Does additive manufacturing have the potential to change the way we handle materials and products and enable circularity? Although the method is well on its way to being developed and applied in various fields, there are still several challenges that need to be overcome before it can contribute to a sustainable society from a systems perspective. This is the argument presented by an international group of researchers in the journal Nature Sustainability.
The transition to a circular economy is a strategy adopted by several countries, including the EU, to achieve the Sustainable Development Goals. A circular economy is characterised by limiting the use of new materials and products, for example through reuse and recycling. In this way, resources are used in a circular way rather than ending up as waste.
The transition to a circular economy requires changes in the manufacturing industry, as sustainable production and consumption are crucial. One production method often highlighted as a sustainable alternative to conventional manufacturing (such as casting and forging) is additive manufacturing, also known as 3D printing.
“Additive manufacturing has many sustainability benefits. For example, it is easier to design different shapes, which means that specialised parts can be produced in a short time. This makes it easier to repair and maintain products, so they can be used for a longer period of time,” says Sophie I. Hallstedt, Professor of Product Development at the Department of Industrial and Materials Science.
Additive manufacturing creates objects from raw materials, such as powders, by building them up layer by layer. It is the opposite of subtractive manufacturing, in which materials are removed to make objects.
“Since you build a product by adding materials, additive manufacturing also has the potential to optimise material use and reduce material waste. It is also possible to achieve lighter design solutions and reduce the weight of, for example, aircraft engines and automotive components,” says Sophie I. Hallstedt.
Initially, additive manufacturing was mainly used to produce prototypes for product development. Today, however, it is widely used to produce finished products, including aerospace components and metal implants such as joint replacements.
Sustainability challenges hinder circularity
Despite the benefits of additive manufacturing, the process cannot yet be considered fully sustainable. In an article published in the journal Nature Sustainability, an international group of researchers presents a vision of how additive manufacturing could contribute to the transition to a sustainable and circular society, but points out that several challenges need to be addressed to make this a reality.
“One of the sustainability challenges of additive manufacturing is that the process often requires a lot of energy. In addition, there are residual products from the manufacturing process that cannot always be reused, which means that there is still some material waste,” says Sophie I. Hallstedt, who is one of the seven authors of the article.
Another challenge with additive manufacturing is that it is expected to evolve rapidly to work on a large scale and be used for mass production. This transformation is expected to take place in the near future.
“Currently, additive manufacturing accounts for about 2 per cent of global manufacturing activity, but by 2032 it is expected to account for more than 9 per cent and be used in several different sectors, such as food and construction,” says Sophie I. Hallstedt.
Holistic approach crucial for sustainability
Beyond the individual challenges, the authors argue that system-level action is needed to achieve the sustainability vision. They emphasise the need for a holistic approach to understanding the changes required and suggest how they can be implemented at a comprehensive level.
“We believe that systems thinking enables sustainable additive manufacturing. We can't just focus on energy savings and reduced material use, but need to take a holistic approach that includes all aspects of sustainability,” says Sophie I. Hallstedt.
“For example, we need to consider which stakeholders need to work together for circularity and how; how we can create longer life cycles for products; and what the social impact is throughout the life cycle.”
Product developers must consider the entire life cycle of a product.
A key part of the vision is that products need to be designed with sustainability in mind early in the innovation process if additive manufacturing is to support both more sustainable and circular solutions. According to the authors, many of the challenges that prevent additive manufacturing from being a circular process can be overcome through sustainable product development.
“Designing products to be easily disassembled and reassembled can extend their life by making them easier to repair, maintain, upgrade and reuse. Another important part of the product development process is choosing the right materials. It is important that the raw material is bio-based or recycled and that it has no negative social impact,” says Sophie I. Hallstedt.
“Product developers must therefore consider the entire life cycle of a product, from the purchase of materials to the usage scenario and end of life.”
Joint efforts needed
As additive manufacturing is still an evolving and growing method, the authors argue that the opportunities to achieve a sustainable process should be explored now, before short-term and resource-intensive approaches become entrenched. However, for the vision of sustainable additive manufacturing to become a reality, all stakeholders must work towards the same goal.
“The vision can only be realised if all actors and stakeholders in the production chain share the same intentions and commitment to sustainability goals. We hope that industry will adopt a long-term ecological, social, and economic systems perspective and invest in sustainable additive manufacturing solutions,” says Sophie I. Hallstedt.
“We also hope that more researchers, together with industry partners, will take an interest in solving the challenges that prevent additive manufacturing from enabling a sustainable and circular society. Our article identifies the main research gaps that need to be addressed.”
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The article "A vision for sustainable additive manufacturing" is the result of a collaboration between researchers from Chalmers, Politecnico di Milano, Delft University of Technology, ETH Zurich, Free University of Bozen-Bolzano, Pennsylvania State University and the Agency for Science, Technology and Research (A*STAR).
The researchers work in the areas of sustainable product development and design for additive manufacturing.
- Full Professor, Product Development, Industrial and Materials Science