Motor stalls at 3000mm/min specifically

[droftarts]

@kalera you can also check your maths with the EMF calculator here: https://www.reprapfirmware.org/

Ian

[Phaedrux]

@droftarts said in Motor stalls at 3000mm/min specifically:

@kalera you can also check your maths with the EMF calculator here: https://www.reprapfirmware.org/

Ian

I ran into an issue with the calculator not allowing me to select a custom lead screw pitch.

[droftarts]

@Phaedrux oh! I think @wilriker maintains the code for that?

Ian

[Phaedrux]

@droftarts Yes I think so. I mean to check it out again to see if it wasn't something I was doing wrong.

[droftarts]

@kalera as you’ve got a Duet 3, you could reduce the micro stepping to x8 and still use interpolation (keeps the motors quiet when moving), unless you really need that much resolution in your Y axis. This should let you run them at higher speed, I think.

Most motors have a full step positional accuracy of +/- 5%, so microstepping above x10 (which is what GeckoDrives use) doesn’t give you more repeatable accuracy.

Ian

[wilriker]

@droftarts said in Motor stalls at 3000mm/min specifically:

@Phaedrux oh! I think @wilriker maintains the code for that?

Ian

Actually, I don't.

@Phaedrux But I can see that this drop-down is misleading. Just enter the desired lead into the "Leadscrew lead" input field. This will make the Leadscrew preset drop-down switch to the otherwise not selectable "custom" value. In fact all preset drop-downs will switch to custom if you modify any of the assigned values manually.

[Phaedrux]

@wilriker @droftarts must have been thinking of the acceleration calculator. Is the EMF calc maintained by @chrishamm?

[wilriker]

@Phaedrux said in Motor stalls at 3000mm/min specifically:

@wilriker @droftarts must have been thinking of the acceleration calculator. Is the EMF calc maintained by @chrishamm?

I think so. But also @dc42 and @T3P3Tony do changes on it every once in a while.

[wilriker]

@droftarts said in Motor stalls at 3000mm/min specifically:

@kalera as you’ve got a Duet 3, you could reduce the micro stepping to x8 and still use interpolation (keeps the motors quiet when moving), unless you really need that much resolution in your Y axis. This should let you run them at higher speed, I think.

Unfortunately not. Since the problem seems to be Back EMF this is bound to RPM of the stepper - independent of how they are achieved by the driver. If it were steprate then lower microstepping would help. But even a Duet 2 is good for about >15000mm/min on an axis with 400 steps/mm.

[kalera]

As promised I'd post an update after testing it. It's been running reliable at 2400mm/min so far. Maybe I'll change the leadscrews to a higher pitch later to achieve higher speeds.

I'm still having some issues with stall detection, but I'll search the forums for some answers on that first