Material Extrusion


There are different material extrusion processes.
Materials can vary from silicon to concrete but extrusion of polymers is most common.
That is why this page focusses on Fused Filament Fabrication (FFF) also commonly known as
Fused Deposition Modelling™ (FDM™) – a trademark registered by Stratasys Inc.

Fused Filament Fabrication (FFF) or aka Fused Deposition Modelling™ (FDM™)

A polymer filament is pressed through a heated nozzle. The nozzle moves in a gantry system in the XY-plane
following the cross-section of the part. The material is deposited on the build platform. After the first layer is finished the build platform drops down by one layer thickness. The next layer of molten filament is applied on the layer underneath and the cycle continuous until the part is finished.

Entry level machines are very affordable, with prices ranging from a few hundred to about $ 3000.
There are even open source and do-it-yourself-kits such as the RepRap Project.
This circumstance created a huge community of people developing the technology further.
The low initial and low running costs are making this technology ideal to apply at schools and universities.

Ultimaker library on the dock

This Ultimaker2 is part of Melbourne’s Library at The Dock equipment. People can learn here how to use open source CAD programs and how to operate this machine as other entry level systems.

Prosumer machines are starting below 10k USD (pure system costs).
This machines are usually used by small businesses and companies which have used service bureaus before.
Some prosumer systems also have the capability to extrude a water desolve-able support structure.
This support structure makes it easier to create intricate designs and reduces manual post processing
of the parts.

Professional machines can cost up to hundreds of thousands of dollars.
With build envelopes of up to 1005 x1005 x1005 mm (XxYxZ) even large parts can be build.

Materials: Typically materials used are ABS, PLA, PC, PS, PEI but there are also more
exotic materials like monolignol  (a bio-degradable material)

Resolution: The layer thickness can vary typically from 0,025 to 1,25 mm.
The accuracy in XY is depending on the diameter of the nozzle outlet,
processing speed and position accuracy of the system.

Applications: Because of the low entry costs and the variety of materials available
FFF  is applied for various applications. The robust parts with reasonable high
geometric accuracy makes this technology attractive for parts for real use.

 

Here just some examples from different industries:

Automotive: Prototypes, Jigs, tool holders and fixations for assembly lines

 

Packaging industry: Tools for paper pulp packaging (link)

 

Medical:

Demonstrators

IMG_1088

This mock-up of a human spine was created built based of CT-data (DICOM) .
It was manufactured at RMITs (Royal Melbourne Institute of Technology) Advanced Manufacturing Precinct.
The part was made as stand to hold the drill-guide made of Titanium using Selective Laser Melting technology.

Read more about the use of FDM™ in medical applications in this blog article