3D printer and printhead unit with multiple filaments

• US 8,827,684 B1
• Filed: 12/23/2013
• Issued: 09/09/2014
• Est. Priority Date: 12/23/2013
• Status: Expired due to Fees

• Current Assignee: Radiant Fabrication
• Original Assignee: Radiant Fabrication
• Inventors: Bakken, Todd J., Patterson, Nathan J., Harris, Kevin L., Schumacher, Nathan D.
• Primary Examiner(s): Bodawala, Dimple
• Assistant Examiner(s): Luk, Emmanuel S
• Application Number:
  US14/139,349
• Time in Patent Office: 260 Days
• Field of Search: 425/131.1, 425/190, 425/131.5, 425/182, 425/192.R, 425/376.1, 264/40.1, 264/28, 264/308, 264/211.21, 264/401, 264/113, 226/181, 226/188
• US Class Current: 425/375
• CPC Class Codes: B29C 64/106 using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material
• CPC Class Codes: B29C 64/118 using filamentary material being melted, e.g. fused deposition modelling [FDM]
• CPC Class Codes: B29C 64/209 Heads; Nozzles

Abstract

A fused filament fabrication printer has a fixed extrusion module having multiple printheads having print tips. The fixed arrangement of the printing heads allows the close spacing of multiple print tips in a printhead unit, and the simple routing of multiple plastic or metal filaments to the individual printing heads. The closely spaced print tips in the printhead unit share common components. An exemplary printhead unit has four printing heads which share a common heating block and heating block temperature sensor. The heating block incorporates a group of four print tips evenly spaced along a line. Each printing head has a separate filament which is controlled and driven by its own stepper motor through the heating block to one of the print tips. Printing of a part is by control of individual stepper motors which drive filaments through the heating block and through one of the printing tips.

Claims

1. A fused filament fabrication printhead unit comprising:

a fixture;

a plurality of stepper motors mounted to the fixture, each stepper motor of the plurality of stepper motors having a motor shaft and a filament drive gear mounted to the motor shaft;

portions of the fixture forming a plurality of filament guide paths, each of the plurality of filament guide paths arranged to guide a filament through the fixture and into engagement with one of the filament drive gears, such that rotation of the filament drive gear drives the filament along one of the plurality of filament guide paths;

an extrusion module mounted to the fixture in filament receiving relation to the filament guide paths, the extrusion module further comprising;

at least one insulating standoff having a thermal conductivity of less than 5 W/(m·

K) mounted to the fixture and supporting a nozzle block with a thermal conductivity greater than 25 W/(m·

K);

a heating element arranged in thermal contact with the nozzle block for heating the nozzle block;

wherein portions of the nozzle block form a plurality of heated guide paths, each heated guide path leading to portions of the nozzle block forming a nozzle with a print tip;

a plurality of thermally insulating filament guides having a thermal conductivity of less than 5 W/(m·

K), each of the thermally insulating filament guides connecting one of the filament guide paths to one of the heated guide paths.

2. The printhead unit of claim 1 wherein the number of stepper motors and print tips is at least 3.

3. The printhead unit of claim 1 wherein the number of stepper motors and print tips is at least 4.

4. The printhead unit of claim 1 wherein the unit comprises at least two extrusion modules mounted to the fixture in filament receiving relation to the filament guide paths, wherein each of said at least two extrusion modules further comprises:

at least one insulating standoff having a thermal conductivity of less than 5 W/(m·

K) mounted to the fixture and supporting a nozzle block with a thermal conductivity greater than 25 W/(m·

K);

a heating element arranged in thermal contact with the nozzle block for heating the nozzle block;

a thermal sensor in temperature monitoring relation to the nozzle block;

wherein portions of the nozzle block form a plurality of heated guide paths each heated guide path leading to portions of the nozzle block forming a nozzle; and

a plurality of thermally insulating filament guides having a thermal conductivity of less than 5 W/(m·

K), each of the thermally insulating filament guides connecting one of the filament guide paths to one of the heated guide paths.

5. The printhead unit of claim 1 wherein the heating element forms a thermal sensor.

22. The printhead unit of claim 1 further comprising a thermal sensor in temperature monitoring relation to the nozzle block.

6. A fused filament printhead unit assembly comprising:

a fixture;

a plurality of plastic filaments;

portions of the fixture forming a plurality of filament guide paths, each of the plurality of filament guide paths arranged to guide one of said plurality of plastic filaments through the fixture;

a plurality of actuators mounted to the fixture, each actuator of the plurality of actuators arranged in driving relation to one of said plurality of plastic filaments;

an extrusion module mounted to the fixture in filament receiving relation to the filament guide paths, the extrusion module further comprising;

at least one insulating standoff having a thermal conductivity of less than 5 W/(m·

K) mounted to the fixture and supporting a nozzle block with a thermal conductivity greater than 25 W/(m·

K);

a heating element arranged in thermal contact with the nozzle block for heating the nozzle block;

a thermal sensor in temperature monitoring relation to the nozzle block;

wherein portions of the nozzle block form a plurality of heated guide paths, each heated guide path leading to portions of the nozzle block forming a nozzle having a print tip; and

a plurality of thermally insulating filament guides having a thermal conductivity of less than 5 W/(m·

K), each of the thermally insulating filament guides connecting one of the filament guide paths to one of the heated guide paths.

7. The fused filament printhead unit assembly of claim 6 wherein the plurality of actuators comprise stepper motors and wherein each stepper motor has a motor shaft and a filament drive gear mounted to the motor shaft in driving relation to one of said plurality of plastic filaments.

8. The fused filament printhead unit assembly of claim 6 wherein there are at least three actuators and at least three print tips.

9. The fused filament printhead unit assembly of claim 8 wherein there are at least four actuators and at least four print tips.

10. The fused filament printhead unit assembly of claim 6 wherein there are at least two extrusion modules mounted to the fixture in filament receiving relation to the filament guide paths, wherein each of said at least two extrusion modules further comprises:

at least one insulating standoff having a thermal conductivity of less than 5 W/(m·

K) mounted to the fixture and supporting a nozzle block with a thermal conductivity greater than 25 W/(m·

K);

a heating element arranged in thermal contact with the nozzle block for heating the nozzle block;

a thermal sensor in temperature monitoring relation to the nozzle block;

wherein portions of the nozzle block form a plurality of heated guide paths, each heated guide path leading to portions of the nozzle block forming a nozzle; and

a plurality of thermally insulating filament guides having a thermal conductivity of less than 5 W/(m·

K), each of the thermally insulating filament guides connecting one of the filament guide paths to one of the heated guide paths.

11. A fused filament fabrication printer comprising:

a frame;

a build platform mounted to the frame with at least three degrees of freedom;

wherein the build platform has a start-print surface;

at least one printhead unit fixedly mounted to the frame, the at least one printhead unit further comprising;

portions of the printhead unit forming a plurality of filament guide paths, each of the plurality of filament guide paths arranged to guide one of a plurality of filaments through the printhead unit;

a plurality of actuators mounted to the printhead unit, each actuator of the plurality of actuators arranged in driving relation to one of said plurality of filament guide paths to drive a filament along one of said plurality of filament guide paths;

an extrusion module forming part of the printhead unit in filament receiving relation to the filament guide paths, the extrusion module further comprising;

at least one insulating standoff having a thermal conductivity of less than 5 W/(m·

K), the at least one insulating standoff positioned between the filament guide paths and at least one nozzle block with a thermal conductivity greater than 25 W/(m·

K);

at least one heating element arranged in heat transfer contact with the nozzle block for heating the nozzle block;

wherein portions of the nozzle block form a plurality of heated guide paths, and a plurality of nozzles, and each nozzle forming one of a plurality of print tips, each heated guide path leading to portions of the nozzle block forming one of the plurality of nozzles; and

a plurality of thermally insulating filament guides having a thermal conductivity of less than 5 W/(m·

K), each of the thermally insulating filament guides connecting one of the filament guide paths to one of the heated guide paths.

12. The fused filament fabrication printer of claim 11 further comprising a thermal sensor in temperature monitoring relation to the nozzle block.

13. The fused filament fabrication printer of claim 11 wherein the plurality of print tips of the at least one printhead unit are on a line extending in a horizontal direction defined by motion of one of the three degrees of freedom.

14. The fused filament fabrication printer of claim 11 wherein the plurality of actuators comprises stepper motors and wherein each stepper motor has a motor shaft and a filament drive gear mounted to the motor shaft in driving relation to a filament in one of said plurality of filament guide paths.

15. The fused filament fabrication printer of claim 11 wherein there are at least three actuators and at least three print tips.

16. The fused filament fabrication printer of claim 11 wherein there are at least four actuators and at least four print tips.

17. The fused filament fabrication printer of claim 11 wherein there are at least two extrusion modules mounted to the fixture in filament receiving relation to the filament guide paths, wherein each of said at least two extrusion modules further comprises:

at least one insulating standoff having a thermal conductivity of less than 5 W/(m·

K) mounted to the fixture and supporting a nozzle block with a thermal conductivity greater than 25 W/(m·

K);

a heating element arranged in thermal contact with the nozzle block for heating the nozzle block;

a thermal sensor in temperature monitoring relation to the nozzle block;

wherein portions of the nozzle block form a plurality of heated guide paths, each heated guide path leading to portions of the nozzle block forming a nozzle with a print tip; and

a plurality of thermally insulating filament guides having a thermal conductivity of less than 5 W/(m·

K), each of the thermally insulating filament guides connecting one of the filament guide paths to one of the heated guide paths.

18. A fused filament printhead unit assembly comprising:

a fixture formed of two opposed motor mount plates joined together;

a plurality of filaments;

portions of each of the two opposed motor mount plates forming a plurality of filament guide paths, each of the plurality of filament guide paths arranged to guide one of said plurality of filaments through the fixture;

a plurality of stepper motors mounted to each of the motor mount plates, wherein each stepper motor has a motor shaft and a filament drive gear mounted to the motor shaft partly occluding one of the plurality of filament guide paths and in driving relation to one of said plurality of filaments;

at least one extrusion module mounted to the fixture in filament receiving relation to at least one of the filament guide paths, each extrusion module further comprising;

at least one standoff mounted to the fixture and supporting a nozzle block;

a heating element arranged in thermal contact with the nozzle block for heating the nozzle block;

a thermal sensor in temperature monitoring relation to the nozzle block;

wherein portions of the nozzle block form at least one heated guide path, each heated guide path leading to portions of the nozzle block forming a nozzle having a print tip; and

a plurality of filament guides, wherein at least one filament guide connects one of the filament guide paths to the at least one heated guide path.

19. The fused filament printhead unit assembly of claim 18 wherein portions of the at least one nozzle block form a plurality of heated guide paths, each heated guide path leading to portions of the at least one nozzle block forming one of a plurality of nozzles, each nozzle forming a print tip;

and

a plurality of filament guides, each of the filament guides connecting one of the filament guide paths to one of the plurality of heated guide paths.

20. The fused filament printhead unit assembly of claim 18 wherein the plurality of filaments are wires of a metal with a melting point of between 90°

C. to 450°

C.

21. The fused filament printhead unit assembly of claim 18 wherein each motor mount plate is integrally formed with a portion of the extrusion module, a portion of the at least one standoff and a portion of nozzle block, so that when the motor mount plates are joined to form the fixture, the extrusion module, the at least one standoff and the nozzle block are also joined, and wherein the same metal forms the mount plates, the extrusion module, the at least one standoff and the nozzle block.