Brand new Glowforge Pro… Using 3 passes to cut cleanly through 1/8" plywood.
The machine is jolting a bit and cutting each pass in a slightly different position. (About 2 thousandths of an inch over in the Y direction.) So the cuts come out as a series of parallel lines and do not cut all the way through.
It seems to only happen on a file with about 30 minutes of engraving that happens first, and then it screws up the cut out lines in the last few minutes of the job. I’m using small rare-earth magnets as hold-downs so I know the material is not moving.
Glowforge support staff will probably ask you to cut the Gift of Good Measure on some proofgrade draftboard. That will help them see if it’s your material or the machine.
You definitely shouldn’t need 3 passes to cut through 1/8" plywood… however, all plywood is different. The plywood you have might need different cut settings than you’re using to get through cleanly. Here’s a popular method for testing new material:
You also might try without your rare-earth magnets as hold downs… I’ve heard some say that magnets can sometimes interfer with things inside the machine… so on the off chance that’s what it is, maybe try without them. Cut some honeycomb hold down pins.
Good luck! If we can’t help you, support staff will come along likely sometime today and sort you out.
Thanks for the reply, I’m able to cut all of my other files just fine, including some that are the same size and shape without the engraving. Some of my parts have the engraving and some do not. For some reason the one with the engraving is messing up the CUT after it successfully makes the engraving. Also I did not use magnets the first time it screwed up. That was only after the first failed attempt because I thought it might be due to material moving. I have experimented with cut power on this plywood and full power + full speed + 3 passes seems to give the cleanest and fastest results. If I cut slower with less passes it burns the edges more.
Have you tried doing the engraving and ignoring the cuts. When that’s finished, just doing the cut lines? Doesn’t seem like it would make a difference, however, you indicated without the engraving it seems to cut fine so worth a shot.
I have noticed sometimes when running the laser at a high speed the it does seem to “jostle” the machine - and while that hasn’t caused me any alignment or positioning problems, I could imagine it could.
Particularly if your belts are loose. Maybe check belt tension?
I also agree with @rvogt 's suggestion. Do the engrave first (ignore the cuts in GFUI), then ignore engrave and just do the cuts (without moving anything inside the machine).
This shouldn’t be necessary, but maybe worth trying to see if it works any differently.
Sometimes full speed just isn’t the best choice. Sometimes it’s actually slower depending on how it calculates the acce/decel plan.
While it does try to plan for this, sometimes the planning isn’t perfect (on any laser), and the motors just don’t have enough holding power for which causes slipping/lost steps (extra steps actually), and lost positioning. It wouldn’t hurt to check the belt tensions to make sure they are ok - they don’t need to be super tight, but they don’t need to be super loose either.
If this is a pretty intricate design, it’s likely never obtaining full speed anyways. So your full speed setting is probably somewhere way less. As is your power setting, since it’s trying to lower the power to accommodate the speed. I would recommend a little bit more experimentation something like 300 speed perhaps. Or 250. It might even make the job faster actually, and just as clean.
I agree with the speed theory… I’ve definitely encountered hard “thunks” at higher speeds when there are sharp edges in my design. Try taking your cut/score speeds down to 300 or below and see if the problem persists. If it does, you may need to tighten your belts.
Hi @blake4 - I’m sorry to hear you’re running into this trouble.
If it’d be possible to snap a photo of your prints that had this issue I’d love to take a look and review, this might help me get a better understand of the underlying issue your printer is having.
If you end up doing the test cut that @rvogt mentioned I’d love to know how it went as well.
Additionally, could you try the following ?
Turn off your printer
Using both hands and touching the metal surfaces, smoothly guide the arm forward and backward across the printer bed, paying attention to any areas where the arm feels stuck, jumps, or has a noticeable change in resistance.
If you notice the arm seeming to get stuck inspect the sides of the laser arm to see if you can spot anything that the arm might be catching on.