SciTech

3-D printing creates objects with a layer-by-layer process

A personal 3-D printer called Fabbster manufactured by the Germany-based company Sintermask. (credit: Creative Tools via Flickr) A personal 3-D printer called Fabbster manufactured by the Germany-based company Sintermask. (credit: Creative Tools via Flickr) The additive manufacturing process used for 3-D printing allows for the creation of intricate shapes. (credit: fdecomite via Flickr) The additive manufacturing process used for 3-D printing allows for the creation of intricate shapes. (credit: fdecomite via Flickr)

By now, you’ve probably heard about a magical device that creates all sorts of objects with the click of a button. You’ve probably heard the word “3-D printer” many times, but how do these devices operate? And most importantly, what can we do with them now and in the future?

3-D printing is the process of making solid objects from digital files. The first machine capable of doing so was invented by Chuck Hull in 1984 and used a process called stereolithography that added layers to an object based on its 2-D cross sections. The material that the object was to be built of would be added in small layers to create a 3-D object, the process of which is called additive manufacturing. This process is very similar to the formation of stalactites and stalagmites, where small layers of minerals are added continuously by water to form a rock formation. This idea makes up the foundation of practical 3-D printing.

In contrast, the method of subtractive manufacturing involves cutting unneeded material off an object to shape a new object. However, this process results in a lot of wasted material. By using additive manufacturing, lighter parts can be created with less energy used to 3-D print. According to energy.gov, this form of 3-D printing uses “up to 50 percent less energy for certain processes compared to conventional manufacturing processes.”

To 3-D print, we need some way to give the machine instructions for making something or, at least, a model of the object to be printed; this is commonly done using computer-aided design (CAD) software. Such software allows designs for any type of object to be converted into easy-to-understand inputs for the 3-D printer.
Once these instructions are sent to the computer, the printer begins to automatically build the object. It uses a process called material extrusion in which the material, usually plastic, is heated until liquefied and forced out of a small nozzle. Because the nozzles are extremely small, at around 0.1 millimeters in diameter, the printer can carefully place the material so that the material forms the design that was made in CAD.

At each step, it finishes a 2-D cross section of the object, very similar to how a glue gun works, as sticks of hardened glue are melted and extruded from the tip after being heated. As the material cools down, it fuses with the layers below. The platform that holds the object is then lowered, allowing the extruder to work on the next level of the 3-D object. This whole process can take anywhere from a few minutes to a few days depending on the object, which can be extremely large and detailed or composed of a few simple layers. After the object is printed, any excess dust or powder must be brushed off or unstuck from the base of the printer.

Over the past few years, the 3-D printer has become extremely important, and new types of 3-D printing have sprung up. For example, material jetting deposits plastic and uses light to harden it; this can produce extremely accurate parts.

There is also binder jetting, which allows thin layers of powder to be put on the platform and sprayed with a glue-like binding solution that is able to accurately combine only the parts that are specified by the CAD file. There is also a newer form of 3-D printing that uses special materials in order to create human body parts. Termed “bio-printers,” these machines use a combination of human cell and tissue in order to create human body parts.

As a result of this surge in interest for 3-D printers, people have been using sites such as Kickstarter to help foster the Maker Movement, which is a push to use 3-D printers to revolutionize business and personal technology. By providing more affordable 3-D printers, they hope to allow people to print products locally
or even straight from their homes to reduce transportation costs and increase affordability.