Wavy lines and scan offset problems

I have an 80 watt co2. Today I have notice wavy lines when engraving in line mode. Also the scan offset is way off when engraving in fill mode.
I had done a test and entered the results in the scan offset adjument section and it was working fine.
Both issues cropped up at the same time and yesterday it seemed to be working fine.
This is just a test piece.

If you slow things down do you get the same result?

Your wavy lines remind me of this from our job quality troubleshooting page: Troubleshooting: Wiggly Lines At Corners - LightBurn Documentation

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Perhaps LightBurn was inadvertently switched from mm/s to inch/s units, in which case the machine will be trying to run much much faster than it used to, limited by the controller’s maximum settings. Higher speeds will produce mechanical shakes and also screw up the Scanning Offset adjustments, which matches the symptoms you describe.

The unit selections are in Edit → Settings:

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The lines were at 210/18 and the fill was 200/20. Originally I was doing it faster but slowing it down didn’t seem to help much.

I almost always keep everything in mm. Too confusing for me to switch back and forth. I may just try to repeat my scan tests.

You need to snug it up… this is mechanical slop as @JessN mentioned and posted in the link to the link ending up here.

If you’re doing the same thing in line mode, why do you use different speed/power settings?

:smile_cat:

That reminded me, I greased the rails last weekend. But like I said the issue just showed up yesterday.

I tightened up the belts but that did not help. Then I changed the font and it helped a little. But you can still see some waviness to the horizontal lines.
The pic on them.eft is before tightening the belt. The pic on the top right is after tightening the belt. The pic on the bottom right is the different font.

This is a mechanical issue… If you notice the squiggly lines are the same as anything that overshoots. It’s especially noted in electronic signals… same idea.

image

This is an electronic ringing, going the opposite way, same way for a mechanical overshoot. The ringing is dampened as it continues.

image

They can be too tight and also too loose…

:smile_cat:

Which belt did you tighten?, The wobble looks like it is in the Y axis, so it would be the Y axis belts that would have to be tightened. But I’m not sure that it is the belt. Check that the laser head assembly has no movement if you wiggle it front to back, and check if the focus lens is secure. If something it is not right this can show up especially during acceleration.

200mm/s is very fast for engraving text, try going 50-100.

Anything loose will cause this… including head, lens or any other part with mass can cause it or exacerbate the ringing.

:smile_cat:

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The belts seem plenty tight now to me but I’m no expert. I’ll check the other components.

I did the x axis. I’ll check the y axis.

Like the three bears, they can be too tight, just right or too loose…

Wish I could tell you a technical way to adjust these, but it’s a trial and error situation until you do it enough to get the feel for it… all I can suggest is move the head or gantry a bit and feel the moving resistance. As you tighten it, it will become more difficult to move… Try to shoot for middle ground. Good and snug, but not too tight…

Good luck

:smile_cat:

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