Abstract:

The advantages of Additive Manufacturing (AM) include the generation of less waste during manufacturing due to its additive process, the capability to optimize geometries and create lightweight components that reduce material consumption as well as energy consumption in use. The research area has therefore exploded, and great expectations are raised, particularly regarding sustainability. However, sustainable development (SD) is not only about environmental issues, but has three dimensions – economic, social and environmental. True sustainability requires a balanced integration of all three.

In this paper, we present an attempt to generalize a 5-step method for SD assessment originally proposed for higher education and apply it to the AM process in a research context, i.e., to assess the sustainability of AM in its impact on human capital (People), natural capital (Planet) and manufacturing capital (Prosperity). According to Ashby, a proposal (articulation) for SD has a prime objective – something it is aiming to achieve or change – and a scale, both physical and temporal. The first step is thus to define the proposal. Secondly, the stakeholders, i.e., people or organizations that are affected by the proposal and their concerns are defined. The third step is to find objective facts, such as quantities of the materials and energy needed to implement the proposal (metal AM) and its impact on the environment. In our case, a compilation of result from our own Life Cycle Inventory (LCI) cradle-to-gate and from literature. The fourth step is to form a judgement in terms of the impact of the facts on the three capitals. The fifth and final step is to reflect over the outcome short and long term.

The main stakeholders are presented in an interest and influence matrix, to clarify their positions. Their concerns, expressed through statements regarding the articulation are summarized. Although this overview is subjective and qualitative, an evidence-supported approach is considered appropriate applying the 5-step methodology to a research question.

To reduce the scope of the fact-finding step, a nickel-based superalloy, IN718, was chosen as an example for the assessment. The following life cycle stages were considered:
(1) Material extraction and production of Alloy 718 (Granta Selector Database);
(2) Powder production via atomization from real industrial data (Sandvik); and
(3) Energy measurements from actual AM production of model work pieces.

A detailed evaluation of AM for this case is presented in terms of the Three Capitals. Selecting AM for production does not automatically ensure less environmental impact, great prosperity and positive social effects. The decision to use these manufacturing processes must be the result of a well-thought, fact-based analysis, as this example demonstrates. In the case of aerospace applications for which batch sizes are small and part complexity is high, the trend towards AM use is strong and relatively easy to justify.

It is unusual to find a transfer of methodology in this direction, and not from research to education. We hope that this study has shown that the 5-step methodology provides a good platform to discuss and scrutinize sustainable development also for topics in research, not only in education. As Industry 4.0 continues to transform society and our lives, education remains highly important in order to benefit from this technology and avoid unintended consequences.

Keywords:

Sustainability, Assessment Methodology, Additive Manufacturing.