Fused Filament Fabrication

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Fused Filament Fabrication

Fused Filament Fabrication(FFF) is a filament based 3D Printing technology. It is one of the most widely available and one of the most cost-effective 3D printing technologies till date. An FFF 3D Printer consists of an extruder, a nozzle, and a platform. The 3D CAD file is input to the FFF printer where the software slices the part geometry into subsequent layers with each layer height corresponding to the selected layer thickness setting.

FFF parts fabricated and post-processed in ABS material. Courtesy: Wild Noodle

The material is wound around the spool in the form of a filament. This filament is input to the extruder. The extruder houses a heater which heats this filament above its glass transition temperature to about 200˚C. Based on the input 3D CAD file data, the material is then deposited on the platform through a nozzle. After depositing the first layer, the platform descends by an amount corresponding to one layer thickness. The average layer thickness in FFF is around 140µm. The nozzle then starts depositing the second layer. The platform descends again and this process continues till the entire part is fabricated layer by layer. In FFF, the parts are fabricated bottom-up.

FFF Printers come with varying layer thicknesses viz. 140µm, 180µm, 300µm etc. Finer the layer thickness, better the surface quality, but more time is required to fabricate the parts and thus higher the cost, and vice-versa. Unlike SLS, FFF parts are fabricated one at a time.

There is support structure generation in FFF technology. The support structures are either fabricated in the same material as is the case in single extrusion nozzles or can be fabricated in different material as seen in the case of dual extruder nozzles.

The density and the geometry of these support structures is designed such that they can be easily removed. Often times the support structures have to be removed manually, but FFF printers are also equipped with soluble support structures. Soluble support structures are fabricated in different material as compared to the parent material in which the part is fabricated and they leave little or no burr marks on the part geometry.

FFF parts can be made hollow to reduce weight and to save material, thereby reducing the overall cost of the part. The way FFF parts are hollowed is different from that seen in SLS technology. FFF parts are made hollow by changing the infill percentage. A 0% infill would correspond to a fully hollow part, whereas a 100% infill would correspond to a fully solid part. But we recommend an infill percentage of at least 30%. Know more about how parts can be made hollow.

An FFF part with 30% infill

FFF parts have a rough surface finish owing to process characteristics and support structure generation. The parts can be polished (sanded) and painted to improve the surface finish.

Painting usually adds a thickness of 100–200µm. The most commonly used material in FFF technology is Acrylonitrile Butadiene Styrene (ABS). FFF finds application in concept models for form validation, and it is the most widely accepted 3D printing technology owing to its cost-effectiveness.

Post-processed FFF part

Summary:

Materials: ABS
Support Structures: Yes
Maximum Bounding size: 300 x 300 x 300 mm
Accuracy: (+/-)300µm

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