3D printing

3D printing, or additive manufacturing, is the process of making a solid object based on a digital 3D model. The printer builds the object layer by tiny layer using specialized machines and materials.

The technology that makes 3D printing possible was developed during the 1980s. One of its primary applications was rapid prototyping. Over time, 3D printers were developed that could use a variety of materials. In addition to manufacturing items, the technology has the potential to be used in medicine and other fields, such as nanotechnology. Researchers are exploring the many possibilities of 3D printing.

Background

Chuck Hull invented 3D printing technology in 1983. The company he worked for used ultraviolet (UV) lamps to make durable table coatings. Hull had an idea to use the UV technology to create working prototypes of computer designs, and he experimented for several months. He was working with acrylic-based substances that were liquid, but instantly became solid under UV light. He eventually worked out a process called stereolithography. It involves using a vat of liquid photopolymer resin, which is laid down in a pattern, layer by layer. Each layer is cured by a UV laser. The layers are extremely thin.

The process begins with a digital scan or a model made using computer-aided design (CAD). Once the object design is complete, slicing software divides it into thin cross sections. These are then printed one layer at a time.

In the beginning, the 3D pieces would sometimes warp and shrink. The pieces could be brittle, and were easily broken. Over time, however, the chemistry was improved to virtually eliminate distortion.

The 3D printing technology appealed to manufacturers and design engineers. Eventually, as the cost of the printers decreased, hobbyists and others began to see the potential of 3D printing.

3D printing has become a manufacturing process. With the use of more materials, including ceramics, food, metal alloys, pure metals, thermoplastics, and thermoplastic composites, it is possible to 3D print many objects.

The building industry has used 3D printed concrete components in construction. Because concrete is not strong enough to bear loads without reinforcement, the printing process must stop frequently to allow steel rebar rods to be inserted. Bionic-mesh-steel-fiber (BMSF) reinforcement inserts have the potential to revolutionize 3D printed concrete. Researchers may be able to develop printers that can layer both the concrete and the fiber reinforcement during the printing process.

Several methods of 3D printing have been developed. The four basic categories of 3D printers are material extrusion, vat photopolymerization, material jetting, and binder jetting.

Material extrusion printers commonly lay down layers of thermoplastics in thin, solid filaments, which are heated until they melt. Manufacturers have developed composites using carbon fiber, carbon nanotubes, metals, and other materials. These printers can also extrude concrete and edible matter. These machines, which are also called fused deposition modeling (FDM), thermoplastic extrusion, plastic jet, fused filament method, and fused filament fabrication, are the most common types. Manufacturers produce both consumer-friendly models and industrial machines.

Vat photopolymerization printers, like those invented by Hull, solidify a photocurable resin. A laser or other source of light works in a vat of liquid photopolymer. The light solidifies layers in turn, either on the surface or at the base of the vat. To make an object using the stereolithography technique, a perforated platform is positioned just below the surface of the liquid polymer. The laser traces the first layer of an object on the surface, making a thin slice of the photopolymer harden. The platform lowers a tiny bit each time, as solid layers are added, until the completed object is built on the platform. The quality of the objects created using vat photopolymerization is high, but so is the cost of running the printer.

Material jetting printers work much like ink-jet printers. Instead of applying ink to paper, the printer sprays liquid layers, and then casts UV light on the material to harden it. The layers then build up. Some machines can print different colors or several materials in one process using multi-nozzle print heads.

Binder jetting printers use print heads to spray binders or glues. These devices bind thin sheets of paper, plastic, or metal together.

Overview

Researchers are exploring a number of applications for 3D printing. A 3D food printer, for example, offers possibilities for gastronomic experimentation as well as science, for example, space exploration. Such printers extrude edible substances through syringes. People have extruded chocolate spreads, liquid cheeses, frostings, and other substances and created unique forms and textures. Commercial ventures have printed custom 3D chocolate faces and 3D printed pastas. Extremely complex foods—such as a vegetable or combination of foods, such as a hamburger on a bun—are not practical applications, but the basic ingredients used to print food could be altered. As an example, patients who are unable to chew often rely on pureed concoctions. A 3D printer could potentially produce a softer version of foods that appeal to patients, with a specialized blend of nutrients, such as added vitamins. Other possibilities include creating meat substitutes using alternative proteins, such as algae proteins instead of animal proteins, or mealworms or other proteins that many consumers reject in their original forms.

Researchers are also looking into the potential for printing foods during long space voyages. Producing a variety of foods would present many challenges, but if scientists can find a way to use a limited number of proteins and other components to create a variety of foods, 3D printing could be useful for space travelers. Researchers are also trying to develop faster ways of printing, since the slow process makes it impractical to create foods on demand.

Some researchers are experimenting with printers that lay down live cells. Some 3D printed tissue is being used to test toxicity of experimental drugs on liver cells. One team created a 3D printed outer ear. It is composed of a scaffold made of hydrogel, cells that will grow into cartilage, and silver nanoparticles that work as an antenna. Scientists believe they may be able to print organs in the future, and researchers are making 3D printed polymer bones custom-made for patients. Others are developing titanium replacement joints. 3D printing has also been used to create prosthetic arms and hands, and in veterinary medicine it has been used to create a variety of prosthetics for animals.

Research scientists have been exploring the possibility of using 3D printing to aid in researching other topics, mainly by printing equipment for use in experiments. One of the most popular uses of 3D printing in a lab setting has been the creation of reaction vessels in which to manufacture chemicals. In 2012 scientists at the University of Glasgow demonstrated that it is possible not only to print the reaction vessel, but to have the printer fill the vessel with the reactants (the components that interact with each other to create the desired chemical) in the process.

In manufacturing, 3D printing has been used for rapid prototyping (quickly creating a prototype of a new part or device). As advances in 3D printing technology expand the materials used beyond plastic, the possibility of creating finished parts or devices by this method has arisen. 3D printing has also been used to manufacture small customizable products to sell, such as phone cases. Customizable 3D printing of jewelry and small art objects has also become popular.

In some cases, 3D printing has been used to produce large products, such as houses. In 2018, for example, a French family moved into a 3D-printed house in Nantes, becoming the first European family to live in a home constructed in that fashion. That same year, the Dutch construction company Van Wijnen announced that, in partnership with the Eindhoven University of Technology, it would be 3D printing houses using a very large printer that would lay down a specially formulated cement. While this method could only be used to create the walls and the houses would otherwise have to be constructed in the standard manner, the process was expected to be faster, less expensive, and less wasteful than the usual method. In 2021, a Dutch couple moved into one of the houses in Bosrijk.

By the 2020s, 3D printing had begun to be used to create high-end clothing items and shoes; in particular, companies such as Nike and New Balance have used it to create custom-fit shoes for professional athletes. A few brands by that time had begun selling 3D-printed shoes to private consumers as well. Other products, including car parts, construction materials, and pharmaceuticals, had also been produced with 3D printing by that time.

While the possibilities of emerging 3D printing technologies produced considerable interest and excitement regarding their potential applications during the twenty-first century, this technology was also not without controversy. A particular area of concern to some lawmakers and activists was the use of 3D printing technology to produce guns and component kits that could be used to assemble homemade guns, often known as "ghost guns." These 3D-printed firearms lacked serial numbers and were often difficult or impossible to trace, and their wide availability in many countries, including the United States, raised concerns over the potential for criminal groups and unlicensed individuals to acquire such weapons. By 2024 fourteen US states had passed laws regulating ghost guns; many of these laws covered guns manufactured with 3D printing and required that these guns be registered with local authorities.

As individuals experiment, they are discovering new applications for 3D printing. The availability of 3D printers means that anyone can design a prototype using a computer, find a 3D printer (some libraries, for example, have invested in the devices), and create a working model. Uses in medicine and science are still being explored and hold the promise of revolutionizing these fields.

Bibliography

Alec. "Kai Parthy Makes Construction 3D Printing Viable with Scalable BMSF Steel Reinforcement Inserts," 3Ders.org, 10 Nov. 2016, www.3ders.org/articles/20161110-kai-parthy-makes-construction-3d-printing-viable-with-scalable-bmsf-steel-reinforcement-inserts.html. Accessed 14 Nov. 2016.

Barnatt, Christopher. "3D Printing." Explaining the Future, 10 Nov. 2016, explainingthefuture.com/3dprinting.html. Accessed 10 Nov. 2016.

Boffey, Daniel. "Dutch Couple Become Europe’s First Inhabitants of a 3D-Printed House." The Guardian, 30 Apr. 2021, www.theguardian.com/technology/2021/apr/30/dutch-couple-move-into-europe-first-fully-3d-printed-house-eindhoven. Accessed 3 Jan. 2023.

Boffey, Daniel. "Netherlands to Build World's First Habitable 3D Printed Houses." The Guardian, 6 June 2018, www.theguardian.com/artanddesign/2018/jun/06/netherlands-to-build-worlds-first-habitable-3d-printed-houses. Accessed 21 June 2018.

"Build a Hand." Enabling the Future, enablingthefuture.org/upper-limb-prosthetics/. Accessed 14 Nov. 2016.

Cano, Lesley M. 3D Printing: A Powerful New Curriculum Tool for Your School Library. ABC-CLIO, 2015.

Columbus, Louis. "The State of 3D Printing, 2018." Forbes, 30 May 2018, www.forbes.com/sites/louiscolumbus/2018/05/30/the-state-of-3d-printing-2018/. Accessed 21 June 2018.

"Downloadable Guns." Everytown for Gun Safety, www.everytown.org/issues/downloadable-guns/. Accessed 12 Jul. 2024.

Hadhazy, Adam. "Will 3D Printers Manufacture Your Meals?" Popular Mechanics, 25 Mar. 2013, YPERLINK "http://www.popularmechanics.com/technology/gadgets/a8816/will-3d-printers-manufacture-your-meals-15265101/" www.popularmechanics.com/technology/gadgets/a8816/will-3d-printers-manufacture-your-meals-15265101/. Accessed 14 Nov. 2016.

Ledford, Heidi. "The Printed Organs Coming to a Body Near You." Nature, 15 Apr. 2015, //www.nature.com/news/the-printed-organs-coming-to-a-body-near-you-1.17320" www.nature.com/news/the-printed-organs-coming-to-a-body-near-you-1.17320. Accessed 14 Nov. 2016.

Lewis, Tim. "Has the 3D Printing Revolution Finally Arrived?" The Guardian, 12 Mar. 2023, www.theguardian.com/technology/2023/mar/12/3d-printing-the-new-technology-comes-into-its-own. Accessed 12 Jul. 2024.

Lipson, Hod, and Melba Kurman. Fabricated: The New World of 3D Printing. John Wiley & Sons, 2013.

Lull, Julia. "See How Kids Are Getting 3D-Printed Hands for Free." Time, 31 Aug. 2015, HYPERLINK "http://time.com/4016974/3d-printed-hands-e-nable/" time.com/4016974/3d-printed-hands-e-nable/. Accessed 14 Nov. 2016.

Ponsford, Matthew, and Nick Glass. "'The Night I Invented 3D Printing.'" CNN, 14 Feb. 2014, www.cnn.com/2014/02/13/tech/innovation/the-night-i-invented-3d-printing-chuck-hall/. Accessed 10 Nov. 2016.

Wanshel, Elyse. "Library Used Its 3D Printer to Make Prosthetic Hand for Girl." Huffington Post, 25 Aug. 2016, HYPERLINK "http://www.huffingtonpost.com/entry/texas-library-3d-printer-prosthetic-limb-girl-katelyn-vincik‗us‗57bdc30ae4b0287a6e7312c0.%20Accessed%2011%20Nov.%202016" www.huffingtonpost.com/entry/texas-library-3d-printer-prosthetic-limb-girl-katelyn-vincik‗us‗57bdc30ae4b0287a6e7312c0. Accessed 11 Nov. 2016.