Abstract: A printing head assembly including a fixing member, two nozzle heads, two driving units, two position-limiting members, and two position-restoring members is provided. Each nozzle head has a filament connection tube and a material extrusion port respectively penetrating through the fixing member, wherein the filament connection tube has a position-limiting portion. The driving units drive the corresponding filaments to feed into the corresponding nozzle heads. The position-limiting members are respectively disposed between the corresponding driving unit and the fixing member, and are connected to the corresponding filament connection tubes. The position-restoring members are respectively disposed between the corresponding position-limiting member and the fixing member.

Abstract: A three-dimensional printing head includes a housing (100), a fusing module (200) arranged in the housing (100), and a heat dissipation module (300). The fusing module (200) is disposed in the housing (100) and includes a feeding tube (210) with both ends open. A feeding inlet (211) for receiving a filament material (20) is at one end of the feeding tube (210), a supplying nozzle (220) is at the other end of the feeding tube (210), and multiple fins (212) are formed outside of the feeding tube (210). A heater (230) is disposed at the supplying nozzle (220) to heat the same for melting the filament material (20). The heat dissipation module (300) includes a fan (310) arranged in the housing (100), and the fan (310) has an inlet side (311) and an outlet side (312) opposite thereto. The outlet side (312) is arranged toward the fusing module (200).