Can i use Nema17's with a smaller holding torque with a Rostock Mini ????

Hi,

I'm wondering if i can use Nema17's with a holding torque of 3,6kg/cm instead of 4,4 Kg/cm.

Is this possible ?????

In the dokumentation is written that a geared extruder needs a holding torque of 4 kg/cm but what about a direct drive bowden extruder. Can you drive this extruder with less than 4 kg ?


Can anyone give me an answer ?
Want to double check before i use the wrong motors.


Daniel

I investigated what kind of motor is used on my Rostock Mini and found out it has holding torque 35 N.cm.
It is about the same motor as the one you want to use but coupled with a 5:2:1 planetary gearbox.
The gearing in the gearbox multiplies the torque so this same motor wouldn't quite have enough torque for a direct drive.

It is Nema 17 motor HUISITONG 42BYGH403AA:

---

All about delta 3d printers in one place [www.deltarap.org]

I don't know for the 3 axis motors, but for the extruder I would use the biggest torque available, since it is a bowden system.

Not to say it cannot work, but it would probably severely limit your maximum extrusion - and thus, printing - speed.

Also a direct drive extruder needs more torque I believe. What filament diameter are you going to be extruding ?

---

Most of my technical comments should be correct, but is THIS one ?
Anyway, as a rule of thumb, always double check what people write.

Think i Would use 1.75 . Is it a difference between pla and abs in extrusion if it is the same diameter ? I mean if u should use a stronger motor for abs or pla ? Sorry but I just printed in pla and don't know the difference. So it means I can use 3.6 kg/cm for the 3 axis but should use one with 4.4 for the direct drive Bowden I woukd use, right ?

If the price difference is not high, get the biggest torque for all the motors - over engineering always work, while getting just enough power might be a source of trouble.

If you are on a budget, you might try the little torque ones for the 3 axis, but I cannot promise you won't regret it...

The direct drive extruder feeding a bowden must have the biggest torque available yes. And you are probably limited to 1.75 mm diameter filament also there (too bad, I did add a little sample of 3mm filament in the package I'm about to send you).

ABS and PLA makes no difference in normal extruder, but using a bowden ABS is more sticky and may need more torque because of the friction in the tube.

---

Most of my technical comments should be correct, but is THIS one ?
Anyway, as a rule of thumb, always double check what people write.