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. 

(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

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. 

Whilst PLA is marketed as biodegradable, it’s important to note that 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, 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 and added cost.

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

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.