What is a reasonable cutting acceleration setting for the MPCNC using a jackpot board with TMC2209s at 0.8A and running Fluidnc? I know the stock config is conservative, and I also know that every machine is different. But I would assume that 1000 mm/s^2 should be easily attainable for XY, and at least 600 for Z. I’m only asking in regards to decreasing cutting time while I’m profiling a part.
Additionally, what kinds of negative effects should I expect when acceleration is too high? I assume lost steps would be the main issue, when forces overcome the holding torque of the steppers.
The default values are reasonable. Any variation from that carries risk of skipping steps. Increasing max feedrate often requires lowering acceleration settings, and quite possibly vice versa.
Yes speed does affect available torque for acceleration, surely these drivers and motors are far more capable at 100-150mm/s than 200mm/s^2 acceleration. This question only arose from when I was using a parallel operation where the tool was moving up and down about 2” while going across a 14” span. I have a hypothesis that increasing acceleration for Z will help with executing these passes faster. Too much, obviously will result in lost steps. But outside of lost steps, what sorts of negative effects should I expect with increased acceleration?
In the 3DP world, high accelerations like 100k (max I’ve achieved on mine was 150k) will create new issues like pressure advance not able to keep up resulting in thinner walls that almost disappears around sharp corners.
If the stock setup isn’t capable of anything above 200, then I haven’t found anything in the forums or documents that states that. I doubt that’s the case though, and hope for more feedback from others who have tried before I potentially break my MPCNC or get hurt.
I only have an LR3, not an MPCNC, so YMMV. I did some rapids at X/Y = 6000 mm/min and some milling at X/Y = 7000 mm/min, and found that it skipped some steps at the default acceleration. (probably due to a very heavy gantry) I slowed it down to 4000 mm/min, with no skipped steps.
Trial and error might get you to faster speeds, or faster acceleration, but as mentioned before, increasing one may mean that you have to decrease the other.
