Living hinge issues

Hey all, I’m still trying to get my sea legs on with my glowforge by trying new things. I used an extension to design a cylindrical living hinge box (I’m new to living hinges), however when cut, it seems so burned and delicate. Attached are pics of the hinge top side (cut side) and bottom side (side facing away from laser) and this sections is about 2.5" x 8.5".
It’s 1/8 birch plywood and I did use masking to “minimize” burning but I think thats all burned away. Regarding settings, I’ve read to just use the preset settings for plywood, but when I do that there are way too many sections the laser doesn’t go all the way through the wood, so I had settings set to 120 speed, full power, and focus set to .125. Are my settings too wrong somewhere, or is the design too small, or something else?
Any help or suggestions anyone can give is greatly appreciated!
Sincerely,
Cliff


I’d guess the design is way too intricate. I’ve never cut “living hinges” but had similar issues with really delicate designs.

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I agree with @eflyguy , I’ve had this happen before. Is there a way for you to increase the spacing in the extension on the cuts you are making? That should markedly help… plus that’s a pretty slow speed…

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here is a screenshot of the extension… I can change the cone height, and the diameter of the small circle and large circle, but it doesn’t let me change the spacing of the LH… I guess I can go in and do it manually (which seems tedious, but easier than creating the whole thing from scratch).

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Thinking outside the box here - set all dimensions to 1/2 (1.5 thick, 35 small/35.5 large) then double the size of the resulting design.

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Thanks @eflyguy I’ll try that. In fact, I might even go down to 1/4 scale… It’s actually a conical box maker, but I wanted it more cylindrical then conical and the size doesn’t have to be exact (for now), just trying to get my feet wet (and jeez I hate wasting wood like this, its getting expensive!)

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  • 125 speed is way too slow for 1/8" birch plywood. That’s the Proofgrade cut speed for 1/4" MDF on a GF Basic, which is more than twice as thick and dense. This slow cut speed is burning up your material.

  • Baltic birch plywood often has glue spots and patches in the inner ply that you won’t be able to cut through at any speed. As almost every sheet tends to have some of those spots, an ultra-dense cut pattern like this living hinge is very likely to lay across one, and that area won’t cut through. The fix for that is to use different material.

  • As mentioned, your design appears to be a lot tighter than necessary. There’s not enough wood left over between the slits. Try a different living hinge design/generator.

  • You shouldn’t set a manual focus height for cuts unless you want to purposely defocus the laser beam for some reason. The autofocus will be more accurate than a typed in number, and a focused beam is going to be the most effective at cuts, especially these short delicate ones.

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In general, to avoid scorching you want to run fast. So instead of slowing your cut down to get through all those last bits run a second pass.

And yes, BB can unfortunately be inconsistent in spots.

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There are examples in this post it’s in the free laser section. Search is your friend I just searched for living hinges.

Welcome to the best place to get help.

Yes I know I have a problem with spelling.

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