Cutting "blind" spots

I’m cutting out an intricate maze using 3mm plywood (covered in blue painters tape). The vast majority of the maze is being cut using Speed 140 at Full Power. However, there are a few areas that are not being cut all the way through. Here’s a photo of the final cut:

However, if you flip over the plywood you’ll see the areas (outlined in red) that aren’t cut all the way through.

I cleaned the light path (e.g., lenses and mirrors) before making this cut. I guess there might be variations in plywood density, but I’ve not noticed missing cuts before. I tried a lower speed (120) and got similar results.

Maybe someone has other ideas??? Thanks!

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Support is not able to comment on non Proofgrade materials. As you stated, it could be variations in the plywood that is causing the issue.

To evaluate whether or not your Glowforge is perfoming properly, Support will want you to print the Gift of Good Measure on Proofgrade material using Proofgrade settings. If it doesn’t print perfectly, post photos (front and back) along with the date and time of the print so that they can access the machine logs quicker.

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That is almost certainly either a void or glue spot in the plywood. It is quite common. There really isn’t anything to be done for it other than avoid it in the first place. Shining a very strong flashlight through the wood can often show you where the spots to be avoided are.

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Thanks! That would explain why the uncut area(s) change from one piece of plywood to the next. I just thought that slower speeds would take care of density changes/glue spots, but, so far, that hasn’t worked. The maze I’m trying to cut out is about 11" x 11" and I’m starting with a 12"x12" piece of plywood. It’s going to be tough to avoid the glue spots. I’ve been finishing the cuts with a thin diamond wire so I have an ultimate solution, but it’s very tedious.

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Some glues are somehow annoyingly totally laser proof (cheaper plywoods that use Bondo filler especially)

If you’re close to cut through try hitting that backside with a small sander, like a palm or orbital.

PS> If you’re making lots of these get yourself some 12" wide masking, it will save you a ton of time vs lining up that blue tape and be cheaper in the end.

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I’ll also recommend that if you’re making a ton of these it’s worth getting plywood that doesn’t have voids. Proofgrade doesn’t - but there are other suppliers of good quality stuff out there too.

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Thanks! I moved to 12"-wide blue tape that seems to work better than the paper film. I plan to make only 4 of these.

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Thanks for the link to higher-quality materials!

That’s quite a maze! Looks cool!

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I purchased the cut file from here (in case you’re interested):

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There’s a trick for 1/8” plywood.

Might help in the future.

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Awesome thanks!

That’s really helpful! In my current situation, I can’t really cut around inconsistencies in the plywood since I’m using just about every square cm of the piece. Luckily, I only need to cut 4 of these mazes and I’m using a superfine wire saw:

to finish the areas that aren’t cutting all the way through. It’s tedious, but doable for the relatively short distance that needs the extra work.

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JUst a few thoughts… I have not used any of the new light ply by GF, but I have used a similar product and it is likely you wont have this issue with these. They are, I beleive, made with lasering in mind. You could also consider a poplar ply. That might be thinner and you might avoid the issue there. I have the issue with birch ply but not poplar. Perhaps the careful use of a Dremel type too could hep with post processing when needed.

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What an interesting tool find! I’ve done a lot of Exacto blade cutting to get a handful of partially cut puzzle pieces to come out, I am definitely going to take a look at the superfine wire saw!

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Micro mark makes tiny saw blades for xactos that you might enjoy.

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Thanks for the link! I’ll give them a go sometime. The wire blade seemed like a good idea, but I think that a diamond one would clog up on wood fibers too fast, and I looked around the google and couldn’t find long saw bladed wires. Oh well, this could work too!

Yes, I’ve tried the MicroMark blades and they do a fine job on the straight lines. Unfortunately, this maze has so many turns I found the diamond wire to work better. The wire is a bit brittle so it can break on occasion, but it didn’t clog up with wood fibers.
Just a follow-up on the plywood material. I found this project board at Home Depot that cuts great with no skips.

https://www.homedepot.com/p/Handprint-Birch-Plywood-Common-1-4-in-x-2-ft-x-4-ft-Actual-0-195-in-x-23-75-in-x-47-75-in-225449/206120891?MERCH=REC--rv_homepage_rr--NA--206120891--N&

It rough-cuts easily with a couple scored lines on both sides and then snapping it off over a countertop edge.

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Hi @dwburger - I think our community folks are right on the money here in regards to this being an issue with voids in the plywood, that’s unfortunately not uncommon.

I hope you’re able to get this project completed, that wire seems like a great tool!

I’m going to go ahead and close this topic as the issue has been addressed