DRIVERS AND STEPS
I have looked around trying to find out how steppers are controlled and would welcome some GOOD advise. I mean good, because the internet contains a minefield of very bad advise and information and you must be very careful what to take for correct or not.
I used a stepper SL 42STH40-1204A. These are, as far as I know, and stand to be corrected, 12V and 1.2Amp rated.
always had drivers fan cooled.
I set up the first 3d printer using Ramps and the Polulu driver A4988 and encountered skipping of steps during print in one axis.
Then a supplier suggested we go for the DRV8825.
When I assembled the first board with the DRV8825, only one or two motors would turn and severely over heat! and I mean overheat! and start loosing steps indiscriminately.
It seems that the current limiter is open.
so what I did, I clamped the motor and set the current to 0.7 Amp.
I found out, that the motor will start making abnormal noise over 0.7 Amp, overheat and even skip steps and go berserk. So found convenient to clamp the motor leads and set the current to this.
I also discovered that with the DRV8825, I hat to double the steps per mm of each axis and extruder motors.
Ramps Boards are dubious in origin and there are a lot of poor clones with poor performance. I have now gone for the static boards, the arduino supplied by them, their DRV8825 and even the Trinsmics. I am waiting for the stuff.
Also had two or three Mega 2500 of chinese origin destroyed at their own accord.
Can somebody give me some more guidance if I am right on track or not?