As the world continues to drown in plastic, the 3D printing community needs to step up and use sustainable methods. The plastic waste still poses an ecological challenge as it finds its way into landfills and pollutes our oceans. To make matters worse, some plastics can take up to a thousand years to fully decompose. But the future doesn’t have to look so bleak because 3D printing enthusiasts can resort to green printing methods and recycle the material from unsuccessful prints and excess filament.
Your 3D trash can easily become a 3D treasure. So let’s reduce plastic waste by learning how to recycle 3D printer plastics such as PETG and PLA.
How is Plastic Recycled?
Plastic materials are sent to a recycling center where they are cleaned, sorted, shredded, and melted down into usable plastic pellets. This process is quite complex because plastics come in different varieties and they mustn't be mixed or contaminated with other materials or they will lose their strength and durability.
There are two types of plastic: thermoset plastics, also known as thermosets, and thermoplastics. Thermosets are plastics that are hardened by curing liquid polymers and resins to obtain a final shape. Thermoplastics on the other hand don’t involve any curing process. They can be molded into shape as soon as they’re heated beyond the plastic’s melting point. Keep in mind that when we’re working with 3D printers, we’re dealing with thermoplastics.
In theory, all thermoplastics can be recycled with varying degrees of efficiency. In reality, not all of them are created equally and some types of thermoplastics may not be processed by the recycling plants in your area. For example, the most common plastics are HDPE and PET, which are used to make plastic bottles. So most recycling facilities are built to process these materials. Another example is PVC, which is heavily recycled in Europe but not as much in the US.
Now, the question is: can 3D printer filament be recycled?
Recycling 3D Printer Filament
The short answer is YES! Most 3D printer materials can be recycled. However, chances are you can’t recycle them with the rest of your plastics. The two main types of printer filament, PETG and PLA, aren’t recycled together with the plastics found in most households. This means that most municipal recycling plants don’t have the means to recycle them, so we can’t simply get rid of our failed projects. Even though PETG is similar to PET/PETE, it has a low melting point and it can reduce the stability of the PET material if they’re recycled together. PLA has the same problem, but it’s made out of biodegradable materials (sugar cane, cornstarch) so it can be composted in appropriate facilities.
The simplest way to recycle 3D printed objects is to contact a recycling facility and ask if they can take them off your hands. You may also find filament recycling services that will be willing to take your unsuccessful prints. Just ask your filament supplier or the manufacturer for options. Some of them offer programs for collecting scraps and they may even reward you. But if you’re an enthusiast and you print a lot of objects as a hobby or for work, you should consider purchasing a recycling machine.
Filament recyclers are the best way of reusing the material from your failed prints and spend less money on the filament. They’re designed to grind the plastic, melt it, and turn it into a new spool of filament. Just keep in mind that some of them will only grind the material while others melt it, so you might need two machines. However, investing in a recycling system can be quite costly and it might not be worth it if you don’t use your 3D printer often. Fortunately, you can also take the DIY path for the most part and create your system.
You can build your own shredder by following online tutorials and checking out open-source designs. Manual shredders are quite easy to make. Some printing enthusiasts have even resorted to using powerful blenders, but that might not be the best idea. Grinding plastic requires a lot of power and most home appliances simply don’t have a powerful enough motor. The simplest solution is to purchase an industrial shredder or make your own.
Next, we need the filament extruder. This is the tough part if you take the DIY route. Building an extruder requires a lot of tools that you might not have. So buying one might make more sense. Again, you have to compare the cost of the amount of filament you’re using with the price of an extruder or full recycling setup. Just keep in mind that some extruders will only extrude PLA and ABS properly and they might not work so well with other materials. Always check the label and the fine print!
But what if you don’t need a recycler or you don’t have the budget for one? Fortunately, there are other options.
Repurposing Filament Scraps
Consider repurposing your filament scraps and print pieces. If you don’t produce many printed objects, using a recycler isn’t worth it and recycling centers won’t be interested either. In that case, you can mix up your leftover filament strands, take your unsuccessful projects, and smash them up into little pieces.
Place everything on a leveled surface, cover them with a piece of cloth or a towel, and smash them to bits using a mallet. Once you end up with a collection of tiny plastic pieces, take a non-stick oven tray or a baking sheet and place everything inside the oven until it melts. PLA will melt at around 130-180℃ and PETG has its melting point at 260℃. Both temperatures can be achieved in a standard kitchen oven.
Once the plastic reaches its melting point, you can get creative and create a lot of items that are useful around the house or decorative. For example, you can use food-grade resin to seal the plastic and use it as a cutting board. You can also cut out coaster shapes and keychain accessories.
You’ve done everything in your power to recycle your plastic waste, but you still didn’t manage to go green? Start using PLA and compost it when it’s no longer usable.
PLA is biodegradable, unlike PETG. This means that it eventually breaks down thanks to water and hardworking bacteria and fungi and it doesn’t take hundreds or thousands of years for that to happen. You can have a PLA compost pile at home, especially if you live in a humid environment. Under the right conditions, it can take up to a year, which isn’t bad when considering that PLA is still a type of plastic. However, it can take longer than that if you live in a dry environment.
The good news is that even if your PLA waste ends up in a landfill, it will still decompose due to water and bacteria. Just make sure you don’t mix it with your regular compost because it doesn’t degrade at the same rate and it can leave toxic residues. You don’t want that in your natural fertilizer mix!
How to Prevent Plastic Waste?
Recycling isn’t the only method of reducing 3D printer waste. Dealing with your plastic build-up is easier when you do everything in your power to prevent it in the first place. Even though we can’t avoid having failed prints, we can still reduce the amount of waste buildup by following these tips:
- Use fewer supports: Using supports is helpful and sometimes necessary, but they’re not needed for every project. Try improving your designs and workflow to remove as many supports as possible. For example, you can use programs like Simplify3D to manually reduce the number of supports. In addition, you can improve the design of the supports and make them simpler.
- Slow down and take it easy: One of the most common reasons behind a failed project is printing too many pieces all at once. When a part fails, it will negatively impact the others that support it and make them unusable, thus creating a lot of plastic waste. It’s preferable to divide your project into multiple stages and go through several prints instead of doing everything in one go. Keep in mind that this depends a lot on your printing experience, but it’s usually better to play it safe anyway.
- Buy recycled filaments: Filament made from recycled plastics is available and by buying it you will contribute to increased sustainability. You can also recycle this type of filament again after using it and further reduce your environmental footprint.
By combining conventional recycling methods with PLA composting and filament repurposing we can significantly reduce our impact on the environment. So start recycling your unsuccessful prints, buy recycled filaments if possible, and repurpose as much of the material as you can. There’s enough plastic waste in the world. Let’s be responsible 3D printing enthusiasts!