DIY Filament Extruder

If you own a 3D printer, you know the struggle when you return to retrieve your print, only to find a pile of garbage instead of a beautiful part. By now, I already have an entire bucket full of failed prints. Instead of throwing them in the trash, I want to recycle them into new filament. After a quick search on the Internet, I couldn't find any filament extruder that I, as a student, could afford.

That's why, I decided to start designing and building my own filament extruder from scratch using Fusion 360. It was a fun project with a lot of troubleshooting needing to be done and many challenges on the way. Although I wouldn't advise anyone to directly replicate my machine, mostly because of the many compromises being done while designing and building this machine, due to my lack of knowledge and the fact, that I wanted to use and recycle already existing parts, I think it's a great starting point for inspiration. However, if you do want to build this exact machine, I've provided as many parts as I could find in a parts list as a PDF.

Of course it won't be factory quality but I think its a really great way of getting a lot of Filament, basically for free. Especially if you just print practical Parts, where the look don't matter.

Anyway, I hope you like this project. Please leave a comment if there are any questions or corrections.

Cedrik

This Instructable was written for the green future Challenge, but due to high shipping times here in Germany I wasn't able to finish the building and testing before the contest ended, that's why I wrote this Post as if I had already finished this project, to not further confuse any reader, of course will it be updated in the Future as soon as the parts arrived at my home.

DISCLAIMER: Please note that I do not assume any responsibility or warranty for the safety, functionality, or any other aspects of the information or instructions provided by me. The use of these instructions or information is at your own risk. I do not accept liability for any damages, direct or indirect, that may result from the use of the provided information, instructions, or materials. It is the responsibility of the user to ensure that all safety precautions are taken and all instructions are followed properly. I strongly recommend reviewing the relevant safety guidelines and seeking professional advice before starting any project.

For easy accessibility I provide the part-list as a PDF. Feel free to modify the lists, so that they fit your needs, because many parts where just used, because I had them lying around. You can also find a 3D model via the printables Link, which should give you a good Idea of the shape and look of the Filament-extruder. Last but not least there is also a circuit diagram and the Source code.

3D-files:https://www.printables.com/de/model/860911-diy-filament-extruder

At first, we will need to 3D print all the necessary parts for our machine. To obtain the 3D files, designed in Fusion 360, simply follow the printable link above and download all the files with "print" at the beginning of their name.

Your settings aren't that important; I personally used 20% infill, two walls, and a 0.6mm nozzle for most prints. As for material, I used PETG, but feel free to use PLA, ABS, or whatever you prefer. The only print I made with a higher wall count of four and 50% infill was the "print_motor-connector.stl" as it has to withstand quite a lot of torque.

First, we need to start with the base plate that will carry all of our parts. I used a 20x40cm wooden plate and screwed four 3D-printed feet onto each corner. To hold the extruder, we will need two 20x20cm wooden plates positioned about 10cm apart, which will be secured with angle brackets (it doesn't matter which ones you choose as we won't be handling a lot of force). Drill a 35mm (its the outer diameter of my tube) hole in both plates at the same height (I measured 5cm from the top). Take your time with this step because it is crucial for the motor to be aligned at a 90° angle relative to the tube.

Now for the most important part: the extruder. We start with the aluminum pipe, which we then insert into the holes of the wooden pieces. After this, we insert the drill bit as the spindle and attach the motor via the 3D-printed holder to the back.

At the front end of the pipe, we add three heat zones. Each zone has two heating resistors, which are glued on opposite sides of the pipe. I glued a piece of thin aluminum on top to improve heat distribution, with each zone covering about 4-5cm. Position the zones with a 90° rotation. Each zone will have a thermistor, strapped to either side.

For the front, we glue (or screw, if you prefer) an endcap with a small hole of about 2mm. When you pull the filament onto a spool, you usually apply a bit of tension, which makes it thinner.

For the electrical installation, make sure to follow the circuit diagram. Don't get confused by my positioning and cable management; the PCB tends to get messy very quickly.

We start with the motor, which we will connect to the positive pole of the power supply via the MOSFET (I used the IRFZ44N). Then, connect it to ground and the PWM pin D3. You can add a diode to protect the microcontroller from high current due to incorrectly connected wires, etc. The same setup will be repeated for the three heat zones. You can optionally add an LED with a suitable resistor to each of the wires coming from the MC if you want status LEDs.

For the thermistors, we will build a voltage divider with a 100k OHM resistor as the known resistor. Then simply connect it to the corresponding analog pins on the MC, and you're ready to go.

Note: Additionally, there will be a display and buttons, but for now, I will do everything with the serial monitor on my laptop for testing purposes. As soon as all the missing parts arrive, I will update this section as well.

Programming the MC is really simple, just download the Arduino IDE from their official Website, connect your Arduino via the provided wire. Choose your Port and your Board, load the provided file in the IDE, upload it to your MC, and then you'r ready to go.

Note: In the Future there will be updates which include the Display, Buttons etc.

One great advantage of this project is that you can find many of the materials you need in your own household waste. Common types of plastic found at home include Polypropylene (PP), Polyethylene Terephthalate (PET), and High-Density Polyethylene (HDPE). These plastics are found in many everyday items such as food packaging, beverage bottles, and cleaning product containers. They are well-suited for this project because they are durable and relatively easy to work with.

On the other hand, some plastics are less suitable, such as Polycarbonate (PC). Polycarbonate is often used in products like CD cases and reusable water bottles. While it is a very strong plastic, it can become brittle when processed and is more difficult to recycle. Therefore, it is better to use plastics like PP, PET, and HDPE, as they are more readily available and easier to handle.

If you live in Europe you can look out for symboles like above to identify which plastic you're currently dealing with.