CN113905872A - System for additive manufacturing of composite structures - Google Patents

Abstract

An additive manufacturing system (10) for manufacturing a structure (12) is disclosed. The additive manufacturing system may include a support (14) and a printhead (16) configured to eject material (R + M) and operatively connected to and movable by the support in a normal direction of travel (34) during material ejection. The printhead may include a module (22) located on a backside of the ejected material relative to the normal direction of travel and configured to compact the material and expose the material to curing energy at a Tool Center Point (TCP).

Description

System for additive manufacturing of composite structures

RELATED APPLICATIONS

The present application is based on and claims priority from patent applications 62/853,610 and 62/981,515 filed on, respectively, 2019, 28, 5 and 2020, 25, the entire contents of which are expressly incorporated herein by reference. This application is also filed as part of us non-provisional application 16/516,113 filed on 7/18/2019, the contents of which are expressly incorporated herein by reference.

Technical Field

The present disclosure relates generally to a manufacturing system, and more particularly to a system for additive manufacturing of composite structures.

Background

Continuous fiber 3D printing (aka

) To the use of continuous fibers embedded in a matrix that are discharged from a movable print head. The matrix may be a conventional thermoplastic, a powdered metal, a liquid resin (e.g., a UV curable and/or two part resin), or a combination of any of these and other known matrices. Upon exiting the print head, a head-mounted curing promoter (e.g., UV light, ultrasonic emitters, heat source, catalyst supply, etc.) is activated to initiate and/or complete curing of the substrate. This curing occurs almost immediately, allowing for the fabrication of unsupported structures in free space. When fibers, particularly continuous fibers, are embedded within a structure, the strength of the structure may be multiplied over the matrix related strength. An example of this technique is disclosed in U.S. patent 9,511,543 ("the' 543 patent") issued to Tyler at 12, 6, 2016.

Although it is not limited to

Provides greater strength, but may provide improvements in the construction and/or operation of existing systems as compared to manufacturing processes that do not use continuous fiber reinforcement. For example, applicants have found that better control over the compaction and curing of the reinforcement can improve the placement, strength, and accuracy of the reinforcement. The disclosed additive manufacturing system is uniquely configured to provide these improvements and/or address other problems of the prior art.

Disclosure of Invention

In one aspect, the present disclosure is directed to an additive manufacturing system. The additive manufacturing system may include a support and a printhead configured to eject material and operably connected to the support and movable by the support in a normal direction of travel during material ejection. The printhead may include a module located on a backside of the ejected material relative to the normal direction of travel and configured to compact the material and expose the material to curing energy at a center point of the tool.

In another aspect, the present disclosure is directed to another additive manufacturing system. Such an additive manufacturing system may include a support and a printhead configured to eject material and operably connected to the support and movable by the support in a normal direction of travel during material ejection. The printhead may include an outer cover located on a backside of the discharged material relative to the normal direction of travel and configured to roll over the material, and a source configured to direct curing energy radially outward through the outer cover.

In yet another aspect, the present disclosure is directed to a method of additive manufacturing a structure. The method can include discharging the substrate-wetted continuous reinforcement through an outlet of the printhead, and pressing the die against the substrate-wetted continuous reinforcement after the discharging to compress the substrate-wetted continuous reinforcement. The method may further include directing curing energy radially outward through the module to the continuous reinforcement members being wetted by the matrix being compressed.

Drawings

FIG. 1 is a diagrammatical illustration of an exemplary disclosed additive manufacturing system;

FIGS. 2, 3 and 4 are isometric, diagrammatic and cross-sectional illustrations, respectively, of an exemplary disclosed portion of the system of FIG. 1; and is

Fig. 5 and 6 are cross-sectional illustrations of other exemplary disclosed portions of the system of fig. 1.

Detailed Description

FIG. 1 illustrates an exemplary system 10 that may be used to fabricate a composite structure 12 having any desired shape. The system 10 may include a support 14 and a deposition head ("head") 16. The head 16 may be coupled to and moved by the support 14. In the disclosed embodiment of fig. 1, support 14 is a robotic arm capable of moving head 16 in multiple directions during manufacture of structure 12. The support 14 may alternatively embody a gantry (e.g., a viaduct or a uni-post gantry) or a hybrid gantry/arm that is also capable of moving the head 16 in multiple directions during manufacture of the structure 12. Although support 14 is shown as being capable of 6-axis movement relative to structure 12, it is contemplated that support 14 may move head 16 in different manners (e.g., along and/or about a greater or lesser number of axes). It is also contemplated that structure 12 may be associated with one or more axes of movement and configured to move independently of and/or in unison with support 14. In some embodiments, the driver may mechanically couple the head 16 to the support 14 and include components that cooperate to move a portion of the head 16 and/or supply power or material to the head.

The head 16 may be configured to receive or otherwise contain a substrate (shown as M). The matrix may include any type or combination of materials that are curable (e.g., liquid resins, such as zero volatile organic compound resins, powdered metals, etc.). Exemplary resins include thermosetting resins, one-part or multi-part epoxy resins, polyester resins, cationic epoxy resins, acrylated epoxy resins, urethanes, esters, thermoplastics, photopolymers, polyepoxides, thiols, olefins, thiol-enes, and the like. In one embodiment, the substrate within the head 16 may be pressurized (e.g., positive and/or negative) such as by an external device fluidly connected to the head 16 via a corresponding conduit (not shown) (e.g., by an extruder, pump, etc. -not shown). However, in another embodiment, the pressure may be generated entirely within the head 16 by a similar type of device. In yet another embodiment, the substrate may be gravity fed into and/or through the head 16. For example, the matrix can be fed into the head 16 and pushed or pulled out of the head 16 along with one or more continuous reinforcement members (shown as R). In some cases, it may be desirable to keep the matrix inside the head 16 cool and/or dark in order to prevent premature curing or otherwise obtain a desired rate of curing after ejection. In other cases, it may be desirable to keep the substrate warm and/or illuminated for similar reasons. In either case, the head 16 may be specially configured (e.g., insulated, temperature controlled, shielded, etc.) to provide these requirements.

The matrix may be used to at least partially coat any number of continuous reinforcements (e.g., individual fibers, tows, rovings, socks, and/or continuous pieces of material) and, along with the reinforcements, form a portion (e.g., a wall) of the composite structure 12. The reinforcement members may be stored within or otherwise pass through the head 16. When multiple reinforcement members are used simultaneously, the reinforcement members can have the same material composition and have the same size and cross-sectional shape (e.g., circular, square, rectangular, etc.), or different material compositions having different sizes and/or cross-sectional shapes. The reinforcement may include, for example, carbon fibers, plant fibers, wood fibers, mineral fibers, glass fibers, plastic fibers, metal fibers, optical fibers (e.g., tubes), and the like. It should be noted that the term "reinforcement" is meant to include both structural and non-structural (e.g., functional) types of continuous material that is at least partially encapsulated in the matrix that is discharged from head 16.

The reinforcement members may be at least partially coated with the matrix when the reinforcement members are inside the head 16, when the reinforcement members are transferred to the head 16, and/or when the reinforcement members are expelled from the head 16. The matrix, the dry (e.g., non-impregnated) reinforcement, and/or the reinforcement that has been exposed to the matrix (e.g., pre-impregnated reinforcement) may be delivered into the head 16 in any manner apparent to those skilled in the art. In some embodiments, filler materials (e.g., chopped fibers, nanoparticles or tubes, etc.) and/or additives (e.g., thermal initiators, UV initiators, etc.) may be mixed with the matrix before and/or after the matrix is coated with the continuous reinforcement.

One or more curing promoters (e.g., UV light, ultrasonic emitters, lasers, heaters, catalyst dispensers, etc.) 18 may be mounted adjacent to (e.g., within, on, and/or adjacent to) the head 16 and configured to increase the curing rate and/or quality of the substrate when discharged from the head 16. The cure facilitator 18 can be controlled to selectively expose portions of the structure 12 to energy (e.g., UV light, electromagnetic radiation, vibration, heat, chemical catalysts, etc.) during material expulsion and formation of the structure 12. The energy may trigger a chemical reaction to occur within the matrix, increase the rate of the chemical reaction, sinter the matrix, harden the matrix, cure the matrix, polymerize the matrix, or otherwise cause the matrix to solidify as it is expelled from the head 16. The amount of energy generated by the cure facilitator 18 may be sufficient to cure the matrix before the structure 12 grows axially from the head 16 beyond a predetermined length. In one embodiment, the structure 12 is at least partially (e.g., fully) cured before the axial growth length becomes equal to the outer diameter of the matrix-coated reinforcement.

The matrix and/or reinforcement members may be expelled together from head 16 via any number of different modes of operation. In a first example mode of operation, the matrix and/or reinforcement is extruded (e.g., pushed under pressure and/or mechanical force) from head 16 as head 16 is moved by support 14 to form features of structure 12. In a second example mode of operation, the reinforcement is pulled at least from the head 16 such that tensile stresses are created in the reinforcement during venting. In this second mode of operation, the matrix can be pressed against the reinforcement so as to also be pulled out of the head 16 with the reinforcement, and/or the matrix can be expelled from the head 16 under pressure with the reinforcement being pulled out. In a second mode of operation, with the reinforcement pulled out of the head 16, the tension created in the reinforcement after curing the matrix may increase the strength of the structure 12 (e.g., by aligning the reinforcement, preventing buckling, uniformly loading the reinforcement, etc.), while also allowing for a straighter trajectory for a greater length of unsupported structure 12. That is, the tension in the reinforcement remaining after curing of the matrix may resist gravity (e.g., directly and/or indirectly by creating a counter-gravity moment) to provide support to the structure 12.

As the head 16 is moved away from the anchor point (e.g., print bed, existing surface of the structure 12, fixture, etc.) by the support 14, the reinforcement members can be pulled from the head 16. For example, at the beginning of structure formation, a length of matrix-impregnated reinforcement may be pulled and/or pushed from head 16, deposited onto the anchor point, and at least partially cured such that the expelled material adheres (or otherwise couples) to the anchor point. Thereafter, the head 16 may be moved away from the anchoring point, and the relative movement may cause the reinforcement to be pulled out of the head 16. As will be explained in more detail below, movement of the reinforcement members through the head 16 can be selectively assisted, if desired, via one or more internal feed mechanisms. However, the rate of expulsion of the reinforcement from the head 16 may be primarily a result of the relative movement between the head 16 and the anchor point, thereby creating tension within the reinforcement. As described above, the anchor point may be moved away from the head 16 instead of or in addition to the head 16 being moved away from the anchor point.

The head 16 may include, among other things, an outlet 22 and a substrate reservoir 24 located upstream of the outlet 22. In one example, the outlet 22 is a single-pass outlet configured to discharge composite material having a generally circular, tubular, or rectangular cross-section. However, the configuration of the head 16 may allow for the exchange of the outlet 22 for another outlet that discharges multiple channels of composite material having the same or different shapes (e.g., flat or sheet-like cross-section, multi-track cross-section, etc.). The fibers, tubes, and/or other reinforcement members may pass through the matrix reservoir 24 (e.g., through one or more internal wetting mechanisms 26 located inside the reservoir 24) and be wetted (e.g., at least partially coated, encapsulated, and/or fully saturated) by the matrix prior to discharge.

The outlet 22 may take different forms. In one example, a guide or nozzle 30 is located downstream of the wetting mechanism 26, and a compactor 32 is behind the nozzle 30 (e.g., during material discharge, relative to a normal direction of travel of the head 16, as indicated by arrow 34). It is contemplated that either the nozzle 30 or the compactor 32 may be used as a Tool Center Point (TCP) for the head 16 to affix the matrix wetting reinforcement at a desired location prior to and/or during curing when exposed to the energy of the curing promoter 18. In some embodiments, it is also contemplated that nozzle 30 may be omitted. Finally, it is contemplated that the TCP of the head 16 may not necessarily be associated with the nozzle 30 or the compactor 32, but may actually be a separate location from these locations where the curing energy is exposed. TCP may also switch locations in some applications.

One or more controllers 28 may be provided and communicatively coupled with support 14 and head 16. Each controller 28 may be embodied as a single processor or multiple processors programmed and/or otherwise configured to control the operation of system 10. The controller 28 may include one or more general or special purpose processors or microprocessors. The controller 28 may also include or be associated with a memory for storing data such as design limits, performance characteristics, operating instructions, tool paths, and corresponding parameters for each component of the system 10. Various other known circuits may be associated with controller 28, including power supply circuitry, signal-conditioning circuitry, solenoid driver circuitry, communication circuitry, and other appropriate circuitry. Moreover, the controller 28 can communicate with other components of the system 10 via wired and/or wireless transmissions.

One or more maps may be stored within the memory of controller 28 and used during the manufacture of structure 12. Each of these maps may include a collection of data in the form of look-up tables, graphs, and/or equations. In the disclosed embodiment, the controller 28 may use these maps to determine the movements of the head 16 required to produce the desired geometry (e.g., size, shape, material composition, performance parameters, and/or profile) of the structure 12, as well as to adjust the operation of the cure promoter 18 and/or other associated components in coordination with the movements.

As shown in fig. 2, 3, and 4, the curing facilitator 18 and the compactor 32 may be integrated into a module 54 that is capable of performing both curing and compacting functions. As shown in these figures, the module 54 may be an independent assembly of multiple components including, among other things, a shaft 164 rotatably mounted to the remainder of the head 16 via spaced bearings 166, a source 168 configured to direct curing energy (e.g., light) into the shaft 164, a distributor 170 positioned about the shaft 164, and one or more covers (e.g., an inner compliant cover 172 and/or an outer protective cover 174) mounted on the distributor 170 that provide a compaction force against the discharged material. Energy directed axially into shaft 164 may be dispersed, concentrated, and/or redirected radially outward by optics (e.g., baffles, lenses, mirrors, polished bores or end walls, etc.) 176 located at an inner end of shaft 164 and one or more radial passages 177 (shown only in fig. 4) formed within shaft 164. Energy may pass through one or more axially extending circumferential slots 178 of the distributor 170 and then through an associated shroud that is at least partially transparent (e.g., about 70-100% transparent) to energy (e.g., optical energy at a wavelength of about 350 and 450nm, such as a wavelength of about 405 nm). In some embodiments, one or more of the slots 178 may be fitted with transparent spacers 180 that help support the cover. In some embodiments, the spacer 180 itself may be an optic whose function is to concentrate, amplify, disperse, and/or aim energy from the source 168.

In some applications, the module 54 (e.g., the outer surface of the cover 174) may form a TCP of the head 16. In these applications, the head 16 may be nozzleless. Thus, the TCP of the head 16 may correspond to an axially-oriented line of contact between the outer surface of the cover 174 and the active surface of the structure 12 (e.g., where the module 54 pushes the wetting enhancements onto the surface). It should be noted that the contact line may be displaced, for example when the head 16 is tilted by the support 14 (see fig. 1) with respect to the printing surface and/or with respect to the direction of travel (e.g. if printing to free space).

In one embodiment, the outer cover 174 may be manufactured from a low friction material (e.g., polytetrafluoroethylene-PTFE, fluorinated ethylene propylene-FEP, etc.). In one example, FEP may be used for the outer cover 174 due to its higher transparency compared to PTFE.

The compliance of the inner cover 172 may allow for sufficient engagement and compression forces on the reinforcement members without the need for very precise positioning of the modules 54. The compliance of the inner cover 172 may also create a flat spot at the area of engagement with the structure 12 (see fig. 6). This flat spot can help the matrix wetting reinforcement to detach from the module 54 and adhere only to the structure 12, and also help the reinforcement to lie more flat against the bottom layer of the structure 12. In addition, the compliance of the inner cover 172 may allow a cutting device (described in more detail below with reference to fig. 5 and 6) to advance a distance in the module 54, thereby improving severing performance. Since the outer cover 174 is engaged with the cutting device, it may be necessary to periodically replace the outer cover. In one embodiment, the inner cover 172 may have a hardness of about 20-50 shore a (e.g., about 40 shore a), and the outer cover 174 may have a greater hardness (e.g., at least 5-10% greater than the hardness of the inner cover 172) to increase the life during cutting. The thickness of the outer cover 174 may be less than the thickness of the inner cover 172 such that the compliance of the inner cover 172 may be effective until the harder outer cover 174. For example, the outer cover 174 may be approximately 1/5-1/25 of the thickness of the inner cover 172. In some embodiments, the outer cover 174 may have less friction than the inner cover 172, helping to prevent the matrix wetting reinforcement from undesirably sticking to the module 54.

Because energy can be directed through the module 54 to the matrix-wetting reinforcement, curing at the TCP (e.g., just before, just above, and/or just after the TCP) is possible. It is envisaged that sufficient curing may occur to tack the reinforcement before minimal movement of the reinforcement away from the TCP location (if present) has occurred. This may improve the placement accuracy of the reinforcement. It is also contemplated that the matrix may be cured only at the outer surface (e.g., sufficient to stick and/or retain the desired shape) or the matrix may be fully cured by exposure only to energy from source 168 (with or without any additional external environmental exposure). In the former case, additional energy exposure (e.g., oven baking, autoclave heating, etc.) may be required after completion of the structure 12.

In one embodiment, the geometry of the distributor 170 may be selected to concentrate energy from the source 168 only at the TCP (i.e., in conjunction with the location and orientation of the radial passage 177). For example, the geometry may allow energy from source 168 to pass through only one slot 178 located closest to (e.g., at) TCP, while preventing energy from passing through other slots 178 further away from TCP at a given time. A thicker walled dispenser with a narrower slot 178 may produce a more concentrated exposure area. In the disclosed example, the axial length of the slots 178 may be about 0-2 times the width of the reinforcement members passing through the distributor 170.

Fig. 5 and 6 show another module 200 that integrates, among other things, curing and compacting functions. Similar to the module 54 of fig. 2-4, the module 200 of fig. 5 and 6 includes a shaft 164 rotatably connected to the remainder of the head 16 via a bearing 166, and a source 168 that directs curing energy (e.g., energy from a UV light, laser, or other curing energy source 202) axially into the shaft 164. Energy may be redirected via optics 176 and passageways 177 at the inner end of shaft 164 to TCP passing radially outward through inner cover 172 and outer cover 174 to head 16. In one embodiment, the TCP is located at the axial center of the distributor 170 (shown in fig. 5). However, it is contemplated that the TCP may be positioned closer to the end of the distributor 170, if desired.

Similar to module 54, module 200 may be configured to prevent energy dissipation and loss as energy passes radially outward through inner cover 172 and outer cover 174. However, the module 200 may do so without the use of the distributor 170, the slots 178, and the spacers 180. Alternatively, the inner cover 172 and/or the outer cover 174 of the module 200 may be segmented via one or more dividers 184. The dividers 184 may be generally planar, arranged at regular intervals from one another, and oriented by the axis of the compaction device 150. The divider 184 may extend radially inward through the outer and inner covers 174, 172 but terminate near or at the axis 164. The divider 184 may be made of a material configured to block or reflect energy from the source 168 to the TCP or otherwise coated, colored, or poured. Any number of dividers 184 can be utilized to create as many separate energy transmission channels as desired (e.g., arcuate segments between adjacent dividers 184). In some embodiments, in addition to divider 184, it is contemplated that one or more dividers 186 in a plane generally orthogonal to the axis of shaft 164 or oriented at an oblique angle relative to the axis may be used to further concentrate energy from source 168 (e.g., direct energy axially toward the TCP). In some applications, the spacing between dividers 184 and/or 186 may be adjusted during material ejection to selectively vary and concentrate the cure path parameters.

Fig. 6 also shows the module 200 as having additional cutting functionality. For example, in some embodiments, the cutting mechanism 188 may be incorporated into the module 200. The cutting mechanism 188 may include components that cooperate to grip, cut, and/or feed the reinforcement members during and/or after a printing operation. These components may include, among other things, a rod 190 pivotably mounted to the shaft 164 at opposite axial ends, a blade 192 affixed to an outer track 194 of the rod 190, and one or more actuators (e.g., linear actuators at each end of the shaft 164) 196 configured to selectively extend and retract the outer track 194 in a radial direction.

During operation, the reinforcement members may be expelled through the nozzle 30 and at least partially wrap the outer cover 174 of the module 200 and reach the nip point at the TCP. The curing energy may be transferred axially into the compaction module 200 and then redirected radially outward to cure the matrix coating the reinforcement at the TCP. When it is desired to shut off the reinforcement members (e.g., at the end of the printing process), the actuator 196 may be energized by the controller 28 (see FIG. 1) to retract the rods 190 radially inward. This action may cause the reinforcement to be sandwiched between the outer rail 194 and the outer cover 174, thereby clamping the reinforcement in the position shown in fig. 6. During retraction and clamping of the rod 190, the blades 192 may be forced through the reinforcement members and against the outer cover 174, thereby severing the reinforcement members.

The bar 190 may remain in the clamped position during the start of the next printing process and rotate with it due to its engagement with the outer cover 174 of the module 200. This rotation may be used to pull the reinforcement out of the head 16 (e.g., out through the nozzle 30, ready for printing) and continue until the outer rail 194 reaches the TCP, at which point the lever 190 may be pushed and/or released to move back radially outward, allowing the rail 194 to rotate back to the exit of the nozzle 30. It is contemplated that return of the track 194 may be facilitated by another actuator (not shown) and/or a spring 198 as desired. By this arrangement, not only is clamping and cutting of the reinforcement provided, but guiding of the severed reinforcement to the TCP is also facilitated.

INDUSTRIAL APPLICABILITY

The disclosed system can be used to fabricate composite structures having any desired cross-sectional shape and length. The composite structure may include any number of different fibers of the same or different types, the same or different diameters, and any number of different matrices of the same or different compositions. The operation of the system 10 will now be described in detail.

At the beginning of a manufacturing event, information regarding the desired structure 12 may be loaded into the system 10 (e.g., into a controller 28 responsible for regulating the operation of the support 14 and/or the head 16). This information may include, among other things, size (e.g., diameter, wall thickness, length, etc.), profile (e.g., trajectory, surface normal, etc.), surface features (e.g., ridge size, location, thickness, length; flange size, location, thickness, length, etc.), connection geometry (e.g., location and size of couplings, tees, joints, etc.), selection of reinforcement, selection of matrix, ejection location, cutting location, curing gauge, compaction gauge, etc. It should be noted that this information may alternatively or additionally be loaded into system 10 at different times and/or continuously during a manufacturing event, if desired. Based on the component information, one or more different reinforcement and/or matrix materials may be installed and/or continuously supplied into the system 10.

To install the reinforcement, individual fibers, tows, and/or ribbons can be passed through the matrix reservoir 24 and outlet 22 (e.g., through features of the nozzle 30 and under the compactor 32). In some embodiments, the reinforcement may also need to be connected to a tensile machine (not shown) and/or to a mounting fixture (e.g., to an anchor point). Installation of the matrix material may include filling the head 16 (e.g., the wetting mechanism 26 of the reservoir 24) and/or coupling an extruder (not shown) to the head 16.

The component information may then be used to control the operation of the system 10. For example, when support 14 is selectively moved (e.g., based on known kinematics of support 14 and/or known geometry of structure 12), the in situ wetted reinforcement can be pulled and/or pushed from outlet 22 of head 16 such that the resulting structure 12 is manufactured as desired.

The operating parameters of the support 14, the cure facilitator 18, the compactor 32, the modules 54 and/or 200, and/or other components of the system 10 may be adjusted in real-time during material discharge to provide a desired adhesion, strength, tension, geometry, and other characteristics of the structure 12. Once the structure 12 has grown to a desired length, the structure 12 may be severed from the system 10.

It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed system. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the disclosed system. For example, while the components of the system 10 (e.g., the dispenser 170, the covers 172 and 174, the spacer 180, the partitions 184 and 186, etc.) have been described and illustrated as separate components, it is contemplated that two or more components of the system 10 may alternatively be integrated, if desired. It is intended that the specification and examples be considered as exemplary only, with a true scope being indicated by the following claims and their equivalents.

Claims (15)

1. An additive manufacturing system (10), comprising:

a support (14); and

a print head (16) configured to eject material (R + M) and operatively connected to and movable by the support in a normal direction of travel (34) during material ejection,

wherein the print head comprises a module (22) located at a rear side of the discharged material with respect to the normal direction of travel and configured to compact the material and expose the material to curing energy at a Tool Center Point (TCP).

2. The additive manufacturing system of claim 1, wherein the module comprises:

an outer cover (174) configured to roll over the material during compaction; and

a source (168) configured to direct the curing energy radially outward through the outer cover.

3. The additive manufacturing system of claim 2, wherein:

the module comprises a shaft (164) on which the outer cover is mounted; and is

The source is configured to direct the curing energy axially into the shaft and then radially outward through the outer cover via a passage (177) in the shaft.

4. The additive manufacturing system of claim 3, further comprising optics (176) mounted inside the shaft and configured to redirect curing energy directed axially into the shaft radially outward.

5. The additive manufacturing system of claim 3, further comprising a slotted dispenser (170) disposed between the shaft and the outer cover.

6. The additive manufacturing system of claim 5, wherein:

the slotted distributor includes a plurality of axially oriented slots (178); and is

The module also includes a spacer (180) through which the curing energy disposed within each of the plurality of axially oriented slots is at least partially permeable.

7. The additive manufacturing system of claim 5, further comprising an inner cover (172) disposed between the slotted dispenser and the outer cover, wherein the inner cover is more compliant than the outer cover.

8. The additive manufacturing system of claim 7, wherein each of the inner cover and the outer cover is at least partially transparent.

9. The additive manufacturing system of claim 1, wherein the module is rotatably connected to a remainder of the printhead via at least one bearing.

10. The additive manufacturing system of claim 1, further comprising at least one divider (184) aligned with an axis of the module and configured to concentrate the curing energy to an arcuate segment of the module.

11. The additive manufacturing system of claim 10, further comprising at least one divider (186) extending radially outward through the module and configured to concentrate the curing energy in an axial direction of the module.

12. The additive manufacturing system of claim 1, wherein the module comprises:

an outer cover (174) configured to roll over the material during compaction;

an arm (190) extending radially outward beyond the outer cover;

a rod (194) connected to the distal end of the arm and extending in an axial direction of the module; and

an actuator (196) connected to the arm and configured to selectively pull the rod radially inward relative to the outer cover.

13. The additive manufacturing system of claim 12, further comprising a cutting device (192) operably connected to the rod.

14. A method of additive manufacturing a structure (12), comprising:

discharging the continuous reinforcement (R + M) wetted by the substrate through an outlet (30) of the print head (16);

pressing a die block (22) against the matrix-wetted continuous reinforcement after ejection to compress the matrix-wetted continuous reinforcement; and

curing energy is directed radially outward through the module to the continuous reinforcement members wetted by the matrix being compressed.

15. The method of claim 14, further comprising concentrating the curing energy at a Tool Center Point (TCP) of the printhead at least one of axially and radially.

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