This is basically a continuation of this thread:
http://forum.seemecnc.com/viewtopic.php ... 28#p105355
But I felt I hijacked wdmarine's thread and was wandering off-topic too much. But it is keeping me busy, hence a new topic in the correct subforum (although this might be of interest to users of other controllers too).
The info in the above mentioned topic made me curious about my own stepper motors, and I checked them out to be Wantai 42BYGHW811P2. I googled for specs: http://www.phidgets.com/documentation/P ... asheet.pdf . Here it shows that they are rated for 2.5 Amps, which looks to be much higher then most others?
Using the formula for calculating the maximum speed (as found on the Duet3d.com wiki) as:
max speed = (4 * pulley_teeth * supply_voltage)/(steps_per_rev * pi * inductance * current) I get this result: But I am having troubles interpreting it. Obviously 0.737 is no nice speed. Would I have to use mA instead of A, then the is even worse. Assuming meters/second the outcome is unreasonably high... What am I missing? And how can I optimize the jerk setting?
Reason I am asking all this is that I have a lot of stringing problems in my prints, and I think I can at least partly counter measure that by optimizing jerk and move speeds, so that the string breaks. It does not do that now. I already put a lot of effort in optimizing retraction settings and extrusion temp... My current config in the duet is this:
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M906 X1200 Y1200 Z1200 E1400 I60 ; Set motor currents (mA); set each extruder explicitly M201 X1000 Y1000 Z1000 E1000 ; Printing Accelerations (mm/s^2) Set all E-motors the same M202 X2000 Y2000 Z2000 E1000 ; Moving Accelerations (mm/s^2) Set all E-motors the same (Not sure it's used in DC42 Duet firmware!) M203 X20000 Y20000 Z20000 E3600 ; Maximum speeds (mm/min) Set all E-motors the same M566 X1200 Y1200 Z1200 E1800 ; Maximum instant speed changes mm/minute. Set all E-motors the same
All tips are welcome, thanks!