3D Printing
What is 3D printing?
3D printing is the process of constructing three-dimensional artifacts that have been designed on a computer, either a CAD model or a digital 3D model. In essence, 3D printers are all computer-controlled additive manufacturing machines, thus making them CNC (Computerized Numerical Control) machines. 3D printers lay down or cure material layer by layer to create a three-dimensional object similar to how paper printers lay down ink in one layer to create a 2D image.
How Does 3D Printing work?
The basic principle followed by a general 3D printer is to construct parts by adding material layer by layer, fusing each layer to make a solid object. 3D printing utilizes the concept of additive manufacturing, i.e., adding material layer by layer to form their work instead of cutting or drilling parts out of a block of raw material to create a particular shape (subtractive manufacturing), thus potentially reducing waste generation.
Some predominant methods of 3D printing
Fused Deposition Modelling:
Materials used in this method: ABS or PLA plastic
Process: The material is melted down by the printer head and extruded onto the printer bed. The extruder head of the printer lays down material layer by layer to build up a 3D model. Each layer fuses to the previous one as it cools. Their precision depends upon the quality of the motors that control the position of the extruder head relative to the build platform, and the fineness of the extruder head as it extrudes material.
Benefits: FDM printers are very common desktop printers because they are inexpensive and easy to build. They are also quite fast compared to the other techniques, as almost no post-processing is needed.
Drawbacks: The layer-by-layer printing in FDM may sometimes lead to problems with warping and minor shrinking, hence printed parts tend to be weak along the horizontal cross-sections.
Stereolithography (SLA)
Materials used in this method: Polypropylene like materials or ABS
Process: Here, a laser is used to solidify liquid resin with ultraviolet light. The laser beam on an SLA printer draws out a slice of the part to cure the liquid resin layer by layer, generating the 3D part. Light causes chemical monomers and oligomers to cross-link together to form polymers. Those polymers then make up the body of a three-dimensional solid.
Benefits: While most other 3D printers print from the bottom of the part and work their way up, SLA printers can print from the top down. SLA printers can be fast and precise because of its top-down nature. The precision of SLA printers allows them to print intricate and delicate structures.
Drawbacks: The resin itself is expensive, and because it is photocurable, its storage requires specialized containers. When they cure, they are usually very brittle and cannot withstand much force. So they are better suited for prototyping rather than production.
Recent developments in the 3D printing industry
3D printing with metal can be a challenging feat. It is easy for microscopic holes to appear in the structure of an item due to the printing process or the materials involved, leading to weaknesses in the finished product. Nevertheless, many companies have made strides in introducing metal 3D printing to large scale industrial applications.
Siemens 3D printed gas turbine blades from a nickel-based alloy, which passed full load testing.
Working in partnership with a commercial vendor, NASA successfully 3D printed a rocket part from two different metal alloys.
Ceramic membrane fabrication for water purification
3D printing technique has received much attention in recent years for membrane fabrication. Membrane preparation involves creating millions of nanofibers that are sub-layered on top of each other and compressed into a thin membrane. Selective Laser Sintering (SLS), the predominant AM technique, is used for fabricating filtration membranes with different shapes, sizes, and controlled porosity.
3D printed vaccines
In 2k17, MIT invented a 3D printed vaccine that offers multiple immunizations with one vaccination. By designing a new 3D printing technique known as SEAL (StampEd Assembly of polymer Layers), the team created 3D microparticles capable of holding vaccine doses. The bio-compatible polymer used to make these micro-particles can be engineered to biodegrade at specific rates, enabling the release of their contents into the body at different stages. Therefore, it is possible to give patients one injection which delivers multiple doses of vaccines over time.
Intersection of 3D printing with robotics
The University of Tokyo built two humanoid robots called Kenshiro and Kengoro, which can perform human activities such as press-ups and stretches. The team was able to replicate some features of the human musculoskeletal system by using 3D printing with metal and plastic. As a result, these robots have imitation human skeletons, tendons, articulated joints, and a central nervous system. The 3D printing of the Kengoro robot from porous metal has even given it the ability to sweat. While this feature might seem a little out of place in a robot, it is highly functional and designed to cool down the robot’s motors when it overexerts itself.
How 3D Printing Could Revolutionize the Future of Development
3D printing is currently being probed as a potential solution that ends world hunger and homelessness. 3D food printer will produce customized, nutritionally-appropriate meals synthesized one layer at a time, from cartridges of powder and oils they buy at a grocery store.
Researchers have figured out how to convert carbon dioxide into the concrete, using 3D printing. Utilizing former waste to create future products makes our society have more efficient consumption. It is envisaged that in the future, with just a single visit to the doctor, babies could receive all the immunizations they need for their first two years.
Article By: Manasa Madela
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