Laser lacks power on multiple prints

Perhaps someone here can help me with this problem since the glowforge staff doesn’t have any recommendations other than “only using proofgrade material”…

I am engraving granite coasters (8 at a time). When I have all 8 coasters in the glowforge and all 8 designs scheduled to engrave, the power is significantly reduced to where the coasters look like garbage. When I delete 6 out of the 8 files the 2 coasters come out perfect. Nothing changes other than deleting the files. Then I will hit ctrl Z to make the 8 files reappear, delete 6 files again (making sure the glowforge will engrave 2 different coasters), and the next 2 coasters print perfect again. It’s only when I want to engrave all 8 coasters during one session that the problem occurs. I’ve rebooted, cleaned every lense and mirror, restarted the computer, but the problem continues to occur. It worked fine about 5 days ago ( I could engrave 8 at one time) but for the last few days I have only been able to do 2 at a time.

Any thoughts??

Are they all the same height? Exactly?

Any discernible pattern? Does the power fade as it goes in any one direction?

Where are the two you are selecting? Opposite ends of the bed? Right next to each other?

If it’s an issue with the laser, it should be able to be replicated on draftboard, or whatever Proofgrade. There needs to be some sort of controls in place to properly troubleshoot.

Same pattern, same settings, same material, all identical. When it engraves 8 coasters the power is immediately reduced from the start. I simply delete 6 out of the 8 and it works fine. I have left the 2 files so that they are next to each other but I suppose I could try at opposite ends.

I would either:

Take a look at where the red dot is falling when it scans the material before the print. It’s possible it’s setting the wrong auto focus height.

Or, change the focal height to be different than the material height (for example, .249” focal height and .250” material height). This will override the autofocus.

I doubt your actual power is changing. And that’s not something you can really discern without testing equipment anyways. Looking like garbage sounds more like a focus issue (which is somewhat power related, since it’s energy being delivered over a larger area, so - less concentrated).


I think that did the trick! The material height is .38 inches so i manually changed to to .379 and it seems to work. Thanks again!

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Pretty much what everyone else said:

Calipers and the shelf measurement feature will get your stone coasters dialed in. The issue is that these things are analog and almost never exactly the same height. Use caution when working with stone coasters for that reason, and measure everything carefully. If they vary by much you’ll see a lot of differences between each one.

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