is this a good option for the extruder screw motor? https://www.ebay.com/itm/86HS118-6004A14-B34-DC-Motor-DM860D-Stepper-Motor-Driver-256microstep-CNC-1KW/202267512082?hash=item2f18154d12:g:MscAAOSwqGlashdU
1kw with its own intergrated speed controller,the disadvantage being that it needs 24V~80V DC or 20V~60V AC to power it
Hello @carmatic
Yes, a stepper motor will work but only for filament/cord extrussion, it will not work for more demanding things like making beams for instance. Even though it shows 1KW, I would never push the stepper that far.
There’s a German guy with a Youtube Channel named Werbewunder who has been playing around with using NEMA steppers for extrusion, more info here:
i have some Nema34s around, can’t be bigger, also have some 5:1 belts around, last time i used them on a 2 tonnes lathe (thread feed) : no problem. let me know, i can make some tests on a extrusion screw (was over due anyways).
should i ? nema 23 can be pretty powerful though
I face the same proble. I use nema 23 but it doesn work. The torque is not enough to push the plastic out of the nozzle. So i want to know which stepper motor is capable to do extrusion with 5/9 inch screw
Is there any formula to calculate the torque of stepper motor we need?
Does the type of plastic affect it or not?
to run a stepper on a exturder you need atleast 150kg.cm of torque so a newma 23 with a 5:1 reduction works. enjoy 
@carmatic Steppers do skipping, but if they are high torque motors the gears might get damaged while skipping.
On regards of the extruder, there is not really a defined minimum torque, but I recommend you a minimum of 60N.m for extruding plastic wire, and a minimum of 350N.m for making beams
On the other hand, the stepper reduction gears are not intented to be used on high torque applications such as an extruder (not even titanium gear steppers). If the extruder gets clogged, your stepper gear teeth will most likely break instantly
my understanding is that a stepper motor will skip when it is overloaded, long before any mechanical damage will occur to it?
does anyone have any data on just how much torque does the precious plastic extruder will require?
@abraxas Correct. On the other hand, the stepper reduction gears are not intented to be used on high torque applications such as an extruder (not even titanium gear steppers). If the extruder gets clogged, your stepper gear teeth will most likely break instantly.
I’ve never thought of steppers to be a good solution to variable speed applications. The torque changes with speed. Here’s a great data sheet that explains the problem:http://www.orientalmotor.com/stepper-motors/technology/speed-torque-curves-for-stepper-motors.html
@carmatic you could also use a Windshield wiper motor and a PWM controller like this one https://www.amazon.com/Puuli-Controller-Switch-9V-60V-Modulator/dp/B016PQ3CGG/ref=sr_1_fkmr0_1?ie=UTF8&qid=1523774699&sr=8-1-fkmr0&keywords=9V-60V+Motor+PWM+CVT+pulse+width+Modulation+Speed+Controller+Stepless+20A%2F600W+Switch+Dimmer+Dimming
the reason I am looking at a stepper motor is because I would like to have more control over the RPM
Using a regular motor would mean purchasing a variable frequency drive which costs as much as the motor itself
Also, for 124.44 Euros, I would rather purchase a 0.5hp motoreducer or a garage door opener motor that will work with 110v or 220v right away and already includes a reduction mechanism