Speed of stepper motor

[mary22Participant @mary22]

I am building my first 3D printer and struggling with challenges. I’m testing my stepper motors and although I can get them to move correctly, I can’t get them to move fast otherwise they get stuck. If I move the motors at a speed above 1500 mm/min in the octoprint, they stop moving and make a horrible noise. The motors run freely and I haven’t loaded them yet.

My printer is a CoreXY model and I only have the xey motors connected to my RAMPS 1.4 board. I am using a DM542T(https://www.oyostepper.de/goods-111-Digitaler-Schrittmotortreiber-DM542T-Schrittmotor-Treiber-10-42A-20-50VDC-f%C3%BCr-Nema-17-23-24-Schrittmotor.html) So far I have connected the driver only to the xey axes. The drive is set to 1/16 microstepping. The power comes from the PC power supply and I have connected the 12V only to the 5A port on the RAMPS.

Il mio motore passo-passo è 23HS22-2804S1（https://www.oyostepper.com/goods-74-Nema-23-Stepper-Motor-Bipolar-126Nm-1784ozin-28A-25V-57x56mm-4-Wires-Φ6mm-Shaft.html）

Am I doing something wrong or are these motors unable to turn faster?

[BazyleParticipant @bazyle]

1500 mm/min is completely meaningless if you do not provide the full details of the set up.
What is more relevant is the number of steps per second. The stepper inertia limits the step rate and then that is reduced as the mechanical resistance increases. And it depends on the drive current/voltage.
It is common to overdrive (V & I) the steppper to get more torque but because of the risk of overheating when stationary then the driver may have a mode drop the current back when not moving. Also it is important for higher speeds to ramp up the step rate, not to whack it straight up to full speed and expect it to keep up.
Steppers have almost nothing in common with DC motors.

[SillyOldDufferModerator @sillyoldduffer]

Hi Mary,

Stepper motors don’t turn quickly, and micro-stepping slows them down.

There are few things that make it worse:

• Using a power supply with fewer rather than more volts.   The volts don’t contribute much to motor power (for which amps are needed), starting with more volts reduces the time taken to get energy into the motor coils.   Better to run your motor off 40V rather than 12V.   Replacing the power supply with a 24V unit might fix it.
• Potentially, using a stabilised rather than an un-stabilised power supply is bad.   Stepping puts a highly intermittent pulse load on the power supply. Whilst zig-zagging volts don’t matter to stepper motor motors, this type of load can serious upset a stabilised power supply.  Unfortunately for hobbyists, it’s much easier to source a mass-produced stabilised power supply.   But these are purpose built to stop volts zig-zagging with no guarantee that their electronics will cope with the electrical load presented by a pulse driven stepper.  Possibly your PC PSU can’t keep up when the motor is driven at high speed.  An oscilloscope would show if  the PSU is struggling or not.
• For it’s own protection against short-circuits, a stabilised power supply is likely to have over-current protection.   What it does during over-currents varies with the design, anything between cutting out entirely and chopping due to fast automatic resets.
• A lesser stabilised power supply nuisance is that even when high pulse-rates are no problem,  they always throttle the volts, which stopping the motor achieving maximum possible speed.

In practice, I drive my steppers with this generic type, photo is an example not a recommendation, because they seem to work OK with steppers.  Not ideal though:

I set the driver and software for reliable stepping.    Stepping motors are for accurate positioning, not speed.   Last thing one needs in a 3D-printer are motor speeds that don’t place the head correctly.

Dave

 

 

 

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