Cutting through wood glue

Hello LightBurn Community,

What are the best practices for cutting through 5mm wood board with glue? The CO2 laser cuts through 2 out of the 3 layers, however the third layer the laser struggles to cut through due to the glue. I tried using more power but it burns the wood more with charring. If there is a tip please let me know. Have a good day!

Thank you

What power laser?

I regularly cut 6mm Baltic Birch plywood with a 100W laser and 80% power at 15mm/s speed cut through it easily with brown (not black) edges.

If you’re cutting too slow the laser might be turning down the power automatically – this got me in the beginning.

I also found that plywood with brown glue between the veneers doesn’t cut as cleanly and leaves smelly black edges with lots of carbon residue.

Thank you for your response. 50 watt laser. Speed 13 mm/sec and power 30%. I attached an image of the cut wood. As you can see its very dark brown to black and not a smooth cut.

Where are you focused at?

Thanks Blake for your response. Just below the surface.

Have you tried moving up or down a couple mm to see if that helps? I’d run some ramp tests though to make sure you’re the appropriate distance to cut through in one pass.

I tried at 19 mm/sec with same power and same results. It takes about 4 passes to cut through on some parts of the wood. Other parts there is no cut through.

Power @ 30% is going to make this a lot harder than it needs to be, depending on how your laser power supply is tuned.

Also, if you are going to do a lot of cutting, it’s worth getting a proper air compressor. It’s a night and day difference cutting with good air assist. I can cut 1/2" plywood (12mm) with a 60w laser at 70% power, 7mm/sec. (make sure min & max power are set the same if you’re cutting slow)

Thank you Oz for your response. Which air compressor do you recommend? Also, how can I tune a power supply? Thank you.

I have a California Air Tools 5510A and have been impressed with it. You need a nozzle that sits relatively close to the material (mine is 6mm from the surface) and has a relatively small opening so it can hold pressure.

For tuning a power supply, there’s usually a small potentiometer (variable resistor) in them that can be used to adjust the maximum current output. If you have a milliamp-meter connected between the negative end of the tube (the beam end) and the power supply you can see what actual power you’re sending to the laser. You adjust the supply until 100% output in the software is the maximum recommended current rating for the tube (or slightly less).

Just checking that the board is not marine/outdoor plywood, the glue they use in that is very hard to cut through, I never had any success with my 40W CO2.

Thank you Oz and Andrew for the information.