What is the most sustainable 3D printing material? As a brand of 3D printer filament, this is a question received on a regular basis.
This article seeks to explore the different factors influencing sustainability – from recycled content and recyclability, through to embodied energy and carbon impact.
What does Sustainable mean?
In 1987, the United Nations Brundtland Commission defined sustainability as “meeting the needs of the present without compromising the ability of future generations to meet their own needs.”
More specifically – when it comes to materials, sustainable materials “can be produced in required volumes without depleting non-renewable resources and without disrupting the established steady-state equilibrium of the environment and key natural resource systems”
The Need for Sustainable Materials in 3D Printing
Zhao et al., (2018)
FDM / FFF 3D printing required plastics as material feedstock. As per 3DHubs 2020 Trends Report, 91% of plastic 3D printing is FDM / FFF, i.e., plastic-based.
Assuming there are more 200,000 3D printers in the UK alone and the market growth rate is 24%, the growth of the technology will increase demand and production for filament, which ultimately exacerbates the waste management challenges around plastic waste.
It is therefore imperative that non-renewable resource depletion is minimised to ensure the established steady-state equilibrium of the natural resource systems is at least maintained.
Measuring Sustainability
How can we measure sustainability? To better inform material selection – especially in 3D printing – it is vital that factors influencing material sustainability are quantified in the same way that mechanical properties are.
Sustainability measurement is the quantitative basis for the informed management of sustainability. As per Samir Jaber, key environmental indicators include: carbon footprint, embodied energy and recycled content. Extending this further, it may also be shrewd to account for the recyclability of a 3D printing material also. This is also in-line with the viewpoint of Sam Ruben; writing for Forbes, Ruben states, “Sustainability [in 3D printing] can be achieved by… the longevity of the materials”.
Can we define the most Sustainable Material for 3D Printing?
Implementing the aforementioned environmental indicators – by using internal information and aggregating secondary data – it is possible to make evidence-based assumptions and present possible options for the most sustainable material with respect to carbon footprint, embodied energy, recycled content and recyclability.
Carbon Footprint
Refers to the total greenhouse gas (GHG) emissions produced throughout the different stages of the material’s life cycle, including production, use and end-of-life.
Methodology: CO2e Analysis
Research: Ingeo (PLA) Eco Profile
Material: PLA
Justification: Natureworks – one of the world’s largest producers of PLA – publish an in-depth eco-profile – a useful tool for determining environmental impact, including greenhouse gas emissions and non-renewable energy use. Based on Ingeo’s research, PLA filament has the lowest carbon footprint, versus other 3D printing materials such as ABS and PET.
Embodied Energy
The sum of the direct and indirect energy inputs involved in extraction, transportation, production and distribution of the material.
Methodology: Life cycle assessment (LCA)
Material: PLA
Justification: The study concluded that both recycled and bio-based materials offer marked environmental benefits over single-use (petrochemical) PET. In summary, “PLA… has lower impacts than both petrochemical PET and bio-based PET.”
Recycled Content
Recycled content refers to the amount of recycled material a material / product contains. For example, if it is made from 70% recycled material input, the remaining 30% would be virgin material.
Methodology: Self-declaration – proportion, by mass, of recycled material in a product.
Research: ISO 14021
Material: PETg
Justification: Filamentive has made a commitment to continually improve its environmental footprint and the sustainability of its products. Recycled materials are used in the production of our 3D printer filament products. As per ISO 14021, PETg includes the highest amount of recycled material – at 99.5% – versus the other conventional (non-engineering) filaments.
Recyclability
In order to assess the recyclability of a given (3D printing) materials, plastic resin codes enable the identification of the type of plastic used so it can be sorted and recycled.
Methodology: Resin codes
Material: PET(g), PP
Justification: As per Which? – UK-based organisation that promotes informed consumer choice – the only polymers with easy to access recycling are Polyethylene Terephthalate (PETg), High Density Polyethylene (HDPE) and Polypropylene (PP). HDPE is not a conventional 3D printing material as so must be discounted for the context of this article. This therefore leaves PETg and PP as the most recyclable 3D printing materials.
Please note: this is third party guidance – always check with your local authority regarding specific plastics and the methods of recycling in your area.
What is the most Sustainable Material for 3D Printing Filament?
As always, the answer depends on the requirements of your 3D printing project (e.g. technical, economic) as well as the particular sustainability focus.
If carbon footprint and / or embodied energy are the most critical indicators for you, PLA filament is the most sustainable material for your 3D printing.
If recycled content is more critical to your 3D printed project, PETg filament is the most sustainable material for 3D printing – but please always check with your filament brand / supplier as recycled content varies brand-to-brand and due to availability of waste streams.
If recyclability is the most important key environmental indicator, PETg filament is the most sustainable material for 3D printing in this scenario. An honourable mention to the increasingly-used Polypropylene (PP).
As 3D printing grows, as will the demand for plastic which directly impacts the environment. Materials sustainability can therefore no longer be ignored if we are to minimise non-renewable resource depletion and production.
Using sustainable materials for 3D printing is crucial in the preservation of natural resource systems – as a planet, the default goal needs to be sustainability.
Filamentive (https://filamentive.com – info@filamentive.com) is the market leader in sustainable materials for FFF 3D Printing. The company was founded to address the environmental need to use more recycled plastics in 3D printing, and also alleviate market concerns over quality and long-term sustainability. Filamentive has experienced rapid growth and continues to address the questions surrounding 3D printing recycled materials. Headquartered in Bradford, United Kingdom, Filamentive materials are trusted by thousands of educators, engineers and makers globally.