Dec 26, 2014 | By Simon

Although pre-wound filament has been a go-to for ease-of-use for many 3D printing enthusiasts, the amount of users who are interested in printing from the cheaper pellet form has been growing exponentially on a seemingly monthly basis.

The downside however, is that a user would have to purchase or create a pellet extruder to create the filament that ultimately becomes their 3D print. While it makes logical sense for those who understand the process, it is yet another complicated step for those who are just starting out in the 3D printing world.

Perhaps one of the easiest-to-use systems that we've seen to-date is electronics engineer, product designer, salesman and self-described "problem solver" Richard Horne's (AKA RichRap) Universal Pellet Extruder. Not only is the pellet extruder well-designed and able to be replicated via free open source files, it is also attractive to the eye and functional with off-the-shelf parts that can be found nearly anywhere in the world.

According to Richard, "This whole area needs more development and a focus from the open-source RepRap community, makers and developers to refine a system to use all sorts of different granules and materials for 3D printing." We couldn't agree more. Thankfully, Richard has shared his entire process on his RichRap blog and has even outlined a variety of pellet materials that can work with his Universal Pellet Extruder.

Previously, Richard has been working on and off to design and test other types of extruders for granular materials for 3D printing, with an initial focus on using sugar due to the high success rate that he found with the edible material before moving his testing on to plastic pellets (resins) that are normally used for injection molding or creating traditional 3D printer filament.

With the ultimate goal of further advancing the open source 3D printing community, Richard has generously uploaded the 3D printable files to 3D printing sharing hub Youmagine in hopes that others will help advance the design and tweak it to their specifications.

As for how the Universal Pellet Extruder is built, Richard started with a J-Head Mk V-BV from HotEnds and a sawed-off 200mm long x 6mm wood Auger bit for feeding the pellets. He also incorporated a NEMA17 stepper motor with a Planetary gear box fitted in order to power the system.

From here, he designed the 3D printable housing that would ultimately house the pellets before they get fed into the auger (running counter-clockwise) and ultimately, extruded out of the J-Head Mk V-BV.

As for mounting the Universal Pellet Extruder, Richard incorporated one of his standard Quick-Fit carriage designs on-board the 3D printer to stabilize the system.

For testing the universal capabilities of the pellet extruder, Richard sourced multiple materials for testing and found success with a variety of sizes of pellets, however he came to the conclusion that smaller is better.

"At the start I cut up normal filament into small pellets - crazy I know, but at least it allowed some testing as I could not find many places last year that would sell me small batches of different plastic pellets."

After further testing of a multitude of material types, he determined that the pellets supplied by ColorFabb work the best in the machine, however it's important to pay attention to the size of the pellets when purchasing.

"The ColorFabb PLA pellets are not the same, they are 'pearls', and unfortunately don't quite work in this size of extruder," he adds. "I bought a lot of these not knowing the size, so check before buying pellets from wherever you manage to source them. "

Due to other projects, Richard ran out of time to further test the Universal Pellet Extruder, however he is excited about the possibilities and wants others to join in on furthering the design with him.

"I ran out of time with this project in the summer (2014) due to other projects and shows, so the files being released still need work and refinement to get to a working solution that can process many different types of material in pellet form….This is a very exciting project, do let me know what you think about it, all and any feedback is good. And if you decide to make one or want to evolve the design, please feel free and spread the word."

You can check out a more in-depth explanation of the project over at Richard's blog and download the project files over at Richard's Youmagine page.


Posted in 3D Printer Accessories


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