Extrusion / FDM / FFF

Fusion Deposition Modelling (FDM)

3D printing utilizing the extrusion of thermoplastic material is easily the most common and recognizable 3DP process. The most popular name for the process is Fused Deposition Modelling (FDM). However, this is a trade name, registered by Stratasys, the company that originally developed it. Stratasys’ FDM technology has been around since the early 1990s and today is an industrial-grade 3D printing process.

The process works by melting plastic filament that is deposited, via a heated extruder, a layer at a time, onto a build platform according to the 3D data supplied to the printer. Each layer hardens as it is deposited and bonds to the previous layer. Stratasys has developed a range of proprietary industrial-grade materials for its FDM process that are suitable for some production applications.

At the entry-level end of the market, materials are more limited, but the range is growing. The most common materials for entry-level FFF 3D printers are ABS and PLA. The FDM/FFF processes require support structures for any applications with overhanging geometries. For FDM, this entails a second, water-soluble material, which allows support structures to be relatively easily washed away, once the print is complete. Alternatively, breakaway support materials are also possible, which can be removed by manually snapping them off the part. Support structures, or lack thereof, have generally been a limitation of entry-level FFF 3D printers. However, as the systems have evolved and improved to incorporate dual extrusion heads, it has become less of an issue.

In terms of models produced, the FDM process from Stratasys is an accurate and reliable process that is relatively office/studio friendly, although extensive post-processing can be required. At the entry level, as would be expected, the FFF process produces much less accurate models, but things are constantly improving. The process can be slow for some part geometries and layer-to-layer adhesion can be a problem, resulting in parts that are not watertight. Again, post-processing using Acetone can resolve these issues.

Learn more about 3D printing & its processes in this concise course - Understanding the A-Z of 3D Printing