm birch plywood completely fairly quickly? I tried a speed of 400 mm/m in 6 loops, but it didn’t work.
Are there any special settings for cutting versus engraving?
Thank you for your support!
Too much speed try 200 full power 3 passes, and overall you have to use airassist
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Where i can find this option?
Additionally I’d advise that you’ve chosen a fairly challenging material and operation (cutting) as a beginner with a relatively low power diode laser.
You’ll need to have a number of factors fairly dialed in to get a quality cut including:
- material holding - you’ll need to ensure that you can hold the material down flat and secure across the entire plane of your planned cut. Any material vibration or movement across a fairly long burn time will result in misalignment or incomplete burn. Flatness directly affects focus which is critically important
- focus - this is hypercritical especially for diode lasers to get any level of high performance and there are various strategies for where to focus (depth wise) based on your operation, material, lens type, and desired effect. For now I’d suggest learning how to get a really tight focus on the surface of your work material
- lens - different lenses are good for different operations. Typically lenses with longer and narrower focal beams (G7 or G8 lens) have been suggested for cutting operations while lenses with shorter and wider focal beams (think G2) have been suggested for engraving operations. I’ve seen a trend to fixed-focus non-replaceable lenses in newer laser modules so you’ll need decide up-front in those cases what you want to do with those.
- air assist - as @killrob has indicated this is really important for cutting operations especially. This is probably the single biggest factor in getting clean burns (ie less scorching). The importance of this goes up the deeper you try to cut.
- material choice - any composite wood material including plywood will be harder to cut than a single-ply natural wood even at the same overall thickness. I think the combination of glues and the cross orientation of the wood fibers makes cutting harder. And of course different woods cut differently.
- cut settings - speed, power, passes - there’s a lot of art here that you’ll have to experiment through. In general you want to be able to do everything as quickly as the combination of all your equipment can support but there’s a cost to that in terms of quality or equipment wear. I’d prefer one more pass to blowing out my laser from running at full load but YMMV. Keep in mind that there’s a direct correlation with high power and reduced working life of the diode.
As you’re learning through this I’d suggest starting with engraving, then moving to cutting easier materials, and then progress to more challenging materials as you refine your skills. Having said that, I’ve seen some people with very tuned diode systems cutting through plywood > 10mm in 1 or 2 passes. That is by no means normal but 3mm birch plywood is certainly achievable.
Hope you enjoy your new toy.
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Please link those cause i think their diode is about 15W in output, with my 7.5W diode i can cut 8mm of Solid wood, not ply, in about 9 or 10 passes
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This is not an option this is a mod that blows air directly over the laser beam on the Surface you are cutting.
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I misremembered some of the numbers but check out this video. Some of the ones I found impressive:
10 mm ply in 10 passes (not 1-2 as I stated)
6 mm ply in 2 passes
3 mm ply in 1 pass
Cutting 10mm plywood with low budget Laser cutter - YouTube
Do you have a picture of this you can share? I’m very curious about surface finish and edge quality. What kind of wood are you cutting?
Here is a little work done
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Nice. Is that straight off the laser or has that been post-processed at all?
No post Processing, you see it as i took it off the laser 
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What compressor do you recommend and what diameter should the blow pipe be? I have a garage solution in mind, so definitely something low budget
I don’t know which laser module you are using but here is my air-assist setup for a Neje A40640 dual-diode ~15W (optical output) laser. Cutting 3mm birch ply at 180 mm/min, 100% power, 1 pass.
In action…
Uses small aquarium compressor similar to this.
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