What Is Fused Deposition Modeling (FDM) and How Does the Process Work?

Fused Deposition Modeling, also known as FDM, was successfully developed in 1988 by the American inventor Scott Crump. It is one of the most widely used rapid prototyping and additive manufacturing processes today.

The materials used in FDM are generally thermoplastic materials such as wax, ABS, nylon, and similar polymers. These materials are typically supplied in filament form. During the printing process, the filament is fed into the print head, where it is heated to a temperature slightly above its softening point so that it melts and becomes suitable for extrusion.

The print head then moves along the cross-sectional contour and internal fill path of the part under computer control. As it moves, the molten material is extruded through the nozzle and deposited layer by layer. After extrusion, the material cools quickly in the build chamber, solidifies, and bonds with the surrounding deposited material as well as the previously formed lower layer.

Unlike some other rapid prototyping processes, FDM does not use a laser. Instead, it relies on the controlled extrusion of a heated thermoplastic filament. During molding, the nozzle is scanned in the X and Y directions according to the digital model data, while the part is built upward layer by layer until the complete three-dimensional component is formed.

Because of its relatively simple process, wide material availability, and practical operating cost, FDM has become a popular technology for prototype development, design validation, functional testing, and low-volume part production.