How Recyclable are 3D Printing Materials?
A few weeks ago I created a LinkedIn Poll, asking, “What is the most important, key environmental indicator when choosing a sustainable material?”
From the four options - Carbon Footprint, Recycled Content, Embodied Energy and Recyclability - option #4 came out on top, with 47% share of the vote.
This got me thinking. At Filamentive, we prioritise recycled materials, yet, there doesn’t seem to be as much industry transparency for the end-of-life (EoL) processing of 3D printing materials (once they become 'waste'); as indicated by the survey, 3D printing users care more about recyclability - rather than the recycled content - when it comes to assessing sustainability of a material.
This article will focus on assessing the recyclability for each of the main 3D printing (filament) materials.?
3D Printing Materials
Based on our 2021 production analysis, the following 3D printing materials (for FFF) have been ranked by volume (i.e., usage) - excluding co-polymers and derivatives of the same material:
How Recyclable is PLA Filament?
PLA filament is made from Poly Lactic Acid which derives from renewable, plant-based sources such as sugar cane.?
Because of its biological origin, PLA products are widely marketed as biodegradable. Whilst technically correct, PLA is PLA is ONLY biodegradable under commercial composting conditions. In practical terms, this is an industrial, heat-controlled environment.
As discussed in this article on the sustainability of PLA, there is no academic research proving that PLA is biodegradable in soil, home-compost or landfill.?
In terms of (mechanical) recycling, this is the lowest environmental impact end-of-life solution for PLA. However, practical access to such recycling is the challenge - without the necessary infrastructure in place, bioplastics like PLA can actually reduce recycling rates by contamination. However, innovative recycling businesses like Looplife Polymers, are working to change this.?
How Recyclable is PETg Filament?
Polyethylene Terephthalate Glycol – or PETg for short – is the second-most popular 3D printing filament. Due to its strength and ease of printing, it is recommended for applications requiring more durability, such as functional prototyping.
In a recent blog post exploring what makes a particular 3D printing material sustainable, evidence suggested that PETg was more environmentally-friendly - versus PLA - when it comes to recyclability.
Used to make everyday products such as soft drinks bottles, PETg is one of the most widely recycled plastics. As outlined by a UK council recycling site, any plastic product with a “number 1” indicates it is PET(g) and can therefore, usually, be recycled as local recycling centres but it is always important to check beforehand as some facilities differentiate between PET and PETg (added glycol).?
How Recyclable is ASA Filament?
ASA filament (Acrylonitrile Styrene Acrylate) is an engineering-grade material for 3D printing - surpassing the traditionally-used ABS for its’? enhanced properties - notably, UV resistance.
Whilst corporate literature claims it is easy to recycle, the UK information site, Which does not define ASA as recyclable (even at specialist points) - instead it would be categorised as code 7 - other which is destined for landfill.?
A potentially niche recycling solution for ASA is seemingly offered by a USA filament business, who (at the time of writing) are, “now accepting scraps of waste filament for recycling into new filament”.
How Recyclable is ABS Filament?
ABS filament (Acrylonitrile Butadiene Styrene) is a widely-used thermoplastic in a variety of manufacturing methods, such as injection moulding. Whilst decreasing in usage relative to other polymers, it is still used frequently in 3D printing, especially for industrial applications.
Again, whilst not widely recycled for consumers, the situation is rather different for industry - a simple Google-search of “ABS recycling” yields a number of results pertaining to businesses offering collection and recycling of ABS scrap. Again, it is important to stress this will vary by city / region / country so it is always important to check locally. Furthermore, it is evident that some recyclers stipulate volumes in the tonnes to achieve the efficiency needed. Effectively precluding hobbyist / small-scale 3D printing users.
DIY Recycling
Whilst many 3D printing materials are not widely recycled, all is not lost. As explained in an article on the 3D Printing Waste Problem, in-situ recycling using a Filament Extruder can be an option for volume users of 3D printing. One of our Architectural clients, Make, did exactly this with their ReMake initiative - creating a fully closed-loop production process by recycling 3D prints into recycled PLA filament for further printing and recycling.?
Whilst technically feasible, it is important to not that is is not always straightforward, and there are many challenges / factors to consider before embarking on this option, including:
So... How Recyclable are 3D Printing Materials?
As is always the case, it depends! Every material presents different recycling challenges - whilst many have proven recycling from the technical point of view, the lack of End-of-Life processing infrastructure prevents the vast majority of 3D printing users from being able to recycle their plastic waste.
As the most popular 3D printing material, solving the PLA recycling problem will prove to be a step-change - more needs to be done but thankfully good work by start-ups such as 3D Printing Waste is already helping to ‘close the loop’ by diverting PLA waste from landfill.
DIY recycling is a micro-scale solution which may prove viable for a select few users, provided the inherent challenges can be overcome.
Collaboration, investment and even legislation is needed to facilitate practicable access to recycling in order for 3D printing to achieve greater Sustainability.?
About the Author
Ravi Toor is Founder / Managing Director at?Filamentive?- the?UK-leading?3D printing filament brand with a specific focus on?sustainable materials -?without compromising quality. Filamentive materials are?trusted by?thousands?worldwide, and are helping educators, engineers?and makers?reduce the environmental impact of 3D printing.
Associate Design Technologist at Perkins Engine Company Limited
2 年Dr. Brian Johnston