I changed my 3018-Pro stepper motors from the 1.8 degree to 0.9 degree stepper motors.
I primarily do laser etching of images. I know I can make my images twice as tall and wide to somewhat compensate, but my biggest issue now are that images way too dark in the dark parts, and in the lighter parts if I try to compensate through faster speed or less laser power they basically barely burned at all. I can’t find a good middle ground of speed/power now.
What can I change in terms of Lightburn’s settings to get this to either take this into account or compensate for this? And does this really negate completely any advantage of having 0.9 stepper motors especially considering I am mostly (but not entirely) doing image burning?
These would be settings that you change on your controller and firmware, not within LightBurn. It’s 1am on a Saturday right now and I want to sleep so I’ll just let you know that there are many resources on how to configure GRBL (assuming you kept the stock control board), and leave you with that.
There are a lot more variables to consider in order to give any advice. What is your laser? What is the wattage, etc? What sorta images are you burning? Do they have enough contrast, and what are you brining said images to?
You’ll need to double those numbers, however your machine is going to be very slow as a result. GRBL on an 8 bit controller can only send 30000 motor pulses per second. If your machine needs 1600 pulses per mm, your maximum speed will be 18.75 mm/sec (1125 mm/minute).
The problems I’ve actually been running into have made me thinking my controller that came with my 3018 (the 8-bit ATmega328P) was too chintzy as things would start misbehaving at higher speeds (which made me initially suspect my motor…which I know now [after replacing them] is not the case).
The biggest problem with the 3018 isn’t really the controller - screw drives require a lot of steps to move them, and they produce good torque, but not much speed, which is great for CNC use where side loads are involved, but not great for lasering where you just want to move fast.
That said, a 32 bit controller would likely be able to move the machine fast enough to be useful.
Kern laser and a few video on youtube I have seen have high speed screws and some are able to get over 2Kmm/s+ raster speeds from them. I cannot find the video it that I seen sometime back from a home builder that accomplished this. But as you said, it required some very high speed motors. I am certain they where all servo driven. I believe the home unit I seen might have used Teknic clearpath hybrids.
Anyhow speaking of clearpath and lasers. Check out this home modified Chinese system with clearpath servos>
(Not screw driven, but none the less very very impressive!)