While additive manufacturing cuts back on waste within the manufacturing industry, 3-D printing actually creates hundreds of tons of waste annually within the consumer segment of the market. Many desktop 3-D printers found in homes rely primarily on thermoplastics, which are discarded and sent to landfills.
Researchers at the MIT Media Lab have been working on an environmentally friendly solution to this issue using natural biodegradable 3-D printing techniques. In a process they call Water-Based Robotic Fabrication, the team has set out to use natural materials to enable greener and perhaps more robust methods of 3-D printing.
The team is working with a group of natural polymers called polysaccharides, including cellulose, starch, hemicelluloses, chitin and chitosan, which are easy and inexpensive to obtain. Polysaccharides, while possessing characteristics including structural and functional diversity and strength, have been shown to have the ability to replace traditional synthetic materials within the additive manufacturing process.
The Water-Based Robotic Fabrication process relies on biodegradable hydrogel composites which are mixed together prior to extrusion and are capable of constructing large-scale 3-D objects. The natural composite materials can be manually mixed prior to their entrance into the volume-driven extruder, or mixed as needed within the machine via the nozzle. With control of the extrusion process in the researchers’ hands, they were able to create a variety of composites without relying on the special formulations that are required with other traditional 3-D printing technologies such as SLS, SLA or FDM.
With this method, once objects are fabricated and are no longer needed, instead of sending them off to a landfill, they can simply be submerged into water and broken down. Conversely, they can also be chemically stabilized via various agents and submerged in water without any degradation at all. Researchers also have investigated ways to provide shape-shifting characteristics to these printed objects when they are introduced to water, or creating objects which release nutrients while they are being broken down.