Inconsistent size shapes

Hello! I’m currently experiencing a really strange issue on my CO2 Laser. I was making a jig to hold square whiskey glasses, and I noticed that each square I cut out was progressively larger and larger in the X direction. The requested size is 2.9", and depending on where I’m engraving along the X-Axis, this varies. So in my case, engraving left to right, the X axis of each square measures 2.88", 2.89, 2.94, 2.99, and 3.04. Now, I engraved two sets of squares, and both the top and bottom set of squares measure the exact same. I did this again after this and got the exact same result and measurements. The Y Axis is exactly 2.9 inches every time. I am running this cut at 90% power at 10mm/s.

Here are the things I’ve checked thus far:
Mirror alignment (I know this should really affect the size of the squares with any serious margin)

Bed Level - I leveled each corner and the center of the bed to equal distances of the tip of the nozzle.

X-Axis Calibration - Though this was slightly off, I should still be making the same size square each time.

Making sure my squares are the same in software because maybe I’m just an idiot. (they’re the same, I used the arrange tool)

Belt Tension - Belt Tension is good.

Stepper Motor Step Screws - Screws are tight, pulley is not slipping.

What machine do you have? - Chinese Laser YH7050 60W with 28"x20" bed

What controller does it have? - Ruida Controller

Are you running the latest version of LightBurn? - Yes

Is the issue new, or has it happened before? - I think it’s been happening for a while without me really noticing, I usually do raster engraving work, and I typically tell the machine to run from the center of the piece. The size of the engraving never really mattered.

What kind of computer is it, and what Operating System is it running? Desktop PC with Windows 11.

Usually, I can troubleshoot my machines without much headache, but I’m kind of stumped on this one, so any help is greatly appreciated.

I just noticed the stepper motor for the X axis is slightly titled making the pulley not parallel with the X gantry. I don’t know if that could cause the issue, but I will fix that and get back with the results.

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It’s fixed! I drilled and tapped larger m5 holes where the existing ones were, since one of them had pulled through which caused the stepper motor to tilt in the first place. I also had to readjust the pulley along the axle since it wasn’t straight with the pulley on the opposite side. I re-tensioned my belt, re-calibrated my x-axis, and all is well. Hope this maybe helps someone else!

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There should be an award for folks who are willing to do whatever’s needed to fix the QC blunders delivered directly to them from the end of the assembly line.

Congratulations … and welcome aboard!


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