Glowforge not cutting through PG Material

Hi Jules,

I see that it’s set to full power but speed of 155:

When I convert one of the engrave layers to manual engrave I see a speed of 1000 w/ full power.

Unfortunately those are the correct settings :slight_smile:️ You need GF official support.


I appreciate the help @jamesdhatch and @Jules! Will await official support :slight_smile:

Yep, sorry…had to get dinner. @jamesdhatch is correct, those numbers are close and should cut through, except for one thing - the focal point listed is a little bit high, which means that you are trying to cut through defocused.

If you want to run one other test to see if it changes things for you, try changing the Focal Point to about 0.12 inches. The actual measured thickness that I get on the Medium Draftboard is 0.123", but they seem to like to set the FP just slightly under the surface.

I’d be interested in seeing if that lets it get all the way through with the cut.

That’s the focal point mine has.

Edit: for Maple Ply - Draftboard says .125

Yeah, my default is 0.125" as well for the Medium Draftboard. I wanted to see if setting it just below the surface doesn’t get it through. I generally measure a thickness on the Maple ply in the range of … :no_mouth:

Holy Eureka! I just discovered something…

The recent batch of maple ply has significantly shifted from the early beta Maple ply thickness. That used to run in the 0.134- 0.136" range and was tough to get through. For that a FP of 0.130 was sitting just below the surface.

But I just shot a measurement on the recent batch of Maple ply that came with the machine (November) and it is only measuring at 0.121". So there might be a lot of unfocused cutting on that batch of Maple ply from a lot of machines. (There have been a lot of incomplete cuts on the Maple lately.)

I wonder if that could be causing it?

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I just did another pass confirming .125" on the medium draftboard and it made no discernible difference. For cuts prior to this issue beginning it seemed like the strength of the laser was increased for the cut, this may have simply been a misinterpretation.

I’m on the Basic model if it matters.

I removed a questioning whether to lower the focal point to 1.20. Please DON’T DO THIS. This thread tells the sad sad tale of poor @logan_liskovec whose laser tube shattered this evening.

Ugh, now I’m that guy… While it’s certainly better to be safe than sorry (as I am), could that have made really made a difference? Truly curious to understand if such a small focus height change could have caused this?

:slightly_smiling_face: No, changing the Focal Point did not cause the tube to shatter. Sometimes there are bad bulbs. Truly sux that you got one.

I’m really not sure but am curious as well. Jules just commented on your thread and indicated that it sounds like you received a bad bulb and that the GF support folk would take care of it for you.

I’d like to understand what the expected constraints are. Can I put a piece of cardstock in there and cut that? Certainly I wouldn’t expect the bulb to break.

Yes, you can, and no it won’t break the bulb. It’s rare, but there can be bad light bulbs. Have you never had one pop when you screwed it in?

Absolutely have. I typically don’t spend this much on a standard light bulb though :slight_smile:

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:slightly_smiling_face: Well, me either, but don’t fret about it - Glowforge will replace it. They are fairly complex bulbs and they take a lot of abuse during travel to get to us.

I do have complete confidence in them and the replacement. Looking forward to using it more than 16 minutes :slight_smile: Though, if we can take any good from this, it did appear that those settings were the right ones for the slightly thinner (~.121 ish) proofgrade maple that has come out of this recent batch. The ruler came right out and the first 2 of the 5 triangle accents fell right out properly too. The other 3, from the back look like there was intermittent or at least a weakening of power leading up to the failure. The 3rd one only one of the lines cut, the forth half just barely scared the back and then nothing for the rest until the end.

At least I know where to start from next time?!

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The focus motor only steps in 0.0278" units. Above 0.125" it will focus at 0.139" and below it will focus at 0.111"

That gives us 16 possible focus heights : 0.000, 0.028, 0.056, 0.083, 0.111, 0.139, 0.167, 0.195, 0.222, 0.250, 0.278, 0.306, 0.334, 0.361, 0.389, 0.417.

Per Glowforge, those focus capabilities for the unit are sufficient to accomplish its cutting function with materials <= 0.250".

So, essentially you can be within +/- 0.014" of your desired focus, and it should still cut without issue.

A very in-depth discussion can be found here:

The “Material Thickness” setting, however is different. While that is used to set the “default” focus (which is then rounded to the nearer of the 16 possible values), it is most importantly used to de-warp the bed image for better optical alignment.

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I measure everything including PG because it’s been changing pretty often on me. I don’t use PG Draftboard to prototype anymore because the thickness isn’t matching the other materials so tabs and slots need to be rejiggered for each material anyway. (My Christmas reindeer in Cherry had to be resized when I used both Draftboard and Maple.)

I’m looking forward to when they get the manufacturing dialed in and Medium means the same thing across the family of hard stuff (wood, ply, draft and acrylic). Until then I measure everything. I also made the mistake of not rotating my stock so I have pieces from a bunch of orders mixed in with each other so I can’t measure one medium maple ply on the shelf and figure it’s the same as the next one in the stack even though I just got 10 sheets in.

Measure twice. Cut onc. :wink:

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Poor onc is always getting cut up. :smile:


Thanks so much for your patience.

Unfortunately your unit has a problem we can’t fix remotely. I suggest we proceed with a warranty replacement and I’ll be in touch via email to sort out the details.

I’m so sorry for the bad news.