How to Recycle 3D Printing Filament Scraps
Print regularly and you soon have a box full of plastic: failed prints, snapped-off supports, brims, purge from colour changes. Throwing it away feels wrong, but tipping everything into one bag and calling it recycling does not work either.
This guide covers what counts as scrap, why sorting is the step that decides everything, and the three routes that follow: reuse it as it is, hand it on, or reprocess it yourself. Turning scrap back into printable filament has its own guide: make your own filament.
What counts as filament scrap?
FDM printing produces waste in more places than failed prints:
- failed and aborted prints
- support structures
- brims and skirts
- purge towers and purge waste from material changes
- calibration lines and test prints
- short lengths left over from spool changes
- retired prototypes and earlier versions
How much you collect depends heavily on how you print. A multi-material system produces purge waste at every colour change, and it adds up quickly. Single-colour prints with few supports leave far less behind.
The step that matters most: sorting
Whatever happens to your scraps later, they are only useful if you know what they are made of. Different plastics melt in different ranges, flow differently and have different chemistry. A mix of several polymers can hardly be reprocessed into anything worthwhile.
So keep materials strictly apart:
- PLA with PLA
- PETG with PETG
- ABS with ABS
- ASA with ASA
- TPU in its own container
- nylon (PA) in its own container
- carbon- and glass-fibre composites separate, ideally by base polymer
The easiest way is a few labelled containers right next to the printer, so every scrap goes into the right one immediately. A few weeks later, a grey failed print is often impossible to identify with certainty.
Scrap whose material you no longer know for sure does not belong in a single-material container. One wrong piece can spoil a whole batch for reprocessing.
Special cases: composites, support and colour
Carbon and glass fibre: filled filaments consist of a base polymer with fibres mixed in. They do not belong with plain scrap of the same plastic, because the fibres change how the material flows and how much it wears machines. More on these materials in the carbon fiber filament guide.
Soluble support: PVA or BVOH residue is not model material. A part with support material still stuck to it is no longer single-material scrap.
Colour: for reprocessing, colour comes second to the polymer. Mixed colours do, however, usually end up as a dark, muddy shade. If you want a particular colour later, sort by colour as well.
Multi-colour prints: a part printed in several colours of PLA is still PLA. A part combining PLA with PETG or TPU is almost impossible to separate and is no longer single-material scrap.
Route 1: reuse scraps as they are
Not every scrap needs reprocessing. Some of it is useful straight away:
- short lengths of filament for small test prints or calibration parts
- the end of a spool for small parts that need only a few metres
- failed but solid prints as spacers, jigs or test pieces
- failed prints and supports for craft, art or school projects
- old prototypes to compare against new versions
Keep short lengths as dry as full spools. A leftover that has lain around unsealed for months prints no better than an open spool. See storing filament.
Route 2: hand your scraps on
If you do not want to reprocess scraps yourself, there are several places sorted waste can go:
- Maker spaces and FabLabs: some workshops collect scraps to reprocess them or use them in projects.
- Municipal collection points: depending on the area, recycling centres accept certain plastics. Whether 3D-printing waste is among them is up to your local authority.
- Specialised 3D-printing recycling services: some companies accept sorted print waste by post and reprocess it.
- Manufacturer take-back schemes: a few filament makers take back empty spools or print waste.
These offers come and go, their terms change and many are limited to certain countries. Before you send anything, check which materials are accepted, whether they must be sorted and who pays for shipping. Clean, sorted scrap is accepted far more readily than a mixed bag.
Route 3: recycle it yourself
With suitable machines, single-material scrap can be turned back into printable filament. Roughly, the process looks like this:
- sort
- clean
- shred
- dry, depending on the material
- extrude
- cool
- measure and control the diameter
- spool
- check with a test print
Melting the plastic is the easy part. The hard part is a diameter that stays consistent along the whole spool. How the steps interact, what matters most and who it pays off for is covered in make your own filament.
What reprocessing does to the material
Every melt cycle puts stress on a plastic. Repeated thermal processing can change the polymer chains, and with them strength, toughness and flow. How much depends on the polymer, the temperature, how much moisture was in the material when it melted, and how often it has already been processed.
Filament made from 100 % recycled material is therefore not automatically equal to virgin material. It can work well for many uses, but test it before relying on it for loaded or dimensionally critical parts.
In practice, recycled material is often blended with virgin pellets to stabilise its properties and processability. There is no fixed ratio that suits every material and every machine: the blend depends on the input material, the process and what the finished part has to do.
Disposal: follow local rules
Scrap that is neither reused nor reprocessed has to be disposed of. No single rule applies in every country or town. Which bin or collection point is right is set by local regulations, and your local waste authority can tell you if in doubt.
PLA and compost: PLA is often described as biodegradable. That does not mean it belongs in a household food-waste bin or a garden compost heap. PLA breaks down under conditions found in industrial facilities, and whether a facility accepts it depends on local rules. More in the PLA guide.
Producing less scrap in the first place
The best scrap is the scrap you never make. A few levers:
- use supports only where the geometry needs them, and orient parts to need fewer
- in multi-material prints, cut down colour changes and check whether your slicer can purge into infill or a sacrificial object
- keep filament dry, since damp material is a common cause of failed prints
- try new settings on small test parts first
Read more: drying filament.
Frequently asked questions
Can I recycle all my filament scraps together?
No. Different plastics melt in different ranges and flow differently. Reprocessing only makes sense with single-material scrap: PLA with PLA, PETG with PETG and so on. Composites and unidentified scraps stay out.
Can PLA go in the food-waste bin?
Not automatically. PLA only breaks down under certain conditions, such as those in industrial facilities. Whether and where PLA waste may be disposed of is set by local rules.
Is recycled filament as good as new filament?
Not automatically. Repeated melting can change a plastic's properties. Recycled filament can work well, but test it before using it for parts that carry load.
Where can I drop off filament scraps?
Options include maker spaces, municipal collection points, specialised 3D-printing recycling services and take-back schemes from some manufacturers. Offers change and differ by country, so check the current terms before sending anything.
What do I do with purge waste from multi-material printing?
Purge waste is scrap like any other, though often in mixed colours. As long as only one polymer is involved, it can be collected as single-material scrap. If the printer switches between different plastics, the purge is usually no longer single-material.
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