1/4" MDF not cutting through

Hi There. I’m still fairly new here, but I’ve been having a lot of issue with cutting 1/4" material. It started with 1/4" baltic birch and now MDF. Nothing i’m doing has helped. Glowforge says its not the machine. I don’t have 1/4" proofgrade to test it so they only see it with 1/8". The image is how it appears once I try and cut. I’m using Thick Draftboard settings. It is also way off from what the camera is reading.

I have tried cleaning, deep cleaning, changing the fan, cleaning the fan, I even ordered a new carriage plate with fan and belt just so I can say I tried everything I felt I could do. I also tried using manual mode, putting in the thickness, adjusting focus height, adjust speed and keeping power to full. I’m just lost. Please help.

1/4" is a stretch for the machine, and generic MDF is typically the worst.

It can be done, many people are using it, but you’re going to need to test to find settings that work for the material you are using. You certainly can’t expect default Proofgrade settings to work with store-bought MDF.

There are plenty of existing threads on how to find those settings. Here’s one:


I haven’t tried 1/4 in MDF, but I had a heck of a time with 1/4 Baltic not wanting to cut all the way through. It would cut in most places, then not in others. The glue up of the material is usually the culprit, on ply.

Have you tried running the project twice, to see if it cut through, on a second attempt (without moving the material in between)?

As for the alignment… Have you run the calibration?

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For 1/4" Baltic birch I run the Med Maple Ply settings with 2 passes and it works 90% of the time. There’s almost always a glue splotch somewhere that needs a knife or dremel to get through tho.

You’ll just have to keep testing. Don’t adjust focus height, use the ‘set focus’ function. Starting with the thick MDF settings, dial down the speed only in increments of 10. If you’re getting a lot of charring run multiple passes.

Also - your lines look on the fat side in your photo, are you certain the lens isn’t upside down?


one thing for sure is that pounding through MDF is going to make your optics get dirty really fast.

  1. Which Glowforge model do you have? The Glowforge Pro is better able to cut 1/4" material consistently than the Basic or Plus. That couple extra watts really shines there.

  2. How old is your Glowforge? The laser tubes are a consumable with a 2 year estimated lifetime from the manufacturer. When the tube on my first Glowforge started losing power after almost 2 years of heavy use, not being able to cut 1/4" material was the main symptom. I was able to do it at slower and slower speeds for a while, then I just couldn’t any more no matter what speed I used.

  3. One thing that helped before the tube started losing power was cleaning the lens with a q-tip dipped in 90% isopropyl alcohol and using a bit more force than usual. Zeiss wipes were not completely removing some of the film buildup from all the MDF I cut, even though it looked “clean” it wasn’t totally. There was a big difference in cutting power after it was actually clean. I also replaced most of the optics after about 18 months.

  4. Where you buy the MDF matters. They’re not all the same thickness nor do they use the same glues, so some MDF is easier to cut than others. Definitely avoid the stuff they sell at Home Depot.


Try Thick Walnut at 150 speed. Make sure your MDF is completely flat. If you can press the material and there is just a little give—it is not flat.

There’s no point in choosing a different material if you’re going to put in a manual speed anyway. Just skip to putting in 150 speed. That’s an odd speed to suggest, though, since it’s faster than the Proofgrade cut speed for 1/4" MDF on any Glowforge model (125 on a Basic or Plus, 132 on a Pro). If it’s not cutting through at 125 it’s not gonna cut at 150.


I’ve had one batch of generic quarter inch MDF cut like butter and the next batch take multiple full power passes to cut through with a super charred edge and wide kerf. It can be very inconsistent.

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I’ve never bought thick PG DB but I tested on some (large) scrap pieces of 1/8" MDF from a few sheets local big-box, all bought at the same time to use on my CNC router. Same inconsistency. Just like Lauan ply, what little I did was enough to convince me to not bother again. I picked up BB from a local Rockler, and have a pretty large stash of medium PG DB but since I started getting PureBond (5/32) from THD, rarely use that either.