Losing cutting power

I’m sure I read a post somewhere on here before from someone with a similar issue, but I couldn’t find it.

I’m noticing that my Glowforge seems to be losing power the further into prints it gets. I noticed this first on a long (maybe 1 hr) print that had lots of engraving and cuts. By the end of the print, the cuts weren’t getting all the way through.

Just last night I ran a print that was all cuts and only 9 minutes and 30 seconds, and by the end of the print it still wasn’t getting all the way through the material. Both of the referenced prints were using Proofgrade materials with Proofgrade settings.

Is anyone else experiencing issues like this? Is this common? I can understand the laser losing some strength over the course of a very long print, but I was surprised that there was an issue with an all-cut, less than 10 minutes print.

Additionally, I’m also seeing a more than 1/4" shift in the image post-print. Anything directly under the camera is aligning pretty much perfectly, but it looks like objects out on the far edges look like they are misaligned by almost 1/2" or more. My understanding was 1/4" or so of shift was common but 1/2" seems excessive, even with the image correction at the far corners or outside edges of the bed. I can upload a photo if needed.

Any help would be appreciated!

If your material is warping over time, it can cause this. That might happen if you cut out shapes early, because internal stresses on the woods can then be released and your interior cutout pieces can bow up.

It’s also possible that if your job is super smoky you could possibly see a buildup of junk on the lenses that might reduce your cutting power over the time of one job. This would have to be an extraordinarily smoky job, and it could indicate that your machine isn’t venting properly.

So, if it were me (generally):
I’d clean your lenses/windows before starting a large job.
I’d save cuts for last. All engraves first, inner cuts next, then outer cuts last.
Check your ventilation setup: is there good flow? Be sure nothing has gotten sucked up under the GF and is blocking your intake. Check your fan to be sure it’s clear of debris (though you’d hear that).


The qtr inch tolerance is not related to the post-print shift. In fact I don’t recall any commitments to constraining the post-print image shift.

The qtr inch tolerance is pre-print. It’s the standard that when you place it on the material in the bed image the print (cut, engrave) will be within a qtr inch of where you placed it. Typically it’s closer but that seems to be machine dependent.

I wouldn’t say that either of the prints I mentioned were extraordinarily smoky, but I will definitely give it a good clean and see if I notice a difference. It needs a cleaning anyway, so perhaps thats the issue. As far as the warping goes, could there really be that much warping or change over a ~10 minute print?

if your material is warped and you pin it down… the material still wants to warp. So if you cut out a long skinny piece in the middle, it will definitely “pop” out of the base material and go back to that original warped shape. you’ve basically cut it free of the pins at that point. You’d probably know if this were your issue.

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I’ve mainly been using Proofgrade plywood lately and there hasn’t been any noticeable warp - and it hasn’t needed to be pinned down. I’m hoping the issue is the lens just needing to be cleaned. I should also mention that the laser is BARELY not making it all the way through the material toward the end of the print and most times I’ll be able to finish the cut with a utility knife, but it just seemed like a really short amount of time for it to lose enough power to not get through 1/8" plywood.

Don’t forget to clean the windows too. The cleaning instructions are on the forum if you’ve never read them.

And he’s talking about the two little round windows in the laser path, not the ones on top of the machine. :upside_down_face:

Plywood throws up more junk than hardwoods…I use it most of the time and I have to clean more frequently than the maintenance instructions suggest.

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Is there a particular side of the bed you appear to be losing power on — not having a full cut through?

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I had similar thought on why my cuts were getting inconsistent–but I wasn’t running nearly as long of a job, but flatness of material is critical, and as evansd2 & others noted, order of the cuts and just cutting will change tension in the material, and what was flat before (esp. in center or other areas hard to pin down) are now lifting off the bed a bit. Hopefully you have areas you can put magnets in the center of the board to help keep it flat.
(And just because it’s proofgrade does not guarantee it will stay flat).

The thickness of your material will affect the apparent shift between the image and the actual cuts, too. Thicker the material & further away from the lens, the worse it will look… not to say there can’t be something going on, but it’s pretty typical… a few others have posted some suggestions to work around this becomes an issue vs. just a nuisance…

I put my material on the bed and then tap it all over the surface lightly with my fingertips. Sometimes it can look totally flat, but not be, and I’ve found it’s easier to hear it than see it. If I tap and hear a dull “thud” it’s good; I’m hitting wood that’s flat against the crumb tray, and getting the thud I’d get from tapping on the tray, but muted by the wood. If I hear a sharper “click” instead, that’s the material hitting against the crumb tray, which means there’s a gap there. I place pins / magnets until I get only dull thuds over the whole area I’m planning to work on.



Not that I’ve noticed - it just seems to be toward the end of the print each time, the last handful of cuts seem to have trouble getting all the way through the material.

I hadn’t considered that the material itself may be warping over the course of the print. I’ve used magnets in the past on lighter materials like thin cork that I was concerned the fans might blow around, but I’ll have to experiment with using magnets when cutting the plywood as well.

Also a good suggestion. I’ll have to test out my other sheets before printing.

Thanks everyone for your input and help!

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Thanks for the great help on this thread, everyone! I’m sorry your prints aren’t turning out the way you expect, @CaptainUns, and many of the tips given above should help considerably.

If you’re still seeing any trouble, however, there are some steps I’d like you to try so we can look into both of the issues you’ve reported. Could you please do the following?

  • Turn off your Glowforge.
  • Please thoroughly inspect your unit and design according to the suggestions in our cut-through troubleshooter.
    • Check the lower door to make sure it closes all the way. It may require some force to open, but open it, wipe any dust off the edges, and close it all the way.
    • Check the lid to make sure it closes all the way. Small particles of material, such as dust or debris, can prevent it from closing completely.
    • Check the surface your Glowforge is on to make sure it’s flat. Ensure it is not twisted slightly and that there is no debris propping up one side of the machine.
  • Turn your Glowforge back on.
  • We included an extra piece of Proofgrade Draftboard with your materials shipment for troubleshooting. Place Proofgrade Draftboard in the bed and print the Gift of Good Measure using the default settings. Please position this print where you usually see the alignment issues you mentioned.
  • When the print finishes, without moving your artwork or your material, take a screenshot of the workspace to show us the difference between the artwork placement and the actual print placement. Make sure to include the rulers in your screenshot and show as much of the bed as possible
  • Mac: Press Shift-Command-4 and click and drag a box around your image. You’ll find the screenshot file saved on your desktop.
  • Windows: Click on the Start Menu and search for the Snipping Tool. Open the Snipping Tool > New then click and drag a box around your image. Click the Save icon and name and save your file.
  • Send us the screenshot along with the date and time of the print and photos of the front and back of the print.
  • Let us know the following:
    • Do the cut-through issues occur only on longer prints, or on certain materials?
    • If you’re experiencing these problems on more than one type of Proofgrade material, which ones?

Thanks in advance.

I just tried to make a simple 4x5" sign out of medium plywood (proofgrade), and etching is OK, but the cut did not go thru. I did not move the board, so was able to just run a second time for cut only to get it through.

This happened last week, too, but I had already moved the material and had to flip the piece over and got reasonably close w/ the cut from the other side nearly matching the first–but it looked like each only just went about 2/3 thru the material.

In both recent cases, the material was flat & not warped–no movement, held down w/ plenty of magnets, and was a small section from full piece, so not hung up on edge of crumb tray causing any tilt…

@bansai8creations, they do not generally re-read topics that they have already responded to. Your best bet is going to be to start a new Topic in the Problems and Support section so that it opens a new ticket. :slightly_smiling_face:

Thanks Jules–I’ll do that–will be a couple days away + will reclean everything & test again.

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And don’t forget to clean the little mirror inside the head. Mine wasn’t cutting through recently (same as described above…it cut through at the beginning of the print, towards the end it wasn’t) and that was the culprit.

How did I miss that there was a mirror in there? :roll_eyes:

It’s been a little while since I’ve seen any replies on this thread so I’m going to close it. If you still need help with this please either start a new thread or email support@glowforge.com.