Article by Michael Tobias
For decades, additive manufacturing (AM), which includes various forms of 3D modeling and printing, has been heralded as a modern-day industrial revolution and an opportunity to make production considerably more environmentally friendly.
But as investment in AM and 3D printing continues to grow exponentially, there is disturbing evidence of a lack of insight in terms of the environmental, energy, and health impacts it can have.
So, the question now is whether 3D printing is sustainable or not.
Growth and Development of AM and 3D Printing
Today, the global AM market is estimated to be worth $15.8-billion and is projected to reach a value of $35.6-billion by 2024.
This is revealed in the most recent annual 3D Printing and Additive Manufacturing State of the Industry Wohlers Report 2019 that incorporates a series of expert reports from 32 countries, details the benefits and challenges of designing for AM, and generally reveals the state of the industry based on data from 2018.
The technology isn’t new – it was originally launched in the 1980s – but it has traditionally been expensive and not universally accessible. In fact, the first industries to make use of it were what one might term cash-rich, including various aerospace, automobile, and medical niches.
Carried out in accordance with ASTM F2792, AM is a process that joins materials to make all kinds of items utilizing 3D model data, usually by adding multiple layers, unlike subtractive manufacturing that successively cuts material away from a solid piece of the raw material, essentially creating waste.
Broadly speaking, 3D printing is considered to be sustainable and environmentally friendly. Those who use it maintain that the process shortens production time by weeks and months, avoids costly mistakes, and ultimately enhances product quality. Finding the right match between a production method and sustainable application remains a challenge.
Terry Wohlers, who is the president of Wohlers Associates, which offers strategic advice on trends in rapid product development including AM and 3D printing, has been quoted as saying he believes 3D printing will help to solve “key sustainability issues.” For instance, when metal is used for subtractive manufacturing, he says as much as 80% of the material ends up as scrap. With 3D printing, a minimal amount of metal is wasted.
There is also reduced waste associated with excess production or items that simply aren’t sold, as well as the ability to reuse (and therefore reduce) plastic waste by recycling it by creating new products or converting it into filaments for printing. And there is a reduction in long-distance transportation because 3D printing can be done on-site. This, in turn, reduces cost and harmful carbon emissions.
Another argument in favor of the sustainability of 3D printing is that it can help to reduce economic balances globally, particularly for developing countries that could print their own equipment for energy generation or medical prosthetics and so on much more economically than manufacturing or importing them.
However, there is also evidence of considerable environmental challenges along with a realization by some researchers that there is not enough data to prove that 3D printing represents a path to sustainable manufacturing. Additionally, even staunch advocates admit that it is still not particularly cost-effective, and there is evidence that it is more wasteful than many experts maintain.
While not all engineers specialize in 3D printing, some who offer mechanical engineering services do, and some have strong feelings regarding the sustainability of the process.
Challenging the Sustainability of 3D Printing
Opposition to the argument that 3D printing is a remarkably sustainable process is quite widespread. Here are a handful of examples.
Felix Preston, a research fellow at Chatham House in London, points out that the wide range of 3D printing methods, possible materials, and applications that may be used while adding to efficiency could easily have life cycle impacts. There is certainly no guarantee that it will result in greener production or consumption, he says.
The problem is that there have been very few studies that have examined the environmental impacts of 3D printing versus traditional manufacturing. These include the use of energy, pollution, and transportation costs.
An engineer, Dr. Bert Bras, who is professor of mechanical engineering at the U.S. Georgia Institute of Engineering, maintains that some materials used for 3D printing require Health and Safety Executive (HSE) expertise. For example, when operators work with fine powdered materials these can cause respiratory problems.
One particularly outspoken critic is 3D expert, Tim Gutowski, professor of mechanical engineering at the Massachusetts Institute of Technology (MIT). His concern is that there is a lack of convincing evidence that that 3D printing will lead to a society that is more sustainable. He strongly believes that it might have the opposite effect.
One argument he puts forward is that while it is easy to combine various mixtures and customize products with 3D printing, it is a much more difficult process to dismantle and break up products so that they can be recycled, particularly if mixed materials have been used. So, while 3D printing has been heralded as a green technology that will reduce waste, it could, in fact, create a different type of waste problem!
Ultimately, he believes that AM should be regarded as an additional tool rather than a substitute for traditional methods. Nevertheless, he believes that 3D printing does have innovative capabilities and the potential to be a sustainable manufacturing method. Where approaches are not “environmentally desirable,” there are undoubtedly opportunities for improvement, he says.
Prof. Gutowski was a contributor and guest editor of Yale University’s 2018 Journal of Industrial Ecology which focused on 3D printing, examining the content of a multitude of studies into the topic.
In the lead editorial, editor-in-chief of the Journal, Reid Lifset said the research clearly indicated that it was too early to state categorically that 3D printing was “the path to sustainable manufacturing.”
Rather, there is a pressing need to learn more about the footprint of materials used, energy consumption during production, and process emissions. While AM is believed to allow zero-waste manufacturing, this is not necessarily true because researchers have shown how sensitive environmental performance is to the patterns of usage and configuration of the materials and machinery used for 3D printing.
So, let’s allow Reid Lifset to have the final say that assesses the realities of sustainability:
“An important implication of the complexity of assessing the environment dimensions of 3D printing is that its adoption and diffusion won’t automatically generate net environmental benefits. Like other technologies, environmental considerations need to be integrated into the design and deployment of 3D printing if it is to realize its full contribution to sustainability.”