Stuttered movement at high speed on CAN bus axes
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My machine has two X motors and one Y motor driven by drivers on expansion boards, EXP3HC's. When I request it to move on these axes at high-ish speeds, like 250 mm/s, it does not execute the move smoothly. Instead, it appears to slow down every several dozens of mm and speed back up.
I have worked on isolating the issue, and I can conclude it is definitely not missing steps. For one the total distance is always correct, and it does not make the sound of missed steps. The problem is also not caused by the system not being able to interpret gcodes fast enough, as the problem can easily be reproduced by a single G1 command on one axis.
My hunch right now is that the movement segments aren't getting communicated through the CAN bus fast enough, so expansion boards decide to slow down as the get through the move queue they have already received, until more segments get through.
Any thoughts? How can I make the machine run smoother at high speeds, or have I reached the limit? On previous firmware builds (like 3.2) it has achieved these speeds, and faster, no problem. The machine is cranking out prints successfully but I think there is an opportunity for improvement of print quality here.
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@Mattq4 do you have bed mesh levelling activated?
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@jay_s_uk I do. I'll turn it off and try it in a couple hours.
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@Mattq4 you'll probably find the z axis isn't moving fast enough for the adjustments to be made when moving at 250mm/s
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@Mattq4 i should add the fix would be up your z axis jerk/acceleration and maybe max speeds etc
