New printing issues with recent motor current change

[REV]

Hi All-

I know there are multiple threads devoted to motor current / temp and I'd like to apologize in advance if I am being redundant in creating this thread. I think I've lurked through most of them, and I still don't have a clear sense of what to do with regard to motor current / temp. Is there a 'current motor current' thread or sticky? b/c the general consensus seems to change a lot. Or is it machine specific? From what I've gleaned from other threads, there is some variability in the Kysan Motors, and apparently some of them are more suited to this application than others. My printer came with the Kysan motors, so, during assembly I changed line 701 of my configuration.h to:

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#define MOTOR_CURRENT {155,155,155,165,0}

Even with the reduced current, I noticed that all 4 stepper motors ran very hot. I never measured the temperature, but suffice it to say that they were too hot to touch for more that a few seconds, and I and a welder, and thus have a considerably higher pain tolerance in my fingers than most people. Nevertheless, I had many successful prints with these current settings (all under 3 hr) and it wasn't until I attempted a 14 hr print that I had a problem. And then, you guessed it, the extruder melted the filament after about 5 hr, and proceeded to air print through the night.

After fixing the extruder and doing some research, I changed my motor current to:

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#define MOTOR_CURRENT {140,140,140,130,0}

This resulted in the motors running much cooler, but some other weird behaviors have cropped up. I have to assume that they are related, but it is not proven. I am getting some stringing or, well I'm not sure what the nomenclature is, for the first time. This could be the .stl? the print head seems to just pause to the side of the print for a few seconds every now and then. Now that I think about it I don't see how this would be related, its probably just circumstantial.

There also seems to be more play in the system, more z banding, more waviness.
This, I think, is related. The motors have less precision, or more jitter, due to the decreased current. So perhaps the answer is either motor fan shrouds, or different motors.

Any thoughts are greatly appreciated,

rev

[Jimustanguitar]

The defacto thread on the topic is mainly only an FYI for those with Kysan motors. The Wantai motors should use the 'stock' current setting in the firmware, and the Kysan folks should lower the current setting to match the motors (although I remember scratching my head about the extruder current not changing). The other good info that I recall from that thread is that 50c is ok but 80 is not.

There's a second string of threads that's reporting a problem with the motors being way too hot. It sounds like your machine falls into this category. I haven't been following it closely because I haven't seen the problem for myself, but I believe that the jury is still out on what the actual cause is. Something's off because that's not right.