1 Topic by mechatronic

  • mechatronic
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Topic: Motor torque calculation

Hello everyone,

This is my first post and i am sorry my poor English. I'm mechatronic student and i have been searching information about filament extruder for 1 month and i started to create my own extruder. But i didn't calculate motor torque. I know 4-10 rpm and 45-60 Nm are ok but i would like to learn how to calculate.

What are the parameters or what are the formulas?

Also i am thinking to use industrial screw like a barrel-screw. What do you suggest  ?

Thank you for answers..

2 Reply by elmoret

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Re: Motor torque calculation

There are definitely formulas in this case, but it turns out they don't always represent reality. They'll get you in the ballpark, but in reality the flow is difficult to model. There are several textbooks on polymer extrusion, and they contain these equations but honestly trial and error is probably faster.

45-60Nm is probably high, especially if you're on the slower RPM speeds.

You can use an industrial screw, but it will be much more expensive.

Filastruder - the robust, inexpensive filament extruder
E3Dv6 All Metal Hotend - the premier 3D printing hotend

3 Reply by mechatronic (edited by mechatronic 2014-07-25 22:22:00)

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Re: Motor torque calculation

now i am a little bit confused because i was thinking that values , i wrote before , is suitable for filament extruder.
what should the properties of dc motor be ? I mean how do i choose right motor ?
Also if 45 Nm is high torque why other extruders have gears (1:600 etc.. ) for increasing torque ? Do i have to use gears ?
and finally,

Does it make a sense to use a industrial screw according to price/performance ratio?
what size commonly used screw do i need for extruder ?
(I am sorry i asked a lot of questions but that's all question marks on my mind)

4 Reply by elmoret

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Re: Motor torque calculation

I meant that 30-45Nm (rated, not stall) is probably a little more like what you actually need.

It makes sense to use an industrial screw if you are building an industrial/commercial extruder. It does not make sense to do so if you are building one for home use.

What is keeping you from purchasing a commonly available kit?

Filastruder - the robust, inexpensive filament extruder
E3Dv6 All Metal Hotend - the premier 3D printing hotend

5 Reply by mechatronic

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Re: Motor torque calculation

It will be my college project and if i do it on my own i will understand exactly what i am doing.. That is why im asking for a lot big_smile