Project Aim

Additive manufacturing (AM) is a rapidly growing sector. According to a 2017 Wohlers Associates report, the industry market will grow 4.3 times to about 26.2 billion by 2022.

Additive manufacturing is generally regarded as more sustainable than traditional manufacturing methods because it is based on material-efficient design. In additive manufacturing, an item is 3D printed by adding material layer by layer. In contrast, subtractive manufacturing, which is what most manufacturing is based on, takes material from a stock and then removes excess, which is disposed of. Ultimately, the subtractive manufacturing process creates more waste than additive manufacturing.

However, the lack of an established end of life (EoL) processing system in additive manufacturing for 3D printed polymer parts has led to increased environmental concerns around this rapidly growing sector. Although 3D printed parts are made with less material, they ultimately end up being disposed of as low value general waste rather than recycled.

The Challenge

HSSMI worked in a collaborative research project called Closed Loop Innovation in Fused Filament Fabrication (CLIFFF) with In-Cycle and GoPrint3D. The project aimed to take 3D printed waste, such as failed or discarded prints, and convert it into high value recycled filaments.

HSSMI led the work on 3 main aspects of the project:

1 – Research the 3D printing industry to identify the main materials and technologies used in 3D printing, as well as the main companies and industries active in 3D printing.

2 - Find the necessary volumes of waste to create a reverse logistics system for collecting and producing recycled filament.

3 – Compare the environmental impact between virgin filament and CLIFFF’s recycled filament.

The Solution

The solution proposed by HSSMI included:

1 - 3D printing market report

The main outcomes of the report developed by HSSMI are:

- Fused Filament Fabrication (FFF) is the leading 3D printing technology, with 66% of the printers on the market being FFF printers.

- Among 3D printing technologies, FFF does not rank as the most precise or the fastest, but its relatively low price and ease of use enables companies to develop cost-effective prototype designs.

- FFF is mainly used for education, rapid prototyping and grips, jigs and fixtures.

- Polylactic acid (PLA) or Acrylonitrile butadiene styrene (ABS) are the preferred materials, as they are easy to use and they have proven to be reliable and have a competitive price, as well as good mechanical properties.

- Packaging and spools are one of the waste streams generated by FFF. Usually a kilogram of filament comes wrapped around a plastic spool weighing about 250 grams.

- Failed prints, prototypes that are not used anymore and support material are also a significant source of waste.

2 - Supply chain engagement

During the project it was determined that the main organisations that generate the most waste are universities. Many of them have several FFF printers that students use for prototyping.

The project found enough PLA waste volumes and tried to develop a closed loop supply chain. However, the main barrier to developing the closed loop supply chain was the quality of the waste collected. The volume of quality waste was not high enough to efficiently sort it. Most of the waste was small pieces and it could not be guaranteed that they were not contaminated, making it very difficult to recycle.

3 - Life Cycle Assessment (LCA)

The results show that the CLIFFF filament is not just competitive in terms of quality and performance but also is more sustainable than any virgin filaments. Many universities and 3D hubs are aware of this and many of them already use recycled filaments. HSSMI expects that the use of recycled filament will become more widespread and generate a commercial opportunity for the filament developed in CLIFFF.

The Approach

1 - 3D printing market report

Throughout this report HSSMI identified sectors that generate plastic waste and their interactions with 3D and additive manufacturing technologies. The report compares different 3D printing technologies and materials, and benchmarks companies that produce recycled filaments.

The report was based on desk research of existing literature, HSSMI’s 3D printing expertise and insights from manufacturers, 3D printing studios, universities, and 3D printing resellers.

2 - Supply chain engagement

HSSMI and GoPrint3D engaged with companies that used FFF technology and PLA material. The aim of this exercise was to find relevant organisations that generate enough PLA waste to develop a reverse logistic supply chain and test the recycling process line developed by In-Cycle.

3 - Life Cycle Assessment (LCA)

Two types of recycled filaments were produced on In-Cycle’s recycling line: 30% recycled PLA and 50% recycled PLA. Both filaments were tested by GoPrint3D. Test results showed the recycled filament was as good as (and better than some) leading brands of filament. i.e overall test results showed CLIFFF filament preformed as well as the recycled Filament from Filamentive and virgin filament from Ultimaker and Filkemp.

HSSMI assessed the carbon emission savings between a virgin PLA filament and the two recycled filaments produced in the CLIFFF project. It is important to highlight that CLIFFF collects binned spools and reuses them, so the production of the spool is not considered in the LCA of the CLIFFF’s filaments.