The FDM technology involves feeding a thermoplastic filament into the FDM printer, which, when the machine reaches a certain temperature, melts the filament and extrudes it from the printer's nozzle. 

These melted materials are then stacked layer by layer, and upon cooling, solidify into a complete model.

However, FDM is not without its drawbacks. 

Common issues include deformation, low dimensional accuracy, and low resolution.

Deformation often occurs due to shrinkage after the newly stacked layer cools. 

In such cases, the printed material shrinks in size, causing the layers below to be pulled upward, resulting in bending deformation. 

Because of the low precision of FDM printing, fine and complex models are usually not suitable for FDM printing.