1. A single screw extrusion sprayer of a 3D printer, comprising:a drive mechanism;
a stir mechanism; and
an extrusion mechanism;
wherein a side of the drive mechanism is connected to the stir mechanism to drive the stir mechanism to rotate, and another side of the drive mechanism is connected to the extrusion mechanism to drive the extrusion mechanism to rotate; and the extrusion mechanism is connected to the stir mechanism to deliver stirred particles to the extrusion mechanism.

2. The single screw extrusion sprayer of claim 1, wherein the drive mechanism comprises a support and a double-shaft stepping motor connected to the support; a side of the double-shaft stepping motor is connected to the stir mechanism through a pair of first bevel gears; and another side of the double-shaft stepping motor is connected to the extrusion mechanism through a pair of second bevel gears.

3. The single screw extrusion sprayer of claim 2, wherein the stir mechanism comprises a first support plate, a stir shaft, a stir claw, a hopper, and a feed tube; the first support plate is connected to the support; one end of the stir shaft is arranged on the first support plate, and the other end of the stir shaft is extended into the hopper; the stir claw is located in the hopper and arranged on the stir shaft; a bottom of the hopper is connected to the extrusion mechanism via the feed tube; and one of the pair of first bevel gears is arranged on the stir shaft, and the other one of the pair of first bevel gears is connected to an output end of a side of the double-shaft stepping motor.

4. The single screw extrusion sprayer of claim 3, wherein the extrusion mechanism comprises a second support plate, a spline shaft, a screw rod, a barrel, and a nozzle; a side of the second support plate is connected to the support; one end of the spline shaft is arranged on the second support plate, and the other end of the spline shaft is connected to the screw rod; the screw rod is inserted in the barrel; the nozzle is arranged at a bottom of the barrel; the feed tube is connected to the barrel; and a heating and heat dissipating assembly is arranged at a lower side of the barrel.

5. The single screw extrusion sprayer of claim 4, wherein the screw rod is provided with a spline; the spline shaft is connected to the screw rod via a spline housing; and the spline shaft is inserted in a threaded lock sleeve to axially lock the spline housing.

6. The single screw extrusion sprayer of claim 5, wherein the screw rod is positioned and supported by a flange bearing and a bearing seat; the barrel is connected to the bearing seat via a screw and the flange bearing; and the bearing seat is positioned on the support via a pin location, and the bearing seat and the support are connected via a bolt.

7. The single screw extrusion sprayer of claim 6, wherein the heating and heat dissipating assembly comprises a heating jacket, a fan, and a heat dissipating sleeve; the barrel is inserted into the heating jacket and the heat dissipating sleeve; the heating jacket is arranged at the lower side of the barrel; the heat dissipating sleeve is located above the heating jacket; and the fan is arranged outside the heat dissipating sleeve and is fixed on the support via a fan base.

8. The single screw extrusion sprayer of claim 7, wherein a heat-insulating plate is arranged between the fan base and the support.

9. The single screw extrusion sprayer of claim 1, further comprising a reinforcing mechanism arranged below the stir mechanism; wherein a side of the reinforcing mechanism is connected to the extrusion mechanism.

10. The single screw extrusion sprayer of claim 9, wherein the reinforcing mechanism comprises a plurality of reinforcing plates and a third support plate; the plurality of reinforcing plates are connected to the third support plate via screws; and the third support plate is fixed on the support via a screw.