You’ve likely heard more about 3D printers in recent years. They print common items like figurines, trinkets, and jewelry. But did you know you could potentially 3D print organs out of cells, or even an entire house? If you can think it, you can (probably) print it. But what are the environmental implications of this new dream-printing tech?
3D printing is a type of manufacturing. Manufacturing processes fall into two main categories: additive and subtractive. 3D printing is an additive manufacturing process whereas typical manufacturing is subtractive.
In additive manufacturing, products are created by laying down successive layers of a given material creating a full object where each layer is a thin cross-section of the object. The layers are printed using layer-by-layer deposition directly from a ‘computer-aided design” (CAD) model, allowing physical objects to be created from a computer-generated geometrical representation.
3D printing was commercialized in 1980 by Charles Hull, and now the process is used for a variety of products such as jewelry, engines, bridges, objects in the aviation industry, the food industry, and even used in medicine making artificial heart pumps, and artificial corneas! Most commonly, 3D printing materials are thermoplastics, ceramics, graphene-based materials, and metal, which could cause some environmental issues that we’ll get into later.
Okay, but how does 3D printing work? There are multiple ways 3D printing is done, all to do with how the material is deposited to create the final object. In basic terms, 3D printing is what happens when you give a kid a glue gun and they make towers of glue. The material is heated until it’s liquid and then is deposited through the print nozzle. Using information from the CAD, the design is ‘split’ into 2D sections so the nozzle knows where the material is supposed to go and the nozzle places the material in thin layers, often no more than 0.1 millimeters thick.
Once the layer solidifies, the process is repeated until there’s a final usable object. Based on the size and the complexity of the object, the turnaround time could range anywhere from minutes to days.
So far, 3D printing seems like a great way to create products for a variety of industries, so what’s the catch? Certain aspects of the 3D printing process cause high levels of energy consumption and can even cause harmful emissions. Many factors in the production process can have an environmental impact, like the time it takes to print an object or the type of material used.
Longer printing times increase the amount of energy consumed and higher-quality prints are done slowly so there’s a large trade-off between energy consumed and product quality.
Energy consumption can be defined in three phases within the printing process:
A solution to the mass amounts of energy used in the printing process lies in the materials used. Utilizing low-temperature materials can decrease energy consumption, as does using machines that can print multiple components simultaneously.
An interesting experiment was done looking at the difference in energy consumption between 3D printing a car phone holder and ordering a similar one from Amazon. The entire supply chain process was examined from start to finish, from the polymer pellets to the researcher’s doorstep measured against the whole process of 3D printing the phone holder.
In the end, 3D printing required less energy in the transportation of the object but used far more energy in production. They concluded in their research that 3D printers require nearly 10 times the energy per 1 kilogram of material compared to standard production processes such as injection molding.
When we think of environmental problems, a big one is always pollution. Printing doesn’t seem like something that would cause a lot of pollution, but it does! Industrial pollution is generated mostly during manufacturing and 19% of the world’s greenhouse gas emissions are related to industrial manufacturing processes. 3D printing produces what’s known as volatile organic compounds or VOCs. There are multiple parameters that can affect VOC emission – the material uses, temperature of machinery, filament color, the amount of heat used on the build plate, and printer model.
VOC emissions are related to the thermal degradation of polymers and other additives. For 3D printers, many models are based on heated thermoplastic extrusion (aka melting plastic) which can be hazardous for some indoor environments due to the VOCs produced. Along with VOCs, 3D printing can emit other particulate matter, gaseous material, and some nanoparticles that could pose potential health risks.
Unfortunately, the materials needed for 3D printing are inherently unsustainable. Obtaining new plastic requires petroleum products for production as well as having high carbon intensity to actually produce the plastic itself. Luckily, 3D printing could use recycled materials or materials other than plastic such as metal which would create a more sustainable outcome.
It’s not all bad news though, 3D printing poses multiple benefits for the environment and sustainability. Though it is still being studied, 3D printing and other additive manufacturing cause significant changes in production cost and manufacturing times, leading to higher efficiency and lower environmental impacts when compared to standard manufacturing processes.
Global waste is at a high: approximately 1.3 billion tons of waste per year is expected to jump to 2.2 billion tons in just 3 years. Luckily, 3D printing could offer a solution by using recycled materials to create products. Up to 95% of the material used in 3D printing can come from recycled materials. But when plastic melts, its chemical bonds weaken so bits of new plastic need to be added to the recycled material to ensure a strong final product.
Along with recycled materials, bio-based polymers could be a solution to the high amount of energy printing requires. Bio-based polymers require a lower temperature which can reduce the amount of energy consumed during printing.
3D printing can increase the efficiency of the production process as well as the time and energy it takes to get products to their destination. When using bio-based polymers to create products, the sourced polymers are biodegradable and non-toxic. Sometimes material can be prepared locally, reducing the amount and cost of energy needed.
When used for small products, 3D printers can fit in an office allowing for parts, prototypes, and products to be produced locally rather than requiring shipping. This results in lower environmental impacts from standard shipping methods such as planes, ships, and trucks. 3D printing allows for on-demand printing of small batches rather than standard methods which mass produce and require warehouses of products that consume energy at an alarming rate.
Simply put, a 3D printer can take the place of multiple pieces of traditional manufacturing equipment due to its versatility. With less equipment needed for production, the need for large manufacturing facilities disappears, as do their associated emissions. These 3D printers can be housed in urban centers closer to residential areas without causing as much social and environmental inequity from emissions and noise pollution, as large factories and warehouses do.
While alternative materials for 3D printing are scarce, there is the ability to print using plant-based materials. A common “eco-friendly” material used for disposables like straws is becoming a popular option for 3D printers. Made from Polylactic acid (PLA), these materials can withstand high temperatures up to 446℉. Though plant-based materials seem like the solution to combat plastic pollution, PLA plastics can still take hundreds of years to break down because they require very particular conditions in order to be able to decompose, making them less viable as an environmentally friendly alternative to traditional plastics.
On the other hand, plastics can be made from algae which could solve parts of the issue of plastic pollution. Algae can be made into bioplastic which is plastic made either partially or fully from biomass or renewable sources, most commonly food crops. They have the same function as standard petroleum-based plastic materials.
Microalgae can grow on organic waste making it a good candidate as a source of biomass. Ideally, we should be efficient and create less food waste. But seeing that we have a bunch, we might as well put it to use by having microalgae eat up waste materials and turn them into building materials. This simultaneously provides materials for manufacturing and reduces carbon in the atmosphere since the algae uses CO2 for growth.
Besides efficiency and the use of recycled materials, 3D printing has had multiple positive impacts on the environment like reducing carbon emissions in some instances, providing new technologies for environmental monitoring as well as providing materials for alternative energy sources.
Reduced carbon emissions are due to 3D printing’s ability to be produced with higher levels of efficiency in the production and transportation process. All products can be produced from digital files rather than being reliant on shipping.
One example is the John Deere company. They’ve developed a distributed manufacturing system so locations can download designs digitally and print products instead of ordering from warehouses, this reduces material waste, shipping distances, and the associated carbon emissions. While 3D printing technology has the potential to cut net CO2 emissions and energy use from industrial processes the sustainability benefits of 3D printing could be offset by a ‘rebound effect’ if the overall activity is increased due to high efficiency.
3D printing can manufacture parts for instrumentation used for air quality monitoring, a nano environmental monitoring system (nEMoS) that quantified air quality was designed using low-cost sensors using 3D printing, the nEMoS reports CO2 concentrations in addition to lighting levels, airspeed, radiant temperature, air temperature, and relative humidity. Under controlled conditions, the nEMoS provided readings within 5% of those by commercial tools.
3D printing can also be used to create filters and scrubbers for pollution removal. A flexible air filter was created to remove nitrous oxide from the air, the product obtained a 52.6% conversion rate which shows incredible progress towards having a method of cleaning up air pollution caused by industry.
Another application of 3D printing is renewable energy. Parts of fuel cells, wind turbines, and solar cells have all been tested with 3D printed components. 3D printing has created three-dimensional photovoltaic cells and has been proven to obtain higher energy densities than standard flat, stationary solar panels.
Additionally, wind turbines have obtained 3D printed blades shaped like plant leaves that reduced wind strain on blades, and the unique geometry was only made possible by the 3D printing process. Small-scale wind turbines have even been produced through 3D printing for residential use, when paired with a generator the total cost was $21.63 and could generate 0.2 kilowatts of energy.
3D printing offers advantages in speed, cost, and the ability to form small complex shapes and designs that can be used for a variety of different purposes including energy production.
We’ve discussed the good, the bad, and the ugly of 3D printing but there are still a few unanswered questions. Here are the broad strokes of it.
The short answer is: yes. Like nearly all manufacturing industries, 3D printing has yet to become eco-friendly. The technology uses larger amounts of energy than milling and drilling machines. And to produce an object of the same weight, the 3D printing process may require 50 to 100 times more electrical energy than standard machines, thereby causing more emissions. Similarly, there is heavy reliance on plastic materials and plastic is not an environmentally friendly material. Studies show that industrial 3D printers have substantial plastic byproducts that get left behind that can’t be reused for anything else. Also, secondhand printing fumes from heated plastic are toxic byproducts.
3D printing is additive manufacturing which only uses the material required for the final product. This immediate material savings. However, 3D printing generates substantial amounts of waste resulting from failed prints or rejected support structures. The number of thermoplastic prints is increasing due to the constant development of additive technology so waste management will eventually become an issue.
On the other hand, 3D printing takes only what is needed and has the potential to decrease the amount of unused product that gets thrown away.
Right now, 3D printing is unsustainable, but it can become sustainable over time. It is likely that as 3D technology becomes more widely used and improved, manufacturing will become more sustainable due to reduced emissions, less waste, ease in making replacement parts, and the ability to use more environmentally friendly materials. If renewable energy is used for production, the environmental cost of 3D printing lessens. Additionally, printing closer to where the product is needed cuts down on emissions from CO2 as well.
3D printing allows for a reduced carbon footprint due to the ability to create products locally. A carbon footprint is defined as the total greenhouse gas emissions expressed as a CO2 equivalent. As of 2020, transportation makes up 27 % of the greenhouse gas emissions. If you cut out the need to transport a product across an ocean or continent, the carbon footprint of that product decreases significantly.
3D printing offers solutions to problems and new designs that were not possible before. For example, General Electric used 3D printing to create fuel nozzles for jet engines that are stronger and lighter than conventional parts.
A new technology called EcoPrinting is a 3D printing process that uses waste polymers as the source material and has a near-zero carbon footprint. The EcoPrinting system is powered by a solar charging battery and has several low-power devices that reduce energy consumption. So far, the EcoPrinting system has been used for humanitarian aid in the Soloman Islands to repair water transmission infrastructure by printing pipe couplers and plumbing seals. Similar technologies will likely evolve with 3D printing systems and provide much-needed services to remote areas with hard-to-find parts.
Studies have shown that 3D printing at an industrial scale has the potential to reduce total primary energy demand by 2.54 exajoules in the next three years which is the equivalent of reducing the global primary energy need by 5%.
While 3D printing can offer short-term sustainable solutions, 3D printing is unlikely to become a major solution to environmental issues. Current technology could reduce 3D printing’s environmental impacts to roughly 70% less per part than standard manufacturing, but this relies on companies choosing non-toxic, renewable materials and printing with low energy consumption in mind.
Consumers need to be aware of the potential dangers of materials being used. Proper disposal methods are critical to reducing environmental impacts from 3D printing before it is a properly environmentally sustainable technology.