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Search direct drive extruder with NEMA 14

Posted by J3d 
J3d
Search direct drive extruder with NEMA 14
June 14, 2018 12:17PM
Hi,

I scavenged a nice little NEMA 14 motor (in an OKI printer/scanner) and I am looking for a model of direct extruder (using an MK7 or MK8 gear), without success.

Can someone send me links for relevant CAD files (preferable openSCAD format)?

This is for our (highly modified) Prusa i3 and we should be able to modify the drawings (to adapt it to our induction sensor, fan, etc.).

Thanks in advance,

J3d
Re: Search direct drive extruder with NEMA 14
June 14, 2018 09:00PM
There's the common Gregs/Wades extruder which is designed in OpenSCAD, I don't imagine in would be very hard to change the hole spacing for the motor mounting bolts. I believe the shaft diameter, bolt size used for mounting etc is all the same between nema 17 and 14, just the mounting bolt spacing is different.

A quick google search of "nema 14 extruder" should do the job for you. Throw in "openscad" and "i3" as needed.
J3d
Re: Search direct drive extruder with NEMA 14
June 15, 2018 02:03AM
Hi Trakyan,

Thank you for your answer.

As you can imagine I already tried to google these keywords but only came up with more or less derived versions of the same basic extruders and with only .stl files.

J3d
Re: Search direct drive extruder with NEMA 14
June 15, 2018 02:40AM
perhaps that is because a nema 14 is just to wimpy for the job....

but regardless..

[www.thingiverse.com]

Is in open scad, is for a nema17, but all dimensions are in a simple array and easily changed for nema 14 dimensions, and it auto scales.
J3d
Re: Search direct drive extruder with NEMA 14
June 15, 2018 02:14PM
Thanks Dust but I want to print flexible filament, among others, therefore no "remote" extruder but one which moves with the x-carriage (this is why I thought a smaller/lighter NEMA14 would help lower the total moving weight)

I should have explained that better in the first post but I do not know the name for this type of extruder, is that a "wade" type?
Re: Search direct drive extruder with NEMA 14
June 15, 2018 02:55PM
I actually have designed NEMA 14 direct extruders that are pretty good with flexible filaments, they were ther base for my current NEMA 17 based direct extruders.
I fear though that the mount they have is anything but standard and they are tailor made for the Merlin hotend using compressed air cooling. If you do use the Merlin hotend i can adjust the mount for you. Modifying the extruder for a different hotend would mean a complete redesign.
Edit: I now use NEMA 17 since it turned out i could lower the weight for each of my X carraiges to a point where i only need NEMA 14 motors to drive the X axis.

Edited 1 time(s). Last edit at 06/15/2018 02:56PM by Srek.


[www.bonkers.de]
[merlin-hotend.de]
[www.hackerspace-ffm.de]
J3d
Re: Search direct drive extruder with NEMA 14
June 15, 2018 04:21PM
Hi Srek,

I use E3D clones, V5 and V6 and an old PEEK hotend, but that should be an easy change that I can do myself, as long as I can get most of the extruder in openSCAD that should be OK.

Where can I find what you designed?

J3d
Re: Search direct drive extruder with NEMA 14
June 16, 2018 02:17AM
Sorry, it is not an easy change, the whole design of the extruder is targeted towards the only 10mm thin Merlin and does not leave room for conventional cooling. Also it is poly modeled, not CAD.
Please find attached the body of the extruder, it might help you getting the shape of the filament path after the MK7 drive right. So far this design is the most practical and reliable of my soft body filament extruders.
The idler uses a 11mm bearing.


[www.bonkers.de]
[merlin-hotend.de]
[www.hackerspace-ffm.de]
Attachments:
open | download - 14 5 Merlin 09.stl (238.4 KB)
open | download - Idler 04.stl (230.9 KB)
Re: Search direct drive extruder with NEMA 14
June 18, 2018 11:02AM
http://thrinter.com/2wd-dual-drive-extruder-designs/

there are a few designs here. go nuts and let us know if they work!
J3d
Re: Search direct drive extruder with NEMA 14
June 19, 2018 03:28AM
Thanks, that seems very impressive
I will have a closer look
Re: Search direct drive extruder with NEMA 14
June 28, 2018 08:33PM
Nema14 is fine, you need to use gears to get the required torque.
See here different approaches: [reprap.org]

Mine use simple regular RC gears. I don't publish the full details as it has features not found in others (all filament as it is fully guided, self cleaning hardened hobbgear, no spring for the idler, sensor to detect the hot end contact with bed for Z homing, compact and lighter than a NEMA17 motor...) currently looking to integrate filament stoppage detection.
I don't want some chinese company to copy and make money from it.

Edited 1 time(s). Last edit at 06/29/2018 03:01AM by MKSA.


"A comical prototype doesn't mean a dumb idea is possible" (Thunderf00t)
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