Finished upgrading the Y axis today. The results, still, aren’t great but the backlash seems to be diminished compared to the beginning of this thread?.
Went ahead and took your advice and started with an octagon, and then a icosagon, and then lastly the obligatory circle again:
The wavy jitter cuts are incredibly unsatisfactory. Jerk is already at its absolute lowest and the cut speed is a paltry 50mm/s
Done any fine tuning of [de]acceleration and constant velocity settings for your motion controller (i.e. Mach3, UCCNC [pg36])?
I had to adjust CV settings to reduce “faceting” on simultaneous X/Y motions (i.e. arcs, diagonals) when I moved to new motion control hardware/software and also tone down [de]acceleration (due to belt stretch when [de]accel the heavier gantry).
I’m not even sure those settings exist in the DSP controller/Lightburn software. The only thing I’m curious about is the min power % setting, which changes the PWM of the beam to reduce power at corners to avoid blowing out corners, but I think applies to circles/line segment nodes too, maybe? Just a weird theory I thought of. We have max power set at 100% and min power set at 11% which was a good recipe for square shapes.
Here is the ‘manual’ I posted earlier in the thread attached here. I can’t seem to find anything in it?
Edit: There is also a ‘start speed’ setting in the DSP. That is also currently set low.
There is this setting as well, and we already have it set to the lowest, but maybe low is a bad thing? Of course this manual doesn’t make alot of sense for most things.
What are your acceleration settings for X and Y? I know that a bunch of laser cutters use ultra lightweight gantry systems for moving their laser head around. Those can accelerate very fast. You however are using a gantry designed for a CNC milling. If the acceleration is too high it could lead to ringing.
Yeah, but then again nothing in the manual really translates to English very well that we’re so familiar with on this forum as far as standard Gcode, so maybe there’s a magic setting value that just needs set correctly.
I am starting to think your controller might be bad honestly. When you made the Octagon the diagonals are wavy but the diagonal gets from the correct vertex to the next on the Octagon. It is almost like X and Y are not properly synced to one another. Basically like it is trying to send X and Y each say 10 step pulses at the same time, but instead X is getting 3, then Y is getting 2, then X is getting 1, then Y is getting 4, then X is getting 6, then Y is getting 4. Both got the correct number of step pulses, but it happened unevenly.
Yup. That sounds like a very likely culprit. Look at his circles in that post too. They look very lop sided.
EDIT: Actually those lop sided circles were not solved from what was said in that post. So never mind. Still could be a controller issue. Which controller are you using?
