What is the cut 'width' of the laser?

I’m new to the laser cutting world, so I’m sorry if this seems like a somewhat elementary question. I was wondering how wide the laser cut is, essentially in terms of material waste when calculating layouts of multiple cut pieces? I have worked with carpentry and water jet tools, and with both you have a cut width that you compensate for in your layouts for material waste. This also requires a cutting head or saw offset calculation, etc. I am guessing with laser there is virtually no cut width, however I wanted to know from the experts. Thanks!


I believe what you are referring to is the Curf which I think I heard in the video is 1/8000th of an inch. either way it is tiny. The one thing to also bare in mind is there is a slight sloping to the cut due to the optics, this and the width is much smaller than a normal laser due to there optical techniques. GF should be able to compensate for this if necisary (don’t quote me on it though, I’m just a fan not employee).

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I believe that I read in the Tested video that the kerf is 0.008". As in “eight one-thousandths of an inch”. But I believe that this also depends on the material?

The kerf will change a bit based on material. Some plastics will react more to the heat, shrinking away from the beam slightly.

I cannot speak specifically for the GF. But in general for laser cuts, the kerf will depend on material thickness.

At the center of your material there should be essentially no loss of material, that is THE focal point. Then you have a very narrow slope up and down from there, forming a large (and skinny) “X” shape from top to bottom of material where you have loss of material.

So cutting paper or other thin tissues, you will ideally have the camera placing the focal point right on the paper, and be unable to tell a cut happened until you pull things apart. But doing a 1/2" material, you would end up potentially with a material loss similar to fine water jet.

Thanks everyone! This answers my question. Thanks for the vocabulary too.

Everyone’s basically got it here - in practice, the kerf is about 0.008 - 0.022 depending on material, settings, etc.


I assume GF has a measure set of kerf values for Proofgrade materials. Could this be released?

Not 100% sure, but you might have just won the coveted Glowforge Longest Necro Post Award. :wink:

As for an answer to your question, I’m not convinced they can provide it. I imagine kerf will vary with tube age, cleanliness, complete flatness of the Proofgrade, and probably a ton of other factors. Of course, I could be completely wrong. :slight_smile:


Quick…someone do a search for a hello world thread!!


Just searched for this answer as I’m cutting tabs for .25 inch material and I’m adding in for kerf in AutoCAD. I’m assuming the thicker the material the more kerf, so I’ll go with .022 and see what happens…

You should run some cutting tests - that’s a pretty big kerf, maybe twice or more. I’d run a couple of 1" squares to see what the real kerf is.

If you’re doing atr inch wood you might want to do 2 passes with the first focused on the surface & the 2nd focused in the center (.125).

So offsetting by 1/128th seemed to work good - a very snug joint at the end. Had to hammer it into place, but worked well.

But I might start another thread on kerf - it’s really driving me a little nuts when NOT using non-proofgrade materials.

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That’s my kerf on 1/8" plywood. It does differ on acrylic and qtr inch ply.


i use .014 for a full kerf, .007 for half on plywood.


Can you explain what you mean by “full” and “half?”


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I often think of half kerfs because if you take the parts that are cut, one side is 1/2 a kerf off of the line.

And happy birthday!


Ah… I see what you’re getting at.

Much thanks!!!

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