In this blog post, we’ll explore the operating principles and materials of 3D printers, as well as their potential applications in the medical and industrial fields, starting from the sense of “free creativity” we experienced with LEGO as children.
The Principles of 3D Printing and Additive Manufacturing
Everyone has likely played with LEGO as a child. LEGO, one of the most popular toys among gifts given by parents, comes in a box filled with countless blocks of similar shapes. By following the instructions or using their imagination to combine the blocks, children experience the joy of creation. Why do children find happiness simply by looking at rectangular blocks? The answer lies in “creation” rooted in “freedom.”
Lego blocks have regular protrusions on their surfaces, allowing them to be stacked by fitting into the grooves of other blocks. By combining these simple blocks, children freely create shapes exactly as they envision them. 3D printers operate on a similar principle. When a user designs a desired object using 3D design software on a computer, the printer builds the model by layering raw material based on that data.
The 3D data created on the computer is broken down into tens of thousands of layers and transmitted to the printer. Each layer is approximately 0.01 mm to 0.08 mm thick, thinner than a single sheet of A4 paper. The shape of each layer varies depending on the cross-section of the object, and the 3D printer forms these thin layers by spraying or curing the material according to that shape, much like an inkjet printer. By stacking these layers sequentially, a three-dimensional object is completed.
The traditional manufacturing method of shaping materials by cutting them is called “subtractive manufacturing,” while the new method of building up layers is called “additive manufacturing.” The 3D printing method using additive manufacturing is commonly referred to as “rapid prototyping.” The three main materials used in rapid prototyping are powder, photopolymer liquid, and plastic filament.
The powder method involves filling a container with powder, such as nylon or calcium carbonate, and using a printer head to spray an adhesive as it passes over the powder, bonding it into the shape of the layer. This process is repeated for each layer, and the object is then immersed in a curing agent to complete it. The method using photopolymer resin involves curing the plastic with light to form layers, while the method using filament involves extruding molten plastic at high temperatures onto the desired points and instantly solidifying it to form layers. Each method has its own advantages and disadvantages depending on the materials and curing methods used.
There are also printers that carve large materials with a rotating blade instead of building layers. These are called “3D carvers”; while they can render curves more smoothly than rapid prototyping methods, they have the disadvantage of being unable to shape areas that the blade cannot reach.
Medical Applications and Industrial Prospects
In medicine, 3D images of the human body have long been obtained using imaging equipment such as MRI and CT scanners. However, images alone make it difficult to fully understand internal structures, leaving room for error and uncertainty. 3D printers create models that accurately replicate the interior of the body, enabling preoperative rehearsals, which significantly help reduce surgery time and risks.
For example, a medical team successfully completed a previously time-consuming separation surgery for conjoined twins in a relatively short time by conducting a dry run using a 3D-printed model after capturing an MRI of the surgical site. 3D printers are also useful for producing prosthetics tailored to each patient’s body. They can precisely create patient-specific prosthetics such as implants or artificial bones.
Technology experts worldwide view 3D printing as the technology that will lead the third industrial revolution, following the internal combustion engine and the computer. Unlike traditional manufacturing, 3D printing has great potential to open up new horizons in manufacturing, and leaders in many countries have already announced plans to expand research, development, and adoption. They can print complex shapes in a single pass, and if an error occurs, the design file can be modified and reprinted immediately, saving both time and money.
Although 3D printing technology is still in its infancy, prices are expected to fall as technology advances, making widespread adoption in households a reality. The range of materials is expanding beyond plastic to include nylon and metals, broadening the scope of applications. In the near future, commercial printers closely integrated into daily life—such as 3D printers for food production—will become common in households, and 3D printers will gradually evolve from expensive specialized equipment into tools accessible to everyone.
