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Today, there are two ways to recycle 3D printed parts. You can turn the plastic back into material that can be reused for 3D printing. Or you can use the recycled plastic to make objects used in other manufacturing processes, such as injection molding.
The extent to which your plastic waste materials can be recycled depends on the type of 3D printing you choose.
There are also an increasing number of opportunities to recycle materials, as an exciting collaboration between HP and the Ford Motor Company demonstrates.
Understanding plastic recycling
You can split 3D printing plastic materials into thermoplastics, thermoset plastics and, elastomers.
Thermoplastics
Thermoplastics are used by nearly all Fused Deposition Modeling (FDM) 3D printers because when they’re heated past their melting temperature, they become pliable and workable. They are also used by powder bed fusion processes like Multi Jet Fusion (MJF) or Selective Laser Sintering (SLS). Thermoplastics don’t need to be cured which means that, in theory, the polymers can be re-melted and recycled.
But different thermoplastics are easier to recycle than others, and not all recycling facilities are able to recycle the same materials.
Thermoset plastics
Thermosets are materials like polyurethane or silicone that are molded and then cured. They’re most commonly found in the resin used for vat polymerization 3D printing processes such as Stereolithography (SLA).
It’s often the case that thermoset plastics need curing. While this makes them perfect for high temperatures, it also means that they can’t be recycled with current recycling methods.
Elastomers
Elastomers can be natural – rubber, for instance – or synthetic, such as thermoplastic elastomer (TPE). There are also thermoplastic rubbers, a type of copolymer made with rubber and plastic. They aren’t widely used in 3D printing and are not recyclable.
Is 3D printing filament recyclable?
Nearly all 3D printer filaments, including nylon and polycarbonate, are classified Type 7 or “Other” by standards organization ASTM International and are not typically recycled by municipal programs. This includes acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), and polyethylene terephthalate glycol (PETG).
Polypropylene (PP), used in 3D printing for printed parts that are durable, water-tight or light, is recycled in some municipalities.
Some materials recovery facilities do pick up #7 curbside, but 3D printed parts will need to be marked with a Resin Identification Code (RIC). This is a code inside a triangle seen on almost all plastic products that identify different types of plastic.
If you don’t use an RIC, your potentially recyclable 3D printed parts containing recyclable filaments will be unmarked and will not be collected curbside.
The best way to find out if your local materials recovery facility will recycle 3D printed objects made from ABS, PLA, PETG, or nylon is to ask them — and also to ask your material supplier for waste characterization guidance.
Designing to reduce plastic waste
Disposing of your 3D printing waste can be a challenge. The trick is to do your best to prevent it in the first place by designing parts intelligently:
- You can eliminate supports wherever you can or design them into the part itself.
- When choosing your industrial 3D printer, consider powder bed 3D printing technologies like MJF that can print large builds filled with hundreds of items.
- Where the print bed is the support base for the 3D printed part you’re building – with Fused Deposition Modelling (FDM) or Fused Filament Fabrication (FFF), for instance — always make sure the beginning layers are adhering to the bed. If they’re not, there’s more chance of failed prints and wasted parts.
Make sure your printer is maintained regularly so it’s reliable and there’s less chance of print failure.
Learn more about how to design parts to reduce material usage by reading our articles on “Design for Additive Manufacturing” and “How expensive is a 3D printer to maintain?”
Case study: Transforming 3D waste into automotive parts — an industry first
Since early 2021, HP and the Ford Motor Company — together with international oral care leader, SmileDirectClub and resin producer, Lavergne - have been pioneering the recycling of 3D printer waste into low-volume vehicle parts. The parts have better chemical and moisture resistance than conventional versions, are 7% lighter and cost 10% less.
The process involves Lavergne, a longtime recycling partner of HP, transforming SmileDirectClub’s dental aligner molds (3D printed with HP Multi Jet Fusion) into high-quality recycled plastic pellets, that can then be used for injection molding of fuel-line clips for Ford. This remarkable new approach has the potential to revolutionize customization of low-volume vehicle parts and accelerate sustainability.
HP and Ford have already identified at least ten other fuel-line clips on other Ford vehicles suitable for being made with 3D printing waste and are working on injection molding those designs.
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