Material extrusion is an additive manufacturing (AM) process where a material, usually a thermoplastic polymer, is forced through a heated nozzle and deposited layer by layer to create a three-dimensional object.
Here's a more detailed breakdown of the process:
1. Material Feed:
- A spool of material, typically in filament form, is fed into the 3D printer. Common materials include PLA (polylactic acid), ABS (acrylonitrile butadiene styrene), PETG (Polyethylene Terephthalate Glycol-modified), and nylon.
2. Heating and Liquefaction:
- The filament is fed into a heated nozzle (also known as a hot end).
- The nozzle is heated to a temperature sufficient to melt or soften the material, making it pliable enough to be extruded. The specific temperature depends on the material being used.
3. Extrusion:
- A pushing mechanism, such as a motor-driven gear or a roller system, forces the softened material through the nozzle.
- The diameter of the nozzle orifice determines the width of the extruded material, influencing the resolution and print time.
4. Deposition:
- The heated nozzle moves along pre-programmed paths, depositing the material onto a build platform or the previous layer.
- The movement is controlled by computer numerical control (CNC) instructions, based on a digital 3D model (usually an STL file) that has been sliced into layers.
5. Layer-by-Layer Build:
- Each layer of material solidifies (cools and hardens) as it is deposited.
- The build platform typically moves down (or the nozzle moves up) a small distance to allow for the next layer to be deposited. This process is repeated until the entire 3D object is built.
6. Cooling and Solidification:
- After deposition, the material needs to cool and solidify to maintain its shape and bond to the previous layer. Some printers incorporate fans or cooling systems to accelerate this process.
In summary, material extrusion uses a heated nozzle to melt and deposit material layer by layer, building a 3D object from the bottom up according to a digital design.
