I read some previous topics about banding lines and artifacts that align with the rotary axis and correspond to the splice edge. I am also having these issues currently. I have been down the rabbit hole and tried all the previously mentioned fixes (not the coding one from 4/2025). Interval size, splice, size various relationships between them. matching and unmatching step count to interval, splice, overlap, etc. Has anyone actually found a fix for this or even identified the actual root cause of the problem? It seems to be somewhat common. I spent a ton of money on a Cloudray GM-100 that i really cant use because no matter what i try I get these really nice lines in the middle of the engraving. Is this just the state of the industry? Does every laser do this? Is it certain laser controllers? certain rotary model?
I’m just trying to figure out if i wasted a lot of money on this and need to cut my loses and do something else because this for me has been a VERY deep rabbit hole
I was just looking for a user’s manual for the GM-100. This appears to be a Galvo laser.
I’m going to move this into the Galvo section to get this post some more attention.
It’s always helpful to include an image of the issue.
Commonly this is a choice of interval. Usually when the step size doesn’t match the digital motor steps. This can cause an extra step…
With a galvo, somewhere this changes from a digital to analog signal, which can also induce strange looking output.
A photo would be good…
I should also add:
Cloudray GM-100 100W
Cloudray D80 Rotary, 12800 steps per rev
I see the square… don’t see where the artifact is occurring during the splice edge. What is this stuff? It doesn’t look like it’s a crosshatch applied.
Im confused, you dont see the lines occuring ~0.4mm apart? cross hatch is turned on as per the config picture. If you have other settings you would suggest, i’m happy to try them
I’ll run one with a wider split size size and post it
I’ve used this and never had this kind of results generated by a crosshatch.
They are equidistant from each other, so that would point to step size or split size. Split size should be a multiple of the step size, so they stay in sync.
Split size is usually, or at least I do, make it a function of the lenses depth of focus (dof).
The dot size stays the same as long as you’re within the dof of the lens. So how far you can rotate between a group of lasing depends on the how deep your dof is for that particular lens.
Does this make sense?
No it does not. I know nothing about depth of focus and hadn’t heard anything about that in my searchings. I was making the split size a multiple of the step size to utilize full steps per lots of other sources on the interweb.
I agree the lines are equidistant and correspnd to the split size so they are about, if not on, the boundary of the split. How do I find my depth of focus for the Cloudray F290 Theta lens? My dot width is 0.080 which i did not set, so not sure where that parameter came from??
There are on-line calculators to help you figure dof out, I use this one.
If you have a manual for your laser source, it should give you the needed information to help you figure it out or be very close.
I’d guesstimate the spot size is closer to 60 microns. These values come from my JPT M60 M7 MOPA source. Dof about 4.27mm.
The beam from your galvo can swing enough around a curve to allow you to retain focus, that contains the same spot size throughout. You can change the focus +/- 1/2 dof. So focused in the center you should be able to move your focus point +/- 2.135mm and still have the same spot size.
If you have an item the diameter of a 55gal drum, there isn’t much change in depth when you move the drum 10mm, so a large split size should work. This way it does a lot of work, then moves the object.
A smaller diameter object will have a greater curve, so you can only follow it a shortened distance before the lens goes out of focus.
I have four lenses, so I have the spot size and dof written down for each lens.. I forget everything… 
I also do that with the co2, especially when cutting, so I can ensure the full material thickness is within the dof for a particular lens.
Hope that makes more sense…
Ok i think i get that. So my 0.402mm split size is well within that dof of ±2.135
If you focus correctly, you can increase the split size, as it’ also dependent on diameter of the object.
A large object has a flatter curve, so you an stay within your dof for more area than you can with a smaller object.
I tried to make a sketch. The center vertical green line is your 4.27mm dof. If you focus in the center of the area (black line), your maximum split size are the endpoints, in red.
These are computed maximums, but they should be close.
Hope this makes more sense?
Ok i got that i’ll work out that number and try it
Let us know if it helps solve the issue.
Good luck.
My bet is on a wrong “Steps per Rotation” or “Object Diameter” value in the Rotary Setup.
Let me explain:
The lines here are the individual segments of the splits (0.402mm in this case).
These 10x0.0402mm rectangles are being processed with Bi-Directional, Cross-Hatch and Line Interval 0.01, according to your cut settings
The gaps between the lines is your rotary advancing, what it thinks is 0.402mm, based on your input for Steps per Rotation and Object Circumference.
Solution (Hopefully):
Open the Rotary Setup window, and click the “Test” button:
The Chuck rotary should rotate exactly 360 degrees, and back.
If it rotates more than one full revolution - Decrease the “steps per rotation”
If it’s spot on, measure the diameter of the object in the chuck and update “Object Diameter”. This will automatically calculate the Circumference.
We also made a video explaining this:
I would get rid of cross hatch and change your angle to be parallel with the rotating axis for testing. Crosshatch and angle would be something to use with the “Run Whole Shapes” enabled and small individual shapes.
I agree. As explained at 3:05 in the linked video.