There’s a lot of buzz around 3D printing and sustainability these days. Consumers are becoming more eco-conscious and new waste reduction laws are under consideration in the U.S. and Europe. This is driving many OEMs to consider innovative ways to reduce their environmental footprint. Can new technologies like additive manufacturing (also known as 3D printing) help OEMs achieve this goal?
3D printing and sustainability
An ambitious 2014 study found that 3D printing could reduce the CO2 emission intensities of industrial manufacturing by up to 5% by 2025. But given that the technology is only starting to go mainstream and there is a wide range of machines, materials and applications available, it’s still difficult to determine how sustainable 3D printing is on the whole.
What most experts agree on is that when used in a distributed fashion, 3D printing can not only lower waste but also CO2 emissions resulting from logistics miles travelled. Consider this scenario, familiar to many OEMs. You’re in charge of purchasing spare parts, several of which are reaching their end of life. You have 1 piece in stock for one of those parts and expect to use 10 pieces in the next 2 years, based on your historical data. Your supplier has a Minimum Order Quantity of 250. If you place that order, you’ll end up throwing away 241 pieces after two years. This scenario incurs your company inventory, transport and scrapping costs, as well as waste. If you used a distributed manufacturing platform to 3D print the part instead, you could save those economic costs. Moreover, you’d be minimizing waste and could produce the part as close to the end customer of possible, reducing CO2 emissions.
Supply Chain Analyst, Elise Valerie Kok, worked with our team to study this type of scenario for her master’s in Operations Management and Logistics. Her research for the Technical University of Eindhoven aimed to determine the type of situations where additive manufacturing would prove most sustainable. Elise developed an environmental model which is useful to quantify the impact of AM in different scenarios.
What we learned about 3D printing and sustainability
The environmental model is based on the Eco-Indicator system, calculating in Eco-Indicator milliPoints (mPts). It considers the following factors:
Let’s look at a specific case study to see how this model is applied. We’ll look at the back cover of an LCD display used in a piece of equipment. The part is non-critical, meaning that the machine can be used in a safe way even when the back cover is damaged. A part replacement is necessary in this case to protect the machine’s LCD screen. Securing the part is also beneficial from a cost perspective, as the OEM incurs a cost of €100 per day for not being able to rent out the machine.
The OEM’s demand forecast for this part is low, at approximately 2 parts per year, or 60 parts over a period of 30 years. They have no spares in stock. This cover is produced with nylon. The production processes used are injection moulding for regular production, and SLS (selective laser sintering) for additive manufacturing.
At first glance, traditional production seems more environmentally efficient given that the SLS machine used has an energy consumption of 1100 mPts/kg compared to the 44 mPts/kg used by the injection moulding machine. However, a study of the complete supply chain and associated costs revealed that there are several situations in which additive manufacturing would be more environmentally sustainable.
Where is AM is more environmentally sustainable?
An analysis of minimum order quantities (MOQ) showed that AM would be more sustainable if the traditional supplier would have an MOQ of 140 or higher, which is very likely in this scenario. In this case, it’s more environmentally efficient to print only the required number of parts as close to the customer location as possible. Not only to prevent waste, but also to minimize the amount of logistics miles traveled.
The second situation in which AM proved more sustainable was when considering the part as part of a portfolio with unpredictable demand. In this case, the OEM will be compelled to overstock even if the demand forecast is highly uncertain, given that they want to prevent downtime costs. In this situation, the environmental costs of traditional production would be at least twice as high as the environmental costs of AM given that a large number of parts would be scrapped.
Finally, the study looked at a scenario in which the company must invest in new moulds or tooling for traditional production. The loss or damage of a mould happens quite often in practice. The analysis showed that even with the smallest injection mould, the sustainability costs are lower for additive manufacturing if there are 3,000 items or less produced — which would definitely be the case here.
In these situations, companies benefit from a much lower environmental impact. Interestingly, the study also found a correlation between lower financial costs and a lower environmental impact in these situations, showing that AM is also a less costly alternative from an end-to-end supply chain perspective.
3D printing is already disrupting traditional supply chains. It may be early to tell if the technology is more sustainable on the whole, but it has proven to be more environmentally friendly for the low volume production of spare parts. In these situations, parts are produced closer to the end customer and on-demand, minimizing waste and logistics emissions. OEMs should take note of these benefits in order to boost their sustainability efforts.
This article was originally published in our Medium blog.