Precision bead forming 3D print head for cementitious materials

An additive manufacturing assembly for manufacturing with a material, comprising:

• a motion device for holding a print head assembly and for moving the print head assembly in three dimensional space during an additive manufacturing process;
• the print head assembly comprising an accumulator comprising an elongated body with an open interior and an inside diameter;
• a slide tube slidably mounted within the open interior of the elongated body, the elongated body having a distal material outlet, the slide tube comprising a conduit for directing the material from a slide tube material inlet to a slide tube material outlet at an open end of the slide tube, the slide tube comprising a sealing piston head having an axial passageway defining the open end, the piston head forming a sliding hermetic seal between the sliding tube and the elongated body, the slide tube having an outside diameter that is less than the inside diameter of the elongated body, the slide tube, elongated body and sealing piston head defining a gas containment space and the sealing piston head and elongated body distally defining an accumulator space between the piston head and the distal material outlet of the elongated body, a gas conduit system for receiving pressurized gas and directing the pressurized gas to the gas containment space, and for exhausting pressurized gas from the gas containment space;
• wherein the gas conduit system is configured such that pressurized gas in the gas containment space will apply pressure to the piston head, the piston head will apply pressure to the material in the accumulator space, and wherein the hermetic seal and the gas conduit system are configured to prevent the pressurized gas from entering the accumulator space and thereby the material, and the pressure applied by the piston head to the material will drive the material through the distal material outlet of the elongated body and material will flow through the axial passageway of the piston head;
• a nozzle assembly comprising a rotatable shaping nozzle with a nozzle opening for discharging the material;
• and
• an extruder for moving the material from the accumulator to the nozzle assembly;
• a source of the material for delivering the material to the print head assembly;
• a source of pressurized gas connected to the gas conduit system;
• and,
• a processor for controlling at least one selected from the group consisting of the movement of the motion device, the delivery of the material to the print head assembly, the delivery and removal of pressurized gas to the gas containment space, the operation of the extruder, and the rotation of the nozzle assembly.

A method of additive manufacturing, comprising the steps of:

• providing a motion device for holding a print head assembly and for moving the print head assembly in three dimensional space during an additive manufacturing process;
• providing a print head assembly comprising an accumulator comprising an elongated body with an open interior and an inside diameter;
• a slide tube slidably mounted within the open interior of the elongated body, the elongated body having a distal material outlet, the slide tube comprising a conduit for directing the material from a slide tube material inlet to a slide tube material outlet at an open end of the slide tube, the slide tube comprising a sealing piston head having an axial passageway defining the open end, the piston head forming a sliding hermetic seal between the sliding tube and the elongated body, the slide tube having an outside diameter that is less than the inside diameter of the elongated body, the slide tube, elongated body and sealing piston head defining a gas containment space and the sealing piston head and elongated body distally defining an accumulator space between the piston head and the distal material outlet of the elongated body,
• providing a gas conduit system for receiving pressurized gas and directing the pressurized gas to the gas containment space, and for exhausting pressurized gas from the gas containment space;
• wherein the gas conduit system is configured such that pressurized gas in the gas containment space will apply pressure to the piston head, the piston head will apply pressure to the material in the accumulator space, and wherein the hermetic seal and the gas conduit system are configured to prevent the pressurized gas from entering the accumulator space and thereby the material, and the pressure applied by the piston head to the material will drive the material through the distal material outlet of the elongated body and material will flow through the axial passageway of the piston head;
• providing a nozzle assembly comprising a rotatable shaping nozzle with a nozzle opening for discharging the material;
• and providing an extruder for moving the material from the accumulator to the nozzle assembly;
• providing a source of pressurized gas connected to the gas conduit system;
• providing a source of the material for delivering the material to the print head assembly;
• and
• providing a processor for controlling at least one selected from the group consisting of the movement of the motion device, the delivery of material to the print head assembly, the delivery and removal of pressurized gas to the gas containment space, the operation of the extruder, and the rotation of the nozzle assembly;
• using the processor to control at least one selected from the group consisting of movement of the motion device, the delivery of material to the print head assembly, the delivery and removal of pressurized gas to the gas containment space, the operation of the extruder, and the rotation of the nozzle assembly according to a predetermined additive manufacturing plan.