This problem is recurring theme. Here is the one where collective of this forum tried to help.
At the end user chose to swap the laser with different model and problem went away. (To me it does not mean that problem is with the laser, rather laser is not a good match to specific controller and its settings.)
Myers, I suggest you carefully read whole linked above thread and try to correlate with what you see and done so far. Note first calibration grid where slower speed have almost no noticeable Moire. It become worse with increased speed.
I’m absolutely certain that this is the same problem. The way moire overlayed and followed side edges - this is the exact same problem.
There was a few more threads of the same/similar issue (where I did not post any comments).
I guess it would be beneficial to all to finally understand root cause of this.
First of all: what are you burning? Appeared to me white paint over MDF.
Have you ever seeing burns from your machine that looks good, meaning without Moire?
My main bet is PWM frequency is too low. That is $33 settings. As lasers getting faster and more powerful - manufacturers trying to increase PWM frequency to increase bandwidth, that is time constant of laser power control filter and resulting delay/latency.
How this happened? I think I have observed pattern (of behavior) here (on this forum) where users somehow blow original settings. That can be unsupported by LightBurn variable type of some controllers (i.e. $22 in GRBLHAL is scalar, not a boolean as LightBurn thinks), or maybe some other variables as well. Maybe user unknowingly applied some other settings.
Before trying anything, can I ask you to save your most problematic work as g-code and post it here. I would like to try to see if there is any chance that Moire is in the g-code. It is unlikely, but to leave no stone unturned - worth trying.
-
My first suggestion would be to play with $33 setting, that on some controllers is PWM frequency. Read it first. Then increase, maybe in 1KHz steps and see the results. It is a probability that controller support only discreet set of valid values. Try 5000, 8000, 10000, 20000, 50000 and 100000. Old GRBL default is 1000 (1KHz), many new controllers now are 5000 (5KHz) default.
-
It might be impossible to apply these settings with LightBurn (variable type conflict). Try reset to defaults. Issue command in terminal “$RST=*” (remove quotes). Here is more about GRBL settings reset. you may want to save all settings first, just in case.
3.Try to disable “dot width correction”, see here. This is very speculative, but would be nice to see the effect.
-
Have you run power/speed grid? Anything interesting to note?
-
You definitely have severe interlacing problem (usually indication of slow laser. Hmm). Try to disable bidirectional burning, do only unidirectional.
Myers, I like to specifically ask you to not disappear, to try above and report the results and any other discoveries. I believe there is definitely public benefit to finally resolve this problem as it started to occur more frequently.