3D-printer system having a pneumatic system for preventing drippage of excess print material

An apparatus comprising:

• a printer cartridge having a cartridge barrel for containing print material;
• an extruder having a nozzle, a syringe barrel, and a lever arm, the lever arm including a plunger, the plunger having (i) a disc and (ii) a portion that extends distally from the disc toward the nozzle and is configured to contact an interior of the syringe barrel, wherein an inlet port is disposed through the portion that extends distally from the disc toward the nozzle;
• and
• a pneumatic system including a pneumatic piston, a solenoid valve and a Y-connector, wherein the pneumatic piston is configured to receive pressurized air from (1) the Y-connector to lower the lever arm into the syringe barrel of the extruder to align the inlet port with an entry point of the extruder enabling the print material to flow into the extruder through the inlet port, and (2) the solenoid valve to raise the lever arm to (i) misalign the inlet port and the entry point to prevent additional print material from flowing into the extruder and (ii) create suction within the syringe barrel thereby preventing the print material from extruding from the nozzle.