What is Material extrusion?
Material extrusion is an additive manufacturing technique which uses continuous filament of thermoplastic or composite material to construct 3D parts. The material in the form of plastic filament fed through an extruding nozzle, where it heated and then deposited onto the build platform layer by layer.
Material extrusion is now the most popular additive manufacturing process in terms of availability for general consumer demand and quality. As per ISO/ASTM 52900-2015, it is one of the 7 Additive manufacturing processes. You can read the other types here.
Material extrusion technology was first developed in the 1980s by S. Scott Crump under the registered name of fused deposition modelling (FDM). The term fused deposition modelling (FDM) and its abbreviation FDM are trademarked by Stratasys Inc, a company co-founded by Scott Crump.
Fused filament fabrication (FFF) is another type falls under this category developed by the members of the RepRap project which is not restricted to use by others. You can read all about RepRap in here. This is also referred to as Plastic Jet Printing.
Following video by Solid Concepts explicitly outlines the Material extrusion process
Pros & Cons of Material extrusion
Advantages of Material extrusion
- Wide selection of print material
- Easily understandable printing technique
- Easy and user-friendly method of print material change
- Low initial and running costs
- Comparable faster print time for small and thin parts
- Printing tolerance of +/- 0.1 (+/- 0.005″)
- No supervision required
- Small equipment size compared to other AM
- Comparably low-temperature process
Disadvantages of material extrusion
- Visible layer lines
- The extrusion head must continue moving, or else material bumps up
- Supports may be required
- Poor part strength along Z-axis (perpendicular to build platform)
- Finer resolution and wider area increases print time
- Susceptible to warping and other temperature fluctuation issues such as delamination
- Toxic print materials