3D PRINTING and SUSTAINABILITY
3d printing and sustainability
Is 3d printing a sustainable manufacturing technology? This is not a question that can be short answered. As we strive for a better future, especially when climate change is and should be in the annual agenda of every company and country, businesses are looking for new paths to optimize their manufacturing processes.
In the field of advanced manufacturing, 3d printing has already been proven to be a sustainable and efficient manufacturing approach. However, to conclude and answer such a difficult question we need to take into account all the steps of the process from raw materials to the logistics of delivering products to end customers and of course waste management. From many aspects, additive manufacturing is more sustainable and efficient than traditional manufacturing methods, however the purpose of this blog is to review those as there are arguments from both positive and negative aspects.
Based on Professor’s Gutowski (MIT, Mechanical Engineering) opinion, there are two important characteristics that established 3d printing as a green technology and was deemed as a sustainable manufacturing technology. The first is that it produces less waste, compared to other methods (CNC for example). A model is printed layer by layer and in the end only the supports have to be removed while in CNC machining or any other similar methods the component would be built by subtracting material. Important to mention here is that the supports can also be recycled too resulting in negligible waste.
Build Stock = sometimes waste
It is important to emphasize that for decades manufacturing companies have been building up according to production planning. That planning information is fed from marketing and planning teams and it never ends on a spot-on result of planned production = orders. Hence, companies define marketing strategies for special offers, discounted products with specific advertisement campaigns etc. The point is, there is always waste, small or large there is always some waste. With 3d printing there is no need to build up stock of any part.
Depending on demand, you can 3d print any part (given you have the equipment and the materials) and with the press of a few buttons you can have as many as you wish in the minimum manufacturing time possible. This is an extremely time and cost-effective process for any manufacturing company.
The second characteristic is reusability. There are hundreds of companies around the globe that collect and convert 3d printed waste into printing usable filaments forming new products. Of course, recycling is not 100% clean either and it will generate a second wave of energy consumption and further environmental emissions.
While on the one hand, recycling is tremendously beneficial for the environment, it still requires this second wave of energy. To take this further, some researchers claim that when comparing industrial 3d printers to injection molding machines, it is estimated that 3d printers require 50 to 100 times higher electrical energy in order to manufacture an object of the same weight (Kurman, M. & Lipson, H. (2013): Is Eco Friendly 3D Printing a Myth? Triple Helix Innovation and Cornell University. http://www.livescience.com/38323-is-3d-printing-ecofriendly.html . Kurman is not alone on this; another researcher claimed that energy consumption on 3d printing processes is estimated to be 100 times higher compared to bulk-forming manufacturing methods.
In support of this claim, they compared FDM with machining and injection molding and they concluded that the largest energy consumption was coming from injection molding followed by FDM and lastly from machining (Yoon, H.S., Lee, J.Y., Kim, H.S.,Kim, M.S., Kim, E.S., Shin, Y.J., Chu, W.S., Ahn, S. H., (2014): A Comparison of Energy Consumption in Bulk Forming, Subtractive, and Additive Processes: Review and Case Study, International journal of precision engineering and manufacturing green technology, Vol. 1, No. 3, pp. 261-279.)
One of the main negative aspects with respect to 3d printing technology is the emissions of volatile organic compounds (VOC), which are very dangerous especially when 3d printers operate in a closed work environment. In his publication (Stephens, B., Stephens, P., Orch, Z. E., Ramos, T., (2013): Ultrafine particle emissions from desktop 3D printers, Atmospheric Environment, Vol. 79, pp. 334-339) Stephens investigated what happens when plastic is heated and used in 3d printing.
The machines which use some of the most common materials, for example PLA (polylactic acid) filament released 20 billion particles per minute while ABS released up to 200 billion particles per minute. Those tiny particles without the necessary personal protective equipment, can settle in the lungs or the bloodstream and cause serious health damage, especially for those who have chronic respiratory diseases (e.g. asthma).
3d printing from design efficiency aspect
With 3d printing and of course CAD systems, a major advantage is that the design engineers can test their designs numerous times, by 3d printing prototypes or simply proof of concept parts. Imagine in the old school days, a designer needed to design something by hand and manufacture it ‘right first time’ with conventional methods.
Nowadays, 3d printing becomes more and more approachable and design offices have a few ready to action 3d printers and with a press of a button they can review or test their design within hours and go back to their drawing desk for a few model improvements or even further optimization. That way again results in massive reduction of material and energy waste allowing engineers to design a product before mass production begins.
Once again, this can be expanded even more to a longsighted view. Improving the design of a part (automotive, aerospace, rail etc.) automatically means optimum weight, geometry and performance of the part. Now, fitting just right optimum parts to an airplane for example, it will result in less fuel consumption compared to parts that have been overengineered.
In a case study, scientists from Northwestern University, used topology optimization for a metal airplane bracket, resulting in 65% weight reduction from 1.09kg to just 0.38kg. The scientists estimated that by using topology optimization in 3d printed parts for a number of routine parts of the aircraft, the overall weight of the aircraft could be reduced by 4 to 7% resulting another 6.4% decrease of fuel consumption. Obviously, the higher the number of the parts on one airplane or the global fleet, the greater the positive impact to the environment.
Is 3d printing a sustainable method?
3d printing as a manufacturing method, grows globally against the conventional manufacturing methods. If we combine the benefits of the additive manufacturing technology with the increase of environmental awareness of the manufacturers around the globe, we might see that 3d printing as a systematic method has offered a small glimmer of hope. 3d printing its definitely not the greenest of the technologies but is on the right direction.
We are all responsible to try and explore new ways that will reduce carbon footprints globally and the sooner we start using our boundless creativity and imagination in finding those ways, the better our planet will become.
If you would like to read further sources and references of this blog about this matter feel free to visit:
• Sustainability of 3D Printing: A Critical Review and Recommendations – (Zhichao Liu Department of Mechanical Engineering, Dalian, Qiuhong Jiang Department of Mechanical Engineering, Dalian, Yang Zhang Department of Industrial Engineering, Texas Tech University Lubbock, TX, USA, Hong-Chao Zhang Department of Mechanical Engineering, Dalian University of Technology Dalian, China, Tao li Department of Mechanical Engineering, Dalian University of Technology Dalian, China)