I’m interested in finding out the duty cycle of my Snapmaker Ray with 20w diode module. I’m working in Greyscale mode.
I’m not quite sure what info or question to start with.
Do I begin with the Dot size (0.1x0.08), The duty cycle eg 1000 (milliseconds) for the Freq, Exposure duration, and the Speed setting…and should I be calculating in Seconds or Milliseconds.
I’ve been watching Russ Saddler and not taking notes but I do it that way because it helps me eventually, to get a deeper understanding and learn other nuances and also the notes are never to hand when I have a detail to check during thought experiments.
To break it down further, most diode lasers operate at a PWM frequency of 1kHz, sending 1000 control pulses to the laser module per second. Some firmware and chipsets combinations allow change to this, I’m not sure about the Snapmaker.
Regarding duty cycle:
Each of those pulses has a duty cycle (%) relating to how long each pulse is in the high state (width of the top of each square wave).
Duty cycle granularity:
A typical modern chipset can give an individual pulse over 1000 distinct lengths (8bit chipsets could only use 256), I can see 1024 on my system.
Boosting PWM frequency will allow laying down discrete pulses faster, good for better resolution at high speeds, but will likely come at the cost of losing duty cycle granularity.
How it comes together:
If the S-value Max power range of your machine is 1000, then programming a cut in LightBurn at 50% would send the machine a gcode command of ‘S500’ which tells the controller to set each PWM pulse high for 50% of every millisecond (when 1kHz).
The laser module uses that 50% duty cycle to modulate laser intensity by switching the diode on for exactly 50% of every millisecond.
Dot size:
If you are running PWM at 1kHz and each pulse creates a 0.1mm wide dot, you could theoretically set the feed rate to 0.1mm per one thousandth of a second (100mm/s) and there would not be any gaps between each dot.
Grayscale:
Can be tricky to work with! Let us know what you are trying to achieve and if you have any specific questions or get stuck feel free to post something here and somebody will help
Many thanks. I had to know the relationship between Speed, Pulse Hz, Duty cycle and pixel dim’s. Mostly I wanted to rewrite the misconceptions and misunderstanding to form a clear mental picture of the process, so it’s really just a learning process.
Two days questioning and pondering with Ai assistance and most of the trash and fog is gone.
