The fused deposition manufacturing (FDM) process was successfully developed by American scholar Scott Crump in 1988. The materials of FDM are generally thermoplastic materials such as wax, ABS, nylon, and the like. Feed in the form of a filament. The material is heated and melted in the spray head. The spray head moves along the cross-sectional profile of the part and the fill path, while extruding the molten material, the material solidifies rapidly and condenses with the surrounding material.
Unlike the above process, the FDM does not use a laser, and the molding material is a filamentous polymer. Prior to the start of forming, the filamentary material needs to be heated in the liquefied tube to a point slightly above its softening point to melt it. During molding, the nozzle is scanned by x-y under computer control, and a semi-flowing polymer is sprayed at the same time. The polymer is cooled and formed in the molding chamber, and is firmly bonded to the already formed lower layer.