[SOLVED] Not cutting through 1/4 maple all the way

Hey y’all,

So I recently ordered some maple plywood through Etsy that is 1/4 inch thick. I masked it and ran it through my machine to do a large job, and much to my chagrin when the job was done I flipped it over and you see the little dogs where it almost cut all the way through, but didn’t quite make it. Like you can see the outline of the back of the cut shape in little points on the back but it didn’t get through enough for me to pop it out.

After many hours of trying the following settings I eventually got a very sloppy cut through but it burned around through the masking and looked pretty unprofessional.
Here are the things I tried:
1: told the machine it was thick maple plywood proofgrade, which again almost made it through.
Then I selected non-PG material and did the following:
2: set the thickness to .375 inches and the cut to 500 speed and full power at auto focus. This didn’t work.
3: set the thickness to .375 inches, cut speed 500, full power, focus height .375 inches. This didn’t work.
4: set the thickness to .5 inches, cut speed 500, full power, focus height .375 inches, e passes. This again almost worked.
5: set the thickness to .5 inches, cut speed 500, full power, focus height .5 inches, 3 passes. Finally this worked enough to pop it out, but it looked very rough.

Any tips or ideas on what’s going on?

Thank you!

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Most plywood has an MDF core, and that can be very difficult to work with and 1/4" is about the limit of the machine. All you can do is test to find what settings work for what you have on-hand.

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One thing to note from your comments - “thickness” sets focus height. If the material is .25" thick, that is what it should be set to. Otherwise your laser is focused above the material which drastically reduces power at the surface.

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Good to know, I was setting it at a higher thickness with the hope that that would cut deeper.

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Using custom settings can be a bit confusing at first. Glowforge wrote up a guide about how they work and I followed up with a guide to testing settings. You can find both posts here in #6:

It seems like you’re digging in to some of the capabilities of your machine, you might like some of the other topics in that link as well. The forum has so much good info.

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You were on the right track when you used Proofgrade settings for thick maple. When that failed, you should have slowed your speed slightly . Increasing the speed reduces the time the laser is focused on any one point of your material and therefore reduces the ability to cut. Changing the thickness means you were trying to cut with a beam that was not focused. You will be well served to read through the materials @evansd2 has suggested.

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You know, that’s not how it works but it makes some sense.

It might be interesting to have an interface where you describe your material and are given (approximate) Glowforge settings.

I’m not sure it could ever be reliable with all the possible variables, nor do I think Glowforge will ever support non-PG materials like that but @Josie’s thought process was interesting.

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that’s exactly how the universal material settings work.

you pick a broad type (wood), then a specific type (maple) and then a material thickness (.125") and then the UCP (universal control panel) gives you suggested settings. it’s a huge database of materials, so lots of good starting points that usually work.

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Yeah that’s why I think Glowforge would never do it. “Usually work” isn’t how they’ve positioned themselves.

… and of course they really want you to use more proof grade. I don’t see a good reason for them to encourage other custom settings, and neither do they (obviously by looking at all the ways they distance themselves from non of materials and settings).

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this is the real reason. their profit model is based at least as much on materials as it is on the machines themselves.

personally, i’m not that fond of the PG plywood. the prefinish is inconsistent, imo. and not smooth, like it is when i put a finish on. the acrylic is fine, but more expensive than other vendors.

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My biggest issue with pg ply is the mdf core. I find the edges unattractive.

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This was the ticket! I slowed my cut speed to 150/Full power after numerous attempts with other numbers and that was the perfect speed to cut through the material and the front and back masking without leaving scorch marks under the masking. Thank you @dklgood and everyone else for your help. I’ll definitely be reading into more of the information sent along in this thread.

I hope y’all all have a fantastic day, you certainly made mine!

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500 seems too high for cutting. I cut my 14" at about 175 speed, full power 1 pass. Cuts every time. Good luck.

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What type of machine, pro/plus/basic? “Full power” is different depending on the model.

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Mine is a plus.

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When did you purchase? The Plus originally came with the same 45W tube as the Pro, but they dropped it to 40W a few years ago.

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I need to correct the setting I gave. I do the 175 speed for thick card stock. For the 1/4 inch I do around 150 speed. Sorry about that.

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Are you sure about that? Card stock is thicker than paper, but 175 full would burn it to a crisp. I tend to do mine at about 350/65.

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Mine is a plus (45 watt) and 150/full power is the exact setting that cuts through the 1/4 Cherry plywood I have with basking on both sides.

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Good for you! Thanks for the feedback on what you discovered.

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