Lining Up Circles for Fourth+ Passes

Needing to do about 5 passes to cut through some plywood on some coasters. The print has some engraving, etc in it, and when I mark all of the extra stuff IGNORE and just try to cut the final circles a few more times, I don’t ever seem to get it to totally match again. I haven’t moved the wood in the GF, but I’m not sure if the focus shifts or whatever.

Is there a best practice so I don’t have to turn those other elements on and off again AND also keep them in alignment for a fourth+ cut?

Ignore the camera, if you haven’t moved anything or powercycled your glowforge, it’ll be spot on.

If you moved the material or your design in the UI or if you re-homed the glowforge for any reason (most likely turning the GF off and back on) it will probably be slightly off.

As stated, the machine is repeatably precise to 1/1000", and focus doesn’t change that.

However, a simpler solution is to simply add 4 more copies of those circles in your design app.

If you make them different colors, you can then choose how many to cut in the GF workspace.

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HOLY CRAP - Freaking Genius. Thank you!!!

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The other possibility is that if you find yourself making that many passes it’s that you may just using the wrong sort of material for this type of laser. I know the specs say up to half an inch thick, but that doesn’t mean it’s even remotely ideal. 1/8" is definitely the sweet spot for most materials in terms of reliable cutting at fast enough speeds to minimize fire risk.

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If I recall the one half inch came from doing 1/4". deep from one side and then having the camera magically realign to perfectly cut the second 1/4" from the back. This I believe was from the pre-sale advertising. I do not recall marketing ever saying that 1/2" material was possible from one side. That was a while ago…

I’ll say that 1/2" is possible, cut from one side, with the right setting and as long as it isn’t a ridiculously dense wood. I can cut 1/2" basswood and cherry hardwood from one side using 3 passes, full power and slow speed. If you’re using a super hard/dense wood, or something super thick, 5 is still a lot of passes. But I see you said plywood… That seems incredibly odd. How thick is your wood? Do you have the power high enough and the speed low enough, without burning?

I have not found the density of the wood to be a problem but I have found the flammability to be a real issue. Half inch maple or walnut can be cut in two passes if necessary but 100 speed and full power will not set them on fire. this is not true of many other species that even if they do not burst into full flame will still allow an ember to live long enough to turn the whole piece to ash.