Gear-based liquefier assembly for additive manufacturing system, and methods of use thereof

Abstract

A liquefier assembly (20) for use in an additive manufacturing system (10) to print three-dimensional parts (22), which includes an upstream pressure-generating stage (52) and downstream flow-regulating stage (52). The upstream pressure-generating stage (52) includes a drive mechanism (46), a liquefier configured (52) to melt a consumable material (48) receive from the drive mechanism (46) to produce a molten material in a pressurized state. The downstream flow-regulating stage (52) includes a gear assembly (52) having a casing assembly (64,66,68) and a pair of gears (74,76) disposed within the interior cavity (78,80) and engaged with each other to regulate a flow of the pressurized molten material (48) through the gear assembly (52) for controlled extrusion.

1 . A liquefier assembly for use in an additive manufacturing system to print three-dimensional parts, the liquefier assembly comprising:
 a first drive mechanism configured to feed a consumable material;   a liquefier configured to receive the consumable material fed from the first drive mechanism, to melt the received consumable material to produce a molten material in a pressurized state; and   a gear assembly comprising:
 a casing assembly comprising;
 an inlet opening configured to operably receive the pressurized molten material from the liquefier; 
 an interior cavity configured to receive the pressurized molten material from the inlet opening; and 
 an outlet opening; 
 
 a first gear disposed within the interior cavity, and configured to rotate under motorized power; and 
 a second gear engaged with the first gear, and configured to counter rotate with the rotation of the first gear, wherein the rotations of the first gear and the second gear regulate a flow of the pressurized molten material from the inlet opening to the outlet opening. 
   
     
     
         2 . The liquefier assembly of  claim 1 , wherein the liquefier comprises:
 a tubular liquefier having a cylindrical or ribbon geometry; and   one or more heating assemblies configured to heat the tubular liquefier.   
     
     
         3 . The liquefier assembly of  claim 1 , wherein the consumable material comprises a filament. 
     
     
         4 . The liquefier assembly of  claim 1 , and further comprising a nozzle operably connected to the casing assembly at the outlet opening, wherein the nozzle is configured to extrude the regulated flow of the molten material. 
     
     
         5 . The liquefier assembly of  claim 1 , wherein the casing assembly comprises:
 a first casing; and   a second casing secured to the first casing, and having the inlet opening, the interior cavity, and the outlet opening.   
     
     
         6 . The liquefier assembly of  claim 1 , and further comprising one or more heater elements secured to the casing assembly, wherein the one or more heater elements are configured to heat the casing assembly. 
     
     
         7 . The liquefier assembly of  claim 1 , and further comprising:
 a second drive mechanism configured to feed a second consumable material;   a second liquefier configured to receive the second consumable material fed from the second drive mechanism, to melt the received second consumable material to produce a second molten material in a pressurized state;   wherein the inlet opening in the casing assembly is also configured to operably receive the second pressurized molten material from the second liquefier.   
     
     
         8 . The liquefier assembly of  claim 7 , and further comprising a manifold operably connected to the inlet opening of the casing assembly, wherein the inlet opening is configured to operably receive the pressurized molten materials from the first and second liquefiers through the manifold. 
     
     
         9 . The liquefier assembly of  claim 1 , and further comprising a second drive mechanism configured to generate the motorized power for rotating the first gear. 
     
     
         10 . The liquefier assembly of  claim 9 , and further comprising one or more communication lines configured to operably connect the first drive mechanism and the second drive mechanism to a controller assembly of the additive manufacturing system. 
     
     
         11 . An additive manufacturing system for printing three-dimensional parts, the additive manufacturing system comprising:
 an upstream pressure-generating stage comprising:
 a first drive mechanism; 
 a liquefier; 
 one or more heater assemblies configured to heat the liquefier; 
   a downstream flow-regulating stage comprising:
 a casing assembly having an inlet opening operably connected to the liquefier, an outlet opening, and an interior cavity interconnecting the inlet and outlet openings; 
 a pair of engaged gears disposed within the interior cavity of the casing assembly; and 
 one or more heater elements configured to heat the casing assembly; 
 a second drive mechanism operably connected to at least one gear of the pair of engaged gears; and 
   a controller assembly operably connected to the first and second drive mechanisms, and configured to command the first drive mechanism to feed a consumable material to the liquefier to produce a pressurized molten material, and to command the second drive mechanism to rotate the pair of engaged gears to regulate a flow of the pressurized molten material.   
     
     
         12 . The additive manufacturing system of  claim 11 , wherein the pair of engaged gears comprises:
 a drive gear having a shaft that is operably connected to the second drive mechanism; and   an idler gear engaged with the drive gear such that a rotation of the drive gear counter rotates the idler gear.   
     
     
         13 . The additive manufacturing system of  claim 11 , wherein the liquefier comprises a tubular liquefier having a cylindrical or ribbon geometry. 
     
     
         14 . The additive manufacturing system of  claim 11 , and further comprising a nozzle operably connected to the casing assembly at the outlet opening, wherein the nozzle is configured to extrude the regulated flow of the molten material. 
     
     
         15 . The additive manufacturing system of  claim 11 , wherein the casing assembly comprises:
 a first casing; and   a second casing secured to the first casing, and having the inlet opening, the interior cavity, and the outlet opening.   
     
     
         16 . A method for printing a three-dimensional part with an additive manufacturing system, the method comprising:
 feeding a consumable material to a liquefier retained by the additive manufacturing system with a drive mechanism retained by the additive manufacturing system;   melting the fed consumable material in the liquefier to produce a molten material;   providing the molten material in a pressurized state to a gear assembly retained by the additive manufacturing system; and   regulating a flow of the pressurized molten material through the gear assembly to extrude the molten material in a controlled manner   
     
     
         17 . The method of  claim 16 , wherein the gear assembly comprises a pair of engaged gears, and wherein regulating the flow of the pressurized molten material through the gear assembly comprises counter rotating the engaged gears. 
     
     
         18 . The method of  claim 16 , wherein the molten material is a first molten material, and wherein the method further comprises:
 feeding a second consumable material to a second liquefier retained by the additive manufacturing system with a second drive mechanism retained by the additive manufacturing system;   melting the fed second consumable material in the second liquefier to produce a second molten material;   providing the second molten material in a pressurized state to the gear assembly with the first molten material; and   regulating the flow of the second pressurized molten material through the gear assembly with the first pressurized molten material to extrude the second molten material in a controlled manner   
     
     
         19 . The method of  claim 16 , wherein regulating the flow of the pressurized molten material through the gear assembly comprises controllably applying an active torque on a drive gear of the gear assembly to drive the pressurized molten material. 
     
     
         20 . The method of  claim 16 , wherein regulating the pressurized molten material through the gear assembly comprises controllably releasing a resistive torque on a drive gear of the gear assembly to drive the pressurized molten material.