Hello Folks!
I really like the features of LB, so as others before, I plan to use LB also for plotting (needle cutting) instead of laser cutting.
Right now my approach is to use different grbl firmware which I can easily change with the open builds controller. The alternative grbl firmware generates a servo PWM signal
on the Pin where usually the Laser PWM is assigned to. So the servo will simply move upon laser signal.
In order to get this work with my needle cutter properly, the code needs a certain delay for the servo to lift the cutter in the up position, before proceeding to the rapid speed movement.
Is there a possibility to set this parameter in LB?
I’m driving a Pen Plotter through Lightburn very successfully, but am currently ignoring the delay to raise and lower the pen.
I look at alternative firmwares which supported Servos, but ended up adding a second Arduino to drive the servo - It reads the spindle/Laser enable signal and uses that to trigger the pen going up and down. I made the sketch store the up/down extent of the servo movement in EEPROM and have a little serial terminal I can connect to to change the positions.
One the one hand it’s overkill, but on the other hand, Arduinos cost nearly nothing
I think the delay is esssetial for my machine, So, If I cannot solve it with lightburn, I may have to use another cam software. In that case I won´t have to swap grbl firmware on my controller each time I change from Laser to Needlecutter, but I would need some kind of microcontroller which generates a pwm servo signal from the Stepper Z axis port which my controller has. (MKS DLC 2.0).
So if you stick with LightBurn, you could knock up a postprocessor to insert a delay: G4 P1 ought to cause the machine to pause for 1 second. So replace every M5 (laser off) with M5 and G4 to cause the machine to pause. You can then generate the GCode in lightburn, post-process it, then load it up and run it. Not as nice, but workable.
I suspect future versions of Lightburn will support either a postprocessor or inserting custom GCode for certain operations - there’s a lot of people looking at using it for Plasma/Vinyl/Pen usages where tweaking the behaviour just a little would help enormously.
