Fascinating 3D printing filaments

3D printing is the future of manufacturing, whether it’s in construction or for products. This production method deposits only the amount of material needed and does so automatically, which saves material, time and energy compared to other manufacturing methods. The filament that goes into 3D printers is what decides the material of the object. Today, we discuss some interesting innovations.

Soil and bacteria
Assistant professor of civil engineering at the University of Arkansas, Michelle Bernhardt-Barry, is working on a process to build houses using soil or sand in places were concrete is not readily available. To bind the soil, Bernhardt-Barry is looking at so-called microbial induced calcium carbonate precipitation (MICP), or, in other words, use bacteria to produce calcium carbonate to use as glue.

Cellulose is one of the most abundant organic materials in the world, giving plants their rigidity. However, the use of cellulose to fabricate 3D printed objects is still tough, as most products made are polluting, combined with plastic or lack scalability. Now, researchers from the Singapore University of Technology and Design have successfully used cellulose to sustainably 3D print large objects. Rather than using green plants, they drew their inspiration from fungus-like microorganisms called oomycetes.

The resulting material is strong, lightweight, inexpensive, and can be moulded or processed using woodworking techniques. It’s biodegradable, and sustainably produced without any solvents.

The use of ceramics is relatively new to 3D printing, especially compared to materials like plastic and metal. To make this type of filament more affordable, Formlabs added ceramic resin to its materials. The resin is a silica-filled photopolymer. When fired, the polymer burns out to form a true ceramic part. The 3D printed parts do not require any post-curing, but they do need to be fired, which causes them to shrink a little.

Experimental design studio Nervous System used Formlabs filament to create art, jewellery and housewares.

Smart ink
Researchers at Dartmouth College developed a “smart ink” that allows 3D printed objects to change shape and colour over time. The ink is made from a polymer-based “vehicle” which can integrate intelligent molecular systems into printing gel.

Instead of hardening after being printed, the material undergoes chemical reactions that lock active molecular ingredients together, setting off transformations. By integrating fluorescent trackers, the objects can change colour. Another ability of the ink is that it can reduce the size of the printed object to merely 1 per cent of the original.

Food waste
About a third of the produced food is wasted. The start-up Genecis has figured out a wat to recycle food waste to turn it into biodegradable plastic PHA with the help of microorganisms. Currently, PHA is made with expensive food crops like corn and sugar cane. By using food waste, the costs can be dramatically reduced.

When combined with PLA, another type of biobased plastic, the PHA can be used to make 3D printing filament.

Researchers at Montana State University are researching if they can use methane-producing microbes in Yellowstone National Park to develop 3D printing filament. Methane is a potent greenhouse agent and a massive contributor to climate change.

Yellowstone is a huge reservoir of these methane-producing microbes. The research aims to develop models explaining the microbes’ metabolism as well as to optimise their ability to produce organic compounds. These compounds could be used to make plastics (including 3D printing filament), biofuels and other commercial products.

Researchers at the University of Toronto developed a handheld 3D printer that produces skin. The ‘filament’ in the printer is made of protein-based biomaterials including the proteins collagen and fibrin.

Researchers at Vanderbilt University included gold nanoparticles in a plastic filament, which helps to find defects in 3D printed objects. The innovative process involves mixing the gold nanoparticles with a dissolved plastic polymer, dispersing it throughout the medium. When it dries and hardens, the plastic is extruded or pressed into gold nanoparticle-filled polymer filaments, or thin tubing, which can then be used in standard 3D printers.

After a part is printed, it goes into a special UV-Vis spectrophotometer to inspect for defects.

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