Steppers vs Servo on 3d Printer Extruder

So I have a delta 3d printer, and the extruder uses a stepper driver. I always try to buy a more precise stepper for this motor because it needs to be driven with better precision than what you get out of a stepper. The best extruders have a 3:1 reduction currently (e3d Bondtech BMG etc). However, there are other extruders that have 40:1 or 30:1 reduction. These extruders have precision but they are constrained by the inertia of their heavy stepper rotors. I think that a servo would be much better at driving a 3d printer’s extruder since they are smoother, and every 3d print has artifacts because of the stepped motors they are using. I have a Rail core that produces phenomenal prints but it still has extrusion artifacts since it’s extruder lacks the resolution to precisely extrude the material that it prints. Is this an application for the O-Drive. I would pay 300.00 to get a great extrusion system that lacks under extrusion, over extrusion and other “features” of an open-loop system. What are your thoughts could this be the into 3d Printers servos don’t seem to fit. The mechanical positioning seems well served by steppers but the extrusion system on 3d printers is not served at all by a stepper.

The problem you’re describing had nothing to do with steppers and more to do with the unpredictable nature of filament extrusion. Bowden setups just add to this as well, as well as your material profiles and materials you use.

A servo is no more smooth or accurate than a properly configured stepper. The only way to properly control extrusion would be to actually measure the amount of molten material at the nozzle, otherwise you’re just estimating the flow based on parameters that you know.


ODrive could be useful for an extruder, not because of precision but because a DC motor could be lighter which would allow more lightweight direct drive extruders.

You could also measure the actual movement of the filament and use that to control the motor, which would provide a better closed loop and control.

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