Here’s Wally cutting a couple squares in the air. Not sure of the jerkiness cause. It could be acceleration settings… Each side of the square is made of many segments defining an arc because of the cartesian to dual polar conversion.
Probably stiction.
Try some graphite or Teflon wax base lubrication with a solvent carrier. White Lightening chain lube.
I really like the design of the wally, but I’m curious to see how the rotating hotend will affect prints (if at all)
I don’t think it’s friction as it’s happening in the z axis as well and the joints are moving the whole time do it’d be under dynamic friction the whole time. @Alan_McNeil , how did changing the acceleration work out. That is interesting that a straight line is now a bunch of arcs, which would make sense that the firmware thinks you’re changing direction constantly
I wonder if you’re hitting the firmware segments/second limit? Maybe try some manual moves to see whether those also stutter?
@Miles_Flavel The question of the rotating hotend has come up before, and the feeling is that it won’t affect things because everything that’s important is on a common axis: filament, the bore of the hotend, and the hole in the nozzle. The heater block is offset, but that’s immaterial.
Just doing some more tests. Running at 25% speed it becomes obvious that the catches are at well defined places, not friction though! It repeats but not on every loop but not randomly. One stutter loop with two stutter points then a totally smooth loop then several with stutters increasing the decreasing then smooth again
I am suspecting math glitches as the F term is often >25000. XY are large too. G1 X941.044 Y1231.943 Z93.06 E0 F25749 for example.
The huge numbers are gradians cuz ‘we aren’t in Kansas anymore Toto.’
try WD-40
The jerkiness seemed to be caused by multiple factors mostly in motions constants like speed, acceleration, jerk. Bit tricky since the XY motors are set to 16s/mm to be gradians (its polar). That led to feed rates up to 40000!
Also a bolt top on right pulley kissing the right motor mount.
with the motors off have you moved the print head by hand? does it feel perfectly smooth?
@James_Zatopa yes it moves nicely by hand. Setting speed and acceleration is odd. cease you are setting the change of angle not distance.
If your board is being bogged down by the calculations you may want to take a look at the replicape or smoothieboard. I’m not sure where your boards limit is but your numbers do sound high. You could drop your micro stepping down to 1/1 or 1/4 to see if that removes the problem. If it does I would suspect you are hitting the limits of your board. If it doesn’t then your problem is elsewhere. Maybe you have a rounding issue somewhere (might be better to truncate?).
BTW it is really cool to see this thing working. IMO this design is the first real step towards a “Reprap” design that follows the projects ideals.