Problems with Baltic Birch Plywood

Community Laser Talk
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Someone at my local Makerspace has run into a problem with recently purchased 1/4" Baltic Birch Plywood. It seems impossible to cut through even though the wood is from a reputable supplier and is advertised as “laser ready”. The issue doesn’t seem to be with the laser cutter – test cuts on other materials work fine. The cutter is a 100W CO2 system.

Has anyone run into similar issues?

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Welcome to our forum @MikeCase. Has the person on at your maker space try cutting another type of 1/4” plywood with no problems? How have they come to the conclusion that it is not hardware or User error on Software settings?

Cheers

Sas

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  1. I have never heard of or seen anyone marketing plywood as Laser Ready.
  2. Labeling aside, a properly operated and running 100W CO2 laser will easily cut through ¼" plywood.
  3. Binders (glues) absolutely affect the cutting or engraving potential, but ¼" plywood should not become impenetrable to a 100W laser. I have had some 3/4" 7 and 8 ply material challenge 140W (while other 5 or 7 ply material is sliced in one pass). But ½" or ¼", has never mattered. So for that 100W machine, I cannot imagine the ¼" plywood being the issue.
  4. It’s always possible that everything I have said is irrelevant and maybe there is some specialized binder that is killing it all. (Maybe something possibly concrete / silica based)
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We did a test cut on a couple of pieces of plywood and everything worked as expected.

The wood with the issue is described as “The thick layers of this Baltic Birch Plywood are designed to smoothly glide through scroll saws and laser cutters”.

I’ve seen an issue in exterior plywood with the laser virtually unable to get through the adhesive, but I wouldn’t have expected a problem on this type of material.

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Occoch comes close to that claim:

http://ocoochhardwoods.com/scroll-saw-lumber/

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@Stroonzo, @MH1644 According to their description it’s NOT plywood or is it glued. Solid hardwood.

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Welcome Mike
There are lots of well informed folks on here and someday I hope to be one of them
Ray

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“Laser” plywood doesn’t use formaldehyde glues. All of our local plywood distributors have products marked as being suitable for lasers.

Check the min power setting. I ran in to the same problem, and it ended up being that the laser was running at too low of a speed and was automatically limiting the laser power.

With a 100W laser you should be able to cut 6mm Baltic Birch at around 80% power and 15mm/s speed. Make min power the same as max power and see if it will cut.

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If the cut has corners (I.e. a square) setting your minimum power the same as max will give you excess burn marks in the corners.

Cheers

Sas

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You are correct - thanks for catching my mistake.

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@MH1644 it’s better then plywood it’s solid :grinning:

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Just thought I would slide in here with basically a similar situation. 1390 platform machine. Running a W6 tube, have not had a chance to do much testing yet but i was having a difficult time dialing in 1/2 BB ply. My power supply is big so I’ve been running power just based on Ma meter. Basically I think about 28Ma is right around 65% power for me. The max recommended. It looks like 7 ply. In the time I had to test I struggled to get through it at many combinations With 40psi air assist. Any certain settings or anything I might be missing?

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Use a long focal length lens. The convergence / sweet spot is longer which is better for cutting. I find that a 101.6 mm lens really is ideal for cutting while still providing great engraving quality for most work. When or if I have extreme detail, I have shorter FL lenses already installed in holders for easy and fast swapping.

Also, I cannot stress how important fume extraction and air assist are. If smoke from the process enters into / obstructs the pathway of the laser, you are significantly reducing the effective power against the material being cut.

Think of fume extraction and air assist in this manner:

  • Fume extraction to prevent obstruction from the laser tube to the lens holder
  • Air assist to mitigate obstruction from the lens to the material
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I would like to think I have adequate air and extraction. I once viewed a focal length chart showing the length the beam stayed in focus but I lost it. I’m not referring to the length required to get to focus but rather the length of the beam when actually in focus.

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Here is a good write up about the tolerances on focal length:
https://buildyourcnc.com/tutorials/tutorial-CO2-Laser-Optics-Lens-Selection-Focal-length

And another good read here:

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If the cut has corners (I.e. a square) setting your minimum power the same as max will give you excess burn marks in the corners.

That’s for testing to eliminate Min Power as the cause.

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Just an update. What I was originally cutting or trying to cut was most likely a Birch Faced wood plywood with no telling what type of glue or core. Now i have acquired some legit imported Russian Baltic Birch that comes in a 5X5 Sheet, I should be able to get some better numbers posted soon. On the 6MM or 1/4 inch class im at about 35 IPM @ 27 Ma with decent success. Ordering a focal lense with longer FL to Help as well.

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The first one’s easy to see Baltic birch plywood has about twice the number of plys as birch plywood, and usually the plys are made entirely of birch. The veneer strata are thicker, and with fewer ply layers there are fewer glue layers. It’s not as stiff as Baltic birch, but it’s also not as heavy.