FFF vs FDM: What’s the Difference? (They’re the Same)

While FFF (Fused Filament Fabrication) and FDM (Fused Deposition Modeling) are often perceived as distinct, they fundamentally represent the same core technology in the 3D printing landscape. The essence of both lies in the additive process of layer-by-layer construction, where thermoplastic materials are heated and extruded through a precision nozzle. 

The term FDM, patented by Stratasys in 1989, is trademarked. In contrast, FFF was coined by the RepRap community as an open-source equivalent when the Stratasys patent expired. The difference is more about branding than technology. 

The core technology behind both FFF and FDM technologies involve melting a thermoplastic material and extruding it layer by layer to build 3D objects.

FFF vs FDM: What’s the Difference?

The primary difference is terminological: The term ‘FDM’, patented by Stratasys in 1989, is trademarked. In contrast, ‘FFF’ was coined by the RepRap community as an open-source equivalent when the Stratasys patent expired. The difference is more about branding than technologyboth terms describe an identical process of heating, extruding, and layering materials to create three-dimensional objects.

The History Behind the FFF and FDM Terminologies

In the late 1980s, Scott Crump, a co-founder of Stratasys, Inc., invented the FDM technology. Crump’s invention involved the use of a heated nozzle to extrude thermoplastic material, layer by layer, to create an object. This process was revolutionary, enabling the conversion of digital designs into physical models with a new level of precision and versatility. 

Recognizing the potential of this technology, Stratasys was quick to secure patents to protect their innovation. The term “Fused Deposition Modeling” and its abbreviation “FDM” were trademarked by Stratasys, becoming synonymous with their brand and technology.

As the patents for FDM began to expire in the early 21st century, the 3D printing industry saw a surge in interest and development from other companies and independent makers. To avoid potential trademark infringement issues with the term FDM, the wider 3D printing community adopted the term “Fused Filament Fabrication” or FFF. This term was not only free from legal encumbrances but also accurately described the process of fabricating objects by fusing filament material layer by layer.

The adoption of the term FFF was also driven by the open-source movement within the 3D printing community. Enthusiasts and small-scale developers, who were instrumental in popularising 3D printing beyond industrial applications, preferred a term that was not tied to a specific company or proprietary technology. FFF became a symbol of the democratisation of 3D printing technology, representing a shared, community-driven approach to innovation and knowledge sharing.

FDM/FFF Printing Process

In both FFF and FDM printing, a continuous filament of thermoplastic material is fed through a hot nozzle. The nozzle heats the filament just enough to melt it, transforming it into a malleable state. 

This molten filament is then precisely extruded onto a build platform, where it cools and solidifies. This process is repeated, layer upon layer, to construct the object from the bottom up. 

FDM/FFF Material Use

A diverse array of thermoplastic materials can be utilised in both FFF and FDM printing, catering to various requirements of strength, flexibility, and thermal resistance. 

Common materials include PLA (Polylactic Acid) for its ease of use and environmental friendliness, ABS (Acrylonitrile Butadiene Styrene) for its strength and durability, and PETG (Polyethylene Terephthalate Glycol) for its clarity and chemical resistance. 

Additionally, specialised filaments like TPU (Thermoplastic Polyurethane) offer flexibility, and composite materials infused with elements like carbon fibre provide enhanced strength and rigidity

FDM/FFF Applications

The versatility of FFF/FDM technology allows for its application across a spectrum of industries. 

In aerospace, it’s used for producing lightweight, durable components. The automotive sector leverages it for prototyping and manufacturing end-use parts. In healthcare, FFF/FDM is instrumental in creating custom prosthetics and patient-specific surgical models. 

Beyond these, it’s also prevalent in consumer goods, architecture, and education, highlighting its adaptability and wide-ranging utility.

Addressing Common Misconceptions

Contrary to common belief, the strength of objects printed using FFF or FDM technology is not inherently limited by the printing method. 

Instead, it is significantly influenced by factors such as the type of filament used — with some materials offering higher tensile strength and durability — and the specific settings during printing, like layer height and print speed. 

Additionally, the design of the object, including the orientation of layers and the inclusion of structural supports, plays a crucial role in determining the final strength.

FFF and FDM printers are capable of producing highly detailed and precise objects, with the level of resolution being a function of several factors. 

The nozzle size determines the minimum feature size the printer can produce, with smaller nozzles allowing for finer details. The layer height, which can often be adjusted, impacts the surface finish; lower layer heights result in smoother surfaces. 

Printer calibration, including bed leveling and extrusion accuracy, also plays a critical role in achieving high-resolution results.

Residual stress and warping are challenges in FFF/FDM printing, but they are not insurmountable. These issues typically arise from uneven cooling of the printed layers, leading to internal stresses and deformation

Strategies to mitigate these include optimising print settings like temperature and cooling speed, using heated beds to ensure gradual cooling, and designing parts with warping in mind. Material choice also influences these factors, as different plastics exhibit varying degrees of thermal contraction.


Several alternatives to FFF/FDM exist, each offering distinct advantages and considerations.

Digital Light Processing is a resin-based 3D printing technology that employs a UV light projector to cure layers of photopolymer resin. It offers higher resolution and detail compared to FFF, but the process can be messy due to the uncured resin and requires a post-curing step.

CLIP utilises a continuous flow of resin and a UV light source to generate parts at a much faster rate than FFF. It is still under development, but it has the potential to revolutionise 3D printing due to its speed and accuracy. 

MJM printers excel in speed by employing multiple jets to deposit photopolymer resin, which is then cured with UV light. FFF printers offer moderate to fast printing speeds, depending on the printer settings.

Keys Takeaways 

The terms FFF and FDM are often used interchangeably in the 3D printing world, but they are essentially the same technology. Both FFF and FDM printers use an extrusion mechanism to deposit layers of molten thermoplastic material, creating three-dimensional objects. 

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