What Material Extrusion isMaterial Extrusion is the generic term for all additive manufacturing processes in which material is dispensed through a nozzle to form shapes . The nozzle is attatched to a print head, which moves along the x-y-z axis. The print head moves up in the z-direction after each layer of material is extruded and stops when the build is complete. This process is also called Fused Deposition Modeling (FDM) .
- The nozzle attached to the printhead deposits material directly onto the build platform.
- The following layers are added on top of the previous layers. The printhead moves up and the build platform remains stationary.
- The layers are melted together upon deposition.
Once the material is extruded, the layers are exposed to the ambient air and harden. There are not additional material used to cure a build.
Materials include polymers and plastics. An example of polymer is Polycarbonate (PC). Thermoplastics are the most popular material for material extrusion. Examples of thermoplastics are Acrylonitrile Butadiene Styrene (ABS), PolyLactic Acid (PLA), High-Impact Polystyrene (HIPS), Thermoplastic PolyUrethane (TPU), aliphatic PolyAmides (PA, also known as Nylon), PolyEther Ether Ketone (PEEK), and PolyEtherimide (PEI) .
Equipment Used Today
The material extrusion process is applicable to many fields. Buildings can be constructed with concrete extrusion machines . Human tissues and organs have been extruded using this technique .
Pros and Cons
- Widespread process 
- Lower cost machines make this process available to a wide audience 
- ABS plastic is a common, easily accessible material that has good structural properties
- The nozzle radius limits and reduces the final quality 
- The accuracy and speed are low when compared to other processes 
- The accuracy of the final model is limited to material nozzle thickness 
- The constant pressure of material is required in order to increase the quality of finish 
Video Demonstration of the Material Extrusion Process
GrafEngin. (2016). material extrusion. Available at: https://www.youtube.com/watch?v=VQR_Q8_KhCs. (12/21/20).