Micro-and MESO-structure control in polymer extrusion additive manufacturing

Abstract

Conventional 3D printing incorporates the use of axisymmetric nozzles and backpressure to horizontal beads with hemispherical ends. Only a subset of the material in conventional beads contributes to the load path as the hemispheres are considered wasted material. The microstructure of conventional beads promotes longer cooling periods and therefore lower manufacturing throughputs. The present disclosure describes the use of non-axi symmetric nozzles without backpressure to control extrudate flow, which enables extrusion of beads with arbitrary shape and direct control of extrudate flow. The microstructure produced through non-axisymmetric extrusion facilitates a significant heat conduction to peripheries of a printed layer, resulting in rapid cooling behavior, which allows higher manufacturing throughputs and prevention of warping and residual stresses in the extrudate.

Description

Attorney Docket No. 2010363-0446MICRO- AND MESO-STRUCTURE CONTROL IN POLYMER EXTRUSION ADDITIVE MANUFACTURINGCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and benefit of U.S. Provisional Patent Application No. 63 / 737,589 filed December 20, 2024, the disclosure of which is incorporated by reference herein in its entirety.FIELD

[0002] The present embodiments described herein relate generally to additive manufacturing and in particular to the implementation of custom extrusion dies and non- axisymmetric nozzles.BACKGROUND

[0003] Conventional 3D printing incorporates the use of axisymmetric nozzles and backpressure to form beads. This process is often wasteful from a process optimization standpoint and may result in horizontal beads with hemispherical ends. Only a subset of the material in conventional beads contributes to the load path, and the hemispheres that protrude from a column of beads are considered wasted material. The extrudate in conventional beads often consists of a microstructure with filler alignment, filler distribution, polymer chain entanglement, and surface energy that are dependent upon processing conditions and backpressure characteristics. These structural characteristics are not directly controllable by manufacturing process inputs. An example of these constraints on extrudate control includes the preferential alignment of fibers in the direction of extrusion, which promotes heat conduction along a printed layer, thereby leading to longer cooling periods. The resulting longer cooling periods lead to longer layer times and lower manufacturing throughputs.SUMMARYPage 1 of 4613172581vllAttorney Docket No. 2010363-0446

[0004] Described herein are part geometries, assemblies, and methodologies for extrusion of custom bead geometries with controlled microstructures using custom extrusion dies. The extrusion process involves use of non-axisymmetric nozzles without backpressure to control extrudate flow, such that bead geometry and internal microstructure characteristics can be tuned to specific applications. The present disclosure enables, among other embodiments of the method, extrusion of tall beads whose aspect ratio (height to width) is larger than the conventional beads. The rapid cooling behavior of tall beads enables higher manufacturing throughputs and prevention of warping and residual stresses in the extrudate. The present disclosure also enables, among other embodiments of the method, fiber orientation control to facilitate a significant heat conduction to the peripheries of a printed layer (i.e., heat transfer is promoted in a direction orthogonal to the print direction), leading to shorter cooling periods.

[0005] In one aspect, the present disclosure is directed to a non-axisymmetric nozzle including: a body comprising an at least partially hollow interior; an inlet disposed at a first end of the body; and a non-axisymmetric outlet disposed at a second end of the body, wherein the inlet and the non-axisymmetric outlet are fluidly coupled.

[0006] In some embodiments, the nozzle includes a wedge configuration comprising a decreasing cross-sectional area from the inlet to a throat portion.

[0007] In some embodiments, the nozzle includes an increasing cross-sectional area from the throat portion to the non-axisymmetric outlet (i.e., extrusion orifice).

[0008] In some embodiments, the throat portion includes a minimum cross-sectional area of the nozzle.

[0009] In some embodiments, the throat portion is disposed downstream of the inlet and upstream of the non-axisymmetric outlet.

[0010] In some embodiments, the nozzle includes at least one internal feature disposed upstream of the throat portion and downstream of the inlet.

[0011] In some embodiments, the nozzle includes a bend portion disposed downstream of the throat portion and upstream of the non-axisymmetric outlet, the bend portion changing the orientation of the nozzle interior by a fixed angle (i.e., the bend portion changing the direction of travel of extrudate flowing therethrough by a fixed angle).Page 2 of 4613172581V11Attorney Docket No. 2010363-0446

[0012] In some embodiments, the fixed angle includes an angle in a range from 80 degrees and 100 degrees.

[0013] In some embodiments, the nozzle includes at least one heater, and / or at least one cooler.

[0014] In some embodiments, the at least one heater is placed on the non-axisymmetric outlet.

[0015] In some embodiments, the at least one cooler is placed on the non-axisymmetric outlet.

[0016] In another aspect, the present disclosure is directed to an extruded bead made from a non-axisymmetric extrusion process, the extruded bead including: a composite material including: a matrix component; and a fiber component, wherein each of the matrix component and the fiber component includes an associated distribution and orientation, and wherein the distribution and orientation of each of the matrix component and the fiber component is prescribed by the non-axisymmetric extrusion process.

[0017] In some embodiments, the extruded bead includes a bead height defined in a direction orthogonal to a surface upon which the bead is extruded; a bead length defined in a direction aligned with a direction of extrusion; and a bead width defined in a direction orthogonal to both the bead height and the bead length, wherein the bead height is greater than the bead width.

[0018] In some embodiments, the bead includes a first cross section defined within a plane that incorporates the bead height and the bead length.

[0019] In some embodiments, the first cross section includes a trapezoidal shape.

[0020] In some embodiments, the first cross section includes a T shape.

[0021] In some embodiments, the first cross section includes a triangle shape.

[0022] In some embodiments, the first cross section includes a D shape.

[0023] In some embodiments, the fiber component includes fiber strands that substantially extend in the directions of the bead height and the bead width, but not the bead length.

[0024] In some embodiments, the extruded bead includes an aspect ratio of the bead height to the bead width is at least 3:1.Page 3 of 4613172581V11Attorney Docket No. 2010363-0446

[0025] In another aspect, the present disclosure is directed to nozzle assembly including: an extruder interface; a rotary union coupled to the extruder interface at a first end of the rotary union; a rotary drive gear coupled to a second end of the rotary union, the rotary union enabling independent rotational movement of the rotary drive gear relative to the extruder interface; and a non-axisymmetric nozzle coupled to the rotary drive gear such that it rotates therewith.

[0026] In some embodiments, the extruder includes a threaded or clamped adaptor configured to be coupled to the rotary union.

[0027] In some embodiments, the assembly includes a fluid channel disposed through each of the extruder interface, threaded or clamped adaptor, the rotary union, the rotary drive gear, and the non-axisymmetric nozzle.

[0028] In another aspect, the present disclosure is directed to a system including the assembly as described herein, the system including an external drive gear operatively coupled to the rotary drive gear for selectively adjusting an orientation of the non-axisymmetric nozzle.

[0029] In some embodiments, in operation, the extruder interface, threaded or clamped adaptor, and first end of the rotary union rotate continuously in a single direction, and at a substantially constant rate, thereby forming a first unitary sub-assembly, and in operation, the rotary drive gear, non-axisymmetric nozzle, and second end of the rotary union are selectively rotated, by the external drive gear at a second substantially constant rate, thereby forming a second unitary sub-assembly.

[0030] In another aspect, the present disclosure is directed to a method of using the system as described herein, including using the system for at least one of an additive manufacturing process and an extrusion process.

[0031] In some embodiments, the method includes using the system for fused filament fabrication (FFF).

[0032] In another aspect, the present disclosure is directed to a manufacturing method including: providing a nozzle assembly including at least an extrusion interface and a non- axisymmetric nozzle configured to selectively rotate independent of a rotation of the extrusion interface, the non-axisymmetric nozzle including a non-axisymmetric orifice configured toPage 4 of 4613172581V11Attorney Docket No. 2010363-0446 discharge extrudate therethrough; and discharging extrudate through the non-axisymmetric nozzle layer by layer, thereby forming at least one extrudate layer.

[0033] In some embodiments, the method includes heating the extrudate prior to discharging extrudate through the non-axisymmetric nozzle, and cooling the extrudate as it passes through the non-axisymmetric nozzle during discharging.

[0034] In some embodiments, the extruded bead is composed at least partially of at least one of wood-fiber reinforced polylactic acid (WF-PLA) and carbon fiber reinforced acrylonitrile butadiene styrene (CF-ABS).

[0035] In some embodiments, the extruded bead is composed at least partially of at least one of a polymer material and a filler material.

[0036] In some embodiments, the extruded bead is composed at least partially of polyethylene terephthalate glycol (PETG).

[0037] In some embodiments, the non-axisymmetric outlet includes a non-axisymmetric extrusion orifice including: a first partial cross-section oriented in a direction aligned with a surface upon which the extrudate is discharged; and a second partial cross-section oriented in a direction orthogonal to a direction of extrusion, wherein, the first partial cross-section and the second partial cross-section form a single orifice.

[0038] In some embodiments, the first partial cross-section includes an incomplete circle and the second partial cross-section includes a slot.

[0039] In some embodiments, a diameter of the incomplete circle is equal to the width of the slot.

[0040] In some embodiments, a diameter of the incomplete circle is larger than the width of the slot.

[0041] In some embodiments, the first partial cross-section includes an incomplete rectangle and the second partial cross-section includes a slot.

[0042] In some embodiments, the first partial cross-section includes an incomplete circle and the second partial cross-section includes a triangle.Page 5 of 4613172581V11Attorney Docket No. 2010363-0446

[0043] In some embodiments, the first partial cross-section includes two slits and the second partial cross-section includes a D-ring.

[0044] In some embodiments, the non-axisymmetric outlet includes a non-axisymmetric extrusion orifice, the non-axisymmetric extrusion orifice defined by a periphery disposed arranged in more than one geometric plane.

[0045] In some embodiments, the non-axisymmetric outlet includes a non-axisymmetric extrusion orifice including at least one linear edge.

[0046] In some embodiments, the non-axisymmetric outlet includes a non-axisymmetric extrusion orifice including at least one curved edge.

[0047] In some embodiments, the at least one internal feature includes a threaded portion.

[0048] In some embodiments, the filler material includes at least one of carbon fiber, glass fiber, and wood flour.

[0049] In some embodiments, the filler material includes an isotropic material.BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Fig. 1 shows an example of a coordinate system used in 3D printing, according to aspects of the present disclosure.

[0051] Fig. 2A shows an example of a common extrudate defect due to the soft limits of 3D printing.

[0052] Fig. 2B shows an example of a common extrudate defect due to the soft limits of 3D printing.

[0053] Fig. 2C shows an example of a common extrudate defect due to the soft limits of 3D printing.

[0054] Fig. 3A shows an exemplary CAD drawing of a non-axisymmetric nozzle, according to aspects of the present disclosure.

[0055] Fig. 3B shows an exemplary CAD drawing of a slot nozzle, according to aspects of the present disclosure.Page 6 of 4613172581V11Attorney Docket No. 2010363-0446

[0056] Fig. 4A shows an exemplary CAD drawing of a triangle nozzle, according to aspects of the present disclosure.

[0057] Fig. 4B shows an example of a cross section of the triangle nozzle, according to aspects of the present disclosure.

[0058] Fig. 5A shows an exemplary CAD drawing of a D-ring nozzle, according to aspects of the present disclosure.

[0059] Fig. 5B shows closeup example of the D-ring nozzle, according to aspects of the present disclosure.

[0060] Fig. 5C shows an example of a cross section of the D-ring nozzle, according to aspects of the present disclosure.

[0061] Fig. 6 shows an exemplary CAD drawing of a non-axi symmetric nozzle assembly, according to aspects of the present disclosure.

[0062] Fig. 7A illustrates an example of a thermal simulation of a wide bead substrate.

[0063] Fig. 7B illustrates an example of a thermal simulation of a tall bead substrate, according to aspects of the present disclosure.

[0064] Fig. 8A shows an example of a wide slot nozzle, according to aspects of the present disclosure.

[0065] Fig. 8B shows an example of a straight-line extrusion test using the wide slot nozzle, according to aspects of the present disclosure.

[0066] Fig. 9A shows an example of a narrow slot nozzle, according to aspects of the present disclosure.

[0067] Fig. 9B shows an example of a straight-line extrusion test using the narrow slot nozzle, according to aspects of the present disclosure.

[0068] Fig. 10A illustrates an experiment to verify extrudate shape consistency using a non-axisymmetric nozzle, according to aspects of the present disclosure.

[0069] Fig. 10B is a graph of the average aspect ratio of printed beads vs mass flow rate using a non-axisymmetric nozzle, according to aspects of the present disclosure.Page 7 of 4613172581V11Attorney Docket No. 2010363-0446

[0070] Fig. 11 shows an example of a tall bead next to stacked conventional beads, according to aspects of the present disclosure.

[0071] Fig. 12A illustrates a SolidWorks example of effective material in stacked conventional beads.

[0072] Fig. 12B illustrates a SolidWorks example of effective material in stacked tall beads, according to aspects of the present disclosure.

[0073] Fig. 13A illustrates a SolidWorks example of stress concentration in inter-bead geometry of stacked conventional beads.

[0074] Fig. 13B illustrates a SolidWorks example of stress concentration in inter-bead geometry of stacked tall beads, according to aspects of the present disclosure.

[0075] Fig. 14A illustrates a SolidWorks example of contact surface area of stacked conventional beads.

[0076] Fig. 14B illustrates a SolidWorks example of contact surface area of stacked tall beads, according to aspects of the present disclosure.

[0077] Fig. 14C illustrates a SolidWorks example of contact surface area of stacked tall beads, according to aspects of the present disclosure.

[0078] Fig. 15A shows an example of a tall bead, according to aspects of the present disclosure.

[0079] Fig. 15B illustrates a SolidWorks example of a tall bead, according to aspects of the present disclosure.

[0080] Fig. 15C shows an example of stacked tall beads, according to aspects of the present disclosure.

[0081] Fig. 15D illustrates a SolidWorks example of stacked tall beads, according to aspects of the present disclosure.

[0082] Fig. 16A illustrates a SolidWorks example of five stacked conventional beads.

[0083] Fig. 16B illustrates a SolidWorks example of five stacked tall beads, according to aspects of the present disclosure.Page 8 of 4613172581V11Attorney Docket No. 2010363-0446

[0084] Fig. 16C illustrates a SolidWorks example of five stacked tall beads, according to aspects of the present disclosure.

[0085] Fig. 16D illustrates a SolidWorks example of five stacked tall beads, according to aspects of the present disclosure.

[0086] Fig. 17A illustrates a SolidWorks example of a conventional bead.

[0087] Fig. 17B illustrates a SolidWorks example of a tall bead, according to aspects of the present disclosure.

[0088] Fig. 17C illustrates a SolidWorks example of a tall bead, according to aspects of the present disclosure.

[0089] Fig. 18A shows an image of the microstructure of conventional beads.

[0090] Fig. 18B shows an image of the microstructure of conventional beads.

[0091] Fig. 19A shows an image of the microstructure of a tall bead, according to aspects of the present disclosure.

[0092] Fig. 19B shows an image of the microstructure of a tall bead, according to aspects of the present disclosure.

[0093] Fig. 20A shows an example of a conventional nozzle.

[0094] Fig. 20B shows an example of a heated / chilled nozzle, according to aspects of the present disclosure.

[0095] Fig. 21A shows an example of a slot nozzle, according to aspects of the present disclosure.

[0096] Fig. 21B shows an example of a triangle nozzle, according to aspects of the present disclosure.

[0097] Fig. 21 C shows an example of a D-ring nozzle, according to aspects of the present disclosure.

[0098] Fig. 22A shows an example of stacked tall beads next to stacked conventional beads, according to aspects of the present disclosure.

[0099] Fig. 22B shows a thermal image of an extrusion of a conventional bead.Page 9 of 4613172581V11Attorney Docket No. 2010363-0446

[0100] Fig. 22C shows a thermal image of the extrusion of a conventional bead.

[0101] Fig. 22D shows a thermal image of an extrusion of a tall bead, according to aspects of the present disclosure.

[0102] Fig. 22E shows a thermal image of the extrusion of a tall bead, according to aspects of the present disclosure.

[0103] Fig. 23A shows an exemplary CAD drawing of a wedge nozzle, according to aspects of the present disclosure.

[0104] Fig. 23B shows an exemplary CAD drawing of a wedge nozzle, according to aspects of the present disclosure.

[0105] Fig. 23C shows an exemplary cross section of a wedge nozzle, according to aspects of the present disclosure.

[0106] Fig. 23D shows an exemplary cross section of a wedge nozzle, according to aspects of the present disclosure.

[0107] Fig. 24 shows an example of stacked hollow beads, according to aspects of the present disclosure.

[0108] Fig. 25 shows an image of the microstructure of a tall bead, according to aspects of the present disclosure.

[0109] Fig. 26A shows graphs of nodal temperature as a function of time, according to aspects of the present disclosure.

[0110] Fig. 26B is a graph of temperature difference as a function of time, according to aspects of the present disclosure.DEFINITIONS

[0111] Additive Manufacturing (AM): As used herein, the term “additive manufacturing” refers to a process that adds successive layers of material to create an object. Additive manufacturing methods include 3-D printing, powder-bed laser printing systems, fused depositionPage 10 of 4613172581V11Attorney Docket No. 2010363-0446 modeling, and other processes capable of creating highly complex assemblies from one continuous material and / or from one continuous build process.

[0112] Bound Metal Deposition™ (BMD): As used herein, the term “bound metal deposition™ (BMD)” refers to an extrusion-based metal additive manufacturing process where metal components are constructed by extrusion of a powder-filled thermoplastic media. Bound metal rods which are metal powder are held together by wax and polymer binder, are heated, and extruded onto the build plate, shaping a part layer-by-layer. Once printed, the binder is removed via the debind process, and then sintered, causing the metal particles to densify.

[0113] Die Swell: As used herein, the term “die swell” refers to a flow effect that occurs in extrusion additive manufacturing where the extrudate experiences rapid stress and dimensional changes upon exiting the nozzle orifice. When the extrudate is released from the nozzle, the presence of a free surface allows it to release its stored elastic energy by enlarging its transversal size. Die swell influences the final dimensions of the printed part and modifies the state of residual stresses.

[0114] Flow Rate: As used herein, the term “flow rate” refers to the amount (i.e., volume) of material extruded from the nozzle as a function of time. Flow rate is influenced by the capacity of the extruder motor and how fast the motor can push the material through the nozzle, as well as by how fast the material is melted by the extruder.

[0115] Feed Rate’. As used herein, the term “feed rate” refers to the speed at which the extruder moves, which affects the speed of the print. It may also be referred to as toolhead velocity.

[0116] Fused Filament Fabrication (FFF): As used herein, the term “fused filament fabrication (FFF)” refers to an extrusion-based 3D printing technique that feeds continuous filament through a heated extruder. As the filament travels through the extruder’s heating zones, it begins to liquify and is deposited along a controlled path to build parts one layer at a time. It may also be referred to as ‘Fused Deposition Modeling’ or ‘Filament 3D Printing’. The mechanics of the extrusion system entail the strand of filament being pushed or pulled (i.e., pultrusion) into a set of direct drive rollers in a pinch system format. This feeds the material into a heating zone and then through a brass or steel nozzle.Page 11 of 4613172581V11Attorney Docket No. 2010363-0446

[0117] G-Code: As used herein, the term “G-Code” refers to a programming language for computer numerical control (CNC) machines. G-code stands for geometric code. G-code commands are provided to a machine controller to instruct the machine where to move, how fast to move, and what path to follow. In additive manufacturing or 3D printing, the G-code commands instruct the machine to deposit material, layer upon layer, forming a precise geometric shape.

[0118] Thickness: As used herein, the term “thickness” refers to the height of extrudate / beads. The direction orthogonal to the print bed is termed the through-thickness direction in the coordinate system of the present disclosure. Since the height of extrudate / beads aligns with the through-thickness direction, the terms height and thickness are used interchangeably, unless otherwise specified.DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

[0119] Conventional 3D printing incorporates the use of axisymmetric nozzles (i.e., the extrusion orifice is symmetric with respect to the direction of extrudate exiting the nozzle) and backpressure (i.e., the reactive force caused by pressuring extrudate through the gap below the nozzle and against a substrate) to form beads. Consequently, the bead geometry is a product of toolhead velocity, extrusion mass flow rate, and offset distance from the substrate. This process is wasteful from an optimization standpoint and results in horizontal beads with hemispherical ends. Only a subset of the material in conventional beads contributes to the load path, and the hemispheres that protrude from a column of beads are considered wasted material.

[0120] The present disclosure describes the use of non-axi symmetric nozzles without backpressure to control extrudate flow, such that bead geometry can be controlled and tuned to specific applications. When extrudate exits a non-axisymmetric nozzle, a large proportion of the mass flow is oriented in the opposite direction of travel of the toolhead, and consequently lower pressure is utilized to form the bead. Removing post-nozzle backpressure from the bead formation process enables faster printing while retaining bond quality. The non-axisymmetric nozzles of the present disclosure enable extrusion of tall beads whose aspect ratio (height to width) is larger than the conventional beads. In some embodiments, the tall beads may include essentially rectangular beads, where the entirety of the bead area contributes to the load path.Page 12 of 4613172581V11Attorney Docket No. 2010363-0446

[0121] According to aspects of the present embodiments, flow of material through a non- axisymmetric nozzle may be controlled such that it is intermittent and modulated according to the processing instructions, and desired outcomes. The extrudate profiles (i.e., bead shapes) are formed such that they bond with prior depositions (i.e., the layer-wise accumulation that is endemic to additive manufacturing). In some embodiments, the machine assemblages (or assemblies) are not static, i.e., a robot moves the extrusion die through space, such that the extrudate accumulates to produce a part.

[0122] The non-axisymmetric nozzles of the present disclosure may be optimized for specific applications including bead geometry (i.e., meso-scale features) or the microstructure of extrudate (e g., fiber orientation, fiber distribution, void distribution, and / or surface roughness). As disclosed herein, extrudate may include a composite material including both a matrix component (i.e., the extrudate material) and a fiber component (i.e., fibers disposed within the matrix or extrudate material). According to aspects of the present embodiments, the positioning, orientation, percent composition, etc. of fibers within the matrix component can affect the resulting work product. For example, in some embodiments, increased insulating effect of the extrudate / work product may be desired, in which case void distribution could be used to arrive at a finished product with enhanced insulating characteristics. In some embodiments, as disclosed herein, fiber orientation along a lateral (rather than longitudinal) direction may lead to quicker cooling of the extrudate, and superior resulting material properties from a structural point of view. In some embodiments, increased surface roughness may be desirable to enhance surface adhesion (i.e., which may be desirable depending on the specific use case). In some embodiments, decreased surface roughness may be desired (for example, for products where a smooth surface finish is favorable compared to a rough surface finish). Fiber distribution can similarly be used to customize material properties and characteristics of the resulting work product.Non-axisymmetric nozzle designs

[0123] According to aspects of the present disclosure, non-axisymmetric nozzles (for example, asymmetric nozzles) can be used to print beads with cross sections that are not limited to, for example, a circular shape. Fig. 1 shows an example of a coordinate system 10 used in 3D printing, according to aspects of the present disclosure. In some embodiments, the coordinatePage 13 of 4613172581V11Attorney Docket No. 2010363-0446 system 10 may include a longitudinal direction 12, a transverse direction 14, and a through- thickness direction 16. The nozzle moves in the longitudinal direction 12 (i.e., direction of extrusion) at a preset distance from a print bed. Successive layers of the extrudate are deposited in the through-thickness direction 16 (i.e., orthogonal to the print bed) and the extrudate cross section (i.e., bead geometry) aligns with transverse direction 14.

[0124] Fig. 3A shows an exemplary CAD drawing 27 of a non-axisymmetric nozzle 11, according to aspects of the present disclosure. In some embodiments, the non-axisymmetric nozzle 11 may include an inlet 13, an elongated body 15, and an outlet 17. The inlet 13 and the outlet 17 may be fluidly coupled and the cross section of the inlet 13 may be larger than the cross section of the outlet 17. Tn some embodiments, the elongated body 15 may include a hollow interior. In some embodiments, the elongated body 15 may include an axisymmetric geometry about the through- thickness direction 16. For example, the body 15 may be substantially cylindrical. In some embodiments, the outlet 17 may include a non-axisymmetric geometry.

[0125] Fig. 3B shows an exemplary CAD drawing 28 of a slot nozzle 30, according to aspects of the present disclosure. In some embodiments, the slot nozzle 30 may include an extrusion orifice 32. In some embodiments, the geometry of the extrusion orifice 32 may include an incomplete circle 34 and a slot 36. The incomplete circle 34 allows the extrudate to exit the slot nozzle 30 in through-thickness direction 16. The slot 36 (i.e., sideways-facing section) allows the extrudate to exit the slot nozzle 30 in longitudinal direction 12.

[0126] Fig. 23A shows an exemplary CAD drawing 38 of a wedge nozzle 40, according to aspects of the present disclosure. In some embodiments, the wedge nozzle 40 may include an extrusion orifice 42.

[0127] Fig. 23B shows an exemplary CAD drawing 39 of a wedge nozzle 40, according to aspects of the present disclosure. In some embodiments, the wedge nozzle 40 may include an extrusion orifice 42. In some embodiments, the geometry of the extrusion orifice 42 may include an incomplete rectangle 44 and a slot 46. The incomplete rectangle 44 allows the extrudate to exit the wedge nozzle 40 in through-thickness direction 16. The slot 46 (i.e., sideway-facing section) allows the extrudate to exit the wedge nozzle 40 in longitudinal direction 12.

[0128] Figs. 23C and 23D show exemplary cross sections 51 and 53 of the wedge nozzle 40, according to aspects of the present disclosure. In some embodiments, the cross sections 51 and Page 14 of 4613172581V11Attorney Docket No. 2010363-044653 may include internal threads 41, a cylindrical zone 43 downstream of the internal threads 41 , a conical zone 45 downstream of the cylindrical zone 43, a throat portion 55 defining the downstream edge of the conical zone 45, and a capillary portion 47. The cylindrical zone 43 may correspond to the elongated body 15 of the slot nozzle 40. The conical zone 45 and the capillary portion 47 may correspond to the outlet 17 of the slot nozzle 40, with the throat portion 55 being defined by the downstream edge of the conical zone 45, 61 in each case. The throat portion 55 is also the portion of the nozzle interior with the minimum cross-sectional area. In some embodiments, the internal threads 41 may promote an increased fiber orientation in the transverse direction 14 and through-thickness direction 16, as the extrudate passes through. In some embodiments, the conical zone 45 reduces a cross-sectional diameter from a larger diameter at the cylindrical zone 43, to a smaller diameter at a mouth 49 portion of the capillary portion 47. In some embodiments, a diameter of the cylindrical portion 43 is about 2.0 to about 3.0 (for example, from about 2.2 to about 2.8, or from about 2.3 to about 2.7, or from about 2.4 to about 2.6) times greater than the diameter of the mouth portion. In some embodiments, the capillary portion 47 includes a narrowed cross section in comparison to the mouth portion 49.

[0129] Fig. 4A shows an exemplary CAD drawing 48 of a triangle nozzle 50, according to aspects of the present disclosure. In some embodiments, the triangle nozzle 50 may include an extrusion orifice 52. In some embodiments, the geometry of the extrusion orifice 52 may include an incomplete circle 54 and a triangle 56. The incomplete circle 54 allows the extrudate to exit the triangle nozzle 50 in through-thickness direction 16. The triangle 56 (i.e., sideways-facing section) allows the extrudate to exit the triangle nozzle 50 in longitudinal direction 12.

[0130] Fig. 4B shows an example of a cross section 58 of the triangle nozzle 50, according to aspects of the present disclosure. In some embodiments, the cross section 58 may include a cylindrical zone 60, a conical zone 61, and a capillary 62. The cylindrical zone 60 may correspond to the elongated body 15 of the triangle nozzle 50. The conical zone 61 and the capillary 62 may correspond to the outlet 17 of the triangle nozzle 50.

[0131] Fig. 5A shows an exemplary CAD drawing 64 of a D-ring nozzle 66, according to aspects of the present disclosure. In some embodiments, the D-ring nozzle 66 may include an extrusion orifice 66. In some embodiments, the geometry of the extrusion orifice 68 may include a D-ring 70 and two slits 72. The D-ring 70 (i.e., sideway-facing section) allows the extrudate toPage 15 of 4613172581V11Attorney Docket No. 2010363-0446 exit the D-ring nozzle 66 in longitudinal direction 12. The two slits 72 allow the extrudate to exit the D-ring nozzle 66 in through-thickness direction 16. The two slits 72 and the D-ring 70 are each downstream of both the conical zone 78 and the capillary 80. In addition, the two slits 72 and the D-ring 70 are continuous with each other to form a continuous orifice such that the two slits 72 form an intersection of the orifice with a bottom surface 71 of the D-ring nozzle 66, and the D- ring 70 forms an intersection of the orifice with a radially outer circumference 73 of the d-ring nozzle 66.

[0132] Fig. 5B shows closeup example 74 of the D-ring nozzle 66, according to aspects of the present disclosure. In some embodiments, the closeup 74 may include the D-ring 70 of the extrusion orifice 68.

[0133] Fig. 5C shows an example of a cross section 76 of the D-ring nozzle 66, according to aspects of the present disclosure. In some embodiments, the cross section 76 may include a conical zone 78 and a capillary 80. The conical zone 78 and the capillary 80 may correspond to the outlet 17 of the D-ring nozzle 66.

[0134] Fig. 6 shows an exemplary CAD drawing of a non-axisymmetric nozzle assembly 82, according to aspects of the present disclosure. In some embodiments, the nozzle assembly 82 may include a Juggerbot extruder interface 84, a national pipe thread (NPT) (i.e., ANSI, ASME, etc., standard) threaded adaptor 86, a rotary union 88, a rotary drive gear 90 and a non- axisymmetric nozzle 92. In some embodiments, the adaptor 86 may be clamped. The nozzle assembly 82 may enable the non-axisymmetric nozzle 92 to match functional capabilities of axisymmetric (i.e., conventional) nozzles. The non-axisymmetric nozzles of the present disclosure may be rotated to direct the extrudate flow properly (i.e., to change the orientation of the non- axisymmetric nozzle 92 as needed based on the direction of extrusion, etc.). The NPT threaded adaptor 86, the rotary union 88, and the rotary drive gear 90 may provide the rotation of the non- axisymmetric nozzle 92. To enable rotary control via G-Code, the nozzle assembly 82 may further require a numerical control capability on Juggerbot interface with Oak Ridge National Laboratory (ORNL). For example, in some embodiments, the rotary drive gear 90 may be externally actuated such that the non-axisymmetric nozzle 92 may be freely rotated (i.e., free of the extruder interface 84) via the rotary union 88 such that any orientation of the non-axisymmetricPage 16 of 4613172581V11Attorney Docket No. 2010363-0446 nozzle 92 may be achieved independent of the position and / or orientation of the extruder interface 84.

[0135] Referring still to Fig. 6, and as described herein, the nozzle assembly 82 may include two unitary sub-assemblies 83, 85, which may each rotate independently from rotation of the other sub-assembly. For example, the nozzle assembly 82 may include a first unitary subassembly 83 including the extruder interface 84, the threaded adapter 86, and a first end (i.e., the top end, as shown in Fig. 6) of the rotary union 88, all being rigidly coupled together and configured to rotate together. The nozzle assembly 82 may also include a second unitary subassembly 85 including a second end (i.e., the bottom end, as shown in Fig. 6) of the rotary union 88, the rotary drive gear 90, and the non-axisymmetric nozzle 92, all being rigidly coupled together and configured to rotate together. In operation, the first unitary sub-assembly 83 may selectively rotate at any desired rotational extruder speed (i.e., according to the desired build parameters, print characteristics, etc.) while the second unitary sub-assembly 85 may be selectively rotated (i.e., independently from the rotation of the first unitary sub-assembly 83) such that the non- axisymmetric nozzle 92 may be oriented at any angle according to the geometry of the object being printed and / or the build process. In some embodiments, the direction and speed of rotation of the first unitary sub-assembly 83 may be different from the direction and speed of rotation of the second unitary sub-assembly 85.

[0136] Fig. 21 A shows an example of a slot nozzle 380, according to aspects of the present disclosure. In some embodiments, the slot nozzle 380 may be printed by a bound metal deposition™ (BMD) machine. In some embodiments, the slot nozzle 380 may include an extrusion orifice 384 and a cylindrical portion 382. The geometry of the extrusion orifice 384 may include an incomplete rectangle 386 and a slot 388, as further described in connection with CAD drawings 38, 39 (i.e., shown in Figs. 23A and 23B).

[0137] Fig. 21B shows an example of a triangle nozzle 390, according to aspects of the present disclosure. In some embodiments, the triangle nozzle 390 may be printed by a bound metal deposition™ (BMD) machine. In some embodiments, the triangle nozzle 390 may include an extrusion orifice 394 and a cylindrical portion 392. The geometry of the extrusion orifice 394 may include an incomplete circle 396 and a triangle 398, as further described in connection with CADPage 17 of 4613172581V11Attorney Docket No. 2010363-0446 drawing 48 / Fig. 4A. Tn some embodiments, the base of the triangle 398 may be larger than the diameter of the incomplete circle 396.

[0138] Fig. 21C shows an example of a D-ring nozzle 400, according to aspects of the present disclosure. In some embodiments, the D-ring nozzle 400 may be printed by a bound metal deposition™ (BMD) machine. In some embodiments, the D-ring nozzle 400 may include an extrusion orifice 404 and a cylindrical portion 402. The geometry of the extrusion orifice 404 may include slits 406 and a D-ring 408, as further described in connection with CAD drawing 64 / Fig. 5A. In some embodiments, the slits 406 may include two side portions that angle inwardly toward each other and that are connected via a center portion.Tall bead extrusion using custom extrusion dies

[0139] According to aspects of the present disclosure, tall beads (for example, beads with aspect ratios above 2, 3, 4, etc.) may be formed using the nozzles and methodologies described herein. Fig. 8A shows an example 108 of a wide slot nozzle 110, according to aspects of the present disclosure. In some embodiments, the wide slot nozzle 110 may include an extrusion orifice 112. The geometry of the extrusion orifice 112 may include an incomplete circle 114 and a slot 116, as further described herein in connection with CAD drawing 28 / Fig. 3A. In some embodiments, the slot width 118 may be equal to the diameter of an incomplete circle 114. In some embodiments, the wide slot nozzle 110 may be printed by a bound metal deposition™ (BMD) machine.

[0140] Fig. 8B shows an example 120 of a straight-line extrusion test using the wide slot nozzle 110, according to aspects of the present disclosure. In some embodiments, the example 120 may include two layers of a tall bead 122. The tall bead 122 may include a trapezoidal cross section where the long base 126 (aligned with transverse direction 14) is slightly longer than the short base 124 (aligned with transverse direction 14) and the height 130 (aligned with through-thickness direction 16) is longer than the short base 124 and the long base 126. The short base 124 may be disposed at the top of the tall bead 122, facing the long base 126 of the next layer of tall bead 122.

[0141] The width of the tall beads of the present disclosure may be limited by the machine capabilities. Expanding the width past the diameter of the most restrictive section in the barrel assembly may cause diminishing returns for the mass flow rate, as an increasing portion of thePage 18 of 4613172581V11Attorney Docket No. 2010363-0446 mass will be distributed normal to the direction of the toolhead velocity, instead of opposite the direction of the toolhead velocity.

[0142] Fig. 9A shows an example 132 of a narrow slot nozzle 134, according to aspects of the present disclosure. In some embodiments, the narrow slot nozzle 134 may include an extrusion orifice 136. The geometry of the extrusion orifice 136 may include an incomplete circle 138 and a slot 140, as further described herein in connection with CAD drawing 28 / Fig. 3A. In some embodiments, the slot width 142 may be much smaller than the diameter of the incomplete circle 138. In some embodiments, the wide slot nozzle 134 may be printed by abound metal deposition™ (BMD) machine.

[0143] Fig. 9B shows an example 144 of a straight-line extrusion test using the narrow slot nozzle 134, according to aspects of the present disclosure. In some embodiments, the example 144 may include a layer of a tall bead 146. The tall bead 146 may include a T-shaped cross section where the arm 148 is at the bottom of the tall bead 146 (i.e., facing the print bed) and the stem 150 faces the next layer of tall bead 148. In some embodiments, the tall bead 146 of the first layer may include a T-shaped cross section and in a subsequent layer, the extrudate flows over the stem 150 to form an oval-shaped arm, as further discussed herein in connection with Fig. 15C. The results in a significant increase in contact surface area between beads, which improves the bond strength. The vertically oriented or compound bond shapes may change the primary mode of load transfer between beads. In a conventional bead undergoing tensile loading, the bond interface is perpendicular to the load path and normal stresses dominate the failure mode. In a T-shaped tall bead 146 undergoing tensile loading, a portion of the bond interface is parallel to the load path, and a shear stress component is introduced to the failure mode, which improves bond strength.

[0144] Fig. 10A illustrates an experiment 160 to verify extrudate shape consistency using a non-axisymmetric nozzle, according to aspects of the present embodiments. In some embodiments, the experiment 160 may include performing single-layer straight-line prints at varying mass flow rates while the feed rate is held constant. In some embodiments, the mass flow rates may be directly proportional to a rotational speed (for example, the rotational velocity of an extrude screw), which may include, for example, the following speeds: 107.54 RPM (line 162), 97.54 RPM (line 164), 87.54 RPM (line 166), 77.54 RPM (line 168), 67.54 RPM (line 170) andPage 19 of 4613172581vllAttorney Docket No. 2010363-044657.54 RPM (line 172). The extrudate shape (i.e., bead geometry) of each print layer is measured as further discussed herein in connection with Fig. 10B.

[0145] Fig. 10B is a graph 174 of the average aspect ratio of printed tall beads vs mass flow rate using a non-axi symmetric nozzle, according to aspects of the present disclosure. In some embodiments, the flow rates may include flow rates that correspond to, for example, 107.54 RPM,97.54 RPM, 87.54 RPM, 77.54 RPM, 67.54 RPM and 57.54 RPM, as further discussed herein in connection with Fig. 10A. In some embodiments, the aspect ratio (thickness to width) of the printed beads are measured at three offset distances from the substrate. For example, the offset distances from the substrate may include 1.6429 mm (data series 176), 2.6429 mm (data series 178), and 3.6429 mm (data series) 180 which are shown on the graph 174 in blue, red and yellow, respectively. In some embodiments, as the flow rate increases from 57.54 PRM the average aspect ratio increases and eventually reaches the peak aspect ratio value of about 3 at the flow rate of87.54 RPM. As the flow rate continues to increase, however, the average aspect ratio starts to decline. This effect is known as feed rate / flow rate coupling phenomenon. At a constant feed rate, as the mass flow rate increases, an over-extrusion occurs which leads to die swell. Since the extrudate expands further in the transverse direction, the resulting bead becomes wider and so the aspect ratio decreases. In order to prevent die swell, calibration of flow rate with feed rate must be conducted, to ensure the exit velocity of the extrudate at sideways-facing section of the non- axisymmetric nozzle (i.e., a tangential velocity of an extruder screw) is equal and opposite to the toolhead velocity (i.e., feed rate, i.e., the linear velocity of the non-axisymmetric nozzle as it translates across the build area). Stated otherwise, peak aspect ratios may be achieved when a tangential velocity of the extruder is set to be equal to (for example, with + / - 1.0% and / or within + / -5.0%) the linear velocity of the non-axisymmetric nozzle 92 in the extrusion direction.Microstructure control

[0146] The microstructure of an extrudate produced by a conventional nozzle is fully dependent on processing conditions and resultant bead geometry. The microstructure may only be indirectly controlled by varying orifice diameters of a nozzle, changing the bead width and / or height, or changing the toolhead speed through space in relation to the volumetric extrusion rate.Page 20 of 4613172581V11Attorney Docket No. 2010363-0446

[0147] One of the improvements provided by the present disclosure is the recognition that controlling microstructure may also be accomplished by using custom nozzle geometries, such that target microstructure characteristics are obtained and / or improved over baseline characteristics. In some embodiments, the internal geometry of a non-axi symmetric nozzle is structured such that internal flow of an extrudate produces an end state (i.e., state of an extrudate when it exits the nozzle) with fibers preferentially aligned. The preferential alignment of fibers may result from combinations of internal fluid flow parameters including the no-slip condition at the fluid / structure interface, velocity distributions through the extrudate profile, and pressure differentials.

[0148] Fiber orientation is one aspect with which microstructure may be controlled. Factors affecting fiber orientation may include bead geometry, internal thread features, 90-degree (or other angle, i.e., from 80 degrees to 100 degrees) internal turns prior to the extrusion orifice, nozzle orientation, and nozzle speed through space (i.e., toolhead feed rate). In some embodiments, fiber content or loading is maintained within a pre-selected range such that sufficient fiber content is present to provide the desired material properties, but is not so high as to cause steric hindrance (i.e., thereby preventing the desired fiber orientation, distribution, etc. from being realized). In some embodiments, fiber loading is maintained at 30% volume fraction or lower. For example, in some embodiments, fiber loading is maintained within a range from about 5% volume fraction to about 30% volume fraction, or within a range from about 10% volume fraction to about 30% volume fraction, or within a range from about 15% volume fraction to about 30% volume fraction, or within a range from about 20% volume fraction to about 30% volume fraction, or within a range from about 25% volume fraction to about 30% volume fraction.

[0149] Conventional extrusion involves a change of direction of material flow which occurs after the extrudate has exited the internal pathway of a nozzle. Therefore, the resultant orientation and distribution of fibers within an extrudate are dependent upon factors that are external to the nozzle shape, such as toolhead feed rate and volumetric flow rate of material exiting the nozzle. The fiber orientation, additionally, is affected by the volume of substrate a material is extruding into (i.e., how close a substrate layer is to the exit orifice of the nozzle). As a result, the fibers change orientation after they exit a conventional nozzle. In some embodiments, a non- axisymmetric nozzle of the present disclosure may accomplish a change of direction of materialPage 21 of 4613172581V11Attorney Docket No. 2010363-0446 flow internally via a custom designed shape. For example, the wedge nozzle 40 may force a partial 90° bend in the flow, which produces fibers that stay aligned in a specific direction during and after they exit the nozzle.

[0150] Extrusion processes offer a large set of possible bead geometries, strictly in terms of possible dimensions, as they are merely variations of a horizontal plate with hemispherical ends. For example, when the distance between nozzle exit orifice and top of substrate remains fixed (i.e., in the through-thickness direction 16), the toolhead feed rate through space remains fixed, and therefore as the volumetric flow rate of extrudate is increased, wider beads are produced. This produces a bead with more fibers aligned horizontally (i.e., in transverse direction 14). If the toolhead federate, for example, is allowed to increase with volumetric flow rate to retain consistent bead geometry, the resulting fiber orientation still changes. This is due to shearing that occurs in the material as it exits the nozzle orifice and depends on toolhead feed rate. In some embodiments, a non-axi symmetric nozzle of the present disclosure offers a smaller set of possible beads, strictly in terms of possible dimensions, to trade generality for efficiency. For example, when the distance between nozzle exit orifice and top of substrate remains fixed (i.e., in the through-thickness direction 16), and volumetric flow rate is increased, the toolhead feed rate must increase to retain the same bead size and avoid instabilities (e.g., sharkskinning and melt fracture). However, there is no shearing at the exit orifice, and the resulting fiber orientation stays consistent.

[0151] In some embodiments, other aspects of microstructure may be controlled including fiber distribution, surface roughness, polymer chain alignment, and porosity / voids. For example, the amount of porosity (e.g., high / low) may be controlled such that the resulting extrudate may be foaming or not foaming, depending on nozzle geometry and processing conditions.

[0152] Bead microstructure is among the dominating factors in extrudate cooling behavior. The microstructure of conventional beads exhibits a prevalent fiber orientation in the longitudinal direction 12 (as further described herein in connection with Figs. 18A and 18B). This fiber orientation promotes heat conduction along a printed layer (longitudinal direction 12), and the lingering heat results in longer cooling periods. The tall beads of the present disclosure exhibit an increased proportion of fiber orientation in the transverse 14 and through-thickness 16 directions (as further described herein in connection with Fig. 19A and 19B). This fiber orientation facilitates a significant heat conduction in transverse 14 and through-thickness 16 directions, and thereforePage 22 of 4613172581V11Attorney Docket No. 2010363-0446 to the peripheries of a printed layer, leading to shorter cooling periods. The rapid cooling behavior of the tall beads enables shorter layer times and consequently, higher manufacturing throughputs.

[0153] In some embodiments, carbon fdled materials are used where the thermal conductivity of carbon fiber compared to resin differs by an order of magnitude (for example, differs by a factor of ten) or greater. In addition, the carbon fibers themselves have aspect ratios. In some embodiments, wood-flour filled materials are used where the thermal conductivity of would flour is lower than the resin. Nonetheless, bead microstructure is the among the primary factors of the cooling behavior of an extrudate.

[0154] Fig. 18A shows an image 346 of the microstructure of conventional beads 186. In some embodiments, the image 346 may be acquired by a scanning electron microscope (SEM). The image 346 may include a cross section of stacked conventional beads 186, acquired in through thickness 16 - transverse 14 plane. An enlarged view of the selected area 348 is shown in image 350, as further discussed herein in connection with Fig. 18B.

[0155] Fig. 18B shows an image 350 of the microstructure of conventional beads 186. The image 350 is an enlarged view of the selected area 348 in image 346, as further discussed herein in connection with Fig. 18A. The image 350 may include fibers 352 and one or more cracks 354. A large proportion of the fibers 352 are oriented in the longitudinal direction 12, which promote head conduction along the printed layer. The one or more cracks 354 are present at the inter-bead bond areas.

[0156] Fig. 19A shows an image 356 of the microstructure of a tall bead 184, according to aspects of the present disclosure. In some embodiments, the wide slot nozzle 110 may be used to print the tall bead 184. In some embodiments, the image 356 may be acquired by a scanning electron microscope (SEM). In some embodiments, the image 356 may include a cross section of a tall bead 184, acquired in through thickness 16 - transverse 14 plane. An enlarged view of the selected area 358 is shown by image 360, as further discussed herein in connection with Fig. 19B.

[0157] Fig. 19B shows an image 360 of the microstructure of a tall bead 184, according to aspects of the present disclosure. The image 360 is an enlarged view of selected area 358 in image 356, as further discussed herein in connection with Fig. 19A. In some embodiments, the image 360 may include fibers 362. An increased proportion of fibers 362 may be oriented in the transverse direction 14 and through-thickness direction 16, which facilitate a significant heatPage 23 of 4613172581V11Attorney Docket No. 2010363-0446 conduction to the peripheries of the printed layer, resulting in faster cooling compared to the conventional beads 186. These results demonstrate the ability of non-axisymmetric nozzles, used at the same volumetric flowrate as that of a conventional nozzle, to produce fiber orientations that are preferrable (from a process and / or performance-based perspective) to those produced with typical nozzle designs, which, as discussed herein, may result in superior material properties achieved through quicker extrudate cooling (due to fiber orientation) as well as enhanced structural characteristics.

[0158] Fig. 25 shows an image 460 of the microstructure of a tall bead, according to aspects of the present disclosure. In some embodiments, the wedge nozzle 40 may be used to print the tall bead. In some embodiments, the image 460 may be acquired by a scanning electron microscope (SEM). In some embodiments, the image 460 may include a cross section of a tall bead, acquired in through-thickness 16 - longitudinal 12 plane. In some embodiments, the image 460 may include fibers 462. An increased proportion of fibers 462 may be oriented in the longitudinal direction 12 and through-thickness direction 16. The wedge nozzle 40 may include a geometry that is designed specifically to produce a fiber orientation that is different from the fiber orientation shown in Figs. 19A and 19B than what has already been documented for tall beads.

[0159] To demonstrate the impact of fiber orientation on cooling behavior of beads, a model comparison of thermal history between nominal (i.e., as measured) and rotated thermal conductivities was performed. In some embodiments, the comparison model may be generated by one or more finite element (FE) processes using isotropic material model (PETG / CF). Table 1 shows the nominal and rotated_thermal conductivities in different directions. In some embodiments, KI 1 corresponds to longitudinal direction 12, K22 corresponds to traverse direction 14, and K33 corresponds to through-thickness direction 16. In this example, the thermal conductivities in longitudinal direction 12 and through-thickness direction 16 are rotated while keeping the thermal conductivity in traverse direction 14.Table 1: Thermal conductivityPage 24 of 4613172581vllAttorney Docket No. 2010363-0446

[0160] Fig. 26A shows graphs of nodal temperature (°C) as a function of time (s), for nominal 470 and rotated 472, according to aspects of the present disclosure. Fig. 26B is a graph of temperature difference (°C) as a function of time (s), according to aspects of the present disclosure. The temperature difference is calculated by subtracting the nominal values 470 from rotated values 472, as shown in Fig. 26A. These results shown in Figs. 26A and 26B demonstrate that, for the first four layers, the rotated material 472 cools faster compared to the nominal material 470. However, for the subsequent layers, rotated material 472 is always warmer.Decreased Residual Stress

[0161] Deformation of a material is a thermally driven process which involves warping and development of residual stresses. For a given temperature difference, the coefficient of thermal expansion (CTE) of the extrudate determines thermal shrinkage or expansion of the extrudate, which translates to thermally induced strains and deformation. In an ideal manufacturing process, if the temperature difference approaches zero, the associated thermally induced strains also approach zero, regardless of the magnitude of CTE. Therefore, processing at cooler temperatures, where a relatively reduced temperature difference between processing temperature and ambient temperature is promoted, warping and subsequent residual stresses in the extrudate are reduced.

[0162] The tall beads of the present disclosure exhibit faster cooling behavior which facilitates not only higher manufacturing throughputs but also reduced temperature differences between the extrudate and the ambient. Since faster cooling behavior is achieved by modifying the bead geometry, the present disclosure may enable use of a great variety of materials without deformations.

[0163] Residual stress is directly proportional to the temperature difference between a bead and the overprint divided by the bead thickness. Calculations show, given the assumptions made on heat distribution within a tall bead, that residual stresses developed by a temperature differential in the extrudate are reduced compared to conventional beads.

[0164] Fig. 7A illustrates an example of a thermal simulation 94 of a wide bead substrate 100. In some embodiments, the thermal simulation 94 may include a wide bead (i.e., conventional bead) 98 and a wide bead substrate 100. In some embodiments, the thermal simulation 94 may bePage 25 of 4613172581V11Attorney Docket No. 2010363-0446 generated by one or more finite element (FE) processes using isotropic material model (PETG). In some embodiments, a temperature scale 96 may indicate the temperature range in °C. For example, the temperature in the thermal simulation 94 may range from about 40 °C to about 250 °C. In some embodiments, the wide bead 98 may include a thickness to width aspect ratio of 1 :2. The thermal simulation 94 may be used to demonstrate the cooling behavior of the wide bead substrate 100. For example, for the wide bead 98 with a temperature of about 250°C, the wide bead substrate 100 may show a temperate of about 160°C.

[0165] Fig. 7B illustrates an example of a thermal simulation 102 of a tall bead substrate 106, according to aspects of the present disclosure. In some embodiments, the thermal simulation 102 may include a tall bead 104 and a tall bead substrate 106. In some embodiments, the thermal simulation 102 may be generated by finite element (FE) processes using isotropic material model (PETG). In some embodiments, a temperature scale 96 may indicate the temperature range in °C. For example, the temperature in the thermal simulation 102 may range from about 30 °C to about 250 °C. In some embodiments, the tall bead 104 may include a thickness to width aspect ratio of 2:1. In order to compare the cooling behaviors of the wide beads 98 and the tall beads 104, the thermal simulation 102 is generated using the process and environmental parameters of the thermal simulation 94. For example, for the tall bead 104 with a temperature of about 250°C, the tall bead substrate 106 may show a temperature of 140°C which is about 20°C cooler compared to that of the wide bead substrate 94, as further discussed herein in connection with Fig. 7A. The demonstrated rapid cooling behavior of the tall beads 104 enables shorter layer times and consequently, higher manufacturing throughputs.

[0166] To demonstrate the rapid cooling behavior of the tall beads of the present disclosure, two extrusion tests were performed using a conventional nozzle and a non- axisymmetric nozzle. The extrusion parameters (including bead cross section, mass flow rate and feed rate) were normalized and the temperature of the extrudate when exiting the nozzle was kept constant.

[0167] Fig. 22A shows an example 410 of stacked tall beads 414 next to stacked conventional beads 412, according to aspects of the present disclosure. In some embodiments, 20 layers of the conventional beads 412 may be required to achieve the print height 416 of 5 layers of tall beads 414. In some embodiments, the total mass of the stacked tall beads 414 may be equalPage 26 of 4613172581V11Attorney Docket No. 2010363-0446 to the total mass of the stacked conventional beads 412. In some embodiments, the total print time of the stacked tall beads 414 may be equal to the total print time of the stacked conventional beads 412 (for example, to normalize as many factors as possible when studying the effect of bead geometry on bead cooling).

[0168] Fig. 22B shows a thermal image 418 of an extrusion of the conventional bead 412. The thermal image 418 may include a conventional nozzle 420 while extruding the conventional bead 412 and a T1 mean temperature 422. The T1 mean temperature 422 may correspond to the temperature of the extrudate while exiting the conventional nozzle 420. The normalized bead cross section may be set to 1, the normalized extruder head speed may be set to 1 and the normalized feed rate may be set to 1. The T1 mean temperature 422 may be set to 232 °C. This is the temperature of the extrudate as it is exiting the nozzle.

[0169] Fig. 22C shows a thermal image 424 of the extrusion of the conventional bead 412. The thermal image 424 may include the conventional nozzle 420 while extruding the conventional bead 412 and a T2 mean temperature 426. The T2 mean temperature 426 may correspond to the temperature of the extrudate at a fixed layer time. The measured T2 mean temperature 426 may be 154 °C. The resulting temperature difference between the T2 mean temperature 426 and the T1 mean temperature 422 for the conventional bead 412 is 78 °C.

[0170] Fig. 22D shows a thermal image 428 of an extrusion of the tall bead 414, according to aspects of the present disclosure. In some embodiments, the thermal image 428 may include a non-axisymmetric nozzle 430 while extruding the tall bead 414 and a T1 mean temperature 432. The T1 mean temperature 432 may correspond to the temperature of the extrudate while exiting the non-axisymmetric nozzle 430. In some embodiments, the normalized bead cross section may be set to 4, the normalized extruder head speed may be set to 0.25 and the resulting feed rate would be 1, thereby matching the feed rate of the conventional bead. The T1 mean temperature 432 may be set to 232 °C to match the T1 mean temperature 422. This is the temperature of the extrudate as it is exiting the nozzle.

[0171] Fig. 22E shows a thermal image 434 of the extrusion of the tall bead 414, according to aspects of the present disclosure. In some embodiments, the thermal image 434 may include the non-axisymmetric nozzle 430 while extruding the tall bead 414 and a T2 mean temperature 436. In some embodiments, the T2 mean temperature 436 may correspond to the temperature of the Page 27 of 4613172581V11Attorney Docket No. 2010363-0446 extrudate at an equivalent layer time that was used for the conventional bead 412, as further discussed in connection with Fig. 22C. The measured T2 mean temperature 436 may be 101 °C. The resulting temperature difference between the T2 mean temperature 436 and the T1 mean temperature 432 for the tall bead 414 is 131 °C. Therefore, even when normalizing for both extruder feed rate, print time, extrudate mass, and extrudate discharge temperature, the tall bead 414 of the present embodiments cools much more quickly than the conventional bead 412.Manufacturing throughput

[0172] This present disclosure involves additive manufacturing (AM). In some embodiments, fused fdament fabrication (i.e., desktop-scale) may be employed. In some embodiments, the “feedstock agnosticism” of the manufacturing process may be facilitated for large scale AM. For example, the capacity of a single-screw extruder to process material with relatively larger and / or rigid fillers (i.e., recycled concrete aggregate) is facilitated by custom nozzle designs in conjunction with modifications to the extruder barrel and / or screw.

[0173] Manufacturing throughput in 3D printing is affected by the machine limits and process limits. The machine limits, also called hard limits or fundamental limits, relate to the safety and design limits of the AM machines. Extrusion limits include screw maximum torque, screw maximum rotational velocity (RPM), and screw maximum acceleration. Movement limits include travel maximum velocity and travel maximum acceleration. Thermal limits include maximum heat band wattage and maximum heat band conductance rate.

[0174] Process limits, also called soft limits, relate to the interaction between material, process, and part geometry. Structural stability is determined by the properties of previously printed material (for example, stand-up times, layer times, upper limits to substrate temperatures) and current extrusion (for example surface quality). Defect formation may be a result of long processing times and part geometry. Long processing times lead to layer separation by affecting interfacial soak temperatures, bond quality, and lower limits of substrate temperatures. Warping and deformation are dependent on thermally induced residual stresses, boundary conditions, and cooling rates.Page 28 of 4613172581V11Attorney Docket No. 2010363-0446

[0175] Fig. 2A shows an example of a common extrudate defect 16 due to the soft limits of 3D printing. In some embodiments, the extrudate defect 16 may include sharkskinning, which is characterized by a sharkskin pattern 18. Sharkskinning is an extrudate instability that occurs at high shear rates at the extrudate / nozzle interface and most commonly in low extrusion temperature profiles (i.e., the nozzle is too cold).

[0176] Fig. 2B shows an example of a common extrudate defect 20 due to the soft limits of 3D printing. In some embodiments, the extrudate defect 20 may include melt fracture, which is characterized by surface undulations 22. Melt fracture is an extrudate instability that occurs at very high shear rates (above the sharkskinning threshold), resulting in a highly turbulent flow.

[0177] Fig. 2C shows an example of a common extrudate defect 24 due to soft limits of 3D printing. In some embodiments, the extrudate defect 24 may include ribboning, which is characterized by large ripples 26 deforming the extrudate. Ribboning is an extrudate instability that occurs when the mass flow rate of the extrudate is significantly higher than the toolhead velocity. Ribboning is an extreme form of over-extrusion in large-scale AM.

[0178] The present disclosure involves higher manufacturing throughputs including increased capability to reach the machine limits rather than the process limits, and increased ability to complete targeted geometries with less material. To demonstrate the shift of manufacturing throughput limits from process to the machine, two sets of tests were performed using wood-fiber reinforced polylactic acid (WF-PLA) and carbon fiber reinforced acrylonitrile butadiene styrene (CF-ABS) composites. Table 2 shows the results of a low temperature bucket test on WF-PLA using a conventional nozzle and a non-axisymmetric nozzle. For a constant torque screw value, the extruder temperature profile of the non-axisymmetric nozzle shows improvements compared to the conventional nozzle.Table 2: WF-PLA bucket testPage 29 of 4613172581V11Attorney Docket No. 2010363-0446

[0179] Table 3 shows the results of a low temperature bucket test on CF-ABS using a conventional nozzle and a non-axisymmetric nozzle. For a constant torque screw value, the extruder temperature profde of the non-axisymmetric nozzle shows improvements compared to the conventional nozzle.Table 3: CF-ABS bucket testIncreased effective cross section in tall beadsReduced chain effect

[0180] According to aspects of the present disclosure, the portion of a printer layer that is load-bearing (for example, to help support a subsequent print layer) may be increased in comparison to printer layers formed via conventional methodologies. Fig. 11 shows an example 182 of a tall bead 184 next to stacked conventional beads 186, according to aspects of the present disclosure. In some embodiments, the conventional beads 186 may include an aspect ratio of about 4. In some embodiments, 6 layers of the conventional beads 186 may be required to achieve the print height 188 of the tall bead 184. As a result, the number of layers in the chain is significantly reduced, which reduces the chain effect in the transverse direction 14. Fewer layers involves fewer polymer welds, and therefore fewer points of failure. Furthermore, the tall bead 184 may include a smooth surface, while conventional beads 184 may include an undesirable surface finish.

[0181] In some embodiments, custom extrusion dies may facilitate producing beads with smooth, resin-rich surfaces. The surface roughness is dependent on length scale and interactions that take place between an extrudate and itself, an extrudate and a nozzle, and an extrudate and a substrate. For example, smooth surface finishes may be achievable with conventional nozzles,Page 30 of 4613172581V11Attorney Docket No. 2010363-0446 under specific processing conditions which are also material specific. In some embodiments, the design considerations of custom extrusion dies to achieve targeted fiber orientation may additionally achieve targeted surface finishes. In some embodiments, the smooth surfaces of the tall bead 184 are the product of a low-shear, low-pressure condition at the location where material exits the nozzle. Smooth interfacial surfaces of the tall bead 184, for example, may produce better polymer welds. The smooth surfaces of a tall bead achieved by a nozzle design, however, is independent of the bead shape (i.e., meso-structure).Increased percentage of effective material

[0182] According to aspects of the present disclosure, the portion of a print material that is wasted within each later may be decreased in comparison to printer layers formed via conventional methodologies. Fig. 12A illustrates a SolidWorks example 188 (among other possible software examples) of effective material in stacked conventional beads 190. Each conventional bead 190 may include a thickness 192 of 1.50 mm, a width 198 of 6.00 mm and a hemisphere 200 on either side. The effective material 202 of the stacked conventional beads 190 may include a total thickness 194 of 3.00 mm, and a width 196 of 4.50 mm. The hemispheres 200 are considered waste (i.e., ineffective) and make up about 21% of the material used for the beads 190. In some embodiments, the waste material may represent an even higher percentage of the material, depending on the geometry of the hemispheres 200 in comparison to the width 198.

[0183] Fig. 12B illustrates a SolidWorks example 204 of effective material in stacked tall beads 206, according to aspects of the present disclosure. In some embodiments, the wide slot nozzle 110 may be used to print the tall beads 206. In some embodiments, the tall beads 206 may include a trapezoidal cross section. The tall bead 206 may include a thickness 208 of 8.00 mm, a width 214 of 4.50 mm at the bottom and a width 212 of 4.20 mm on the top. The difference between the short base (i.e., the width 212) and the long base (i.e., the width 214) of the trapezoidal cross section of tall bead 206 contributes to the formation of excess material 215 on either side. The effective material 216 of the stacked tall beads 206 may include a total thickness 210 of 16.00 mm, and a width 212 of 4.20 mm. The ineffective material on the two sides of the tall beads 206 make up about 4% of the used material. Therefore, the use of non-axisymmetric nozzles and the printing of tall beads 206 may result in an increased percentage of effective material in the transversePage 31 of 4613172581V11Attorney Docket No. 2010363-0446 direction 14 (and a decrease in the percentage of waste material), compared to the conventional beads 190, as further discussed herein in connection with Fig. 12A.Reduced stress concentration in tall beads

[0184] According to aspects of the present disclosure, the print methodologies and / or bead geometries result in reduced stresses (i.e., inter-bead stresses) in the printed workpiece, compared to workpieces made from conventional methodologies. Fig. 13A illustrates a SolidWorks example 218 of stress concentration in inter-bead geometry of stacked conventional beads 190. Example 218 includes a closeup of stacked conventional beads 190 where the two hemispheres 200 meet at an interfacial angle 220. The sharp interfacial angle 220 causes higher stress concentration in transverse direction 14.

[0185] Fig. 13B illustrates a SolidWorks example 222 of stress concentration in inter-bead geometry of stacked tall beads 208, according to aspects of the present disclosure. In some embodiments, the wide slot nozzle 110 may be used to print the tall beads 206. In some embodiments, example 222 may include a closeup of stacked tall beads 206 and an interfacial angle 224. The near-right interfacial angle 224 may reduce the stress concentration in transverse direction 14, compared to the conventional beads 190, as further discussed herein in connection with Fig. 13 A.Increased contact surface in tall beads

[0186] According to aspects of the present disclosure, the print methodologies and / or bead geometries result in increased contact surface area (i.e., between adjacent print layers), when compared to workpieces made from conventional print methodologies. Fig. 14A illustrates a SolidWorks example 226 of contact surface area of stacked conventional beads 190. Each conventional bead 190 may include a thickness 192 of 1.50 mm, a width 198 of 6.00 mm and a hemisphere 200 on either side. The stacked conventional beads 190 may include a total thickness 194 of 3.00 mm. For a print length of 10 mm, the maximum cross-sectional surface area in transverse direction 14 is 60 mm2. The contact surface area of the stacked conventional beads 190 is defined as the area corresponding to the total thickness 194 and a width 196. For the print lengthPage 32 of 4613172581V11Attorney Docket No. 2010363-0446 of 10 mm, the contact surface area is 45 mm2. Accordingly, 25% of the cross-sectional surface area does not contribute to the contact surface area (i.e., is wasted).

[0187] Fig. 14B illustrates a SolidWorks example 228 of contact surface area of stacked tall beads 206, according to aspects of the present disclosure. In some embodiments, the wide slot nozzle 110 may be used to print the tall bead 206. In some embodiments, the tall beads 206 may include a trapezoidal cross section. The tall bead 206 may include a thickness 208 (i.e., trapezoid height) of 8.00 mm, a width 214 of 4.50 mm (i.e., long base) at the bottom and a width 212 of 4.50 mm (i.e., the short base) on the top. The stack of the two tall beads 206 may include a total thickness 210 of 16.00 mm. In some embodiments, for a print length of 10 mm, the maximum cross-sectional surface area in transverse direction 14 is 45 mm2. The contact surface area of the two tall beads 206 is defined as the area corresponding to the total thickness 210 and the width 212. In some embodiments, for the print length of 10 mm, the contact surface area is 42 mm2. Accordingly, only 7% of the cross-sectional surface area does not contribute to the contact surface area (i.e., is wasted). Therefore, the use of non-axisymmetric nozzles and the printing of tall beads 209 may result in an increased contact surface area for a given maximum cross-sectional surface area in the transverse direction 14, compared to the conventional beads 190, as further discussed herein in connection with Fig. 14A.

[0188] Fig. 14C illustrates a SolidWorks example 230 of contact surface area of stacked tall beads 232, 233, according to aspects of the present disclosure. In some embodiments, the triangle nozzle 392 (as shown in Fig. 21B) may be used to print the tall beads 232, 233. In some embodiments, the tall bead 232 may include a triangular cross section. The tall bead 232 may include a thickness 234 (i.e., triangle height) of 6.00 mm, and a width 236 of 6.00 mm (i.e., triangle base). In some embodiments, the tall bead 233 may include a lobe 240 on either side, as the extrudate flows over the tall bead 232. The lobes 240 may include a width 242 of 1.50 mm. The stack of the two tall beads 232, 233 may include a total thickness 238 of 9.00 mm. In some embodiments, for the print length of 10 mm, the contact surface area is 67 mm2. Therefore, the use of non-axisymmetric nozzles and the printing of tall beads 232,233 may result in an increased contact surface area in the transverse direction 14, compared to the conventional beads 190, as further discussed herein in connection with Fig. 14A.Page 33 of 4613172581V11Attorney Docket No. 2010363-0446Customized external structure

[0189] According to aspects of the present disclosure, customized nozzle geometries may be used to print beads with user-defined cross-sections.

[0190] Fig. 15A shows an example 244 of a tall bead 146, according to aspects of the present disclosure. In some embodiments, the narrow slot nozzle 134 may be used to print the tall bead 146. In some embodiments, the tall bead 146 may include a T-shaped cross section where the arm 148 is at the bottom of tall bead 146 and the stem 150 faces arm 148 of the next layer of tall bead 148.

[0191] Fig. 15B illustrates a SolidWorks example 246 of a tall bead 146, according to aspects of the present disclosure. In some embodiments, the narrow slot nozzle 134 may be used to print the tall bead 146. In some embodiments, the tall bead 146 may include a T-shaped cross section, an arm 148 and a stem 150. In some embodiments, the arm 148 may include a thickness 252 of 1.50 mm, and a width 250 of 12.00 mm. In some embodiments, the stem 150 may include a thickness 254 of 9.00 mm, a width 248 of 2.00 mm at the bottom (i.e., facing the arm 148), and a width 256 of 1.00 mm at the top (i.e., facing the next layer).

[0192] Fig. 15C shows an example 258 of stacked tall beads 260, 262, according to aspects of the present disclosure. In some embodiments, the narrow slot nozzle 134 may be used to print the tall beads 260, 262. In some embodiments, the tall bead 260 may include a T-shaped cross section where the arm 264 is at the bottom of the tall bead 260 and the stem 266 faces the next tall bead 262. In some embodiments, the tall bead 262 may include a T-shaped cross section where the arm 268 is at the bottom of tall bead 262, facing the stem 266 of tall bead 260, and a stem 270 at the top. In some embodiments, the arm 268 may include an oval shape as the extrudate flows over the stem 266. There is a significant increase in contact surface area between the beads 260 and 262, which acts to improve the bond strength. Vertically oriented or compound bond shapes may change the primary mode of load transfer between beads. In conventional bead bonds undergoing tensile loading, the bond interface is perpendicular to the load path and normal stresses dominate the failure mode. In T-shaped tall beads 260, 262 undergoing tensile loading, a portion of the bond interface is parallel to the load path and a shear stress component is introduced to the failure mode, which improves bond strength.Page 34 of 4613172581V11Attorney Docket No. 2010363-0446

[0193] Fig. 15D illustrates a SolidWorks example 272 of stacked tall beads 260, 262, according to aspects of the present disclosure. In some embodiments, the narrow slot nozzle 134 may be used to print the tall beads 260, 262. In some embodiments, the tall bead 260 may include a T-shaped cross section, an arm 264 and a stem 266. In some embodiments, the arm 264 may include a thickness 276 of 1.30 mm, and a width 274 of 12.00 mm. In some embodiments, the tall bead 262 may include a T-shaped cross section, an arm 268 and a stem 270. In some embodiments, the arm 268 may include an oval shape with a thickness 282 of 6.30 mm. In some embodiments, the stem 266 and the arm 268 may include a total thickness 278 of 8.20 mm. In some embodiments, the Stem 270 may include a width 282 of 0.50 mm. In some embodiments, stacked tall beads 260, 262 may include a total thickness 280 of 16.00 mm.

[0194] Fig. 16A illustrates a SolidWorks example 286 of five stacked conventional beads 190. Each conventional bead 190 may include a thickness 192 of 1.50 mm, a width 198 of 6.00 mm and a hemisphere 200 on either side. Five stacked conventional beads 190 may include a total thickness 288 of 7.50 mm.

[0195] Fig. 16B illustrates a SolidWorks example 190 of five stacked tall beads 206, according to aspects of the present disclosure. In some embodiments, the wide slot nozzle 110 may be used to print the tall bead 206. In some embodiments, the tall beads 206 may include a trapezoidal cross section. The tall bead 206 may include a thickness 208 (i.e., trapezoid height) of 8.00 mm, a width 214 of 4.50 mm (i.e., long base) at the bottom, and a width 212 of 4.20 mm (i.e., the short base) on the top. The five stacked tall beads 206 may include a total thickness 292 of 40.00 mm.

[0196] Fig. 16C illustrates a SolidWorks example 294 of five stacked tall beads 296, according to aspects of the present disclosure. In some embodiments, the wide slot nozzle 110 may be used to print the tall bead 296. In some embodiments, the tall beads 296 may include a trapezoidal cross section. The tall bead 296 may include a thickness 298 (i.e., trapezoid height) of 8.00 mm, a width 300 of 5.00 mm (i.e., long base) at the bottom, and a width 302 of 3.00 mm (i.e., the short base) on the top. The five stacked tall beads 296 may include a total thickness 304 of 40.00 mm.

[0197] Fig. 16D illustrates a SolidWorks example 306 of five stacked tall beads 208, according to aspects of the present disclosure. In some embodiments, the slot nozzle 40 may bePage 35 of 4613172581V11Attorney Docket No. 2010363-0446 used to print the tall bead 308. In some embodiments, the tall beads 308 may include a barrelshaped cross section. The tall bead 308 may include a thickness 310 of 10.00 mm, a width 314 of 5.00 mm at the bottom and bottom, and a width 312 of 7.00 mm in the middle. The five stacked tall beads 308 may include a total thickness 316 of 50.00 mm.

[0198] Fig. 17A illustrates a SolidWorks example 318 of a conventional bead 190. The conventional bead 190 may include a thickness 192 of 1.50 mm, and a width 198 of 6.00 mm. The conventional bead 190 includes a solid cross section.

[0199] Fig. 17B illustrates a SolidWorks example 320 of a hollow bead 322, according to aspects of the present disclosure. In some embodiments, the D-ring nozzle 66 may be used to print the hollow bead 322. In some embodiments, the hollow bead 322 may include a D-shaped cross section. The hollow bead 322 represents an example of a cellular cross section. The hollow bead 322 may include a stem 326 at the bottom, a bowl 324, and a hollow space 334. In some embodiments, the stem 326 may include a width 328 of 12.00 mm and a thickness 330 of 1.00 mm. In some embodiments, the stem 326 and the bowl 324 may include a thickness 332 of 7.00 mm. In some embodiments, hollow beads may provide novel applications such as thermal energy storage, routing, embedded sensing, and lightweighting.

[0200] Fig. 17C illustrates a SolidWorks example 336 of a hollow bead 337, according to aspects of the present disclosure. In some embodiments, a modified D-ring nozzle may be used to print the hollow bead 337. In some embodiments, the hollow bead 337 may include a double D- shaped cross section. The tall bead 337 represents an example of a multi-cellular cross section. The hollow bead 337 may include a stem 326 at the bottom, two bowls 324, and two hollow spaces 334. In some embodiments, the stem 326 may include a width 338 of 16.00 mm and a thickness 342 of 1.00 mm. In some embodiments, the stem 326 and the bowl 324 may each include a thickness 334 of 5.00 mm.

[0201] Fig. 24 shows an example 450 of stacked hollow beads 452, 454, according to aspects of the present disclosure. In some embodiments, a D-ring nozzle 66 may be used to print the hollow beads 452, 454. In some embodiments, a hollow bead 452 may include a D-shaped cross section where the stem 326 is at the bottom of the hollow bead 452, and a bowl 324 faces the next hollow bead 454. The D-shaped cross section of a hollow bead 452 may be formed when the D-ring nozzle 66 deposits material on a planar surface. In some embodiments, a hollow beadPage 36 of 4613172581V11Attorney Docket No. 2010363-0446454 may include scallops 456. A scallop 456 may form due to an interlayer adhesion between the substrate (i.e., first) layer and the current (i.e., second) layer, resulting in weak interlayer bonding. In some embodiments, a stack of hollow beads including perfect D-shaped cross sections may be achieved by maximizing physical contact between layers (i.e., beads).Heated / Chilled Nozzle

[0202] According to aspects of the present disclosure, nozzles with heating and cooling functionality may be used to selectively heat and / or cool the extrudate as it is being discharged from the nozzle. Fig. 20A shows an example 364 of a conventional nozzle 366. The conventional nozzle 366 includes a heater 368. The heater 368 is a single heating band that heats the entire conventional nozzle 366. The extended discharge duration of an extrudate from the conventional nozzle 366 may result in extrudate temperature remaining above thermal degradation threshold.

[0203] Fig. 20B shows an example 370 of a heated / chilled nozzle 372, according to aspects of the present disclosure. In some embodiments, the heated / chilled nozzle 372 may include a non- axisymmetric slot nozzle. In some embodiments, the heated / chilled nozzle 372 may include a heater 374, a heater 376, and a cooler 378. An extrudate passing through the heated / chilled nozzle 372 may be heated by the heater 372, and cooled down by the cooler 378, and further reheated by the heater 376. In some embodiments, the cooler 378 may enable localized rapid cooling of the extrudate. The heated / chilled nozzle 372 may allow the effective use of materials with a broad range of melt temperatures before reaching the machine limits.

[0204] According to aspects of the present disclosure, extrudate micro-structure and mesostructure parameters / characteristics such as bead geometry, surface roughness, fiber orientation, fiber distribution, porosity, and / or heat transfer characteristics may be selectively and preferentially controlled using custom extrusion dies including internal threading, internal bends, internal conical portions, and / or various extrusion orifice geometries, in connection with tool head feed rate, extrudate heating, extrudate cooling, nozzle orientation, volumetric flow rate and / or specific material systems.EQUIVALENTSPage 37 of 4613172581V11Attorney Docket No. 2010363-0446

[0205] Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the disclosure described herein. Therefore, the scope of the present disclosure is not intended to be limited to the above Description.Page 38 of 4613172581V11

Claims

Attorney Docket No. 2010363-0446CLAIMSWhat is claimed:

1. A non-axisymmetric nozzle comprising: a body comprising an at least partially hollow interior; an inlet disposed at a first end of the body; and a non-axisymmetric outlet disposed at a second end of the body, wherein the inlet and the non-axisymmetric outlet are fluidly coupled.

2. The nozzle of claim 1, wherein the nozzle comprises a wedge configuration comprising a decreasing cross-sectional area from the inlet to a throat portion.

3. The nozzle of claim 2, further comprising an increasing cross-sectional area from the throat portion to the non-axisymmetric outlet (i.e., extrusion orifice).

4. The nozzle of claim 2, wherein the throat portion comprises a minimum cross-sectional area of the nozzle.

5. The nozzle of claim 2, wherein the throat portion is disposed downstream of the inlet and upstream of the non-axisymmetric outlet.

6. The nozzle of claim 2, further comprising at least one internal feature disposed upstream of the throat portion and downstream of the inlet.

7. The nozzle of claim 2, further comprising a bend portion disposed downstream of the throat portion and upstream of the non-axisymmetric outlet, the bend portion changing thePage 39 of 4613172581V11Attorney Docket No. 2010363-0446 orientation of the nozzle interior by a fixed angle (i.e., the bend portion changing the direction of travel of extrudate flowing therethrough by a fixed angle).

8. The nozzle of claim 7, wherein the fixed angle comprises an angle in a range from 80 degrees and 100 degrees.

9. The nozzle of claim 2, further comprising: at least one heater, and / or at least one cooler.

10. The nozzle of claim 9, wherein the at least one heater is placed on the non-axisymmetric outlet.

11. The nozzle of claim 9, wherein the at least one cooler is placed on the non-axisymmetric outlet.

12. An extruded bead made from a non-axisymmetric extrusion process, the extruded bead comprising: a composite material comprising: a matrix component; and a fiber component, wherein each of the matrix component and the fiber component comprises an associated distribution and orientation, and wherein the distribution and orientation of each of the matrix component and the fiber component is prescribed by the non-axisymmetric extrusion process.Page 40 of 4613172581V11Attorney Docket No. 2010363-044613. The extruded bead of claim 12, comprising: a bead height defined in a direction orthogonal to a surface upon which the bead is extruded; a bead length defined in a direction aligned with a direction of extrusion; and a bead width defined in a direction orthogonal to both the bead height and the bead length, wherein the bead height is greater than the bead width.

14. The extruded bead of claim 13, further comprising a first cross section defined within a plane that incorporates the bead height and the bead length.

15. The extruded bead of claim 14, wherein the first cross section comprises a trapezoidal shape.

16. The extruded bead of claim 14, wherein the first cross section comprises a T shape.

17. The extruded bead of claim 14, wherein the first cross section comprises a triangle shape.

18. The extruded bead of claim 14, wherein the first cross section comprises a D shape.

19. The extruded bead of claim 13, wherein the fiber component comprises fiber strands that substantially extend in the directions of the bead height and the bead width, but not the bead length.

20. The extruded bead of claim 13, comprising an aspect ratio of the bead height to the bead width is at least 3: 1.Page 41 of 4613172581V11Attorney Docket No. 2010363-044621. A nozzle assembly comprising: an extruder interface; a rotary union coupled to the extruder interface at a first end of the rotary union; a rotary drive gear coupled to a second end of the rotary union, the rotary union enabling independent rotational movement of the rotary drive gear relative to the extruder interface; and a non-axisymmetric nozzle coupled to the rotary drive gear such that it rotates therewith.

22. The assembly of claim 21, wherein the extruder comprises a threaded or clamped adaptor configured to be coupled to the rotary union.

23. The assembly of claim 21, further comprising a fluid channel disposed through each of the extruder interface, threaded or clamped adaptor, the rotary union, the rotary drive gear, and the non-axisymmetric nozzle.

24. A system comprising the assembly of claim 23, the system comprising an external drive gear operatively coupled to the rotary drive gear for selectively adjusting an orientation of the non-axisymmetric nozzle.

25. The system of claim 24, wherein, in operation, the extruder interface, threaded or clamped adaptor, and first end of the rotary union rotate continuously in a single direction, and at a substantially constant rate, thereby forming a first unitary sub-assembly, and wherein, in operation, the rotary drive gear, non-axisymmetric nozzle, and second end of the rotary union are selectively rotated, by the external drive gear at a second substantially constant rate, thereby forming a second unitary sub-assembly.Page 42 of 4613172581V11Attorney Docket No. 2010363-044626. A method of using the system of claim 25, comprising using the system for at least one of an additive manufacturing process and an extrusion process.

27. The method of claim 26, comprising using the system for fused filament fabrication (FFF).

28. A manufacturing method comprising: providing a nozzle assembly comprising at least an extrusion interface and a non- axisymmetric nozzle configured to selectively rotate independent of a rotation of the extrusion interface, the non-axisymmetric nozzle comprising a non-axisymmetric orifice configured to discharge extrudate therethrough; and discharging extrudate through the non-axisymmetric nozzle layer by layer, thereby forming at least one extrudate layer.

29. The method of claim 28, further comprising: heating the extrudate prior to discharging extrudate through the non-axisymmetric nozzle, and cooling the extrudate as it passes through the non-axisymmetric nozzle during discharging.

30. The extruded bead of claim 12, wherein the extruded bead is composed at least partially of at least one of wood-fiber reinforced polylactic acid (WF-PLA) and carbon fiber reinforced acrylonitrile butadiene styrene (CF-ABS).

31. The extruded bead of claim 12, wherein the extruded bead is composed at least partially of at least one of a polymer material and a filler material.Page 43 of 4613172581V11Attorney Docket No. 2010363-044632. The extruded bead of claim 12, wherein the extruded bead is composed at least partially of polyethylene terephthalate glycol (PETG).

33. The nozzle of claim 1, wherein the non-axi symmetric outlet comprises a non- axisymmetric extrusion orifice comprising: a first partial cross-section oriented in a direction aligned with a surface upon which the extrudate is discharged; and a second partial cross-section oriented in a direction orthogonal to a direction of extrusion, wherein, the first partial cross-section and the second partial cross-section form a single orifice.

34. The nozzle of claim 33, wherein the first partial cross-section comprises an incomplete circle and the second partial cross-section comprises a slot.

35. The nozzle of claim 34, wherein a diameter of the incomplete circle is equal to the width of the slot.

36. The nozzle of claim 34, wherein a diameter of the incomplete circle is larger than the width of the slot.

37. The nozzle of claim 33, wherein the first partial cross-section comprises an incomplete rectangle and the second partial cross-section comprises a slot.

38. The nozzle of claim 33, wherein the first partial cross-section comprises an incomplete circle and the second partial cross-section comprises a triangle.Page 44 of 4613172581V11Attorney Docket No. 2010363-044639. The nozzle of claim 33, wherein the first partial cross-section comprises two slits and the second partial cross-section comprises a D-ring.

40. The nozzle of claim 1, wherein the non-axi symmetric outlet comprises a non- axisymmetric extrusion orifice, the non-axisymmetric extrusion orifice defined by a periphery arranged in more than one geometric plane.

41. The nozzle of claim 1, wherein the non-axisymmetric outlet comprises a non- axisymmetric extrusion orifice comprising at least one linear edge.

42. The nozzle of claim 1, wherein the non-axisymmetric outlet comprises a non- axisymmetric extrusion orifice comprising at least one curved edge.

43. The nozzle of claim 6, wherein the at least one internal feature comprises a threaded portion.

44. The extruded bead of claim 31, wherein the filler material comprises at least one of carbon fiber, glass fiber, and wood flour.

45. The extruded bead of claim 31, wherein the filler material comprises an isotropic material.Page 45 of 4613172581V11

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