How is the thermoplastic filament prepared before extrusion in FDM?

In the Fused Deposition Modelling (FDM) process, the preparation of thermoplastic filament involves heating the material to just about its melting point. This is crucial because it allows the filament to reach a viscosity that is suitable for extrusion through the printer's nozzle. At this temperature, the thermoplastic becomes soft enough to flow but not so hot that it loses its structural integrity, which ensures that it can be drawn through the nozzle accurately and consistently.

Heating the thermoplastic filament to this optimal temperature helps achieve good layer adhesion during the printing process. If the filament were cooled below its melting point, it would be solid and unable to be extruded. Compressing it into a solid block would also prevent it from being extruded properly, as the filament needs to maintain a specific diameter and consistency to fit through the nozzle. Blending with other materials can modify the properties of the filament but is not a necessary step for preparing the filament specifically for the extrusion process.

Thus, the heating process is a critical step in ensuring that the thermoplastic can be effectively and efficiently used in 3D printing.