Recycled PLA Filament
When we first started experimenting with recycled PLA filament in the 33d.ch workshop, the half-empty spool of standard PLA lay next to the machine – and the question hung in the air: Is the recycled stuff really suitable for everyday use, or is it just for the conscience? After a few calibration cubes, failed clips, and a rather deformed housing, it was clear: The differences to classic PLA are smaller than many think – but they decide in everyday life whether your parts will hold or break at the wrong moment. Studies show that recycled PLA can significantly reduce environmental impact and greenhouse gas emissions with similar print quality, if recycling and energy use are organized cleanly (sciencedirect.com) (ncbi.nlm.nih.gov).
In this post, we summarize what we at 33d.ch look for in recycled PLA: from the basics and preparation to step-by-step settings on the printer – including typical pitfalls that happened to us at the beginning. The target audience is hobby makers, schools, and SMEs who want to set up a noticeably more sustainable 3D printing setup with reasonable effort, without making major compromises on print quality.
Source: Own depiction
Basics & Benefits of Recycled PLA
When using recycled PLA filament it practically comes down to two things: Firstly, the print quality must be right – meaning a clean print surface, reasonable dimensional accuracy, and sufficient durability for your application. Secondly, you want to improve your ecological balance without having to worry about clogged nozzles or brittle parts with every print run ( (sciencedirect.com).
PLA itself is a bioplastic, usually made from corn or sugarcane starch, which can have a more favorable CO₂ footprint compared to traditional petrochemical plastics – especially when energy consumption and disposal are also considered ( (ijert.org) (sciencedirect.com). Recycled PLA (rPLA) is produced when production waste, rejects, or used PLA components are crushed, reprocessed, and extruded into filament again – often as a mixture of recycled and new material, sometimes with a very high recycling content ( (mdpi.com) (filamentive.com).
Several studies show that the mechanical properties of recycled PLA in terms of tensile and flexural strength are often only slightly below those of fresh PLA, sometimes even very similar, as long as the material has not been remelted too often and the process is managed cleanly ( (mdpi.com) (sciencedirect.com) (sciencedirect.com). Manufacturers like Prusa or Filamentive report that their rPLA filaments are as easy to print in everyday use as standard PLA and are suitable for prototypes, gadgets, enclosures, and everyday objects ( (prusa3d.com) (filamentive.com).
Regarding the ecological footprint: A life cycle assessment of PLA shows that recycling PLA causes significantly lower greenhouse gas emissions than incineration or landfilling, as material and energy are used again ( (ncbi.nlm.nih.gov). Manufacturers of recycled filaments refer to CO₂ reductions of around 35 to over 50 percent compared to non-recycled filament, when production and material origin are taken into account ( (filamentive.com).
If you generally want to print more sustainably, you can recycled PLA combine with recycled PETG (rPETG), rPET, or recycled polypropylene. This covers different temperature ranges and loads while remaining with materials with a reduced resource footprint ( (materially.eu) (3dtrcek.com) (packagingeurope.com).
rPLA in comparison – rough guide
| Application | Standard PLA | Recycled PLA | rPETG / rPET |
|---|---|---|---|
| Prototypes, decoration | Very easy to print | Very easy to print | Good, slightly more challenging |
| Functional parts indoor | Limited temperature resistance | Similar, slightly more brittle possible | Significantly more robust and tougher |
| Ecological footprint | Better than ABS, but virgin material | Significantly less primary material | Less primary material, complex process |
In our projects at 33d.ch, we use rPLA wherever parts are regularly replaced or have mainly visual and light mechanical requirements – for example, sample parts for customers, holders in labs, or simple enclosures for sensors. For heavily loaded clips and parts in mechanical engineering, we often opt for rPETG or technical plastics, but consciously keep rPLA in mind for everything that should meet the 'sweet spot' of everyday usability and more sustainable material.
Preparation & Setup
Before you start, a clean setup is worthwhile: You need an FDM 3D printer with a well-calibrated motion and extrusion system, ideally with a heated print bed and a location without drafts ( (lancashire.ac.uk). For recycled PLA filament the same types of printers are suitable as for standard PLA, but filament handling and cooling are a bit more important. Many rPLA filaments run at 190 to 220 °C at the nozzle and 40 to 60 °C at the heated bed – the exact values are in the data sheet ( (filamentive.com) (prusament.com).
A 20 mm calibration cube and a small functional part have proven effective as test objects, for example a hinge or a clip that you will actually use later ( (printables.com) (printables.com). This way, you can quickly see if dimensional accuracy, surface finish, and layer adhesion are right.
A dry storage location for your filament is essential: a closed box with desiccant, ideally with a hygrometer. rPLA also absorbs moisture, which is reflected in bubbles, a rough surface, and poor layer adhesion ( (nice-cdn.com). If the filament "crackles" during printing or extrudes very matte and porous, a drying cycle is worthwhile – often at around 50 °C for a few hours ( (nice-cdn.com) (filamentive.com).
Quick check before the first rPLA print
In our workshop, this quick check has proven useful before the first print with a new rPLA spool: The printer is stable and draft-free, the bed is leveled and clean, a functional PLA profile is loaded in the slicer, the filament is dry and free of knots, test models and calipers are ready, and you have a rough idea of how long the print will run and approximately how much material will go through ( (3dbenchy.com) (ncbi.nlm.nih.gov). If these points are checked off, the chance is very high that the first rPLA run will be more exciting than frustrating.
In terms of power consumption, we see values of around 100 to 150 watts in continuous operation for typical desktop FDM printers in customer projects, depending on the device and temperature. Over several hours, this quickly adds up to 0.8 to 1.2 kWh ( (snapmaker.com) (solartechonline.com). Printing multiple smaller parts at once instead of each holder individually saves not only time but also energy.
Step-by-step: Introducing rPLA in everyday life
Source: filamentive.com
Step 1: Define the goal and choose test parts. Consider what you want to cover with recycled PLA filament : decoration, prototypes, enclosures, lightly stressed functional parts, or recurring small series ( (filamentive.com). For this, take a 20 mm calibration cube for dimensional accuracy and a hinge or clip that snaps into place – this way you'll immediately feel the layer adhesion ( (printables.com) (printables.com). We internally like to use 3D Benchy or small enclosures as well, to immediately see typical problem areas like overhangs and bridges ( (3dbenchy.com).
Step 2: Create a reference print with standard PLA. First, print both test parts with your usual PLA profile (e.g., 0.2 mm layer height, 3 perimeters, 15–30% infill) at known temperatures and fan settings ( (filamentive.com). Note down the target nozzle temperature, bed temperature, speed, fan profile, and retract values – we have such a 'basic profile' visibly displayed on the wall for each printer. Later, you can directly compare rPLA against it ( (obico.io).
Step 3: recycled PLA filament set according to the data sheet. Then switch to rPLA, use the PLA profile, and only adjust the temperatures – for example, 200–215 °C at the nozzle and 50–60 °C at the bed for Prusament PLA Recycled ( (prusament.com) (prusa3d.com). Many manufacturers recommend the same or slightly higher target nozzle temperature as for standard PLA, because rPLA melts differently depending on the mix ( (mdpi.com) (sciencedirect.com). We usually start in the middle of the recommended range and pay close attention to the first two layers.
Step 4: Check print quality and dimensional accuracy. After printing the rPLA cube, measure the edges with calipers and compare them to 20 mm – deviations of ±0.1–0.2 mm are normal for many desktop printers ( (printables.com). Check the side surfaces in the light: clean layers, no prominent zippers, sharp corners like the PLA reference ( (3dbenchy.com). If you see fine gaps or underextrusion, a temperature increase of 5 °C or a slight flow correction usually helps.
Step 5: Test layer adhesion and function. For the hinge or clip, it gets serious: open, bend, click. Studies on recycled PLA show that tensile strength only decreases moderately with controlled recycling and remains close to fresh PLA ( (mdpi.com) (sciencedirect.com). In practice, this means for us: If a clip does not break immediately along the layers during normal use, but only under gross overload, we use rPLA for similar parts. However, if the clip has to withstand strong bending stress daily, we switch to PETG or rPETG ( (3dtrcek.com).
Step 6: Compare warping, smell, and surface. When starting the print, check if corners lift or if the first layer adheres unevenly. Many rPLA filaments behave very similarly to good PLA in terms of warping – meaning, practically warp-free with appropriate bed temperature and a clean Z-offset setting ( (filament2print.com) (spectrumfilaments.com). In terms of smell, we usually notice no significant difference in the workshop compared to normal PLA, which is a clear comfort advantage compared to ABS or ASA – good ventilation remains mandatory, however ( (3d-fabrik.at) (filamentive.com).
Step 7: Optimize energy consumption and slicer strategy. Studies on the sustainability of FFF printing show that, in addition to the material, print duration, infill strategy, and the electricity mix are decisive: Shorter print times, bundled jobs, and optimized infill patterns save energy and material ( (mdpi.com) (ncbi.nlm.nih.gov). An 8-hour print with around 0.1–0.15 kWh per hour amounts to roughly 0.8–1.2 kWh ( (snapmaker.com). If you model and slice your parts so that they are not bulkier than necessary, you save both electricity and rPLA ( (solartechonline.com) (sciencedirect.com).
Common Problems & Solutions
Uneven extrusion is one of the classic issues with recycled PLA filament : visible lines, thin spots, gaps in the infill. Often, fluctuating filament diameter or moisture in the material is the cause ( (filamentive.com). The combination of a good manufacturer (with documented diameter tolerance), dry storage, and slightly increased nozzle temperature often ensures a stable print surface ( (filamentive.com) (mdpi.com).
Another issue that annoyed us at the beginning: nozzle clogging with individual rPLA batches. In studies with recyceltem PLA it is described that in isolated cases clogging occurred while the comparison sample with fresh PLA ran cleanly ( (sciencedirect.com) (researchgate.net). Our practical solution: Hotends that are easy to clean, regular 'cold pulls', and in stubborn cases, a clear cut – different spool, different batch, different manufacturer.
The third problem we see, especially with functional parts: brittle breakage behavior after prolonged use or at lower temperatures. PLA generally loses toughness when it is heated repeatedly or aged significantly ( (ncbi.nlm.nih.gov) (sciencedirect.com). Repeatedly recycled PLA shows a decrease in impact strength in studies, while tensile strength often remains in an acceptable range with good process management ( (mdpi.com) (sciencedirect.com). For us, this means: rPLA is rather for moderately stressed parts and prototypes, not for safety-critical parts or spring mechanisms with continuous oscillation.
A real example from our workshop: A customer wanted strong clips for cable chains made of rPLA because the material fit the project ecologically well. The first print looked great, but some parts broke along the layers when clipping them in. We then increased the nozzle temperature, chose more perimeters, and slightly rounded the geometry – this made the clips significantly more robust ( (3dbenchy.com) (ncbi.nlm.nih.gov). For the final, permanently stressed clips, we ultimately switched to rPETG – rPLA remained in the project for prototypes and visual parts ( (3dtrcek.com).
Variants & Adaptations
Source: filament.ch
Once your rPLA profile is set, you can gradually expand your sustainable setup. An obvious direction is other 'green' filaments, such as recycled PETG, which is obtained from defined recycling streams and is designed for higher temperatures and greater loads ( (3dtrcek.com) (formfutura.com). Such materials combine robust performance with reduced use of primary raw materials – if recycling and production are transparently documented ( (materially.eu).
Recycled PP or PE-based filaments are also interesting, where research institutes and companies are actively working to transform packaging waste into printable filaments ( (packagingeurope.com) (materialdistrict.com). Projects like the collaboration between Fraunhofer IFAM and universities show that high-quality 3D printed products can be created from household packaging if sorting and processing work well ( (fraunhofer.de). However, in practice, we often find that such filaments are still rather experimental – in everyday use, we rely much more on rPLA and rPETG today.
There are also adjustment screws for the spool: rPLA manufacturers use cardboard cores or complete cardboard spools made from recycled, sometimes FSC-certified materials ( (spectrumfilaments.com) (formfutura.com) (filamentive.com). Prusament combines a cardboard core with light side parts made of recycled polycarbonate for PLA Recycled ( (prusa3d.com) (prusa3d.com). At 33d.ch, we consistently sort empty spools – cardboard goes into waste paper or is repurposed for holders and winding projects, robust plastic spools are reused internally as long as they are mechanically sound.
If you want to go a step further, you can shred rejected prints and leftovers yourself and re-extrude them. Desktop shredders like the Felfil Shredder+ transform old prints into granules ( (felfil.com). Systems like 3devo, ProtoCycler, or Recyclebot combine shredding and extrusion into new filament ( (3devo.com) (redetec.com) (wikipedia.org). Before you invest here, we recommend user reviews and guides – consistently good filament is more challenging than it looks at first glance ( (filamentive.com) (arxiv.org).
Source: YouTube
Recommended video: This YouTube video practically demonstrates how a specific rPLA filament behaves in printing, with close-ups of surfaces and sensible starting settings.
FAQ & Conclusion on Recycled PLA
Source: digitmakers.ca
Question 1: How strong is recycled PLA compared to normal PLA?
Laboratory studies show that
recyceltes PLA
with controlled recycling, it is often in the same range as fresh PLA in terms of tensile strength and stiffness, with sometimes slightly lower impact strength ( (mdpi.com) (sciencedirect.com). In our workshop, we notice the difference mainly with very thin or heavily stressed clips – for enclosures, holders, and sample parts, rPLA usually works without problems.
Question 2: What applications is rPLA particularly suitable for – and where not?
rPLA works very well for prototypes, decorative parts, interior housings, and lightly stressed functional parts ( (filamentive.com) (spectrumfilaments.com). It is less suitable – like standard PLA – for components above approx. 50–60 °C ambient temperature or for parts with high impact and continuous bending stress, such as spring mechanisms or exterior parts in direct sunlight ( (prusament.com) (filament2print.com). Here, we prefer to switch to rPETG or technical plastics ( (3dtrcek.com).
Question 3: How should I store recycled PLA?
rPLA should be stored cool, dry, and protected from light, just like normal PLA. Manufacturers recommend closed boxes with desiccant, especially for cardboard spools ( (nice-cdn.com) (filamentive.com) (formfutura.com). If filament audibly "crackles" or prints very roughly, a drying run at around 50 °C usually helps – this has saved several supposedly "bad" rolls at 33d.ch.
Question 4: Is a personal filament recycler worthwhile for makers, schools, or SMEs?
Systems like 3devo, ProtoCycler, or Recyclebot show that it is technically possible to reprocess rejected prints into filament ( (3devo.com) (redetec.com) (wikipedia.org). However, in practice, we see that consistent quality, clean diameter, and reproducible properties require quite a bit of know-how and maintenance ( (arxiv.org) (filamentive.com). For most schools and SMEs, it is more worthwhile to start with good rPLA and rPETG filaments and minimize waste before investing in their own recycling equipment.
Question 5: How significant is the ecological advantage really?
Life cycle analyses show that PLA recycling causes significantly fewer greenhouse gas emissions compared to incineration or landfilling ( (ncbi.nlm.nih.gov) (sciencedirect.com). Manufacturers talk about CO₂ savings of around a third and more when switching to recycled filaments ( (filamentive.com). In combination with short print times, sensible infill strategies, and – where possible – renewable electricity, the effect becomes much more noticeable in everyday life ( (ncbi.nlm.nih.gov) (mdpi.com).
Mini-conclusion: What you can get out of rPLA
- Use rPLA for prototypes, enclosures, and lightly stressed functional parts – here, the ratio of quality and sustainability fits particularly well.
- Keep a clean PLA reference profile ready and introduce rPLA systematically with test cubes and functional parts.
- Invest a little time in drying, storage, and temperature tuning – this prevents 80% of typical problems.
- Combine rPLA with rPETG or other recycled filaments if you need higher temperatures or more toughness.
- The greatest sustainability lever is achieved when material choice, printing strategy, and electricity mix are aligned.
Source: YouTube
Recommended video: This video clearly shows how rejected prints can be recycled into new filament – including the pitfalls that should be considered for your own recycling setup.