Unexplained Jagged Edges (Stair Stepping) on Laser Test Pattern

I’m getting jagged edges on a test pattern generated with JTech Photonic 3.8 Watt laser on X-carve.
This is after tuning pots, adjusting V-wheels and tightening belts (per recommendations found in forum).

The problem is barely noticeable when the test pattern is generated at 20 in/min.
However, same pattern generated at 40 in/min shows major waviness/stair stepping/jaggies, even on some vertical lines, and especially text. Is there some other variable I haven’t considered?

I tried belt tightening (and loosening) - no major impact.
I tightened and then loosened v-wheels until they barely spin per instruction - no major impact.
Lastly I adjusted X and Y G-shield potentiometers (I have original X-Carve) to 75% of max. (Really thought that would finally fix issue. But no joy!)

How far off the material do you have the laser set. Jtech recomends a 3.8 to be 3" off the material when focused.

Laser mount wiggle??? That is what increasing speed seems to indicate.

Just noticed you are only using 1 screw to hold the mount. Not good.

I spoke with Jay of JTech last week and he said I should adjust laser to between 1 and 1.5 inch focal length. Which I did to address more efficient cutting (not to address this topic). I get a much finer laser point and improved cutting. Current focal length from bottom of focus ring to material is 1.48945 inches. (Was 2.5 before change).

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I was using 2 screws with the standard mount before before I lowered the focal length. Still had the issue when focal length was at 2.5 inches.
I damped vibration with the wire shown going from laser to screw on other side of Dewalt spindle mount.
Seems pretty sturdy but I can buy in to vibration as potential cause.

I’ll make a new mount and see if that fixes the issue.

Is this project a raster project or a vector project? In raster, the laser moves left and right and turns on an off. In vector, the laser turns on an follows the lines and shapes you defined.

It looks like this may have been done in raster in which case there are settings for how far the laser advances with each pass. If this is too great, it will give the stair step effect. If it is too small, it will take a long time to finish.

This design lends itself to a vector approach which should run faster and give you smoother results.

It’s vector.

I’m designing new mount right now using a .5 x .75 x 4.25 aluminum angle. That should hopefully minimize jaggies.

Here are pics of custom JTech Photonic 3.8 Watt Suckit™ Dust Boot X Carve Side Mounting Kit adapter I’m going to make.


Dimensions for Suckit Mount with Added Holes

I made the mount shown. It helped a lot but there still some jaggies. I concluded with further testing that vibrations from the inertia generated by sudden changes in direction, acceleration and deceleration is causing the jaggies.

So for the next test I dropped the the default UGS acceleration from 500 mm/sec^2 to 50 mm/sec^2 and kept the overall feed rate at 40 in/min and got the excellent desired results shown.

So bottom line, use a stable mount and drop acceleration for laser jobs where vibration is more of a factor.
Will set it back to 500 mm/sec^2 for end mills jobs.

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Just found out about the screw conversion kit from https://mfxworkshop.com/shop/.
Seriously thinking about pulling the trigger. $550 it appears.
Would love to not have to deal with belts and the promise of improved accuracy.