3-D printing is a process referred to as Additive Manufacturing which constructs an object through sequential layering of a delegated material. This machine fabricates the product by jetting out a resin-like mixture that hardens into a plastic, metal, or other synthetic material. No replicating, completely up to the designer with no manufacturing restrictions other then what is possible and impossible due to the general laws of physics and nature. This not so new technology is finally being integrating into more businesses and manufacturing companies including dentistry, orthodontics, shoes, fashion, toys, and automotive industries. Being able to create a product using the exact amount of material needed with laser accurate detail and no waste is more than just beneficial, it’s revolutionizing industries. 3-Dimensional printing has practical applications in just about every field creating a product, including food.
As with a laser or inkjet printer, the process of creation starts with a concept or idea conceived onto a computer document, or in this case, a 3-dimensional layout or design drawn with a computer. Instead of a document file, the users will be creating an STL (.stl) or Stereolithography file, which is basically a Cartesian coordinate grid in three dimensions. The printer will then process the data by slicing the virtual blueprint vertically and creating a 2-D model one slice at a time. This is similar to the way a CT scan (or CAT scan) works taking images of the brain one slice at a time. The sequential layering allows for a more intricate building process, being able to create elaborate inner chambers and honeycomb textures with controllable porosity and channel size throughout a single item. After slicing and processing the given design, the printer will lay down the slices as successive layers of liquid, powder, titanium, wire, wax, or other given materials to construct the model from a series of coordinate cross sections. The cross sections directly correspond with the given or created STL file. Each layer is joined together or automatically fused to create the final shape or desired product. The printing process can take anywhere from a couple hours to days depending on the size of the object. This is only a fraction of the time spent on fabricating the same products using subtractive manufacturing or molding techniques. Moreover, there is little to no waste from the start of a project to the end of a project, unlike traditional manufacturing methods.
Many different materials can be used for 3D printing, including ABS plastic sheets, PLA, polyamides, glass filled polyamides, stereolithography materials, silver, titanium, steel, wax, photopolymers and polycarbonates. The material components used for 3-D printing are ever growing and evolving. As long as the material can be melted, sintered, laminated, or molded / modeled together it can be a viable candidate in additive manufacturing. The most popular, especially with the home users, is the ABS plastic sheets, being colorful, light weight, durable, and affordable. There are many other types of thermoplastics including PLA / polylactic acid which is a type of polyester, polyamides or nylon, and glass-filled polyamides which is fiber-glass woven into the nylon creating an extremely strong and durable plastic.
The plastics are extruded from the printer in a process called Fused Deposition Modeling, melting the thermoplastic material with the use of a heated printhead nozzle, ejecting small beads of the material one layer at a time which solidifies almost instantly at room temperature. Metals, plasters, and ceramic glass materials are generally in the form of a wire or powder solution before being melted or sintered via heat or laser into the desired shapes. Paper, metal sheets, foil, and plastic films can also be used in some 3-D printers that laminate the material into successive layers to form the 3-Dimensional objects. The other additive manufacturing technology involves the use of light to connect or fuse together the molecules of a substance forming the desired shape. Photopolymers are needed for light polymerization to take place which is an interesting material that literally washes away with cold water unless struck or excited by UV light which hardens the solution. Solidified Photopolymers generally feel and act much like a hardened rubber.
With so many applications, the 3-D printers are appealing to a broad array of businesses and organizations, including NASA. Facing the problem of freeze dried foods breaking down micronutrients over time due to their natural sugars and enzymes, researchers and developers at NASA have pioneered a project to create a complete nutritional food system that contains no waste or wrappers. By substituting plastics and metals for food powders, they have been able to create cookies and pizza with only the use of a 3-D printer. In order to accomplish this task, the team at NASA has the 3-D component delivering macronutrients like starch, protein, and fat which provide structure and texture, while the micronutrients are sprayed on afterward, delivering the smell and flavor components. The Macronutrient feed stocks are stored in a dry, sterile container and fed directly to the printer. The printer will combine water or oil with the extruding macronutrient feed stocks depending on the digital recipe to minimize waste and spoilage. Users can also modify textures and flavors at this macronutrient construction stage. The micronutrients are stored as liquids, aqueous solutions, or dispersions in sterile pouches and are jetted onto the Macronutrient structure before completion. The result is fresh pizza and cookies in space.
Researchers from Harvard and the University of Illinois have teamed up to develop a 3-D printed battery. The battery is smaller than a grain of sand and about as powerful as your cell phone battery. They used two separate lithium metal oxide pastes shaped into a comb-like formation, which hardened to create an anode and cathode. Several hospitals are also using 3-D printing technology to create individualized prosthetics that can be designed to the exact specifications needed. The quality of prosthetic material the printer can produce has also improved to be lighter and stronger than the usual molded prosthetics. The dentistry and orthodontics fields have perhaps had the most integration with these machines to date. Many offices are now creating their own correctable or invisible alignment retainers with the use of 3-D printing. This also cuts out a major cost and saves a tremendous amount of time, by not having to employ a third party to manufacture their goods. With the more recent metals and alloys being utilized, car and gun manufactures are finding these machines to be invaluable.
Additive manufacturing has no doubt had a tremendous impact on the companies already using these machines. As they become more affordable, their impact on society and businesses will increase as will the demand. Imagine being able to create specialized tools, toys, furniture, house wares (even electronic components such as lamps), food, and just about any product at home. 3-D printing makes all this reality. The impact 3-D printing will have on society and businesses will revolutionize the way we live and carry out our normal routines. And being able to specialize and control every detail and feature of a 3-D manufactured object has model enthusiasts excited. They are now able to create exact replica models of train cars, planes, ships, and automobiles. Even big cooperations such as Nike have invested in these machines due to their variant production capabilities and cost effectiveness. Many artists have also started experimenting with additive manufacturing to bring their creative visions to life that would not otherwise be possible through subtractive manufacturing or molding.