DefinitionFDM (fused deposition modeling) is a material extrusion 3D printing process that melts a thermoplastic filament and deposits it through a heated nozzle, layer by layer, to build a part.
Explained
How Does FDM 3D Printing Work?
A spool of solid thermoplastic filament is fed into a heated nozzle, which brings it to a semi-solid state. The nozzle traces the outline and infill of one layer onto the build platform. The platform then steps down, or the nozzle steps up, and the next layer is deposited on top. Slicing software cuts the CAD model into layers and generates the toolpath (G-code) the printer follows.
The process was patented by S. Scott Crump in 1989 (granted 1992). The patent describes supplying material "in the form of a flexible strand of solid material from a supply source, such as a reel." The name fused deposition modeling was introduced by the company Crump co-founded to commercialize it. After the original patent expired, the term fused filament fabrication (FFF) came into use for the same technology. Under ISO/ASTM 52900, both belong to the material extrusion category.
FDM has three well-known trade-offs. Layer lines are visible, so surface finish is the weakest point of the process. Overhangs need support structures. Parts are also anisotropic: strength measured along the layers differs from strength measured across them.
FDM Materials and What They Are For
| Material | Key properties | Typical applications |
|---|---|---|
| PLA | Rigid, easy to print, biodegradable | Concept models, non-functional display parts |
| ABS | Durable, post-processable, mild chemical resistance | Functional prototypes, housings, enclosures |
| PETG | Tough, low warping, mild chemical resistance | Transparent covers, food-contact prototypes |
| TPU | Flexible, impact resistant | Gaskets, protective covers, flexible joints |
| Nylon (PA) | Strong, wear resistant, slightly flexible | Gears, brackets, functional components |
| ASA | UV resistant, weatherable, ABS-like | Outdoor prototypes, exposed enclosures |
When to Choose FDM
- Early iterations and concept models. FDM has the shortest lead time of NICE Rapid's 3D printing processes: 1–2 days.
- Large parts. FDM has the largest build volume of NICE Rapid's plastic processes, at 500 × 500 × 500 mm (19.7 × 19.7 × 19.7 in).
- Orient for load. Because strength varies with build direction, choose the build orientation with the main load path in mind.
- Don't use it for tight fits or cosmetic faces. NICE Rapid holds FDM parts to ±0.3 mm (±0.012 in) with 100–300 µm layers. Where fit or finish matters, SLA (±0.1 mm) or SLS (±0.2 mm) is the better choice.
Key takeaways
- FDM melts thermoplastic filament and deposits it layer by layer through a heated nozzle.
- It is the simplest and usually lowest-cost 3D printing method.
- Layer lines are visible, overhangs need support structures, and parts are anisotropic.
- Common materials include PLA, ABS, PETG, TPU, nylon and ASA.
- Best suited for concept models, large parts and early fit checks; not ideal for tight tolerances or cosmetic surfaces.
- NICE Rapid offers 1–2 day lead times, a 500 × 500 × 500 mm build volume and ±0.3 mm tolerance.
References
- US Patent 5,121,329 (S. S. Crump), Apparatus and method for creating three-dimensional objects — patents.google.com
- NIST, Additive Manufacturing: Material Extrusion — nist.gov
- 3D/4D Printing of Polymers: Fused Deposition Modelling (FDM), Selective Laser Sintering (SLS), and Stereolithography (SLA) — pmc.ncbi.nlm.nih.gov
- A Comprehensive Overview of Additive Manufacturing Processes Through a Time-Based Classification Model — pmc.ncbi.nlm.nih.gov