As an environmentally-conscious 3D printing filament brand, we are continuously engaged in the discourse around the problem of 3D printing waste, and have previously been transparent on the internal challenges of receiving waste 3D prints (to recycle). To further explain the current situation – as of July 2020 – we thought we would explain, in greater detail, some of the barriers which prevent a mainstream, 3D printing recycling service being viable.
Note: we are aware of the great work done by TerraCycle – specifically their 3D Printing Materials Zero Waste Box. Feedback from some of our customers suggests their pricing is quite high (approx. £8/kg for their Large box), plus given they are selling a product, we feel this is significantly different to a proposed service (waste management).
(Lack of) Material Standardisation
There are several material options for FDM / FFF 3D printing. This was exemplified in early 2019 when we sent-out a Material Sustainability Survey to customers and industry contacts.
As you can see from the table below, many different materials are being used – including, but not limited to: PLA, PETg, ABS, TPU, Nylon, ASA and Polycarbonate.
Whilst this material variety is certainly beneficial for the applications of 3D printing, it is unfortunately a barrier to the efficiency of recycling 3D printing waste.
Transnational waste management specialists, Veolia, also highlighted the problem of (non)standardised polymers – calling for greater uniformity in the materials used to enable collection and recycling of materials “without worries about obscure elements contaminating the process”.
Contamination Risk
Linked to the above, the usage of several 3D printing materials poses a risk of contamination. Many 3D printed parts look similar, even if they are produced from different polymers – e.g. PLA and PETG. Without proper sorting at source, there is a high risk of the waste returned being made up of various polymers as opposed to the intended, singular waste stream. As reported by All3DP, “contaminating one type of recycled plastic with another can seriously reduce the strength and longevity of the final material”.
Whilst technology such as NIR optical sortation can identify & sort different polymers, the technology is still its infancy, and it has been reported that standards of quality and yield achieved by NIR optical sorting facilities vary enormously.
PLA Problem
If we were to see material standardisation – whilst also reducing (if not eliminating) contamination risk – it is almost certain that PLA would be the material of choice, as more than 95% of 3D printing users use it. However, PLA could be viewed as a victim of its own success.
PLA is a bioplastic – which basically means it’s a plastic made from plant / biological material, instead of oil. Whilst recycling PLA is technically possible, it is not (currently) practical. Because PLA is of different origin to regular plastic, it must be kept separate when recycled, otherwise it can contaminate the recycling stream – thus making such streams unsaleable. Furthermore – as reported by the BBC – technology for plant-based compostables has come so far that it is hard to tell which is plastic and which is bio-plastic (PLA). In Wales, this has ultimately led to PLA products – such as food & drink containers – ending up in landfill.
Whilst PLA is marketed as biodegradable, it’s important to note that academic research has proven PLA is only biodegradable under industrial / anaerobic composting conditions – no evidence exists to prove biodegradability in soil, home compost or landfill.
The Guardian found that only a handful of anaerobic digesters exist (in the UK, at least), and even then without a centralised infrastructure, the average consumer is unable to access such facilities.
Quality Control
A more general problem with recycled (PLA) plastic is the impact on quality. An academic study found that there were “significant deteriorations in most mechanical properties after three recycling cycles” – which basically means that even if waste could be successfully separated, and reprocessed, the filament produced would be inferior. To counteract this, virgin polymer can be added (percentage compounding) however, this may ultimately negate the environmental benefit as eventually, the virgin material needed will be greater than recycled plastic (in ratio).
Reverse Logistics
Even if contamination and quality barriers were overcome, we still have the headache of (reverse) logistics.
Plastic has a high volume-to-weight ratio which can make collection less efficient than the collection of other recyclables that inherently weigh more – this is a major reason why plastic waste recycling rates are low in general. In a nutshell, plastic is expensive to transport.
Furthermore, as of July 2020, we do not yet manufacture in-house, so any returned waste would need to be sent to one of our production partners – possibly via a Material Recovery Facility (MRF) – which presents further operational challenges.
Economics
As the saying goes “Money makes the world go round”. In this context, any 3D printing waste recycling service needs to be financially viable.
Example costs include, but not limited to:
Shipping (inbound & outbound)
Manufacture of boxes / cartons / bins
Storage
Inspection → Separation → Reprocessing
Manufacturing
Administration
Sales & Marketing
Furthermore, Willingness to Pay (WTP) will inherently vary across customer segments – i.e. a business may be more inclined (and capable) of paying for waste management, as opposed to an individual (hobbyist).
The business model itself will also influence pricing – for example, if a market-viable, 100% recycled PLA could be produced from recycled 3D prints, it could be viable to absorb (some) recycling costs, to then be offset by product sales. However, should plastic waste streams need to be processed by external recycling partners, such costs would need to be passed onto the consumer – be it through product pricing and/or a separate cost for waste management – i.e. a service charge.
Conclusion
“Recycling only works when there’s someone on the other side of the equation”.
To enable an efficient 3D printing waste recycling service, we need to find solutions to each individual challenge, as opposed to tackling one giant problem. If we do so, those involved in the value chain – from PLA manufacturers, through 3D printing filament suppliers and retailers, and eventually 3D printer operators – can implement the required actions they are in control of, ensuring each piece of the puzzle is solved – in theory, at least!
Despite the challenges, recycling 3D printing waste has long been an aspiration of Filamentive – and no doubt others involved in the industry – and we’re continuously engaged in research surrounding the possibility of closing the loop in FDM / FFF 3D printing.
If/when such a service becomes operationally and financially viable, we will be one step closer to achieving a Circular Economy and reduce – if not eliminate – plastic waste within 3D printing.
