Stepper Motor Gantry Wheel Issues?

Hey GF!

I have been struggling with figuring out proper belt tightness time and time again but unsure if that has actually been the issue or not.
The designs I’ve been pulling out of the laser engraved lately have all looked ‘stretched’ or like it has been skipping. (Photo for reference)

I did a bit more looking around and it looks like maybe the grooves on the left x-axis gantry wheel may have some grooves that have melted? (Attached video for reference)

Trying to pinpoint it all and can attach more photos of the machine and the ‘gift of good measure’ in the next day or so.

I don’t keep the lower door fully open, I have a solution for that so debris still goes out of the rear with an in-line fan.

You think it may just be the belt?

My machine looks just as bad right now. I was a repair tech for long enough to be very leery of “deep-cleaning.” The important bits are clean; the rest is just aesthetics, and that could very well be the case here also. (As a matter of fact, you can see in the photo that the rails and top of the head are clean.) And don’t assume that just because the door is open in the photo, it was open while the job was running. The lid is up too, and you didn’t jump to any conclusions about that.


It’s definitely a mechanical issue. The simplest would be that the air assist is hitting your material during the print and pulling the head out of alignment. If that’s not it, then I think you’re on the right track looking at the belt / pulley wheel as the next likely suspect.

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@geek2nurse thank you for your positive help!
As for the air assist, the material only measures 1.10” and I have to use .5” to raise it to engrave-able height, so my caliper reads:
1.6” before engrave.

(Something to note: it only really skips on engraves, I do not really notice any skipping on scores or cuts)

I’m still trying to make sure I properly tighten the belt using the step-by-step guide by Glowforge, where the right gantry wheel gets fully extended with the belt on it then tightened.

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Interesting. What sort of engrave speeds are you using? Might be worth trying lower speeds to see if that helps.

But first, do a Gift of Good Measure on PG with PG settings, and post that, so Support can help when they get here – they can’t really help with non-PG stuff.

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I’m quite OK with @geek2nurse on this 2 points. unless I am mistaken, it is impossible to do a job with lower door opened.

I have had the idea to try this one time and there was an error message to close the door before starting a print.

There are ways to print with the front door open, but it is not approved by Glowforge. Search Beyond the Manual and you may be enlightened.

Here are the Gifts of Good Measure.
I did one above the other to see if there was a pattern to the flaws, but unsure.
( And yes the lid is up :joy: @geek2nurse ) haha

Does something like this look like an X-Axis related problem?
I have never loosened or tightened the
Y-Axis wheels as I do not want to run the risk of making them too tight or loose, but if I need to to fix this problem I can.

That sure looked like a nice project you were working on. I hope you get it sorted out and can post some pics of a finished product.

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Here are some photos of carriage plate.
The one thing I see out of the ordinary is photo #3.

I circled the center bolt where it looks like the belt has been rubbing up against it.
The belt does not have any cracks but has discoloration on the bottom where it has rubbed against the bolt.

Your belt is too loose. If it’s relaxing enough to make contact with the screw on the carriage plate, it loose enough to skip. Couple that with high-speed engraving and you… well, you see what happens. :sunglasses:

The belt should be tight enough that, with light pressure, you can press together the lengths of the belt that face each, but only when your fingers are positioned 4" or more away from the pulleys at either end of the belt path. At distances less than 4", you should not be able to press the belt lengths together without exerting a lot of pressure.

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@yoyodyne2112 okay!

So in regards to tightening the right X axis wheel, I was trying to stick to the glowForge recommendation of extending it with the belt attached and then tightening.

Do you recommend extending the wheel fully and then slipping the belt over after?

(I guess a better way to ask is how much of a gap does the wheel have from the right side?)

I prefer to loosen the idler pulley so that it slides under moderate pressure. There is no set distance that the wheel should be in relation to the gantry support, the final position is completely dependent on the length of the belt (which is supposed to be 1176mm), but if your belt has been skipping or being overtightened, it may have stretched and is now longer than normal, a condition that would also lead to more skipping and tension issues.

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Did you forget to include them? I don’t see a photo. :slight_smile:

Very nice!

Hello @gkbowtique - I’m sorry to hear you’ve run into this trouble.

But it looks like you’ve received lots of great help from folks in here, I love to see that!

I believe everyone is right on the right track here as far as where your trouble is stemming from, in regards to the belt being overly loose. It’s possible the belt may have become stretched and we can always send a new one your way if you’d like to try and see if that helps.

As @geek2nurse had mentioned it doesn’t appear the photos of the Gift of Good measure came through, do you mind adding those?

Also, please let us know if you’re still struggling with tension after the steps @yoyodyne2112 had shared.

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Here is after tightening a bit more!
I may have overextended the belt as I previously extended the wheel fully to the right, tightened it down, then put the belt on.