Interesting situation. I have a Monport with MOPA 60w JPT and when I do a material test, I can set the line interval past (lower than ) the limit of 0.001mm for a material test, but cannot program the work with anything lower than that.
There is a difference in results during the test, indicating the test settings actually does make a difference on the machine.
Thoughts?
0.001mm (1um) is much smaller than any fiber laser kerf that I know of…
Why, exactly are you doing that needs this?
25,400 dpi is pretty optimistic.
If you mean that you can go lower on the layer settings… I’m afraid Lightburn would have to respond to that… Maybe @Rick could enlighten us.
When pursuing colors on stainless, the .001 seems to become a target often enough. I had inadvertently set the material test below (0.0004) and the test settings took it. It also was WAAAY slower to finish that segment, and it did make a difference in the test result. But when I tried to replicate the result in a real setting, lightburn would not allow it.
As for the reason, …I guess because getting certain colors with the MOPA becomes an art. The kerf may be more, but the over-layering of the lines does seem to change the result
I’ve also found the interval to be a variable that seems to make color variations easier.
I’ve never tried to go this low. What it changes is the amount of heat in the metal…
You should be able to change other settings, such as pulses/mm to accomplish similar heating. Maybe this spreadsheet will help…
60watt JPT MOPA Pulses per mm.xlsx.txt (20.6 KB)
If you change the interval, such as lowering it by 50% it will take twice as long to complete the job… it will take twice as many scans to cover the same area.
We’ll have to wait for a more definitive answer from the Lightburn people…
Sorry about that…
Thanks for the chart Jack. I’ll have to look at it a bit.
I will say that it is interesting that the galvo itself seems to be able to achieve the slight variation… Maybe it isn’t really moving at all in the added lines, but simply adding heat. 
It’s really hard to tell what this stuff is doing without some kind of specialized equipment.
Using the preview and the layer, the closest I can get line increment is 0.0010mm. Smallest square I can draw is 0.01mm so I have 10 intermediate lines. Won’t show cross hatch at 0 or 90, but will show cross hatch at 45, but only the 4 longest lines ea way. Cloned layer and set as line to make a “Follow Border”
Smallest square in material test I can draw is 1.0mm Smallest line increment still 0.0010mm.
Curious if the servo/mirrors in the galvo head and the BJJCZ board can replicate this. (I understand the square’s total width is equal or smaller then the beam width).
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