摘要：
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 extrusion 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 extruding the filament from the extrusion nozzle.
权利要求：
What is claimed is:
1. A method for additive manufacturing of a part, the method comprising:
supplying an unmelted fiber reinforced composite filament including at least one axial fiber strand extending within a matrix material of the filament;
feeding the fiber reinforced composite filament at a feed rate;
heating the fiber reinforced composite filament in a transverse pressure zone to a temperature greater than a melting temperature of the matrix material to melt the matrix material interstitially within the filament;
applying an ironing force to the melted matrix material and the at least one axial fiber strand of the fiber reinforced composite filament with an ironing lip as the fiber reinforced composite filament is deposited in bonded ranks to the part; and
translating the ironing lip adjacent to the part at a printing rate that maintains a neutral to positive tension in the fiber reinforced composite filament between the ironing lip and the part, the neutral to positive tension being a tension less than that necessary to separate a bonded rank from the part.
2. The method of claim 1, wherein the supplying of unmelted fiber reinforced composite filament includes supplying an unmelted void free filament, having no substantial air gaps within the matrix material, and the feeding the fiber reinforced composite filament includes feeding an unmelted fiber reinforced composite along a clearance fit zone that prevents buckling of the fiber reinforced composite filament
3. The method of claim 1, wherein the matrix material comprises a thermoplastic resin having an unmelted ultimate tensile strength of approximately 10 through 100 MPa and a melted ultimate tensile strength of less than 10 MPa, and the at least one axial strand includes a stranded material having an ultimate tensile strength of approximately 200-100000 MPa.
4. The method of claim 3, further comprising heating the fiber reinforced composite filament in a non-contact zone, and controlling at least one of the feed rate and the printing rate to maintain the neutral to positive tension in the fiber reinforced composite filament between the ironing lip and the part primarily via tensile force within the at least one axial fiber strand extending along the filament.
5. The method of claim 1, further comprising maintaining a substantially constant cross sectional area of the fiber reinforced composite filament in clearance fit zone, the non-contact zone, the transverse pressure zone, and as a bonded rank is attached to the workpiece.
6. The method of claim 5, wherein the filament has a cross sectional area greater than lxlOE- 5 square inches and less than 2xlOE-3 square inches,
7. The method of claim 5, wherein the at least one axial strand includes, in any cross-section area, between 100 and 6000 parallel continuous axial strands.
8. The method of claim 1, further comprising cutting the fiber reinforced composite filament at or adjacent one of the clearance fit zone or the ironing lip.
9. The method of claim 1, further comprising:
drawing the fiber reinforced composite filament in the transverse pressure zone from a connection to a first portion of the part;
translating the transverse pressure zone through free space; and
ironing to reconnect the fiber reinforced composite filament to a second portion of the part.
10. A method for additive manufacturing of a part, the method comprising:
supplying an unmelted void free fiber reinforced composite filament including at least one axial fiber strand extending within a matrix material of the filament, having no substantial air gaps within the matrix material;
feeding the unmelted fiber reinforced composite at a feed rate, along a clearance fit zone that prevents buckling of the fiber reinforced composite filament,
threading the fiber reinforced composite filament to contact the part in a transverse pressure zone;
translating the transverse pressure zone relative to and adjacent to the part at a printing rate to bring an end of the fiber reinforced composite filament to a melting position; and
melting the matrix material interstitially within the filament at the melting position.
11. The method of claim 10, wherein the melting further comprises ironing the melted matrix material and the at least one axial fiber strand of the fiber reinforced composite filament by applying an ironing force with an ironing lip heated to a temperature greater than the melting temperature of the matrix material as the fiber reinforced composite filament is pressed in bonded ranks to the part, and the translating the transverse pressure zone translates the ironing lip at a printing rate that maintains a neutral to positive tension in the fiber reinforced composite filament between the ironing lip and the bonded ranks, the neutral to positive tension being a tension less than that necessary to separate a bonded rank from the part.
12. The method of claim 11, further comprising controlling the height of the ironing lip from the top of the part to be less than a diameter of the filament.
13. The method of claim 10, wherein the matrix material comprises a thermoplastic resin having an unmelted elastic modulus of approximately 0.1 through 5 GPa and a melted elastic modulus of less than 0.1 GPa, and the at least one axial fiber strand includes a stranded material having an elastic modulus of approximately 5-1000 GPa.
14. The method of claim 10, further comprising heating the fiber reinforced composite in a non-contact zone immediately upstream of the ironing, and controlling at least one of the feed rate and the printing rate to induce compression along the filament within the non-contact zone, primarily via axial compressive force within the at least one axial fiber strand extending along the filament.
15. The method of claim 14, further comprising controlling at least one of the feed rate and the printing rate to compress the fiber reinforced composite filament and translate an end of the filament abutting the part laterally underneath an ironing lip to be ironed by application of heat and pressure.
16. The method of claim 15, wherein the clearance fit zone includes at least one channel forming a clearance fit about the fiber reinforced composite filament, and the fiber reinforced composite is maintained at a temperature below a glass transition temperature of the matrix material throughout the at least one channel. .
17. The method of claim 10, further comprising cutting the unmelted fiber reinforced filament at or adjacent the clearance fit zone.
18. The method of claim 10, further comprising preventing the filament from touching a heated wall of a cavity defining the non-contact zone.
19. The method of claim 10, further comprising touching the filament to a heated ironing lip in the transverse pressure zone to melt the matrix material of the filament.
20. The method of claim 10, further comprising:
pressing the melted matrix material and the at least one axial fiber strand into the part in the transverse pressure zone to form laterally and vertically bonded ranks, and
flattening the bonded ranks on at least two sides by applying an ironing force to the melted matrix material and the at least one axial fiber strand with the ironing lip, and applying an opposing reshaping force to the melted matrix material and the at least one axial fiber strand as a normal reaction force from the part itself.