lil bit of everything here
i find that steppers, left idling, can get hot from their angular position. think about it. they have 200 steps say. they land on one of them, theyre fine, they dont require much power to stay put.
when they stop on one of the halfway steps due to microstepping, a lot of power is consumed as first one coil is energised, pulling things that way, then the other.
hysteresis and eddy currents and such forth. but then, clicking can be other things to. i dont argue that there can be other things afoot.
the stepper, or the drive clicks?.
anyways. a fair temperature rise at times in steppers, i consider fairly normal, especially when idle!
i may be wrong, its just my theory.
mine never seem to get as hot when being used heavily as when idling, at least. strange that?
acceleration curves. and velocity.
obviously you found that in motor tuning. i advise starting low, and working up. 100IPM. 10 for accel. or .25 seconds or something. you can almost count down its acceleration curve. its guaranteed to never skip a step, under the heaviest of cuts.
the machine is useless if it loses steps just by making rapid moves!
akin to a drag car...you dont go nowhere if you just spin the wheels, no matter how much power you have! its all about controlling that power
also, if it can accelerate fast enough, it will break things due to g forces... unlikely but theres the possibility. more likely to break tools when zeroing! slow and steady does it. slow accel is real nice when jogging up to a surface. gives you some time
other times its annoying as all hell! its a compromise...
you increase it to what looks good. i think i run mine so its at 0.1 seconds, or about 12. as for max speed...kernel speed can also affect this, but...starting with the lowest, default kernel speed, set max speed so it can beat a snail there, isnt scary fast, and doesnt obviously lose steps!
its only a lil mill, it doesnt need much
all that overdoing it achieves is frustration.