Welcome to our informative series on 3D printing. In this piece, we will cover what it is, how it’s used and what we can expect in the future.
3D printing, also known as additive manufacturing, is an emerging technology that has experienced a boom in recent years. Although the innovation that started the 3D printing movement began in the 1980s, it was not until the last 10 to 15 years that a more rapid growth has occurred. Printing a three-dimensional object is no longer a novel idea, and there are a variety of applications for 3D printing across many industries.
How 3D printers work
Although individual 3D printers have somewhat different approaches to producing a 3D object, the basic premise is the same. The first step is to create a computer-aided design (CAD) model, which is a computer file that stores all of the physical information about the object. This is a complex digital model, and often requires multiple iterations to correct errors that are flagged by the software as the CAD is created.
Once all errors have been resolved, the CAD runs through another type of software colloquially known as a “slicer”. This software separates the 3D object into multiple layers, which eventually become the stacked layers comprising the finished product. Think of it like a sliced loaf of bread. The 3D printing process is much like this: many layers are printed on top of one another in varying shapes, following the specifications of the CAD model, and when they’ve all been stacked together you end up with a 3D object.
The engineering that goes into the 3D printers varies according to many different elements, including the object’s size, complexity, eventual use and the material. One process is called fused filament fabrication, which builds an object in layers, or slices, from the bottom up. Fused filament fabrication includes a horizontal surface that moves up and down, and the object is printed onto this surface. The material of choice is fed from above and melted just before it is deposited as one of the layers.
After each layer is added, the horizontal surface upon which the object is being built lowers slightly, allowing the next layer to be printed. This process repeats over and over until the eventual 3D object is whole. Depending on the shape of the object, horizontal supports are sometimes necessary to maintain the integrity of the object until it is completed, thereby avoiding the problem with layers being printed in mid-air that would, obviously, fall due to gravity, as well as compromise the stability of the 3D object.
Another 3D printing process also builds an object from the bottom up, but it does this upside down. This type of 3D printing is called stereolithography. As before, the 3D object is built upon a horizontal surface that moves up and down. However, with stereolithographic 3D printing there is an additional horizontal surface, this one transparent, as well as vertical structures around the sides, creating something like a tank. The transparent surface is covered with a liquid printing material, and the two horizontal surfaces start very close together.
The key differentiator to this type of 3D printing is what causes the material to harden: a laser is positioned beneath the transparent horizontal surface and directs its beam according to the CAD model, causing the liquid printing material to harden as the laser’s beam hits it. The first layer binds to the upper horizontal surface, and then that surface moves up very slightly. The laser then directs its beam to create the next layer, again following the CAD model, and binding itself to the first layer. This process is repeated over and over until the 3D object is complete
Now that we’ve identified the different types of 3D printing, our next segment will cover how these technologies are used.