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3D Printing

Additive vs. subtractive manufacturing

Additive manufacturing boasts several sustainably-sound advantages, in particular with regards to the amount of material necessary for part manufacturing. According to some authors, traditional manufacturing processes (referred to as subtractive) can waste up to 90% of the material, while the more popular additive manufacturing processes produce almost no waste. Other advantages include:

  • Local production. With “a printer in every home,” as some visionaries suggest, models to be printed are transferred electronically and then produced on site, reducing both transportation and packaging.
  • Production based on demand. There is no waste or storage required since only what is necessary is produced.
  • Better design. Products can be designed based on user needs rather than the limitations of mass production.
  • Personalization. Each object can be personalized to optimize its characteristics and better meet user needs.
  • Easier prototyping. Prototypes can be manufactured on site by the same team. This saves time and transportation. Also, design errors can be detected before launching large-scale production.
  • Greener material. One of the types of plastic most commonly used in 3D printing, Polylactic acid (PLA), is manufactured from corn or other plants. Bioplastics are also compostable under certain conditions.
  • Lighter parts. In aeronautics, for example, parts can be created with a bee-hive type of hollow structure that is lighter and sturdier than the same part built as a solid piece (less material used means more fuel efficiency and lower CO₂ emissions). It is impossible to create such structures through traditional methods.
  • Easier recycling. The recycling of 3D-printed products is easier due to the materials used, especially plastics, which can be recuperated and recycled at home through projects such as Recyclebot (see below).
  • Contribution to the knowledge economy. Democratic access to the production of objects.
  • More sustainable objects. Possibility to extend the service life of objects by reproducing replacement parts otherwise inaccessible or designing new made-to-measure parts.

However, there are a few downsides to mention:

  • Recycling of print waste. Not all additive manufacturing processes are created equal; some still produce a lot of non-recyclable waste. Photosensitive inkjet printing creates more waste than traditional manufacturing methods!
  • Are the materials really greener? Manufacturing plastic from food biomass is often criticized since it uses land that could otherwise be cultivated for human and animal consumption. Second or third generation bioplastics are currently manufactured from production waste. Manufacturing of these bioplastics and their composting (which can only be carried out at high temperatures in industrial facilities) nonetheless demand a lot of power. Composting also releases a lot of methane, a more polluting greenhouse gas than CO₂.
  • Safety of materials. Some materials release toxic emissions and are not adequately controlled and monitored by authorities when produced outside traditional factories.
  • Safety of produced objects. There is no quality control at the production site. The safety of the parts produced is not tested or guaranteed. Extra caution is therefore required.
  • High dependency on plastics. Many argue that fused filament fabrication (FFF), which is set to experience a huge boom in the near future, will contribute to making us even more dependent on plastic.
  • High power demand. Industrial-scale additive manufacturing requires a lot of electricity, especially for materials such as metal. Globally speaking, fossil fuels or nuclear energy remain the main sources of power. In Quebec, however, the production of hydroelectricity leaves a smaller footprint on the environment.

Green projects

Several initiatives have taken shape to optimize the ecological potential of 3D printing. Some examples include:

  • Recyclebot: An open-source project to develop a machine that can convert certain types of domestic plastic waste into a plastic filament that is compatible with FFF 3D printers. Both ecological and cost-efficient!
  • Perpetual Plastic Project: An interactive mobile installation that demonstrates how to recycle plastic at home. The plastic is washed, dried, shredded and melted on site into a filament and then transformed into new objects with a 3D printer.
  • The Plastic Bank: An initiative to give value back to plastic by transforming it into an exchange currency for 3D-printed objects. A way to give economic power back to developing countries.
  • Protoprint Project: A social company from India that allows waste collectors (who make a living from resale) to transform the plastic they find into “fair-trade” filaments for 3D printers. The company also offers printing services to companies and local universities.


Markus Kayser's Solar Sinter uses the sun’s rays to fuse together grains of sand

3D Printing at the Library

Did you know? Your library offers low-cost 3D printing services!

Loyal to our mission to support teaching and research, we want to make this innovative technology accessible for its high educational and social potential.

Visit the 3D Printing page for more information.

What about Fab Labs?

When discussing sustainable development, it’s impossible not to bring up the emerging Fab Labs - FABrication LABoratories, whose recent history is closely tied to 3D printing. These workshops, in which we can find manufacturing tools that range from sewing machines to CNC machines and 3D printers, allow amateur or professional DIY enthusiasts from all walks of life to get together and share knowledge and creativity.

Off-Campus Access to Documents

If you are a member of the Polytechnique Montréal community, you can access all of the Library’s electronic subscription resources from off-campus by configuring our proxy server in your browser. Direct access to some of our resources (without configuring the proxy) is also available through the links marked by an arrow Green arrow in our list of all databases.

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