Aug 28, 2016 | By Andre

For any 3D printing to ever take place on a spool based FDM 3D printer you require plastic filament to satisfy the role of the toner cartridge found in traditional 2D printers. And just like with their 2D counterparts, filament in its pre-packaged 3D printable form is much more expensive than if you sourced the ink, or in this case plastic yourself. All you need to make your own is a personal filament extruder such as Filabot or Filstruder and the raw plastic pellets (which can be had for about a fifth the cost of what you’d pay for filament on a spool).

But maybe you’re like Instructables user Pa Lemur and couldn't be bothered to pay for the pellets when there’s free plastic lying around in just about every recycling bin on earth. And heck, for anyone that’s done a lot of 3D printing in the past, you know the waste produced from failed 3D prints alone might be enough to convince you to make your own 3D Printer Part Recycling Grinder.

Although I should warn, unlike many Instructables projects mentioned on our site, this one isn’t for the casual weekend Maker. Without access to a machine shop, Pa Lemur only had the basic tools available in his garage and admitted the project took roughly 40 hours to complete.

The concept behind the grinder works in a fashion similar to scissors with a progressively forward closing cutting faces. Everything is held together with more bolts than are necessary to increase stiffness and the construction of the tool described as anything but pleasant.

Further descriptions of the process to manufacture the plastic grinder include everything from “incredibly labor intensive and fairly time consuming” to “you need to be capable of high intensity work for hours at a time.” A limited disclaimer even concludes with “don't start this without assessing your own physical and time limitations.”

But if you are one that wouldn’t mind hours of hard labour to crush free plastic to feed into your filament extruder and are in possession of a decently equipped tool shed, please read on. If you think about it, the approximately $52 worth of raw materials necessary to build the device is just over what you might pay for a single 1kg spool of filament. What would you rather have, a machine that can convert free plastic (not factoring in the cost of the extra calories you’ll need to consume to  operate the device) into filament forever or a single spool for that same price?

While no 3D printing or knowledge of electronics are needed for the project, gluing, metal part filing, cutting, rotary tools, abrassive wheels and a drill capable of plowing through metal are all required elements to complete the device.

Once all the parts are cut correctly, assembling the grinder involves stacking, threading, drilling and repeating until eventually all the blades fit next to each tight and together as a completed 3D Printer part recycling hand made grinder.

Tests from the Instructables prototype show it is capable of cutting up parts upto 1/4” thick in solid PLA wall but realized it might have difficulty with sturdier materials like polycarbonate.

One of the drawbacks is that the blade for chopping things up is about 0.5” square opening which means only very little pieces can go through for grinding at a time. Also, it was noticed that some PETE plastic got hung up in the blades at times but at the end of the day this is a work in project.

It’s possible that the hard work and dedication to practically forge the grinder together won’t pay off by way of saving money on material. But what is certain is that someone out there decided he wanted to make his own filament from old plastic, got his hands dirty and got it done. And on top of that, was generous enough to share his experience and tutorial with all of the internet to see (for no cost at all).



Posted in 3D Printing Materials



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MarcC wrote at 8/29/2016 11:17:12 AM:

Good attempt however video shows that its not quite there yet suggest that rotor blades have a small hook or return so that material can be caught and dragged sequentially into shredder. Additionally also possibly too large of a gap between stator and rotor components dragging material in and creating high friction. I always wounder if people who attempt to recycle polymers understand that many of them are like chalk and cheese, many of the PET grades once processed their properties are changed dramatically and become almost unusable afterwards unless they are further processed.

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