A Nema14 Dual Driver Geared Extruder

In an earlier post Dual Drive Geared Extruder I described a dual drive geared extruder made entirely from scratch and explained why this design could be better than others projects of geared extruders. With ABS and hot end set to 220C and a 0.4 mm nozzle the extruder yielded a flow rate of 25 mm3/s, a good result. But the overall assembly was bulky (but no problem if its used as a Bowden extruder). In a new post Nema14 Dual Drive Geared Extruder I describe a more compact version of a Dual Drive Geared Extruder, made with a Nema14 motor. The motor/drives transmission rate was 69:15. The motor used (Applied Motion model 5014-819) was saved from an old table scanner. Each motor coil have a resistance of 3.8 Ohms and a recommended motor current of 0.5 A. A A4988 driver from the RAMPS1.4 shield can easily run such a motor, but as the motor size and current were small, I wondered if I could obtain a reasonable flow rate. To my surprise, I could obtain a flow rate of almost 22 mm3/s, similar to the former development. At the end of this post is a video that shows a test of the extruder. It was possible to obtain 1.75mm filament feed rates of almost 10 mm/s (or flow rate of almost 25 mm3/s) without slipping or motor stalling.

Pretty nice! It's always nice to see people trying stuff like this.

I suspect that you'll get different numbers when the nozzle is positioned a typical layer thickness away from a print or bed.

I worked on a different type of geared extruder years ago, when 3 mm filament was still a thing...

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

As previously stated, no need for such compexity when using a properly made hobbwheel with sharp teeth and of a bigger diameter than the common ones (most are just regular small module gear).

I saw the hobbgear you made and althoguh the teeth seem sharp, the diam is too small and therefore not that many teeth biting the filament. Stainless steel is not the best material either. Personally I use soft steel that I caseharden.
Far easier to get sharp and very hard teeth that way.

Edited 3 time(s). Last edit at 02/23/2020 12:30PM by MKSA.

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

last time I ordered dual gears from china it was $3.50 with the bearings and one axle. got a second axle with some more bearings for cheap. I really want see improved designs that can reduce the weight reduce the size.

Edited 1 time(s). Last edit at 03/29/2020 11:16AM by longbeardpolymer.

My original printer is around 7 or 8 years old now and still uses the same filament drive. I think I made it from stainless, non hardened steel - anyway, its still operating perfectly well after all these years. For me, it's the design of the wheel that makes the difference. I made mine then and on my later printers using a tapped "V pulley" style groove - not a round groove. They exert plenty enough force even on 1.75mm filament.

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Waitaki 3D Printer

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waitaki
My original printer is around 7 or 8 years old now and still uses the same filament drive. I think I made it from stainless, non hardened steel - anyway, its still operating perfectly well after all these years. For me, it's the design of the wheel that makes the difference. I made mine then and on my later printers using a tapped "V pulley" style groove - not a round groove. They exert plenty enough force even on 1.75mm filament.

This just reminded me that I have one tiny MK8 style gear that I once bought that didn't have much thread on it, more like scratches in the metal instead of real teeth. Maybe I can add some deeper grooves myself with a 3mm tap...

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