Liquefier assembly for use in extrusion-based additive manufacturing systems

• US 9,022,771 B2
• Filed: 01/03/2014
• Issued: 05/05/2015
• Est. Priority Date: 09/22/2010
• Status: Active Grant

• Current Assignee: Stratasys Incorporated
• Original Assignee: Stratasys Incorporated
• Inventors: Swanson, William J., Johnson, Kevin C., Hjelsand, Timothy A., Batchelder, J. Samuel
• Primary Examiner(s): Del Sole, Joseph S
• Assistant Examiner(s): Sultana, Nahida
• Application Number:
  US14/147,065
• Publication Number:
  US 20140120197A1
• Time in Patent Office: 487 Days
• Field of Search: 264/308, 264/113, 264/40.6, 264/176.1, 425/375, 425/190, 425/191, 425/192.R, 425/3, 425/113, 425/376.1, 425/378.1, 425143-144
• US Class Current: 425/378.1
• CPC Class Codes: B29C 2948/92571 Position, e.g. linear or angular
• CPC Class Codes: B29C 48/02 Small extruding apparatus, e.g. handheld, toy or laboratory extruders
• CPC Class Codes: B29C 48/05 Filamentary, e.g. strands
• CPC Class Codes: B29C 48/265 Support structures or bases for apparatus, e.g. frames
• CPC Class Codes: B29C 48/3003 Materials, coating or lining therefor
• CPC Class Codes: B29C 48/865 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: B29L 2009/00 Layered products
• CPC Class Codes: B33Y 30/00 Apparatus for additive manufacturing; Details thereof or accessories therefor

Abstract

A liquefier assembly for use in an extrusion-based additive manufacturing system, the liquefier assembly comprising a downstream portion having a first average inner cross-sectional area, and an upstream having a second average inner cross-sectional area that is less than the first inner cross-sectional area, the upstream portion defining a shoulder configured to restrict movement of a melt meniscus of a consumable material.

Claims

1. An extrusion head for use in an extrusion-based additive manufacturing system, the extrusion head comprising:

a drive mechanism configured to feed a filament of a consumable material at multiple feed rates;

a liquefier comprising;

an upstream portion configured to receive the fed filament from the drive mechanism, wherein the upstream portion has an upstream inner surface facing inward and compositionally comprising a fluorinated polymer, and wherein the upstream inner surface has an upstream average inner cross-sectional area;

a downstream portion configured to receive the consumable material from the upstream portion, wherein the downstream portion has a downstream inner surface facing inward and compositionally comprising a metallic material, and wherein the downstream inner surface has a downstream average inner cross-sectional area that is greater than the upstream average inner cross-sectional area; and

a shoulder located at an intersection of the upstream portion and the downstream portion;

an external heater configured to conduct heat to the received filament in the downstream portion to produce a molten material having a meniscus, wherein the shoulder of the liquefier is configured to restrict upward and downward movements of the meniscus while the drive mechanism feeds the filament; and

an extrusion tip coupled to the downstream portion.

2. The extrusion head of claim 1, wherein the fluorinated polymer for the inner surface of the upstream portion comprises polytetrafluoroethylene.

3. The extrusion head of claim 1, wherein the downstream average inner cross-sectional area is at least 105% of the upstream average inner cross-sectional area.

4. The extrusion head of claim 3, wherein the downstream average inner cross-sectional area ranges from about 110% of the upstream average inner cross-sectional area to about 150% of the upstream average inner cross-sectional area.

5. The extrusion head of claim 1, wherein the upstream portion comprises a hollow liner having the upstream inner surface.

6. The extrusion head of claim 1, wherein the shoulder has a sloped profile relative to a cross section of the liquefier, wherein the cross section of the liquefier is taken perpendicular to a longitudinal axis of the liquefier.

7. The extrusion head of claim 1, wherein the upstream inner surface has a rectangular inner cross-section.

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

a liquefier comprising;

an upstream portion that comprises a hollow liner having a plurality of apertures plurality of apertures each configured to receive a consumable material, wherein the plurality of apertures each has an upstream inner surface with an upstream average inner cross-sectional area;

a downstream portion configured to receive the consumable materials from the plurality of apertures of the upstream portion, wherein the downstream portion comprises a downstream inner surface having a downstream average inner cross-sectional area that is greater than a sum of the upstream average inner cross-sectional areas of the plurality of apertures; and

a shoulder located at an intersection of the upstream portion and the

downstream portion that is configured to restrict upward and downward movements of a meniscus of the consumable materials;

an external heater configured to conduct heat to the received consumable materials in the downstream portion; and

an extrusion tip coupled to the downstream portion.

9. The liquefier assembly of claim 8, wherein the upstream inner surface of each of the plurality of apertures compositionally comprises a fluorinated polymer.

10. The liquefier assembly of claim 8, wherein the upstream inner surface of each of the plurality of apertures has a rectangular inner cross-section.

11. The liquefier assembly of claim 8, wherein the consumable material that each of the plurality of apertures is configured to receive comprises a solid filament.

12. The liquefier assembly of claim 8, wherein the upstream inner surfaces for the plurality of apertures each has a surface energy less than about 75 millinewtons/meter.

13. The liquefier assembly of claim 8, wherein the downstream average inner cross-sectional area is at least 105% of the sum of the upstream average inner cross-sectional areas.

14. The liquefier assembly of claim 13, wherein the downstream average inner cross-sectional area ranges from about 110% of the sum of the upstream average inner cross-sectional areas to about 150% of the sum of the upstream average inner cross-sectional areas.

15. An extrusion head for use in an extrusion-based additive manufacturing system, the liquefier assembly comprising:

a drive mechanism configured to feed a filament of a consumable material having an average filament diameter at multiple feed rates;

a cylindrical liquefier comprising;

an upstream portion configured to receive the filament, wherein the upstream portion has an upstream inner surface having an upstream average inner diameter that ranges from about 101% to about 110% of the average filament diameter; and

a downstream portion configured to receive the consumable material from the upstream portion, wherein the downstream portion has a downstream inner surface with a downstream average inner diameter that is at least 105% of the upstream average inner diameter; and

a shoulder located at an intersection of the upstream portion and the downstream portion;

an external heater configured to conduct heat to the received filament of the consumable material in the downstream portion to produce a mold material having a meniscus, wherein the shoulder of the cylindrical liquefier is configured to restrict upward and downward movements of the meniscus while the drive mechanism feeds the filament; and

an extrusion tip coupled to the downstream portion.

16. The extrusion head of claim 15, wherein the upstream inner surface compositionally comprises a fluorinated polymer, and the downstream inner surface compositionally comprises a metallic material.

17. The extrusion head of claim 16, wherein the fluorinated polymer for the inner surface of the upstream portion comprises polytetrafluoroethylene.

18. The extrusion head of claim 15, wherein the downstream average inner diameter ranges from about 110% of the upstream average inner diameter to about 150% of the upstream average diameter.

19. The extrusion head of claim 15, wherein the upstream portion comprises a hollow liner having the upstream inner surface.

20. The extrusion head of claim 15, wherein the shoulder has a sloped profile relative to a cross section of the cylindrical liquefier, wherein the cross section of the cylindrical liquefier is taken perpendicular to a longitudinal axis of the cylindrical liquefier.