PART HOLDER FOR ADDITIVE MANUFACTURING SYSTEM Related Applications

[0001] This application is based on and claims the benefit of priority from United States Provisional Application No. 62/417,709 that was filed on 11/4/2016, the contents of which are expressly incorporated herein by reference.

Technical Field

[0002] The present disclosure relates generally to a part holder and, more particularly, to a part holder for an additive manufacturing system.

Background

[0003] Additive manufacturing is a process of creating three-dimensional parts by depositing overlapping layers of material under the guided control of a computer. One technique of additive manufacturing is known as fused-deposition modeling (FDM). In FDM, a heated thermoplastic is pushed through a print head having a desired cross-sectional shape and size. The print head is moved in a predefined 2-dimensional trajectory as the thermoplastic discharges from the print head, such that the thermoplastic is laid down in a particular pattern and shape of overlapping layers. The thermoplastic, after exiting the print head, hardens into a final form. Another technique of additive manufacturing is known as continuous composite three-dimensional printing (CC3D). In CC3D, a continuous fiber is pushed and/or pulled through the print head along with a thermoset resin to act as reinforcement for the solidified part. Upon exiting the head, one or more cure enhancers mounted to the head instantly cure the thermoset resin, allowing for 3-dimensional printing in free-space.

[0004] Although both FDM and CC3D printing techniques can be used to fabricate parts that are acceptable for many applications, these techniques may be limited due to their ability to access all sides of a part during fabrication. In particular, most parts are anchored in some manner (e.g., to a build platform) during fabrication, and access by the head to a side of a part adjacent the anchor can be blocked by the part. This may limit printable features and/or an order in which the features can be printed.

[0005] The disclosed part holder and system is directed to addressing one or more of the problems set forth above and/or other problems of the prior art.

Summary

[0006] In one aspect, the present disclosure is directed to a part holder for an additive manufacturing system. The part holder may include a first ring configured to provide mounting for a part during additive manufacturing. The part holder may also include a second ring configured to internally receive the first ring. The first ring may be moveable relative to the second ring.

[0007] In another aspect, the present disclosure is directed to another part holder for an additive manufacturing system. This part holder may include a first ring, and at least one anchor point extending radially inward from the first ring and configured to support a part during additive manufacture. The part holder may also include a second ring configured to internally receive the first ring. The first ring may be connected to the second ring at a pivot point, and configured to pivot about an axis passing through the pivot point. The second ring may be connectable to a build platform at a second pivot point, and configured to pivot about a second axis passing through the second pivot point. The part holder may also include at least one actuator configured to cause pivoting of at least one of the first and second rings.

[0008] In another aspect, the present disclosure is directed to a system for additively manufacturing a part. The system may include a head configured to discharge a continuous fiber at least partially coated with a matrix to form the part, a support configured to move the head during discharge, and a part holder configured to provide access to multiple sides of the part during discharge. The part holder may include a first ring configured to provide mounting for the part, a second ring configured to internally receive the first ring, and an actuator configured to move the first ring relative to the second ring. The system may further include a controller in communication with the support and the actuator. The controller may be configured to coordinate movements of the head and the part via activation of the support and the actuator. Brief Description of the Drawings

[0009] Fig. 1 is a diagrammatic illustration of an exemplary disclosed manufacturing system; and

[0010] Figs. 2 and 3 are diagrammatic illustrations of exemplary part holders that may be used in conjunction with the system of Fig. 1.

Detailed Description

[0011] Fig. 1 illustrates an exemplary system 10, which may be used to continuously manufacture a composite part 12 having any desired cross-sectional shape (e.g., circular, rectangular, or polygonal). System 10 may include at least a support 14, a head 16, and a part holder 18. Head 16 may be coupled to and moved by support 14 during discharge of composite material into part holder 18. In the disclosed embodiment of Fig. 1, support 14 is a robotic arm capable of moving head 16 in multiple directions during the discharge of composite material, such that a resulting longitudinal axis (e.g., a trajectory) of part 12 is three-dimensional. It is contemplated, however, that support 14 could alternatively be an overhead gantry or a hybrid gantry/arm that is also capable of moving head 16 in multiple directions during fabrication of part 12. Although support 14 is shown as being capable of 6-axis movements, it is contemplated that any other type of support 14 capable of moving head 16 in the same or a different manner could also be utilized. In some embodiments, a drive may mechanically couple head 16 to support 14, and include components that cooperate to move portions of and/or supply power to head 16.

[0012] Head 16 may be configured to receive or otherwise contain a matrix material. The matrix material may include any type of matrix material (e.g., a liquid resin, such as a zero volatile organic compound resin; a powdered metal; etc.) that is curable. Exemplary resins include thermosets, single- or multi-part epoxy resins, polyester resins, cationic epoxies, acrylated epoxies, urethanes, esters, thermoplastics, photopolymers, polyepoxides, thiols, alkenes, thiol-enes, and more. In one embodiment, the matrix material inside head 16 may be pressurized, for example by an external device (e.g., an extruder or another type of pump - not shown) that is fluidly connected to head 16 via a corresponding conduit (not shown). In another embodiment, however, the pressure may be generated completely inside of head 16 by a similar type of device. In yet other embodiments, the matrix material may be gravity-fed through and/or mixed within head 16. In some instances, the matrix material inside head 16 may need to be kept cool and/or dark to inhibit premature curing; while in other instances, the matrix material may need to be kept warm for the same reason. In either situation, head 16 may be specially configured (e.g., insulated, chilled, and/or warmed) to provide for these needs.

[0013] The matrix material may be used to coat, encase, or otherwise surround any number of continuous reinforcements (e.g., separate fibers, tows, rovings, and/or sheets of material) and, together with the reinforcements, make up at least a portion (e.g., a wall) of composite part 12. The reinforcements may be stored within (e.g., on separate internal spools - not shown) or otherwise passed through head 16 (e.g., fed from external spools). When multiple

reinforcements are simultaneously used, the reinforcements may be of the same type and have the same diameter and cross-sectional shape (e.g., circular, square, flat, etc.), or of a different type with different diameters and/or cross-sectional shapes. The reinforcements may include, for example, carbon fibers, vegetable fibers, wood fibers, mineral fibers, glass fibers, metallic wires, optical tubes, etc. It should be noted that the term "reinforcement" is meant to encompass both structural and non-structural types of continuous materials that can be at least partially encased in the matrix material discharging from head 16.

[0014] The reinforcements may be exposed to (e.g., coated with) the matrix material while the reinforcements are inside head 16, while the reinforcements are being passed to head 16, and/or while the reinforcements are discharging from head 16, as desired. The matrix material, dry reinforcements, and/or reinforcements that are already exposed to the matrix material (e.g., wetted reinforcements) may be transported into head 16 in any manner apparent to one skilled in the art.

[0015] The matrix material and reinforcement may be discharged from head 16 via at least two different modes of operation. In a first mode of operation, the matrix material and reinforcement are extruded (e.g., pushed under pressure and/or mechanical force) from head 16, as head 16 is moved by support 14 to create the 3-dimensional shape of part 12. In a second mode of operation, at least the reinforcement is pulled from head 16, such that a tensile stress is created in the reinforcement during discharge. In this mode of operation, the matrix material may cling to the reinforcement and thereby also be pulled from head 16 along with the reinforcement, and/or the matrix material may be discharged from head 16 under pressure along with the pulled reinforcement. In the second mode of operation, where the matrix material is being pulled from head 16, the resulting tension in the reinforcement may increase a strength of part 12, while also allowing for a greater length of unsupported material to have a straighter trajectory (i.e., the tension may act against the force of gravity to provide free-standing support for part 12).

[0016] The reinforcement may be pulled from head 16 as a result of head 16 moving away from one or more anchor points 20 located inside of part holder 18. In particular, at the start of structure-formation, a length of matrix-impregnated reinforcement may be pulled and/or pushed from head 16, deposited onto anchor point 20, and cured, such that the discharged material adheres to anchor point 20. Thereafter, head 16 may be moved away from anchor point 20, and the relative movement may cause the reinforcement to be pulled from head 16. It should be noted that the movement of reinforcement through head 16 could be assisted (e.g., via internal feed mechanisms), if desired. However, the discharge rate of reinforcement from head 16 may primarily be the result of relative movement between head 16 and anchor point 20, such that tension is created within the reinforcement. It is contemplated that anchor point 20 could be moved away from head 16 instead of or in addition to head 16 being moved away from anchor point 20.

[0017] One or more cure enhancers (e.g., a UV light, an ultrasonic emitter, a laser, a heater, a catalyst dispenser, a microwave generator, etc.) 22 may be mounted proximate (e.g., within, on, and/or trailing from) head 16 and configured to enhance a cure rate and/or quality of the matrix material as it is discharged from head 16. Cure enhancer 22 may be controlled to selectively expose internal and/or external surfaces of part 12 to energy (e.g., UV light, electromagnetic radiation, vibrations, heat, a chemical catalyst or hardener, etc.) during the formation of part 12. The energy may increase a rate of chemical reaction occurring within the matrix material, sinter the material, harden the material, or otherwise cause the material to cure as it discharges from head 16.

[0018] A controller 24 may be provided and communicatively coupled with support 14, head 16, and any number and type of cure enhancers 22. Controller 24 may embody a single processor or multiple processors that include a means for controlling an operation of system(s) 10 and/or 12. Controller 24 may include one or more general- or special-purpose processors or microprocessors. Controller 24 may further include or be associated with a memory for storing data such as, for example, design limits, performance characteristics, operational instructions, matrix characteristics, reinforcement characteristics, characteristics of part 12, and corresponding parameters of each component of system 10. Various other known circuits may be associated with controller 24, including power supply circuitry, signal-conditioning circuitry,

solenoid/motor driver circuitry, communication circuitry, and other appropriate circuitry.

Moreover, controller 24 may be capable of communicating with other components of system 10 via wired and/or wireless transmission.

[0019] One or more maps may be stored in the memory of controller 24 and used during fabrication of part 12. Each of these maps may include a collection of data in the form of lookup tables, graphs, and/or equations. In the disclosed embodiment, the maps are used by controller 24 to determine the locations of existing anchor points 20 within part holder 18, as well as desired characteristics of cure enhancers 22, the associated matrix, and/or the associated reinforcements at different locations within part 12. The characteristics may include, among others, a type, quantity, and/or configuration of reinforcement and/or matrix to be discharged at a particular location within part 12, and/or an amount, shape, and/or location of desired curing. Controller 24 may then coordinate operation of support 14 (e.g., the location and/or orientation of head 16) and/or the discharge of material from head 16 (a type of material, desired performance of the material, cross-linking requirements of the material, a discharge rate, etc.) with the locations of anchor points 20 and the operation of cure enhancers 22, such that part 12 is produced in a desired manner.

[0020] Fig. 2 illustrates an exemplary part holder 18 that may be used to hold part 12 during additive manufacture by head 16 (referring to Fig. 1) in the manner described above. In this example, part holder 18 is a gyroscopic holder having at least two rings, including a first ring 26 nested at least partially inside of a second ring 28. First ring 26 may be connected to second ring 28 by one or more pivot points 30; and second ring 28 may be connectable to a build platform 32 by one or more additional pivot points 34. With this configuration, second ring 28 (together with first ring 26 and part 12) may be pivotal about a first axis 36 in a first direction, while first ring 26 (together with part 12) may be pivotal about a second axis 38 in a second direction that is substantially orthogonal to the first direction. In the disclosed embodiments, first and second rings 26, 28 are concentric, and each of axes 36, 38 passes through a common center of first and second rings 26, 28. It is contemplated, however, that first and second rings 26, 28 could be eccentric and/or that one or both of axes 36, 38 could be misaligned with (i.e., not pass through) the centers of one or both of first and second rings 26, 28.

[0021] Part 12 may be suspended inside of first ring 26 by any number of fibers connected to any number of different anchor points 20 that extend radially inward from first ring 26. In some embodiments, anchor points 20 may lie in the same general plane as first ring 26, while in other embodiments, anchor points 20 may protrude axially out of the plane of first ring 26. It is also contemplated that anchors points 20 may be adjustable (e.g., manually and/or automatically moved into or out of first ring 26, for example via a threaded interface) and/or fabricated by head 16 in-situ.

[0022] Any number of actuators 40 may be connected to first and/or second rings 26, 28 and configured to selectively rotate and/or translate the corresponding ring(s) and part 12 during discharge of material from head 16. In this manner, sides of part 12 normally blocked from head 16 by build platform 32 may be accessed during fabrication. It is contemplated that operation of actuators 40 may be coordinated (e.g., by controller 24 - referring to Fig. 1) with movement of head 16 and/or structure 14.

[0023] A second part holder 18 is shown in Fig. 3, and includes features similar to those of first part holder 18 shown in Fig. 2. Instead of including complete rings, however, second part holder 18 may include only partial rings (e.g., arcuate segments) 42, 44 that do not completely encircle part 12. Like rings 26, 28, rings 42, 44 may nest together and be capable of relative pivoting during activation of actuators 40. The segmented nature of rings 42, 44 may allow for even greater access to part 12 by head 16.

Industrial Applicability

[0024] The disclosed system may be used to continuously manufacture composite structures having any desired cross-sectional shape and length. The composite structures may include any number of different fibers of the same or different types and of the same or different diameters. Operation of system 10 will now be described in detail.

[0025] At a start of a manufacturing event, information regarding a desired part 12 may be loaded into system 10 (e.g., into controller 24 that is responsible for regulating operations of support 14, head 16, cure enhancers 22, and/or actuators 40). This information may include, among other things, a size (e.g., diameter, wall thickness, length, etc.), a contour (e.g., a trajectory), surface features (e.g., ridge size, location, thickness, length; flange size, location, thickness, length; etc.), connection geometry (e.g., locations and sizes of couplings, tees, splices, etc.), etc. It should be noted that this information may alternatively or additionally be loaded into system 10 at different times and/or continuously during the manufacturing event, if desired. Based on the component information, one or more different reinforcements and/or matrix materials may be selectively installed and/or continuously supplied into system 10. In some embodiments, the fiber(s) may also need to be connected to a pulling machine (not shown) and/or to a mounting fixture (e.g., to anchor point 20). Installation of the matrix material may include filling head 16 and/or coupling of an extruder (not shown) to head 16.

[0026] The component information may then be used to control operation of system 10. For example, the reinforcements may be pulled and/or pushed along with the matrix material from head 16. Support 14 may also be controlled to selectively move head 16 in coordination with movement of rings 26, 28 and/or 42, 44, such that an axis of the resulting part 12 follows a desired trajectory. Once part 12 has grown to a desired length, part 12 may be severed from system 10 in any desired manner.

[0027] The disclosed part holders 18 may be particularly applicable and useful with additive manufacturing systems discharging continuous fibers. For example, in some situations, the continuous fibers discharging from head 16 may need to wrap around part 12. The disclosed part holders 18 may be capable of rotating (e.g., flipping over) part 12, such that all sides can be accessed and overlaid with the continuous fibers. In addition, in some situations, it may not be possible for head 16 to move in a required trajectory relative to part 12 (e.g., due to space constraints around part 12). Without this relative movement, a head 16 that relies solely on pulling of the continuous fibers may be unable to correctly discharge the necessary material. In these situations, part holder 18 may be capable of generating relative rotation between part 12 and head 16 that causes the material to be pulled out of head 16, even though head 16 is temporarily remaining stationary.

[0028] It is contemplated that anchor points 20 could be used for quality control purposes, if desired. For example, anchor points 20 could be used to test for continuity (e.g., electrical and/or optical continuity) of the fibers that extend therefrom throughout part 12. Specifically, controller 24 could cause an electrical charge and/or light signal to be directed through anchor point 20 and into the associated fiber. Controller 24 may then monitor for receipt of the electrical charge and/or light signal within head 16 (e.g., with a sensor mounted inside of head 16), and determine a level of continuity within the fiber based on the receipt.

[0029] 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 only two rings are shown in part holder 18, part holder 18 could have any number of rings that pivot and/or translate relative to each other and relative to support 14. In addition, although actuators 40 are only described as being associated with pivot points 30, it is contemplated that similar actuators could be associated with one or more of anchor points 20, 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.