JP2022534864A - System for additive manufacturing of composite structures - Google Patents

Abstract

An additive manufacturing system (10) is disclosed for use in manufacturing a structure (12). The additive manufacturing system is configured to dispense material (R+M) with a support (14), is operably connected to the support, and is movable by the support in a vertical direction of travel (34) during material dispensing. and a printhead (16) that is The printhead includes a module (22) positioned on the trailing side of the ejected material with respect to the direction of vertical movement and configured to compress the material and expose the material to curing energy at the tool center point (TCP). obtain. [Selection drawing] Fig. 1

Description

RELATED APPLICATIONS This application is based on and claims priority benefit from 62/853,610 and 62/981,515, filed May 28, 2019 and February 25, 2020, respectively, and all the contents of which are expressly incorporated herein by reference. This application is also a continuation-in-part of U.S. Nonprovisional Patent Application No. 16/516,113, filed July 18, 2019, the contents of which are expressly incorporated herein by reference.

TECHNICAL FIELD The present disclosure relates generally to manufacturing systems and, more particularly, to systems for additively manufacturing composite structures.

Continuous fiber 3D printing (aka CF3D®) involves the use of continuous fibers embedded within a matrix ejected from a moving printhead. The matrix can be conventional thermoplastics, powdered metals, liquid resins (eg, UV curable and/or two-component resins), or combinations of any of these and other known matrixes. Upon exiting the printhead, head-mounted curing enhancers (eg, UV light, ultrasonic emitters, heat sources, catalyst supplies, etc.) are activated to initiate and/or complete curing of the base material. This curing occurs almost instantly, allowing unsupported structures to be manufactured in free space. When fibers, especially continuous fibers, are embedded within the structure, the strength of the structure can be doubled beyond that dependent on the matrix material. An example of this technique is disclosed in U.S. Pat. No. 9,511,543, issued Dec. 6, 2016 to Tyler (the "'543 patent").

CF3D® provides increased strength compared to manufacturing processes that do not utilize continuous fiber reinforcement, yet can provide improvements in the structure and/or operation of existing systems. For example, Applicants have discovered that better control over compression and stiffening of the stiffeners can improve placement, strength, and accuracy of the stiffeners. The disclosed additive manufacturing system is uniquely configured to provide these improvements and/or to address other problems of the prior art.

In one aspect, the present disclosure relates to an additive manufacturing system. The additive manufacturing system may include a support and a printhead configured to eject material, operably connected to the support, and movable by the support in a direction of vertical movement during material ejection. The printhead may include a module positioned on the trailing side of the ejected material with respect to the direction of vertical movement and configured to compress the material and expose it to curing energy at the center point of the tool.

In another aspect, the present disclosure relates to another additive manufacturing system. The additive manufacturing system may include a support and a printhead configured to eject material, operably connected to the support, and movable by the support in a vertical direction of travel during material ejection. . The printhead had an outer cover positioned on the trailing side of the ejected material relative to the direction of vertical movement and configured to roll over the material and configured to direct curing energy radially outward through the outer cover. source.

In yet another aspect, the present disclosure relates to a method of additively manufacturing a structure. The method consists of ejecting a matrix-wet continuous reinforcement through the outlet of the printhead and compressing the matrix-wet continuous reinforcement by pressing a module against the matrix-wet continuous reinforcement after ejection. can include The method may also include directing curing energy radially outward through the module to the continuous reinforcement wetted with the matrix being compressed.

1 is a schematic diagram of an exemplary disclosed additive manufacturing system; FIG. 2, 3 and 4 are isometric, schematic and cross-sectional views, respectively, of an exemplary disclosed portion of the system of FIG. 2, 3 and 4 are isometric, schematic and cross-sectional views, respectively, of an exemplary disclosed portion of the system of FIG. 2, 3 and 4 are isometric, schematic and cross-sectional views, respectively, of an exemplary disclosed portion of the system of FIG. 2 is a cross-sectional view of another exemplary disclosed portion of the system of FIG. 1; FIG. 2 is a cross-sectional view of another exemplary disclosed portion of the system of FIG. 1; FIG.

FIG. 1 shows an exemplary system 10 that can be used to manufacture composite structures 12 having any desired shape. System 10 may include support 14 and lamination head (“head”) 16 . Head 16 is coupled to support 14 and can be moved by support 14 . In the disclosed embodiment of FIG. 1, support 14 is a robotic arm capable of moving head 16 in multiple directions during fabrication of structure 12 . Alternatively, support 14 may embody a gantry (eg, overhead bridge or single post gantry) or hybrid gantry/arm that also allows head 16 to move in multiple directions during fabrication of structure 12 . can. Although support 14 is shown as being capable of six-axis movement relative to structure 12, support 14 can be moved in different ways (e.g., along or about a greater or lesser number of axes). ), it may be possible to move the head 16 . It is also contemplated that structure 12 may be associated with another axis of motion and configured to move independently and/or in concert with support 14 . In some embodiments, a drive may mechanically couple head 16 to support 14 and cooperate to move a portion of head 16 and/or to supply power or materials to head 16. may contain components.

Head 16 may be configured to receive or otherwise contain a matrix (denoted as M). The matrix may comprise any type or combination of curable materials (eg, liquid resins such as zero volatile organic compound resins, powdered metals, etc.). Exemplary resins include thermosets, one-part or multi-part epoxies, polyester resins, cationic epoxies, acrylated epoxies, urethanes, esters, thermoplastics, photopolymers, polyepoxides, thiols, alkenes, Thiol-enes and the like are included. In one embodiment, the matrix inside the head 16 is for example external devices (eg, extruders, pumps, etc.—not shown) that are fluidly connected to the head 16 via corresponding conduits (not shown). can be pressurized (eg, positively and/or negatively) by However, in another embodiment pressure may be generated entirely inside the head 16 by a similar type of device. In still other embodiments, the preform may be gravity fed into and/or through head 16 . For example, a base material may be fed into head 16 and extruded or withdrawn from head 16 along with one or more continuous reinforcements (denoted as R). In some cases, the matrix inside the head 16 may need to be kept cool and/or dark to prevent premature curing or otherwise to obtain the desired cure rate after dispensing. In other instances, it may be necessary to insulate and/or illuminate the matrix for similar reasons. In either situation, head 16 may be specially configured to provide these needs (eg, insulation, temperature control, shielding, etc.).

The matrix can be used to at least partially cover any number of continuous reinforcements (e.g., separate fibers, tows, rovings, socks, and/or sheets of continuous material), together with the reinforcements. , may constitute a portion (eg, a wall) of composite structure 12 . The stiffener may be stored within head 16 or may otherwise pass through head 16 . When multiple stiffeners are used simultaneously, the stiffeners are of the same material composition and have the same sizing and cross-sectional shape (e.g., circular, square, rectangular, etc.) or material compositions with different sizing and/or cross-sectional shapes. can. Reinforcing materials can include, for example, carbon fibers, plant fibers, wood fibers, mineral fibers, glass fibers, plastic fibers, metal fibers, optical fibers (eg, tubes), and the like. The term "stiffener" is meant to encompass both structural and non-structural (e.g., functional) types of continuous material that are at least partially encased in the matrix material expelled from head 16. Please note that

While the stiffener is inside the head 16 and while the stiffener is passed over the head 16 and/or while the stiffener is being expelled from the head 16, the stiffener is at least partially embedded in the matrix. can be coated. The matrix, the dry (e.g., non-impregnated) reinforcement, and/or the reinforcement already exposed to the matrix (e.g., pre-impregnated reinforcement) may be used in any manner apparent to those skilled in the art. can be transmitted to head 16 at . In some embodiments, the filler material (e.g., chopped fibers, nanoparticles or tubes, etc.) and/or additives (e.g., thermal initiators, UV initiators, etc.) are coated on the continuous reinforcement by the matrix. It can be mixed with the base material before and/or after.

one or more curing enhancers (eg, UV light, ultrasonic emitters, lasers, heaters, catalyst dispensers, etc.) 18 are mounted proximate (eg, within, on, and/or adjacent to) head 16; It may be configured to enhance the cure speed and/or quality of the base material as it is expelled from head 16 . Curing enhancer 18 selectively exposes structure 12 to energy (eg, UV light, electromagnetic radiation, vibration, heat, chemical catalysts, etc.) in portions during material ejection and formation of structure 12 . can be controlled. The energy can cause chemical reactions within the matrix, speed up chemical reactions, sinter the matrix, harden the matrix, solidify the matrix, polymerize the matrix, or otherwise It may harden the base material as it is ejected from the head 16 . The amount of energy generated by cure enhancer 18 may be sufficient to cure the base material before structure 12 axially grows beyond a predetermined length from head 16 . In one embodiment, the structure 12 is at least partially (eg, fully) cured before the length of axial growth equals the outer diameter of the matrix-clad stiffener.

The base material and/or reinforcement material may be expelled together from head 16 through any number of different modes of operation. In a first exemplary mode of operation, base material and/or stiffeners are forced out of head 16 (e.g., pressure and/or or extruded under mechanical force). In a second exemplary mode of operation, at least the stiffener is pulled from the head 16, thereby creating a tensile stress in the stiffener during dispensing. In this second mode of operation, the parent material may adhere to the stiffener thereby being pulled from the head 16 with the stiffener and/or the parent material may be expelled from the head 16 under pressure with the stiffener pulled. In a second mode of operation, the stiffeners are being pulled from the head 16, such that the resulting tension in the stiffeners may increase the strength of the structure 12 (e.g., align the stiffeners, inhibit buckling). , evenly loading the stiffeners, etc.), which also allows longer lengths of the unsupported structure 12 to follow a more straight track after curing of the matrix. That is, the tension in the stiffener remaining after the base material cures acts against gravity (e.g., directly and/or indirectly by creating a moment that opposes gravity) to provide support for the structure 12 . can provide

The stiffener may be pulled from head 16 as a result of head 16 being moved by support 14 away from an anchor point (eg, print bed, existing surface of structure 12, fixture, etc.). For example, at the start of construct formation, a length of matrix-impregnated reinforcement is pulled and/or extruded from the head 16, laminated onto the anchor points, at least partially cured, and ejected. Material attaches (or bonds) to the anchor point. The head 16 can then be moved away from the anchor point and relative motion can pull the stiffener away from the head 16 . Movement of the stiffener through the head 16 may be selectively assisted via one or more internal feeding mechanisms as needed, as described in more detail below. However, the ejection speed of the stiffener from the head 16 may be primarily a result of relative motion between the head 16 and the anchor point, thus creating tension within the stiffener. As discussed above, the anchor point may be moved away from head 16 instead of, or in addition to, head 16 being moved away from the anchor point.

Head 16 may include, among other things, outlet 22 and matrix reservoir 24 located upstream of outlet 22 . In one example, outlet 22 is a single channel outlet configured to dispense composite material having a generally circular, tubular, or rectangular cross-section. However, the configuration of head 16 allows outlet 22 to be replaced with another outlet that dispenses multiple channels of composite material having the same or different geometries (e.g., flat or sheet-like cross-sections, multi-track cross-sections, etc.). can make it possible. Fibers, tubing, and/or other reinforcing materials may pass through the matrix reservoir 24 (eg, through one or more internal wetting mechanisms 26 located inside the reservoir 24) and the matrix prior to ejection. can be wetted (eg, at least partially coated, surrounded and/or completely saturated) by

The outlet 22 can take different forms. In one example, a guide or nozzle 30 is positioned downstream of wetting mechanism 26 and compactor 32 tracks nozzle 30 (eg, relative to the direction of vertical travel of head 16 during material discharge, represented by arrow 34). Either nozzle 30 or compactor 32 may serve as a tool center point (TCP) for head 16 such that when exposed to energy by cure enhancer 18, it is wetted by the base material before and/or during cure. It is considered to attach the stiffened stiffener to the desired location. It is also contemplated that nozzle 30 may be omitted in some embodiments. Finally, it is contemplated that the TCP of head 16 may not necessarily be associated with nozzle 30 or compactor 32, but instead may be a location of curing energy exposure separate from these locations. TCP may switch places in some applications.

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

One or more maps may be stored in the memory of controller 28 and used during fabrication of structure 12 . Each of these maps may contain collections of data in the form of lookup tables, graphs, and/or equations. In the disclosed embodiment, a map can be used by the controller 28 to generate the desired shape (eg, size, shape, material composition, performance parameters, and/or contour) of the structure 12 . and coordinate the motion of the stiffening enhancer 18 and/or other related components in concert with the motion.

As shown in FIGS. 2, 3 and 4, the curing enhancer 18 and compactor 32 may be integrated into a module 54 capable of performing both curing and compaction functions. As shown in these figures, the module 54 includes, among other things, a shaft 164 that is rotatably mounted to the rest of the head 16 via spaced bearings 166, directs curing energy (e.g., light) into the shaft 164. A source 168 configured to direct, a distributor 170 positioned about the shaft 164, and one or more covers (e.g., an inner compressor) mounted over the distributor 170 that provide a compressive force to the dispensed material. It may be a self-contained assembly of multiple components, including client cover 172 and/or outer protective cover 174). Energy directed axially into shaft 164 is formed within 176 optical elements (e.g., baffles, lenses, mirrors, polished bores or end walls, etc.) located at the inner end of shaft 164 and within shaft 164. It may be distributed, focused, and/or redirected radially outward by one or more radial passages 177 (shown only in FIG. 4). The energy may pass through one or more axially-extending circumferential slots 178 of the distributor 170, and then for energy (eg, optical energy at a wavelength of about 350-450 nm, such as a wavelength of about 405 nm). through an associated cover that can be at least partially transparent (eg, about 70-100% transparent). In some embodiments, one or more of the slots 178 may be fitted with transparent spacers 180 to help support the cover. In some embodiments, spacer 180 can itself be an optical element that functions to focus, amplify, distribute, and/or direct energy from source 168 .

In some applications, module 54 (eg, the outer surface of cover 174) may form the TCP of head 16. FIG. For these applications, the head 16 can be nozzleless. Thus, the TCP of head 16 corresponds to an axially oriented line of contact between the outer surface of cover 174 and the active surface of structure 12 (e.g., module 54 presses wetted reinforcement against the surface). obtain. that the contact line can shift, for example, when the head 16 is tilted by the support 14 (see FIG. 1) relative to the printing surface and/or relative to the direction of travel (eg, when printing into an open space); Please note.

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

The compliance of inner cover 172 may allow proper engagement and compressive force against stiffeners without requiring high precision in module 54 positioning. The compliance of inner cover 172 may also provide a flat spot in the area of engagement with structure 12 (see FIG. 6). This flat spot helps the matrix wet stiffener to disengage from the module 54 and adhere only to the structure 12, and also to make the stiffener flatter against the underlying layers of the structure 12. can help Additionally, the compliance of the inner cover 172 allows the cutting device (described in more detail below with reference to FIGS. 5 and 6) to be pushed a distance into the module 54, thereby improving the cutting performance. can be improved. Outer cover 174 may need to be replaced periodically due to engagement with cutting devices. In one embodiment, the inner cover 172 may have a hardness of about 20-50 A Shore (eg, about 40 A Shore) and the outer cover 174 may have a higher hardness (eg, inner 172 cover at least 5-10% greater than the hardness of The thickness of the outer cover 174 may be less than the thickness of the inner cover 172 so that the compliance of the inner cover 172 may still be effective through the stiffer outer cover 174 . For example, outer cover 174 can be about 1/5 to 1/25 the thickness of inner cover 172 . In some embodiments, the outer cover 174 may have a lower friction than the inner cover 172 to help prevent undesirable adhesion of matrix wet reinforcement to the module 54 .

Curing in TCP (eg, immediately before, immediately above, and/or immediately after) may be possible because energy may be directed through the module 54 to the matrix-wet reinforcement. It is conceivable that sufficient stiffening can occur to fasten the stiffener before little, if any, movement of the stiffener away from the TCP location occurs. This can improve the placement accuracy of the reinforcing material. The base material may be cured only on the outer surface (e.g., sufficient to retain and/or maintain a desired shape), or the base material may be exposed to the source 168 (in addition or without any external environmental exposure). It is believed that full curing can be achieved by exposure only to energy from the . In the former case, additional energy exposure (eg, oven baking, autoclave heating, etc.) may be required after structure 12 is completed.

In one embodiment, the shape of distributor 170 may be selected (ie, in relation to the location and orientation of radial passages 177) to focus energy from source 168 only on TCP. For example, the geometry allows energy from the source 168 to pass through only one slot 178 located closest to (e.g., to) the TCP, while energy may flow further from the TCP at a given time. It may be prohibited from passing through other distant slots 178 . A thicker walled distributor with narrower slots 178 may produce a more focused exposure area. In the disclosed example, slot 178 may have an axial length of about 0-2 times the width of the stiffener passing over distributor 170 .

Figures 5 and 6 show, among other things, another module 200 that integrates stiffening and compression functions. Similar to the module 54 of FIGS. 2-4, the module 200 of FIGS. 5 and 6 includes a shaft 164 rotationally connected to the rest of the head 16 via bearings 166, and curing energy (eg, UV light, laser, or energy from other curing energy source 202 ) axially into shaft 164 . The energy may be redirected radially outward through the inner and outer covers 172 , 174 to the TCP of the head 16 via an optical element 176 located at the inner end of the shaft 164 and passageway 177 . In one embodiment, the TCP is axially centered in distributor 170 (shown in FIG. 5). However, it is contemplated that TCP could be placed closer to the end of distributor 170 if desired.

Similar to module 54, module 200 may be configured to contain energy dissipation and loss as it passes radially outward through inner and outer covers 172, 174. FIG. However, module 200 may do so without distributor 170 , slot 178 and spacer 180 . Alternatively, the inner and/or outer covers 172, 174 of the module 200 may be segmented via one or more dividers 184. Partitions 184 may be generally flat, sculpted at regular intervals from each other, and oriented through the axis of compression device 150 . Partition 184 may extend radially inward through outer and inner covers 174 , 172 but terminate before or at shaft 164 . Partition 184 may be made of, or otherwise coated, colored, or infused with a material configured to block or reflect energy from source 168 towards TCP. Any number of partitions 184 may be utilized to create the desired number of isolated energy transfer channels (eg, arcuate segments between adjacent partitions 184). For example, in some embodiments, in addition to partition 184 , one or more partitions 186 that lie in planes oriented generally perpendicular to the axis of shaft 164 or at an oblique angle are used to remove the can be further focused (eg, the energy can be directed axially into the TCP). In some applications, the spacing between partitions 184 and/or 186 may be adjustable during material dispensing to selectively vary and focus curing path parameters.

FIG. 6 also shows that module 200 additionally has a cutting function. For example, in some embodiments, cutting mechanism 188 may be incorporated into module 200 . Cutting mechanism 188 may include components that cooperate to clamp, cut, and/or feed stiffeners during and/or after a printing operation. These components include, among other things, a bar 190 pivotally mounted at opposite axial ends to shaft 164, a blade 192 attached to an outer rail 194 of bar 190, and a radially extending outer rail 194. One or more actuators 196 (eg, linear actuators at each end of shaft 164) configured to selectively extend and retract may be included.

During operation, the stiffener may be expelled through the nozzle 30 and at least partially wrapped around the outer cover 174 of the module 200 to reach the TCP nip point. Curing energy may flow axially into the compression module 200 and then be redirected radially outward to cure the base material coating the reinforcement in TCP. When it is desired to cut the stiffener (eg, at the end of a printing pass), actuator 196 may be energized by controller 28 (see FIG. 1) to retract bar 190 radially inward. This action pinches the stiffener between the outer rail 194 and the outer cover 174 so that the stiffener can be clamped in the position shown in FIG. During retraction and clamping of bar 190, blade 192 may be forced through the stiffener and against outer cover 174, thereby cutting the stiffener.

The bar 190 can remain in a clamped position during the beginning of the next printing pass, and through engagement with the outer cover 174 of the module 200 can be rotated therewith. This rotation may serve to pull stiffeners out of head 16 (eg, through nozzles 30 in preparation for printing) and continue until outer rail 194 reaches the TCP, at which point bar 190 pushes. Released and/or released, it can be moved back radially outward and the rail 194 can be rotated back to the outlet of the nozzle 30 . It is contemplated that return of rail 194 may be facilitated by another actuator (not shown) and/or spring 198, if desired. This configuration not only provides for clamping and cutting of the stiffener, but may also facilitate guiding the cut stiffener to the TCP.

Industrial Applicability The disclosed system can be used to manufacture composite structures having any desired cross-sectional shape and length. A composite structure may include any number of different fibers of the same or different types and of the same or different diameters and any number of different matrix materials of the same or different configurations. The operation of system 10 will now be described in detail.

At the start of a manufacturing event, information regarding the desired structure 12 can be loaded into the system 10 (eg, into the controller 28 responsible for coordinating the motion of the support 14 and/or head 16). This information includes, among others, size (e.g. diameter, wall thickness, length, etc.), contour (e.g. trajectory, surface normal, etc.), surface features (e.g. ridge size, position, thickness, length, etc.). flange size, position, thickness, length, etc.), connection geometry (e.g. position and size of couplings, tees, splices, etc.), reinforcement material selection, base material selection, discharge position, cutting position, Including hardening specifications, compression specifications, etc. Note that this information may alternatively or additionally be loaded into system 10 at different times and/or continuously during a manufacturing event, as desired. Based on the component information, one or more different stiffener and/or matrix materials may be installed and/or continuously supplied to system 10 .

Individual fibers, tows, and/or ribbons can be passed through matrix reservoir 24 and outlet 22 (e.g., through features in nozzle 30 and under compactor 32) to load reinforcements. and). In some embodiments, stiffeners may also need to be connected to pullers (not shown) and/or attachment fixtures (eg, anchor points). Installation of the matrix material may include coupling the fill head 16 (eg, the wetting mechanism 26 of the reservoir 24) and/or the head 16 of an extruder (not shown).

The component information can then be used to control the operation of system 10 . For example, the in-situ wetted stiffener may provide a head position when the support 14 is selectively moved (e.g., based on the known kinematics of the support 14 and/or the known shape of the structure 12). As it can be pulled and/or extruded from 16 outlets 22, structure 12 is manufactured as desired.

The operating parameters of support 14 , stiffening enhancer 18 , compactor 32 , modules 54 and/or 200 , and/or other components of system 10 are the desired bonding, strength, tension, shape, and other properties of structure 12 . It can be adjusted in real time during material dispensing to provide properties. Once structure 12 has grown to the desired length, structure 12 can be disconnected from 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, although components of system 10 (eg, distributor 170, covers 172 and 174, spacer 180, dividers 184 and 186, etc.) are described and shown as separate components, two or more of system 10 It is envisioned that components may alternatively be combined as 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)

An additive manufacturing system (10) comprising:
a support (14);
a printhead (16) configured to dispense material (R+M), operably connected to said support and movable by said support in a vertical direction of travel (34) during material dispense;
The printhead is positioned on the trailing side of the dispensed material relative to the vertical movement direction and is configured to compress the material and expose the material to curing energy at a tool center point (TCP). ), an additive manufacturing system (10). an outer cover (174) configured to roll over the material during compression;
and a source (168) configured to direct the curing energy radially outward through the outer cover. the module includes a shaft (164) to which the outer cover is attached;
3. The source of claim 2, wherein the source is configured to direct the curing energy axially into the shaft and then radially outwardly through the outer cover via passages (177) in the shaft. additive manufacturing system. 4. The additive manufacturing of claim 3, further comprising an optical element (176) mounted inside said shaft and configured to redirect said axially directed curing energy radially outwardly to said shaft. system. The additive manufacturing system of claim 3, further comprising a slotted distributor (170) positioned between the shaft and the outer cover. said slotted distributor comprising a plurality of axially oriented slots (178);
The additive manufacturing system of claim 5, wherein the module further comprises a spacer (180) at least partially transparent to the curing energy disposed within each of the plurality of axially oriented slots. . 6. The additive manufacturing system of claim 5, further comprising an inner cover (172) positioned between the slotted distributor and the outer cover, the inner cover being more flexible than the outer cover. 8. The additive manufacturing system of claim 7, wherein each of the inner cover and the outer cover are at least partially transparent. The additive manufacturing system of claim 1, wherein the module is rotationally connected to the remainder of the printhead via at least one bearing. The additive manufacturing system of claim 1, further comprising at least one divider (184) aligned with an axis of the module and configured to focus the curing energy onto an arcuate segment of the module. 11. The additive manufacturing of claim 10, further comprising at least one partition (186) extending radially outwardly through the module and configured to focus the curing energy axially of the module. system. the module
an outer cover (174) configured to roll over the material during compression;
an arm (190) extending radially outwardly beyond said outer cover;
a bar (194) connected to the distal end of the arm and extending axially of the module;
and an actuator (196) connected to the arm and configured to selectively pull the bar 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 bar. A method of additively manufacturing a structure (12), comprising:
ejecting a matrix-wet continuous reinforcement (R+M) through an outlet (30) of the printhead (16);
pressing a module (22) against said matrix-wet continuous reinforcement after ejection to compress said matrix-wet continuous reinforcement;
directing curing energy radially outwardly through the modules to a continuous reinforcement wetted with the preform being compressed. 15. The method of claim 14, further comprising at least one of axially and radially focusing the curing energy to a tool center point (TCP) of the printhead.

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