Hi all, new forum member here.
I have literally spent months trying to get grayscale to work properly on my machine. I have tried both Marlin and GRBL firmware, as well as various plugins and software to no avail. I was hoping I would have luck with Lightburn but this too seems to be unsatisfactory.
I initially used Marlin firmware on an Arduino Mega 2560 (clone) with Lightburn but have now switched to GRBL on an Arduino Uno (clone).
No matter what I do there is very little difference across grayscale % power - see images.
My current hardware and firmware is:
Laser diode 15w - https://www.aliexpress.com/item/33022812797.html?spm=a2g0s.90423220.127.116.11424c4ddjNaEf
Arduino Uno (clone)
CNC shield V3.51
Within Lightburn I have set the maximum power at S600 (being 60% of the 1000 that GRBL allows) to ensure I do not shorten the life of the laser.
As can be seen, between 100% and 50% at 600, 700, and 800 mm/min there is no/very little variation in darkness. At 40% there is a drop-off in darkness, and nothing at 30%, 20% or 10%. A similar thing is seen at 1100mm/min but the drop-off is at 50%.
I am suspecting that given I have used a variety of hardware, firmware, and software it must be an issue with the laser itself (or the laser driver), although it says it supports TTL/PWM.
Any help in getting it to give better results is appreciated.
On a side-note, I am also in the process of building a CO2 laser engraver which I will use Lightburn with as Lightburn is the best front-end software I have come across.
Thanks in advance.