What is the first step in the basic principles of FDM?

The process of Fused Deposition Modelling (FDM) begins with unwinding a filament of thermoplastic from a spool. This is a fundamental step because the material used in FDM is typically a thermoplastic filament that is available on spools in various diameters (most commonly 1.75 mm or 2.85 mm). The filament must be fed into the printer’s extrusion system, where it will be heated and melted to be deposited layer by layer onto the build platform.

This initial step is crucial as it sets the stage for the subsequent phases of the FDM process, including melting, extrusion, and deposition. Without this unwinding of the filament, none of the other processes—such as moving the deposition head or the actual printing—could occur, as there would be no material to work with. Thus, the unwinding of the thermoplastic filament is indeed the foundation upon which all other actions in the FDM procedure are built.