In this blog post, I will explain the operating principles and advantages of FDM 3D printers, with a focus on the characteristics of PLA and ABS, two of the most common filament materials.

Overview and Use Cases of FDM 3D Printers

Earlier this year, a hospital in Seoul used a 3D printer to recreate the kidney tissue and cancerous tissue of individual kidney cancer patients to plan customized surgeries. By physically verifying the condition of each patient’s kidney through the printed models, the surgeons were able to prepare for and successfully complete the surgery by removing only the necessary areas while preserving healthy tissue. As such, 3D printing technology is being utilized in various fields—including medicine, manufacturing, construction, and design—and with the recent proliferation of home 3D printers, the need for related knowledge is growing.

How FDM Works

FDM (Fused Deposition Modeling) 3D printers use an additive manufacturing process that heats solid filament at the nozzle to melt it, then extrudes it layer by layer to build a structure. The process begins by setting up the build plate, which serves as the base for the printed object. It is desirable for the build plate to have a slight degree of stickiness to prevent the object from slipping. Filament wound onto a spool is loaded into the printer, and once the design data for the object to be printed is input, the nozzle heats up to melt the filament and extrude it in a liquid state. The bed and nozzle move according to the design, building up the structure layer by layer starting from the bottom. Since the filament is very thin, it solidifies immediately after extrusion, allowing the next layer to be deposited. The main components of the machine include the filament roll, the extrusion nozzle, and the bed that supports the printed object.

Advantages of Additive Manufacturing

Additive manufacturing technologies such as FDM offer several advantages over traditional subtractive manufacturing methods, such as CNC milling. Subtractive manufacturing involves cutting away material, resulting in significant material waste, whereas additive manufacturing is economical because it builds up only the necessary amount of material. Furthermore, while subtractive manufacturing has limitations when it comes to internal structures or complex shapes that are difficult for tools to access, additive manufacturing can gradually realize almost any form, making it advantageous for producing complex structures. For these reasons, FDM 3D printers are widely used across various fields.

Filament Requirements and Primary Materials

Filaments used in FDM 3D printers must meet several requirements. First, they must possess thermoplastic properties, meaning they can melt and deform when heated, and they must maintain a consistent shape and density to ensure stable extrusion from the nozzle. It must have appropriate viscosity to set without sagging after extrusion, and once the object is complete, it must possess the necessary strength, heat resistance, and flexibility. In particular, strength, heat resistance, and flexibility must be considered as properties of the filament after it has solidified following extrusion.

PLA (Poly Lactic Acid)

PLA stands for Poly Lactic Acid. It is a thermoplastic resin made by polymerizing lactic acid, which is obtained by decomposing and fermenting starch extracted from plants such as corn or sweet potatoes. Because it is made from plant-based raw materials, it is relatively safe and can be used for food containers; it is also considered eco-friendly as it is 100% biodegradable.
It is naturally transparent and glossy, making it easy to color and giving it an attractive appearance, so it is widely used for creating household models. Additionally, its relatively fast printing speed makes it advantageous for producing large models. On the other hand, while it is harder than ABS, it has lower flexibility and can break easily upon impact; it also has a low melting point, making it prone to warping in high-temperature environments.

ABS (Acrylonitrile Butadiene Styrene)

ABS is a plastic blend named after the initials of its three components—acrylonitrile, butadiene, and styrene. It is a material with good strength and relative flexibility, making it easy to process. It is suitable for manufacturing products that consist of multiple parts assembled together, and it has excellent heat resistance due to a higher melting point than PLA. Therefore, it is a suitable material for applications requiring use in high-temperature environments, such as the production of industrial parts. However, since it is made from petroleum-based raw materials, it is harmful to the environment if not recycled, and it emits a distinctive odor during processing. Additionally, it is not as rigid as PLA, so the likelihood of warping increases in large-scale models.

Metal Filaments and Their Limitations

Although still in the development stage, 3D printing methods using metal materials do exist. For example, some technologies are attempting to print metal by extruding it in filament form, much like pulling out strands of noodles. This method has advantages such as reduced geometric constraints, allowing for printing without the need for separate support structures. However, they require high temperatures sufficient to melt metal, which makes them costly and involves long solidification and post-processing times. Therefore, technical improvements are needed to ensure commercial viability and cost-effectiveness. If these drawbacks can be overcome, the scope of application is likely to expand in fields where metal is heavily used, such as construction and manufacturing.

Conclusion

We have examined the operating principles of FDM 3D printers, the advantages of the additive manufacturing process, and the characteristics of the representative filaments, PLA and ABS. As an additive manufacturing method, FDM reduces material waste and enables the production of complex shapes, making it economical and widely applicable. PLA is eco-friendly and has an attractive appearance, making it suitable for home use, while ABS offers high strength and heat resistance, making it suitable for industrial applications. Technologies utilizing metal materials also hold significant potential for development; if miniaturization and cost reduction are achieved in the future, the range of applications for 3D printers is expected to expand further.