Liquefier assembly for additive manufacturing systems, and methods of use thereof

• US 9,327,447 B2
• Filed: 10/04/2013
• Issued: 05/03/2016
• Est. Priority Date: 10/04/2013
• Status: Active Grant

• Current Assignee: Stratasys Incorporated
• Original Assignee: Stratasys Incorporated
• Inventors: Batchelder, J. Samuel, Swanson, William J., Johnson, Kevin C.
• Primary Examiner(s): Ochylski, Ryan
• Application Number:
  US14/046,290
• Publication Number:
  US 20150096717A1
• Time in Patent Office: 942 Days
• US Class Current: 1/1
• CPC Class Codes: B29C 48/802 Heating
• 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
• CPC Class Codes: B29C 64/40 Structures for supporting 3D objects during manufacture and intended to be sacrificed after completion thereof
• CPC Class Codes: B29K 2105/0067 Melt
• CPC Class Codes: B33Y 30/00 Apparatus for additive manufacturing; Details thereof or accessories therefor

Abstract

A liquefier assembly for use in an additive manufacturing system, which includes a rigid member having a gap, a liquefier tube operably disposed in the gap, one or more heater assemblies disposed in the gap in contact with the liquefier tube, and configured to heat the liquefier tube in a zone-by-zone manner, preferably one or more thermal resistors disposed in the gap between the rigid member and the heater assemblies, and preferably one or more sensors configured to operably measure pressure within the liquefier tube. The one or more heater assemblies may be operated to provide dynamic heat flow control.

Claims

1. A liquefier assembly for use in an additive manufacturing system, the liquefier assembly comprising:

a rigid member comprising one or more thermally-conductive materials, and having a gap extending along a longitudinal axis;

a liquefier tube disposed within the gap, and having an inlet end and an outlet end offset along the longitudinal axis;

a heater assembly disposed in the gap and in contact with the liquefier tube, wherein the heater assembly is configured to heat the liquefier tube in a zone-by-zone manner along the longitudinal axis;

a thermal resistor disposed in the gap between the rigid member and the heater assembly, wherein the thermal resistor is configured to conduct a portion of the heat from the heater assembly to the rigid member; and

a heat sink unit coupled to the rigid member to draw the conducted heat away from the rigid member.

2. The liquefier assembly of claim 1, wherein the rigid member comprises a clam block having a base portion connected to a pair of arms, which collectively define the gap.

3. The liquefier assembly of claim 2, wherein a portion of the heat sink unit extends through the base portion of the rigid member.

4. The liquefier assembly of claim 1, wherein the liquefier tube comprises a ribbon liquefier tube.

5. The liquefier assembly of claim 1, wherein the liquefier tube comprises a cylindrical liquefier tube.

6. The liquefier assembly of claim 1, wherein the thermal resistor compositionally comprises sheet mica.

7. The liquefier assembly of claim 1, wherein the thermal resistor comprises a plurality of segments configured to reduce thermal spreading along the resistor block in directions along the longitudinal axis.

8. A liquefier assembly for use in an additive manufacturing system, the liquefier assembly comprising:

a pair of heater assemblies configured to receive a liquefier tube, wherein the pair of heater assemblies are in mating contact with and disposed on opposing sides of the retained liquefier tube;

a pair of thermal resistors disposed against the pair of heater assemblies, opposite of the retained liquefier tube; and

a rigid member configured to retain the pair of thermal resistors, the pair of heater assemblies, and the retained liquefier tube under compression, wherein the rigid member is also configured to conduct heat from the pair of thermal resistors.

9. The liquefier assembly of claim 8, wherein the pair of heater assemblies are configured to heat the retained liquefier tube in a zone-by-zone manner.

10. The liquefier assembly of claim 8, and further comprising a heat sink unit configured to draw the heat from the rigid member.

11. The liquefier assembly of claim 8, wherein the thermal resistors each comprise a plurality of segments configured to reduce thermal spreading along the thermal resistor.

12. The liquefier assembly of claim 8, wherein the thermal resistors each compositionally comprise a material selected from the group consisting of sheet mica and one or more positive temperature coefficient materials.

13. The liquefier assembly of claim 8, wherein the liquefier tube comprises a ribbon liquefier tube.

14. The liquefier assembly of claim 8, and further comprising a sensor configured to operably measure pressure within the retained liquefier tube.

15. A method for extruding a material from a liquefier assembly in an additive manufacturing system, the method comprising:

feeding a filament to a liquefier tube of the liquefier assembly;

generating heat with a heater assembly in contact with the liquefier tube;

conducting a first portion of the generated heat to the liquefier tube to heat the fed filament; and

drawing a second portion of the generated heat to a thermal resistor in contact with the heater assembly, opposite of the liquefier tube.

16. The method of claim 15, wherein generating the heat with the heater assembly comprises generating the heat in a zone-by-zone manner along a longitudinal axis of the liquefier tube.

17. The method of claim 15, and further comprising conducting the drawn second portion of the generated heat to a heat sink unit.

18. The method of claim 15, wherein the liquefier tube comprises a ribbon liquefier tube, and wherein feeding the filament comprises feeding a ribbon filament.

19. The method of claim 15, and further comprising operably measuring pressure within the liquefier tube.

20. The method of claim 15, and further comprising:

retaining the thermal resistor, the heater assembly, and the liquefier tube with a rigid member; and

conducting the second portion of the generated heat from the thermal resistor to the rigid member.