The process of turning shredded plastic into filament involves sorting, cleaning, drying, grinding, extruding, and cooling the plastic. This way, you can recycle plastic waste and use it for 3D printing new objects. In this article, we will explain each step in detail and provide some tips and resources to help you get started.
The first step is to sort the plastic by type and color. Different types of plastic have different melting points and properties, so you need to separate them before extruding. You can use the resin identification code (RIC) to identify the type of plastic by the number and symbol on the bottom of the container. For example, PET (polyethylene terephthalate) is marked with the number 1 and a triangle, while HDPE (high-density polyethylene) is marked with the number 2 and a triangle.
You also need to sort the plastic by color, as mixing different colors will result in a muddy or dull filament. You can either choose to make single-color filament or create interesting effects by mixing similar shades of the same color.
Cleaning the Plastic
The next step is to clean the plastic to remove any dirt, labels, stickers, glue, or other contaminants. You can use a knife, scissors, or a heat gun to peel off the labels and stickers. You can also soak the plastic in warm water and detergent to dissolve the glue and wash off the dirt. Make sure to rinse the plastic well and remove any metal caps, rings, or other non-plastic parts.
The third step is to dry the plastic to remove any moisture. Moisture can cause bubbles, cracks, or weak spots in the filament, so you need to make sure the plastic is completely dry before extruding. You can use an oven or a polymer dryer to dry the plastic. The temperature and time will depend on the type and amount of plastic, but a general guideline is to dry the plastic at 160°C for 4 hours[^1^][2].
Grinding the Plastic
The fourth step is to grind the plastic into small granules or flakes. This will make it easier to feed the plastic into the extruder and ensure a consistent flow. You can use a shredder, a grinder, a blender, or a food processor to grind the plastic. You can also buy pre-shredded plastic from online suppliers or local recycling centers. The ideal size of the plastic granules is between 2 and 4 mm, but you can experiment with different sizes to see what works best for your extruder.
Extruding the Plastic
The fifth step is to extrude the plastic into filament. You will need a filament extruder, which is a device that melts the plastic and pushes it through a nozzle. You can buy a commercial filament extruder, such as the 3devo Precision 350, or build your own, such as the Recycle Plastic Into 3D Printer Filament at Home project. You will also need a spooler, which is a device that winds the filament onto a spool.
The extrusion process involves setting the right temperature, speed, and diameter for the filament. The temperature will depend on the type of plastic, but a general range is between 160 and 260°C. The speed will depend on the size and shape of the nozzle, but a general range is between 1 and 10 mm/s. The diameter will depend on the calibration of the extruder and the spooler, but a common size is 1.75 or 2.85 mm.
You can use a digital caliper to measure the diameter of the filament and adjust the settings accordingly. You can also use a filament sensor to monitor the quality and consistency of the filament. You should aim for a smooth, round, and uniform filament that matches the specifications of your 3D printer.
Cooling the Filament
The final step is to cool the filament to solidify it and prevent it from sticking or deforming. You can use a fan, a water bath, or a cooling tower to cool the filament. You can also use a traction system, such as a pair of rollers, to pull the filament and stretch it slightly. This will help to reduce the diameter and improve the strength of the filament.
You should store the filament in a dry and dark place, preferably in a sealed bag with a desiccant. This will prevent the filament from absorbing moisture and losing its quality.
Conclusion
Turning shredded plastic into filament is a great way to recycle plastic waste and create your own custom filament for 3D printing. By following the steps above, you can turn plastic bottles, containers, or scraps into useful and valuable filament. You can also experiment with different types of plastic, colors, and additives to create unique and creative filament.
We hope this article has inspired you to try this process and make your own filament. If you have any questions or feedback, please let us know in the comments below. Happy extruding!
