STEPPER MOTORS ?? What should be used??

Hi,

I am currently building a Mendel. I ran into a small problem here. I am looking for the stepper motors that should be used. Is there any certain specs.

As far as I know that what really matters is the frame size, either a NEMA 17 or NEMA 14 motor. Also the torque should be 1400 g-cm or more. What about other factors such as the stepping angle size, weight of the motor, the voltage. I have seen a lot of people posting various motors with various specs.

I am looking for a decent motor, which would give me the best printing quality. So what are the important factors I am looking to??

Another thing !! I have known that the lower the step angle, the better. However, I don't think it is irreparable if the step angle is 1.8deg/step or even 3.6deg/step.I believe the stepper motor drivers are capable of micro-stepping. Meaning, it can control the current going to the phases of the stepper, allowing it to accurately do half or even quarter stepping. IS THAT POSSIBLE To BE DONE in A mendel ??


Thanks,
Khaled

microstepping is not accurate, especially if the motor is putting out more than about 15% of the torque it's capable of. The greatest advantage of microstepping is increased firmware precision, reduction or elimination of mid-band resonance effects, and smoother movement at low speeds.

your most critical aspects are motor voltage and torque. you want lots of torque at a fairly low voltage. My motors are rated NEMA17, 0.44Nm, 2.77v. The stepper drivers control current, not voltage, so it doesn't matter that I drive them from a 12v supply as long as I set the current limit correctly.

Note that the reprap extruder board does NOT have current control of the stepper, but it does have a software-configurable power level which you can use to avoid burning the motor out.

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Wooden Mendel
Teacup Firmware

... if you can get hands on BergerLahr/Positec-motors-drivers at ebay, then you'll have high precision microstepping motors capable of 1000 steps (0.36 deg) per rev in normal mode until 20kHz and 10000spr (0.036 deg) in microstepping mode with max 200kHz stepping pulse.

The drivers have the same controlling pins (STEP, DIR) as common stepper-electronics and are driven by the power line (325 Volts and until 2Amps) ... the 368-motors have 1.1Nm, 397 have 2Nm and 3910=4Nm.

When applied with a 5:1 planetary gearbox you'll rise the steps per rev. 5-fold, but reduce the rpms accordingly ...

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Viktor
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Hello people,
With colleagues from my university we are starting to build a Mendel and we are preparing the ordering list for all the parts. Can you please share, how much and what kind of motors we do need! Thank you in advance!