A4T WWBMG, which stepper motor to use?

[uwedamm]

A4T documents NEMA17 for WWBMG (Wrist Watch bontech mini geared)
https://github.com/Armchair-Heavy-Industries/A4T/tree/main/STL/WW-BMG for A4T

M3x16 SHCS to attach NEMA 17 stepper motor

Original WWBMG documents NEMA14
https://github.com/bythorsthunder/Voron_Mods/tree/main/Wristwatch_Extruder_BMG

Nema 14 Motor 10T.

Both is possible? Which to use for which purpose?

I have got CW2 equipped with LDO-36STH20-1004AHG(VRN)
Can I use same for WWBMG? (AFAIK it is sized Nema 14)

What is the difference of:
LDO-36STH20-1004AHG(VRN): Part of the LDO Voron 2.4 motor set
LDO-36STH20-1004AHG(XH): can be ordered as well
Is it only the length of the cable (VRN seems to have short cable, suitable for the nighthawk).
Length is 20mm for both of them.

Any suitable alternative exist on aliexpress or similar (I am living in germany, aliexpress usually works fine)?

When I think about my typical use-case:
400mm/s max speed
0.4mm nozzle
0.4mm max layer height
1.75mm filament
I come to:
400mm/s * ((0.4*0.4mm²)/1.75mm^2) ~ 10mm/s (~24mm^3/s = pi*1.75 mm^2/4 * 10mm/s)

Using 50/10 gear ratio and rotation distance of ~23mm/U (Bondtech gearset)
I come to 10mm/s/23mm*50/10 ~ 2U/s
which is quite slow for Nema 14
So I assume using 8T or even better 6T would improve max pressure and still provides
suitable speed for the extruder.

Am I right?
Thanx for reading!
Uwe

 

[thomasfjen]

Hi there!
Both Extruder Variants use the nema14 extruder. In your case I would simply reuse your existing one, you still could upgrade to a 8t or 6t later on. If going with wwbmg from thor make sure you use the usermod for smaller gear tooth counts, then you don't have reprint that later on.

I

 

[uwedamm]

Does this mean, the A4T version for WW-BMG is already the 8T/6T version? Which can also be used for 10T?