Filament Extruder
Towards the end of my junior year of high school, my group and I worked on a project that was based off of a human centered design. I was the project manager and I wanted to involve the environment in this project, and implement my love for 3d printing. I had the idea of making a machine that would take plastic recycling or failed prints from the 3d printer, and convert it back to filament.  I wanted to get my school involved, so I decided to redesign the recycling system here at MHS to be a comprehensive system that separates plastic from paper. We would then use the plastic that we collect through recycling to make recycled 3D printer filament, therefore putting the recycled plastic to good use! As you can see, the picture on the right is a CAD model I designed, which was my final prototype and what I based the construction off of.
Materials and explanations
PLA (Polylactic acid) is a plastic substitute made from renewable resources such as starch, sugar cane, or usually corn, which is used in the 3d printing industry to produce physical objects by melting PLA into a very hot extruder, which lays the plastic out layer by layer. Plastics that are derived from biomass, are known as bioplastics. For years now PLA has been used as an alternative to most plastics which are made from the polymerization of nonrenewable resources. PLA is biodegradable, and has very similar characteristics with polypropylene (PP), polyethylene (PE), or polystyrene, which are seen in many plastic grocery bags and plastic bottles. This type of plastic can be produced using already existing petrochemical industry plastics, which makes it very cost efficient to produce. Since 2015, PLA has been the second largest production volume of any bioplastic, other known as thermoplastic starch. Much of these plastics take 6-12 months to successfully biodegrade. In order to convert failed PLA 3D prints as well as recycled plastics, I would need to create a machine which heats up this plastic at a specific temperature, with a large auger drill bit pushing this plastic to the end of a metal pipe through a nozzle that is slightly larger than the filament you desire. The materials for this construction would include a cartridge heater (used in 3D printers), a metal pipe, a nozzle of desired filament diameter, a gearbox motor, a pid controller (controls cartridge heater temperature), a solid state relay, a fuse, a 12v power supply, and of course, some failed 3D prints and plastic bottles.
Melting point of pla: 180°-220°
Melting point of polyethylene terephthalate(plastic bottle): >500°
Blueprints
Click photos for descriptions
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