Stepper Motors??

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

You will be ok with 1.8 degrees per step. Here in the US lin engineering and interinar seem to be the best sources of steppers. I would strongly suggest the highest torque (within reason) Nema 17s you can get for your budget.

Nema17 1.8deg/step (200 step/rev) 0.44Nm motors work for most of us. There are lots of ~0.24Nm NEMA17s around, these are strong enough for the axes but not the extruder. Mine are rated 1.68A, 2.77v and my microstepping driver (pololu A4983 carrier) takes care of driving them from 12v.

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Wooden Mendel
Teacup Firmware

If you use Nopheads no compromise worm driven Extruder a I have just experimented with you can get 4.7kg or more of pull from a 0.101 Nm NEMA 14 stepper.




I had slipping problems from drive shafts and gears so have not managed to get the stepper to maximum torque yet i.e when the stepper says hey too heavy and stalls.

You can see how tiny the steeper is in this picture.

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Bodge It [reprap.org]
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How to Build a Darwin without any Rep Rap Parts [repstrapdarwin.blogspot.com]
Web Site [www.takeaway3dtech.com]

Is this too much motor for a Darwin type device that might also have a CNC as a tool?

[www.phidgets.com]

Phidgets looks to have a good selection of motors...but i do not know pricing from other places so I cannot say whether they compare favorably.