Constant pressure filament driver for extruder heads in three-dimensional object printers

Patent metadata

Field	Value
Publication number	US-2018111306-A1
Application number	US-201615334721-A
Country	US
Kind code	A1
Filing date	Oct 26, 2016
Priority date	Oct 26, 2016
Publication date	Apr 26, 2018
Grant date	—

Abstract

An additive manufacturing system includes a slip clutch coupled to an actuator of a mechanical driver that feeds solid extrusion material into a heater for supplying thermoplastic material to a manifold in an extruder head. A speed of the actuator can be set to enable the actuator to operate at a rotational speed that is slightly greater than the rotational speed of the mechanical mover. This configuration enables the pressure of the thermoplastic material in the manifold of the extruder head to be in a predetermined range no matter how many nozzles are opened in the extruder head.

First claim

What is claimed:

1 . An apparatus comprising:
an extruder head having a manifold configured to store thermoplastic material and at least one nozzle through which thermoplastic material from the manifold can be emitted; a heater having a channel through which extrusion material can pass and at least one heating element configured to thermally treat the extrusion material in the channel to melt the extrusion material to form thermoplastic material, the channel in the heater being fluidly connected to the manifold in the extruder head to enable the thermoplastic material to enter the manifold; an actuator having an output shaft; a mechanical mover operatively connected to the output shaft of the actuator to enable the actuator to operate the mechanical mover, the mechanical mover being positioned to apply a force to the extrusion material to move the extrusion material from a supply of extrusion material to the channel in the heater when the actuator operates the mechanical mover; and a slip clutch operatively connected to the output shaft of the actuator to limit a force exerted by the mechanical mover to the extrusion material.

2 . The apparatus of claim 1 wherein a speed for the actuator is set to enable the output shaft of the actuator to rotate at a rate greater than the rate at which the mechanical mover rotates.

3 . The apparatus of claim 2 further comprising:
a sensor configured to generate a signal indicative of the rate at which the mechanical mover rotates; and
a controller operatively connected to the sensor and the actuator, the controller being configured to adjust rotation of the output shaft of the actuator with reference to the signal generated by the sensor.

4 . The apparatus of claim 1 further comprising:
a sensor configured to generate a signal indicative of a pressure of the thermoplastic material within the manifold; and
a controller operatively connected to the sensor and the actuator, the controller being configured to adjust rotation of the output shaft of the actuator with reference to the signal generated by the sensor.

5 . The apparatus of claim 1 , the controller being further configured to:
adjust a torque set point of the slip clutch with reference to print conditions or adjust a pressure set point for operating the actuator with reference to print conditions.

6 . The apparatus of claim 5 wherein the print conditions are one or more of a type of extrusion material being moved to the heater, a temperature of the thermoplastic material, a speed at which the extruder head is being moved, and a position of a feature being formed on the object.

7 . The apparatus of claim 1 wherein the mechanical mover is one of a roller, a rotating auger, or a rotating screw.

8 . The apparatus of claim 1 wherein the slip clutch is one of a torque friction disc clutch, a magnetic particle clutch, a magnetic hysteresis clutch, a ferro-fluid clutch, an air pressure clutch, or a permanent magnetic clutch.

9 . The apparatus of claim 3 further comprising:
at least one valve operatively connected between the at least one nozzle and the manifold, the at least one valve being configured to open a channel between the manifold and the at least one nozzle selectively; and
the controller being further configured to operate the at least one valve to extrude thermoplastic material from the at least one nozzle selectively.

10 . The apparatus of 3 , the controller being further configured to:
operate the actuator to produce a pressure of the thermoplastic material in the manifold in a predetermined range before the controller operates the extruder head to form an object with the thermoplastic material.

11 . The apparatus of claim 3 , the controller being further configured to:
detect a clogging of the at least one nozzle with reference to a signal generated by a sensor that is indicative of a pressure in the manifold or a speed of the output shaft of the actuator; and adjust a speed of the mechanical driver or a torque set point of the slip clutch in response to detection of the clogging of the at least one nozzle.

12 . A method comprising:
operating a mechanical mover to exert a force within a predetermined range to move extrusion material into a heater; operating the heater to melt the extrusion material and form thermoplastic material that moves towards an extruder head that extrudes the thermoplastic material; and limiting with a slip clutch a force exerted by the mechanical mover to the extrusion material.

13 . The method of claim 12 further comprising:
operating an actuator coupled to the mechanical mover at a speed that enables an output shaft of the actuator to rotate at a rate greater than the rate at which the mechanical mover moves the extrusion material.

14 . The method of claim 13 further comprising:
generating with a sensor a signal indicative of the rate at which the mechanical mover rotates; and
adjusting with a controller rotation of the output shaft of the actuator with reference to the signal generated by the sensor.

15 . The method of claim 13 further comprising:
generating with a sensor a signal indicative of a pressure of the thermoplastic material within the extruder head; and
adjusting with a controller rotation of the output shaft of the actuator with reference to the signal generated by the sensor.

16 . The method of claim 12 further comprising:
adjusting a torque set point of the slip clutch with reference to print conditions or adjusting a pressure set point for operating the actuator with reference to print conditions.

17 . The method of claim 16 wherein the print conditions are one or more of a type of extrusion material being moved to the heater, a temperature of the thermoplastic material, a speed at which the extruder head is being moved, and a position of a feature being formed on the object.

18 . The method of claim 12 wherein the operation of the mechanical mover is operation of a roller, a rotating auger, or a rotating screw.

19 . The method of claim 12 wherein the operation of the slip clutch is operation of a torque friction disc clutch, a magnetic particle clutch, a magnetic hysteresis clutch, a ferro-fluid clutch, an air pressure clutch, or a permanent magnetic clutch.

20 . The method of claim 14 further comprising:
operating with the controller at least one valve operatively connected between the at least one nozzle and the manifold to extrude thermoplastic material from the at least one nozzle selectively.

21 . The method of 14 further comprising:
operating the actuator to produce a pressure of the thermoplastic material in the manifold in a predetermined range before the controller operates the extruder head to form an object with the thermoplastic material.

22 . The method of claim 14 further comprising:
detecting a clogging of the at least one nozzle with reference to a signal generated by a sensor that is indicative of a pressure in the manifold or a speed of the output shaft of the actuator; and
adjusting a speed of the mechanical driver or a torque set point of the slip clutch in response to detection of the clogging of the at least one nozzle.

Assignees

• Xerox Corp

Inventors

• Mandel Barry P
• Nystrom Peter J
• Lynn Christopher G
• Clark Robert A
• Mantell David A

Classifications

• B29C48/92

  Measuring, controlling or regulating · CPC title

• B33Y30/00 Primary

  Apparatus for additive manufacturing; Details thereof or accessories therefor · CPC title

• B29C2948/9239

  Screw or gear · CPC title

• B29C48/2552 Primary

  provided in the feeding, melting, plasticising or pumping zone, e.g. screw, barrel, gear-pump or ram · CPC title

• B29C64/343

  Metering · CPC title