1 Topic by Claghorn

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Topic: Extruders that use pellets directly?

I keep stumbling across articles about large form 3D printers that have special extruders that use pellets directly rather than filament, but I've never seen any details about how these extruders work (and all my google searches seem to be cluttered with 10,000,000 results for pages that want to sell me pellets :-).

Anyone have any pointers to details on one of these extruders? I'm just curious about how the heck they work. The best I can visualize is something like a filastruder with the output feeding directly into a bowden tube :-).

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2 Reply by jagowilson

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Re: Extruders that use pellets directly?

There was one called Sculptify if I recall. The fundamental flaw with them is they have not effectively managed retraction yet.

3 Reply by Jmtyra (edited by Jmtyra 2015-01-29 03:13:34)

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Re: Extruders that use pellets directly?

RichRap has a downloadable design for a 'universal pellet extruder' and a blog post with details:
(Edit: tried to post a link, but the forum said 'no way'...Google "RichRap Universal Pellet Extruder")

It's on my to-do list of things to try. wink

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4 Reply by Claghorn

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Re: Extruders that use pellets directly?

Interesting. The RichRap design seems to use a drill bit as an auger - no trouble getting parts to try it out :-).

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5 Reply by elmoret

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Re: Extruders that use pellets directly?

Pellet extrusion printing isn't going to replace filament printing for a number of reasons, primarily:
you can't retract well
you can't mix color well (with pellets, concentrated color pellets are used)
you can't meter the feed precisely (depending on how pellets pack into the auger, expect flowrate to vary +/-30% while printing)
pellet based will be heavier than filament based, and therefore slower
etc etc.

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

6 Reply by elmoret

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Re: Extruders that use pellets directly?

Claghorn wrote:

The best I can visualize is something like a filastruder with the output feeding directly into a bowden tube :-).

Stratasys holds a patent on that.

https://www.google.com/patents/US201003 … &cl=en

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

7 Reply by Claghorn

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Re: Extruders that use pellets directly?

elmoret wrote:

Stratasys holds a patent on that.

Well, at least I visualized a patentable idea (though given some of the patents issued, that may not be much of a feat :-).

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8 Reply by Billsrf

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Re: Extruders that use pellets directly?

http://soliforum.com/i/?qpVRib3.jpg

elmoret wrote:
Claghorn wrote:

The best I can visualize is something like a filastruder with the output feeding directly into a bowden tube :-).

Stratasys holds a patent on that.

https://www.google.com/patents/US201003 … &cl=en

I hate to tell you that is a compounder for blending different types of filament. I'm not sure feeding a printer from a filament extruder is a patentable piece of equipment. it would fall under a natural process. Just my 2-Cents

9 Reply by joachim

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Re: Extruders that use pellets directly?

Hi Billsrf, A very interesting picture in your last post.  The most proffesional built pellet/granule extruder I seen.   Do you know where can I find more info about this extruder?

10 Reply by Billsrf

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Re: Extruders that use pellets directly?

Yes , I build these in my shop

11 Reply by joachim

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Re: Extruders that use pellets directly?

That's perfect. I just send an Email to you through this forum about the extruder.