THREE DIMENSIONAL PRINTING

• US 20140328964A1
• Filed: 07/17/2014
• Published: 11/06/2014
• Est. Priority Date: 03/22/2013
• Status: Active Grant

• Current Assignee: MarkForged, Inc
• Original Assignee: MarkForged, Inc
• Inventors: GOZDZ, Antoni S., MARK, Gregory Thomas
• Granted Patent: US 9,149,988 B2
• Time in Patent Office: Days
• US Class Current: 425/166
• 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 64/393 for controlling or regulating additive manufacturing processes
• CPC Class Codes: B29C 70/20 oriented in a single direction, e.g. roofing or other parallel fibres B29C70/083, B29C70/226 take precedence
• CPC Class Codes: B29K 2077/10 Aromatic polyamides [polyaramides] or derivatives thereof
• CPC Class Codes: B29K 2307/04 Carbon

Abstract

Various embodiments related to three dimensional printers, and reinforced filaments, and their methods of use are described. In one embodiment, a void free reinforced filament is fed into an conduit nozzle. The reinforced filament includes a core, which may be continuous or semi-continuous, and a matrix material surrounding the core. The reinforced filament is heated to a temperature greater than a melting temperature of the matrix material and less than a melting temperature of the core prior to drag the filament from the conduit nozzle.

Claims

1. A three dimensional printer for additive manufacturing of a part, comprising:

a build platen for receiving and supporting the part;

a print head opposing the build platen, the print head including a conduit nozzle having an ironing outlet lip and a heater that heats the ironing outlet lip;

a motorized feeding mechanism constructed and arranged to drive a void free composite filament in an unmelted state into the conduit nozzle and toward the ironing outlet lip, wherein the composite filament includes a matrix material permeating a core of at least one axial strand extending substantially continuously within the filament;

a motorized three axis translation mechanism constructed and arranged to translate the conduit nozzle and a build platen with respect to one another;

a controller operatively connected to the heater, the feeding mechanism and the three axis translation mechanism, the controller controlling the velocity of the print head, an unattached terminal end of the void free composite filament, and the build platen to continuously iron melted matrix material including the at least one axial strand by substantially simultaneously;

heating the ironing outlet lip to a temperature greater than a melting temperature of the matrix material;

compacting the filament with the heated ironing outlet lip; and

tensioning at least one non-molten axial strand within the filament between the part and the outlet lip to pull the filament out of the conduit nozzle.

2. The three dimensional printer of claim 1, further comprising a motorized cutter operatively connected to the controller and positioned between the ironing outlet lip and the feeding mechanism, wherein the matrix material comprises a thermoplastic resin, and wherein the controller further controls the cutter to sever the filament at a location where a temperature of the matrix material is less than a melting temperature of the matrix material.

3. The three dimensional printer of claim 2, wherein the motorized cutter is positioned at or adjacent at least one of the receiving tube and the conduit nozzle outlet to cut the core reinforced filament at or adjacent at least one of the receiving tube and the conduit nozzle outlet.

4. The three dimensional printer of claim 1, further comprising a receiving tube leading to the conduit nozzle, having a clearance fit path that prevents buckling of the unmelted void free core reinforced filament, and positioned between the ironing outlet lip and the feeding mechanism, wherein the controller further controls the feeding mechanism to drive the filament into the receiving tube.

5. The three dimensional printer of claim 4, wherein the receiving tube forms a portion of a cold feed zone having a temperature lower than a melting temperature of the matrix material.

6. The three dimensional printer of claim 1, wherein a cavity channel having a larger inner diameter than the clearance fit path is arranged between the ironing outlet lip and the feeding mechanism, and wherein the filament substantially rigidly extends from the clearance fit path into the cavity channel of the eyelet such that at least some portion of the matrix material of the filament does not contact a side wall of the cavity.

7. The three dimensional printer of claim 6, wherein the controller further controls the velocity of the print head, the unattached terminal end of the void free composite filament, and the build platen to drive the filament extending substantially rigidly from the clearance fit path past the cavity channel to contact the unattached terminal end of the filament to the part, and to displace the filament towards the ironing outlet lip by translating the conduit nozzle and the part with respect to one another while the terminal end of the filament is anchored to the part.

8. The three dimensional printer of claim 6, wherein the controller further controls the velocity of the print head, the unattached terminal end of the void free composite filament, and the build platen to buckle the filament, and wherein the unattached terminal end of the driven filament remains at least partially unmelted until it contacts the ironing outlet lip.

9. The three dimensional printer of claim 1, wherein the controller further controls the velocity of the print head, the unattached terminal end of the void free composite filament, and the build platen to continuously iron melted matrix material including the at least one axial strand in a first direction in a first portion of a part and in a second direction in a second portion of the part.

10. The three dimensional printer of claim 1, wherein the at least one axial strand extending continuously within the filament includes, in any cross sectional area, a plurality of individual strands extending continuously within the filament.

11. The three dimensional printer of claim 1, wherein the ironing outlet lip is rounded, and wherein the controller further controls the velocity of the print head, the unattached terminal end of the void free composite filament, and the build platen to pull the core reinforced filament through the rounded ironing outlet of the conduit nozzle as the filament leaves the print head.

12. The three dimensional printer of claim 1, wherein the controller further controls the velocity of the print head, the unattached terminal end of the void free composite filament, and the build platen to the ironing the core reinforced filament to apply a compaction force to the filament with a rounded portion of the rounded ironing outlet lip as the filament is being deposited.

13. The three dimensional printer of claim 1, the motorized feeding mechanism further comprising a slipping mechanism, wherein the controller further controls the motorized three axis translation mechanism velocity with respect to the feeding mechanism velocity to maintain a tension along the at least one axial strand greater than a force threshold of the slipping mechanism.

14. The three dimensional printer of claim 1, wherein an individual strand length of the at least one axial strand extending within the filament is equal to or longer than twice the length of a melt zone of the conduit nozzle.

15. The three dimensional printer of claim 1, wherein the controller further controls the velocity of the print head, the unattached terminal end of the void free composite filament, and the build platen to tension the filament in the conduit nozzle from a connection to a first portion of the part, translate the conduit nozzle through an open gap, bridge the filament across the open gap;

and iron the filament to reconnect the filament to a second portion of the part.

16. The three dimensional printer of claim 1, wherein the controller further controls the velocity of the print head, the unattached terminal end of the void free composite filament, and the build platen to maintain a clearance between the ironing outlet lip and a top of the part to be less than a diameter of the filament.

17. The three dimensional printer of claim 1, wherein the controller further controls the velocity of the print head, the unattached terminal end of the void free composite filament, and the build platen to:

apply a compression pressure directly with the ironing outlet lip to force the core reinforced filament having an initial cross-sectional shape to compress into an underlying part and form a second cross-sectional compacted shape having at least one axial strand in a changed position therein, and

maintain a substantially matched velocity of the at least one axial strand and matrix material throughout the conduit nozzle, the linear feed rate of core reinforced filament having the initial shape being substantially the same as the linear deposition rate of the second compacted shape.

18. The three dimensional printer of claim 16, wherein the controller further controls the velocity of the print head, the unattached terminal end of the void free composite filament, and the build platen to:

iron an initial cross-sectional shape of a substantially rounded filament with multiple axial strands therein into a substantially compressed, wider than tall second cross-sectional shape with strands redistributed therein, moving the multiple axial strands to vertically compress and horizontally spread.

19. The three dimensional printer of claim 1, further comprising:

a cutting mechanism constructed and arranged to cut the filament at a location downstream of the ironing outlet lip.

20. The three dimensional printer of claim 1, wherein the filament has an outer diameter of that is greater than or equal to 0.010 inches and less than or equal to 0.030 inches, and where the number of strands in a cross-sectional area is approximately 1000 strands.

21. The three dimensional printer of claim 1, wherein the matrix material of the filament is formed from one of semi-aromatic polyamides, and semi-aromatic polyamide blends with linear polyamides.