3D Printing Primer

Chapter 2. Polymer Extrusion (FDM/FFF)

Process name	Description of method	Machine cost	Upkeep cost	Open source?	Primary distributors
Fused filament fabrication (FFF)/ material extrusion	Heat up plastic and squeeze out layers. Other materials possible.	Low	Low	Yes	Commercial: Stratasys Consumer: Many RepRap-derived options

Fused filament fabrication (FFF) systems can be thought of as simple robots with a thermoplastic extruder attached to a Cartesian (sometimes pseudo-Cartesian) gantry. The extruder lays down a thin line of polymer, drawing the desired object out layer by layer onto the print bed by following a predefined toolpath. The extruded material is not technically melted (unless something goes wrong), but it is softened to the point where it is willing to self-adhere to the similar material beneath it.

It is possible to create fine-looking but poor-quality parts, if the extruded polymer is too cold and doesn’t properly adhere to the materials underneath. The extruder is generally the most problematic part of the process, because it must operate continuously and consistently.

The vast majority of the 3D printers commonly appearing in offices, classrooms, libraries, makerspaces, dorm rooms, garages, and basements are designed to operate on the same basic principle. As they are becoming the most ubiquitous type of 3D printer in the consumer space, they are particularly important to understand.

Figure 2-1 shows an example of an FFF system that includes structural ...