Plastic Pellet Maker

Getting custom colors for my desktop injection molding machines is a challenge. Most production injection molding machines use a screw to mix and compress (and heat) the plastic before injection. Those machines allow you to use raw plastic along with a colorant called masterbatch to create just about any color you want.

But my machines are plunger-style machines, and therefore do a very poor job mixing the masterbatch into the raw pellets. So I hatched a plan to use a Filastruder to extrude custom filament and then chop it into pellets.

I started by creating the chopper (I still haven't built the Filastruder, for reasons I'll explain below). I have videos below that take you through my development process until the final version.


You can download the STL (for 3D printed parts) and STEP (for machined parts) from here:


Most of the following links are all "Amazon Associate" links, which means I get a small amount from Amazon. This supports my efforts in a small way without any cost to you.

Development Videos

Pellet Maker Part 7

This is the final version, which uses aluminum parts instead of 3D printed parts for the frame (the 3D printed parts tended to break easily). I've chopped quote a few roles of filament using this version.

Pellet Maker Part 6

I create 3D-printed parts that allow for precise speed control of a Chicago Electric 98179 corded drill (available from Harbor Freight). I also ground flats on the shaft of the forstner bit so it doesn't slip in the drill chuck.

Pellet Maker Part 5

This is the episode where I ground a back relief into the forstner bit. This also goes over the wiring for the stepper motor controller I used.

Pellet Maker Part 4

Pellet Maker Part 3

Pellet Maker Part 2

Pellet Maker Part 1


  1. Great work am looking to start a plastic recycling business knowing it can be done is nice though I can't understand any of the gadgets

  2. Hi John. I'm very happy to see your progress on this project. Would you be able to make the stl files from prior versions of this available? I would like to try to make the 3D printed parts more rigid, as I don't have access to CNC. Thank you! -Mike


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