U.S. patent application number 17/659968 was filed with the patent office on 2022-08-04 for system for additively manufacturing composite structures.
This patent application is currently assigned to Continuous Composites Inc.. The applicant listed for this patent is Continuous Composites Inc.. Invention is credited to Dan Budge, TREVOR DAVID BUDGE, Kyle Frank Cummings, Nathan Andrew Stranberg.
Application Number | 20220242060 17/659968 |
Document ID | / |
Family ID | |
Filed Date | 2022-08-04 |
United States Patent
Application |
20220242060 |
Kind Code |
A1 |
BUDGE; TREVOR DAVID ; et
al. |
August 4, 2022 |
SYSTEM FOR ADDITIVELY MANUFACTURING COMPOSITE STRUCTURES
Abstract
A system is disclosed for additively manufacturing a composite
structure. The system may include a support, and a print head
connected to and moveable by the support. The system may also
include an encoder configured to generate a signal indicative of an
amount of material passing through the print head, and a controller
in communication with the encoder. The controller may be configured
to selectively implement a corrective action in response to the
signal.
Inventors: |
BUDGE; TREVOR DAVID; (Coeur
d'Alene, ID) ; Stranberg; Nathan Andrew; (Post Falls,
ID) ; Cummings; Kyle Frank; (Everett, WA) ;
Budge; Dan; (Harrison, ID) |
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Applicant: |
Name |
City |
State |
Country |
Type |
Continuous Composites Inc. |
Coeur d'Alene |
ID |
US |
|
|
Assignee: |
Continuous Composites Inc.
Coeur d'Alene
ID
|
Appl. No.: |
17/659968 |
Filed: |
April 20, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16531055 |
Aug 3, 2019 |
11338528 |
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17659968 |
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62730541 |
Sep 13, 2018 |
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International
Class: |
B29C 69/00 20060101
B29C069/00; B29C 64/209 20060101 B29C064/209; B29C 64/255 20060101
B29C064/255; B29C 64/165 20060101 B29C064/165; B29C 64/321 20060101
B29C064/321; B29C 64/118 20060101 B29C064/118; B29C 64/268 20060101
B29C064/268; B29C 64/314 20060101 B29C064/314; B33Y 50/02 20060101
B33Y050/02; B29C 64/20 20060101 B29C064/20; B29C 64/393 20060101
B29C064/393; B22F 10/10 20060101 B22F010/10 |
Claims
1. A method of additively manufacturing a composite structure,
comprising: wetting a continuous reinforcement with a matrix inside
a print head to form a composite material; discharging from the
print head the composite material; moving the print head during
discharging of the composite material; generating a signal
indicative of a first amount of the composite material discharged
from the print head; determining a second amount of the composite
material expected to be discharged from the print head; and
selectively implementing a corrective action based at least in part
on a difference between the first and second amounts.
2. The method of claim 1, further including determining a travel
distance of the print head, wherein determining the second amount
of the composite material includes determining the second amount of
the composite material based at least in part on the travel
distance of the print head.
3. The method of claim 2, further including determining that least
one of untacking or breakage of the composite material has occurred
based at least in part on the first amount of the composite
material being less than the second amount of the composite
material.
4. The method of claim 2, further including: attempting to sever
the composite material discharging from the print head; and
determining that severing of the composite material has failed
based at least in part on the first amount of the composite
material being greater than the second amount of the composite
material.
5. The method of claim 4, wherein selectively implementing the
corrective action includes attempting an additional severing
operation to sever the composite material.
6. The method of claim 1, wherein selectively implementing the
corrective action includes at least one of generating a flag
indicating a potential malfunction, pausing of a current printing
operation, or cancelling the current printing operation.
7. The method of claim 1, further including exposing the composite
material discharging from the print head to a cure energy.
8. The method of claim 1, further including directing the composite
material from a supply to the print head, wherein the signal is
associated with the supply.
9. The method of claim 1, further including passing the composite
material through a feeder to a nozzle of the print head, wherein
the signal is associated with the feeder.
10. The method of claim 1, further including: receiving an
indication of a tacking operation in which the composite material
is secured to a surface; and determining, based at least in part on
the indication, that the second amount of the composite material is
greater than zero.
11. A method for additively manufacturing a composite structure,
comprising: discharging from a print head a composite material,
including a continuous reinforcement at least partially coated with
a matrix; moving the print head during discharging of the composite
material; generating a signal indicative of an amount of the
composite material discharging from the print head during movement
of the print head; determining a movement distance of the print
head during discharging; and selectively implementing a corrective
action based at least in part on the movement distance and the
amount of the composite material.
12. The method of claim 11, wherein, when the amount of the
composite material passing through the print head is less than the
movement distance of the print head, the method further includes
determining that at least one of untacking or breakage of the
continuous reinforcement has occurred.
13. The method of claim 12, wherein selectively implementing the
corrective action includes at least one of: generating a flag
indicating that a malfunction has occurred; pausing of a current
printing operation; or cancelling of the current printing
operation.
14. The method of claim 11, further including severing the
composite material passing through the print head, wherein when the
amount of the composite material passing through the print head is
greater than the movement distance of the print head, the method
further includes determining that the severing of the composite
material has failed.
15. The method of claim 14, wherein selectively implementing the
corrective action includes attempting an additional severing of the
composite material.
16. The method of claim 11, wherein: the amount of the composite
material is zero based on implementation of a severing operation;
and the amount of the composite material expected to be passing
through the print head is greater than zero based on implementation
of a tacking operation.
17. The method of claim 11, further including wetting the
continuous reinforcement with the matrix at a wetting location
inside the print head, wherein generating the signal includes
detecting the amount between the wetting location and a supply of
the continuous reinforcement.
18. A method of additively manufacturing a composite structure,
comprising: discharging from a print head a composite material,
including a continuous reinforcement at least partially coated with
a matrix; determining an amount of the composite material being
pulled through the print head during discharging; moving the print
head during discharging of the composite material; determining a
travel distance of the print head; and selectively implementing a
corrective action based on a difference between the amount of the
composite material and the travel distance.
19. The method of claim 18, wherein, when the amount of the
composite material passing through the print head is less than the
travel distance of the print head, the corrective action includes
at least one of generating a flag indicating that at least one of
untacking or continuous reinforcement breakage may have
occurred.
20. The method of claim 18, further including selectively severing
the continuous reinforcement, wherein when the amount of the
composite material passing through the print head is greater than
the travel distance of the print head, the corrective action
includes attempting to sever the continuous reinforcement again.
Description
RELATED APPLICATIONS
[0001] This application is a divisional application of U.S.
Non-Provisional application Ser. No. 16/531,055 that was filed on
Aug. 3, 2019, which is based on and claims the benefit of priority
from U.S. Provisional Application No. 62/730,541 that was filed on
Sep. 13, 2018, the contents of all of which are expressly
incorporated herein by reference.
TECHNICAL FIELD
[0002] The present disclosure relates generally to a manufacturing
system and, more particularly, to a system for additively
manufacturing composite structures.
BACKGROUND
[0003] Continuous fiber 3D printing (a.k.a., CF3D.RTM.) involves
the use of continuous fibers embedded within a matrix discharging
from a moveable print head. The matrix can be a traditional
thermoplastic (e.g., solid or liquid), a powdered metal, a
thermoset resin (e.g., a UV curable, heat curable, and/or two-part
resin), or a combination of any of these and other known matrixes.
Upon exiting the print head, a head-mounted cure enhancer (e.g., a
UV light, an ultrasonic emitter, a heat source, a catalyst supply,
etc.) is activated to initiate and/or complete curing of the
matrix. This curing occurs almost immediately, allowing for
unsupported structures to be fabricated in free space. When fibers,
particularly continuous fibers, are embedded within the structure,
a strength of the structure may be multiplied beyond the
matrix-dependent strength. An example of this technology is
disclosed in U.S. Pat. No. 9,511,543, which issued to Tyler on Dec.
6, 2016 ("the '543 patent").
[0004] Although CF3D.RTM. provides for increased strength, compared
to manufacturing processes that do not utilize continuous-fiber
reinforcement, improvements can be made to the structure and/or
operation of existing systems. The disclosed additive manufacturing
system is uniquely configured to provide these improvements and/or
to address other issues of the prior art.
SUMMARY
[0005] In one aspect, the present disclosure is directed to an
additive manufacturing system. The additive manufacturing system
may include a support, and a print head connected to and moveable
by the support. The system may also include an encoder configured
to generate a signal indicative of an amount of material passing
through the print head, and a controller in communication with the
encoder. The controller may be configured to selectively implement
a corrective action in response to the signal.
[0006] In another aspect, the present disclosure is directed to
another additive manufacturing system. This system may include a
support, a print head connected to and moveable by the support, and
an encoder configured to generate a signal indicative of an amount
of continuous reinforcement passing through the print head. The
system may also include a cure enhancer configured to apply a cure
energy to a matrix coating the continuous reinforcement, and a
controller in communication with the support, the encoder, and the
cure enhancer. The controller may be configured to determine an
actual amount of the continuous reinforcement passing through the
print head, and to make a comparison of the actual amount to a
travel distance of the print head. The controller may also be
configured to selectively perform at least one of the following
when the comparison indicates that the actual amount is less than
the travel distance: generating a notification alerting a
technician of a potential malfunction, pausing a process of the
print head, cancelling the process, or restarting the process.
[0007] In yet another aspect, the present disclosure is directed to
a method for additively manufacturing a composite structure. The
method may include discharging from a print head a path of
composite material, including a continuous reinforcement at least
partially coated with a matrix, and determining an amount of the
composite material being pulled through the print head during
discharging. The method may also include moving the print head
during discharging of the composite material and determining a
travel distance of the print head. The method may further include
selectively implementing a corrective action based on a difference
between the amount of the composite material and the travel
distance.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is an isometric illustration of an exemplary
disclosed additive manufacturing system; and
[0009] FIG. 2 is a diagrammatic illustration of an exemplary
disclosed print head that may be utilized with the system of FIG.
1; and
[0010] FIGS. 3 and 4 are diagrammatic illustrations of another
exemplary disclosed print head that may be utilized with the system
of FIG. 1.
DETAILED DESCRIPTION
[0011] FIG. 1 illustrates an exemplary system 10, which may be used
to manufacture a composite structure 12 having any desired
cross-sectional shape (e.g., ellipsoidal, polygonal, etc.). System
10 may include at least a moveable support 14 and a print head
("head") 16. Support 14 may be coupled to and configured to move
head 16. 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, such that a resulting longitudinal
axis of structure 12 is three-dimensional. It is contemplated,
however, that support 14 could alternatively be a gantry, a hybrid
gantry/arm, or another type of movement system that is capable of
moving head 16 in multiple directions during fabrication of
structure 12. Although support 14 is shown as being capable of
multi-axis movement (e.g., movement about six or more axes), it is
contemplated that any other type of support 14 capable of moving
head 16 in the same or in a different manner could also be
utilized, if desired. In some embodiments, a drive may mechanically
couple head 16 to support 14 and may include components that
cooperate to move and/or supply power or materials to head 16.
[0012] Head 16 may be configured to receive or otherwise contain a
matrix. The matrix may include any type of material (e.g., a liquid
resin, such as a zero-volatile organic compound resin; a powdered
metal; a solid filament; etc.) that is curable. Exemplary matrixes
include thermosets, single- or multi-part epoxy resins, polyester
resins, cationic epoxies, acrylated epoxies, urethanes, esters,
thermoplastics, photopolymers, polyepoxides, thiols, alkenes,
thiol-enes, reversible resins (e.g., Triazolinedione, a
covalent-adaptable network, a spatioselective reversible resin,
etc.) and more. In one embodiment, the matrix 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 matrix pressure may be generated
completely inside of head 16 by a similar type of device. In yet
other embodiments, the matrix may be gravity-fed through and/or
mixed within head 16. In some instances, the matrix inside head 16
may need to be kept cool and/or dark to inhibit premature curing;
while in other instances, the matrix may need to be kept warm for
similar reasons. In either situation, head 16 may be specially
configured (e.g., insulated, temperature-controlled, shielded,
etc.) to provide for these needs.
[0013] The matrix may be used to coat, encase, or otherwise at
least partially surround or saturate (e.g., wet) any number of
continuous reinforcements (e.g., separate fibers, tows, rovings,
ribbons, and/or sheets of material) and, together with the
reinforcements, make up at least a portion (e.g., a wall) of
composite structure 12. The reinforcements may be stored within
(e.g., on separate internal spools) or otherwise passed through
head 16 (e.g., fed from one or more 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, hollow, solid, 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 discharging from head 16.
[0014] The reinforcements may be exposed to (e.g., coated with) the
matrix while the reinforcements are inside head 16, while the
reinforcements are being passed to head 16 (e.g., as a prepreg
material), and/or while the reinforcements are discharging from
head 16, as desired. The matrix, dry reinforcements, and/or
reinforcements that are already exposed to the matrix (e.g., wetted
reinforcements) may be transported into head 16 in any manner
apparent to one skilled in the art.
[0015] The matrix and reinforcement may be discharged from head 16
via at least two different modes of operation. In a first mode of
operation, the matrix 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 structure
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 may cling to the reinforcement and thereby also be pulled
from head 16 along with the reinforcement, and/or the matrix 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 with the reinforcement, the
resulting tension in the reinforcement may increase a strength of
structure 12 (e.g., by aligning the reinforcements, inhibiting
buckling, equally distributing loads, etc.), while also allowing
for a greater length of unsupported structure 12 to have a
straighter trajectory (e.g., by creating moments that oppose
gravity).
[0016] The reinforcement may be pulled from head 16 as a result of
head 16 moving away from an anchor point 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 a stationary or moveable anchor point 18, and cured, such that
the discharged material adheres to anchor point 18. Thereafter,
head 16 may be moved away from anchor point 18, and the relative
movement may cause additional reinforcement to be pulled from head
16. It should be noted that the movement of the reinforcement
through head 16 could be assisted (e.g., via internal feed
mechanisms), if desired. However, the discharge rate of the
reinforcement from head 16 may primarily be the result of relative
movement between head 16 and anchor point 18, such that tension is
created within the reinforcement.
[0017] Any number of reinforcements (represented as "R") may be
passed axially through head 16 and be discharged together with at
least a partial coating of matrix (matrix represented as "M" in
FIG. 2). At discharge (or shortly thereafter), one or more cure
enhancers (e.g., one or more light sources, ultrasonic emitters,
lasers, heaters, catalyst dispensers, microwave generators, etc.)
20 may expose the matrix coating to a cure energy (e.g., light
energy, electromagnetic radiation, vibrations, heat, a chemical
catalyst or hardener, or other form of actively-applied energy).
The cure energy may trigger a chemical reaction, increase a rate of
chemical reaction already occurring within the matrix, sinter the
material, harden the material, or otherwise cause the material to
cure as it discharges from head 16.
[0018] A controller 22 may be provided and communicatively coupled
with support 14, head 16, and/or any number and type of cure
enhancers 20. Controller 22 may embody a single processor or
multiple processors that include a means for controlling an
operation of system 10. Controller 22 may include one or more
general- or special-purpose processors or microprocessors.
Controller 22 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 structure 12, and
corresponding parameters of each component of system 10. Various
other known circuits may be associated with controller 22,
including power supply circuitry, signal-conditioning circuitry,
solenoid/motor driver circuitry, communication circuitry, and other
appropriate circuitry. Moreover, controller 22 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
22 and used during fabrication of structure 12. Each of these maps
may include a collection of data in the form of models, lookup
tables, graphs, and/or equations. In the disclosed embodiment, the
maps are used by controller 22 to determine desired characteristics
of cure enhancers 20, the associated matrix, and/or the associated
reinforcements at different locations within structure 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 structure 12, and/or an amount,
intensity, shape, and/or location of desired curing. Controller 22
may then correlate 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 operation of cure enhancers 20, such that
structure 12 is produced in a desired manner.
[0020] A cross-section of an exemplary head 16 is disclosed in
detail in FIG. 2. As shown in this figure, head 16 may include,
among other things, a matrix reservoir 24 and an outlet (e.g., a
nozzle) 26 removably connected to matrix reservoir 24. In this
example, outlet 26 is a multi-channel nozzle configured to
discharge composite material having a generally rectangular, flat,
or ribbon-like cross-section. The configuration of head 16,
however, may allow outlet 26 to be swapped out for another outlet
26 (not shown) that discharges composite material having a
different shape (e.g., a circular cross-section, a tubular
cross-section, etc.). Fibers, tubes, and/or other reinforcements
may pass through matrix reservoir 24 and be wetted (e.g., at least
partially coated and/or fully saturated) with matrix material prior
to discharge.
[0021] It has been found that, in some applications, more time may
be required for the matrix to fully saturate and/or encapsulate the
associated reinforcement than is possible during travel of the
reinforcement through matrix reservoir 24. In addition, it can be
difficult to ensure that gravity does not cause the matrix to leak
from reservoir 24 through outlet 26 in an uncontrolled manner. In
these and other applications, the reinforcement may be selectively
wetted or otherwise coated or saturated with the matrix at a
location upstream of reservoir 24. Reservoir 24 may still be used
in these applications, left empty, or completely omitted, as
desired.
[0022] FIG. 2 illustrates a wetting mechanism ("mechanism") 27,
which can be used together with or in place of reservoir 24.
Mechanism 27 may be configured to receive reinforcement (e.g., a
dry or pre-impregnated reinforcement from an internal and/or
external spool 36) and matrix (e.g., via an inlet 30), and to
discharge a matrix-wetted reinforcement, which can then be
discharged by head 16 in the manner described above. Mechanism 27
may be a relatively closed and higher-pressure device or a
relatively open and lower-pressure mechanism, as desired. For
example, the supplied reinforcement may be routed through a bath of
liquid matrix that is contained within mechanism 27.
[0023] Mechanism 27 may be an assembly of components that cooperate
to saturate, coat, encapsulate, or at least partially wet the
reinforcement passing therethrough with a desired amount of matrix,
without significantly increasing tension within the reinforcement.
These components may include, among other things, a matrix
reservoir 28 that is in fluid communication with inlet 30, a feeder
32 that is configured to direct reinforcement into matrix reservoir
28, and a regulator 34 located at an exit of matrix reservoir 28
that is configured to limit an amount of matrix allowed to leave
mechanism 27 with the reinforcement.
[0024] Matrix reservoir 28 may function similar to matrix reservoir
24 described above, but is located in substantial isolation from
head 16 (e.g., isolated from outlet 26). That is, matrix reservoir
28 may not be internal to head 16, so as to reduce a likelihood of
matrix material passing undetected and/or in undesired amounts
through outlet 26. In the embodiment where the internal matrix
reservoir 24 of head 16 is eliminated, the external wetting
mechanism 27 may feed directly into a stand-alone outlet 26. In
embodiments where matrix reservoir 24 is retained, matrix reservoir
24 may primarily be used to collect excess resin that drips from
the reinforcement during passage through head 16. It is
contemplated that matrix reservoir 24 could be used to apply
additional matrix and/or a different matrix (e.g., a catalyst or
outer coating) to the already wetted reinforcement. It is further
contemplated that matrix reservoir 28 could be internal to head 16
(e.g., within the same housing), if desired.
[0025] It should be noted that matrix reservoir 28 may be
substantially sealed (e.g., via one or more o-rings, gaskets, etc.
--not shown), such that matrix reservoir 28 may be tilted or even
completely inverted, without significant matrix leakage. It should
also be noted that, although inlet 30 is shown as being located at
a lowest gravitational point of matrix reservoir 28 (e.g., to allow
for filling and draining via the same port), this location could be
changed. Likewise, although a reinforcement inlet and a
reinforcement exit are both shown as being located at higher
gravitational points of matrix reservoir 28, these locations could
also change. The current configuration allows for gravity to pull
excess matrix from the exiting reinforcement back into matrix
reservoir 28.
[0026] Matrix reservoir 28 may be manually and/or automatically
filled with matrix. For example, when a periodic inspection of
matrix reservoir 28 reveals a low-level status, additional matrix
may be directed through inlet 30 (e.g., via opening of a valve
and/or activation of a pump--both not shown). Alternatively, a
sensor (e.g., a resistive level or acoustic sensor--not shown) may
be used to automatically direct additional matrix through inlet 30
in response to a detected low-level status. In another embodiment,
matrix may be directed through inlet 30 based on an assumed
consumption rate, in addition to or instead of the other fill
strategies disclosed above.
[0027] Feeder 32 may be located between a supply of reinforcement
(e.g., spool) 36 and matrix reservoir 28 and configured to reduce
tension within the reinforcement through outlet 26 by selectively
pulling reinforcement from spool 36. In particular, when spool 36
is full of reinforcement, it may have a larger mass and associated
inertia. If the reinforcement were to be pulled from spool 36
through outlet 26 simply by movement of head 16 away from anchor
point 18, as described above, enough tension could be created
within the reinforcement to disrupt anchor point 18 under some
conditions, break the reinforcement, and/or cause uneven printing
within structure 12. Accordingly, feeder 32 may selectively pull
the reinforcement from spool 36 (and feed the reinforcement into
matrix reservoir 28, in some applications) at rate that is about
equal to a rate at which the fiber is discharging through outlet
26. Feeder 32 may include, among other things, at least one roller
(e.g., two rollers 38 and 40 that are biased towards each other via
a spring 42). One or both of rollers 38, 40 may have
friction-increasing features (e.g., teeth) to help reduce slippage
of the reinforcement through feeder 32, and/or be powered to rotate
(e.g., by a motor--not shown).
[0028] In one example, feeder 32 may alternatively or additionally
function as an encoder, monitoring usage of reinforcement by head
16 and/or an amount of reinforcement remaining on spool 36. In this
example, at least one of rollers 38, 40 may include indexing
elements (e.g., a slotted disk, an imbedded magnet, an optical
stripe, etc. --shown only in FIG. 3) 41 that are detected by an
associated sensor (e.g., an electronic eye, a camera, a hall-effect
sensor, etc. --shown only in FIG. 3) 43. Based on a sensed number
of revolutions of roller(s) 38, 40, an amount of reinforcement
passing through feeder 32 may be determined. It should be noted
that, although feeder 32 is shown as being located upstream of
matrix reservoir 28, feeder 32 (or only indexing elements 41 and
associated sensor 43) could alternatively be located downstream, if
desired.
[0029] Matrix regulator 34 may be located at a reinforcement exit
point of mechanism 27 and configured to mechanically remove excess
matrix from the reinforcement passing therethrough. In the
disclosed embodiment, matrix regulator 34 includes one or more
wipers (e.g., two opposing wipers) 44 that engage the wetted
reinforcement. Wipers 44 may be biased towards each other (e.g.,
via coil springs 45) to sandwich and/or flexible to deform around
the reinforcement. Matrix reservoir 28 may be generally open to a
lower side of wipers 44, such that removed matrix may be pulled by
gravity back into reservoir 28 and reused. It should be noted that
wipers 44, in addition to regulating an amount of matrix left
clinging to the reinforcement, may also be used to induce a desired
level of tension within the reinforcement, in some applications.
For example, the spring rate of coil springs 45, the flexibility of
wipers 44, and/or an engagement angle of wipers 44 may be
selectively and/or actively adjusted to thereby adjust the tension
level.
[0030] Any number of pulleys or other similar routing devices 46
may be arranged to help route the reinforcement along a desired
path through wetting mechanism 27. For example, one or more routing
devices 46 may be at least partially submerged inside matrix
reservoir 28 at a location between feeder 32 and regulator 34. In
another example, one or more routing devices 46 may be located
outside of matrix reservoir 28 at locations between regulator 34
and outlet 26 (e.g., above matrix reservoir 24 and in axial
alignment with outlet 26). Routing devices 46 may be driven or spin
freely, as desired.
[0031] It should be noted that, although mechanism 27 is shown as
being mounted to print head 16, which is in turn mounted to support
14, the reverse could be true. In addition, mechanism 27 could be
mounted to support 14 completely independent of head 16, if
desired. Likewise, instead of being located axially adjacent head
16, mechanism 27 could alternatively be located axially in line
with head 16 (e.g., axially aligned with outlet 26). Other
configurations may also be possible.
[0032] It is contemplated that feeder 32, when functioning as an
encoder in the manner described above, may be utilized to determine
when print head 16 and/or the manufacturing process has
malfunctioned. Malfunctions experienced by print head 16 can
include untacking of a path of discharged composite material (e.g.,
during cornering) and breaking of the reinforcement within the
path. These malfunctions may be determined, for example, via a
comparison of an actual amount (e.g., a length) of reinforcement
passing through feeder 32 with an expected amount. In particular,
when the actual amount is less than the expected amount (e.g., by
at least a threshold margin), controller 22 may determine that
either the reinforcement has become untacked from a remaining
portion of structure 12 and is being towed through a shorter arc
cutting across a desired corner or that the reinforcement has
completely broken and is no longer being pulled out through outlet
26.
[0033] The expected amount of reinforcement passing through feeder
32 may be determined in any number of ways. For example, the
expected amount may be determined based on progress of print head
16 through a tool path sequence and a known length of the sequence.
In another example, the expected amount may be determined based on
monitored movement of print head 16 away from anchor point 18.
Other methods may also be utilized.
[0034] Once controller 22 determines that a malfunction has
occurred, several actions may be responsively taken. For example,
controller 22 may generate an alert indicating that the print
process may have failed and that a technician should check the
process. Additionally or alternatively, controller 22 may pause the
process and await a confirmation from the technician that the
process should continue. In some situations, controller 22 may
cancel the process completely and, in some embodiments, restart the
process.
[0035] It is contemplated that any of these above described
responses may be selectively implemented based on a severity of the
malfunction. For example, if the difference between the actual and
expected reinforcement amounts is below a first threshold (e.g.,
indicating only that a corner may have been cut or cut by only a
small amount), only the notification may be generated. While, if
the difference is greater than the first threshold (e.g.,
indicating that the reinforcement may have broken), controller 22
may pause and/or cancel the process. Other responses may also be
possible.
[0036] FIGS. 3 and 4 illustrate another exemplary head 16 that may
be used with one or both of matrix reservoir 24 and mechanism 27
(referring to FIG. 2). In this example, outlet 26 may not resemble
the nozzle shown in FIGS. 1 and 2. Instead, outlet 26 of FIGS. 3
and 4 may be associated with a trailing compactor 48 (i.e.,
trailing relative to a normal travel direction of head 16, as
represented by an arrow 50) that functions as a tool-center-point
of head 16.
[0037] Compactor 48 may be used to apply pressure to material
discharged from head 16 via outlet 26. In addition, in some
instances, compactor 48 may be driven to propel head 16 (e.g., via
a motor 51) and/or selectively paired with another roller 52 to
pull the reinforcement through outlet 26. In this way, less (if
any) tension may be generated within the reinforcement outside of
head 16 due to movement of head 16 away from anchor point 18
(referring to FIG. 1). This may allow for the residual level of
tension within each individual reinforcement to be more accurately
controlled.
[0038] In one example, roller 52 may be biased toward compactor 48
(e.g., via a coil spring 54 and a lever arm 55), such that the
reinforcement(s) are sandwiched therebetween. Lever arm 55 may
extend between compactor 48 and roller 52, with coil spring 45
being located at an end adjacent compactor 48. Roller 52 may be an
idler-type of roller or, alternatively, may itself be driven (e.g.,
in addition to compactor 48 or instead of compactor 48 being
driven) to rotate in a direction opposite that of compactor 48. For
example, roller 52 may be operatively driven by motor 51 via a gear
train 56 (shown only in FIG. 4), while compactor 48 is directly
driven by motor 51. It is contemplated that a clutching mechanism
(not shown) could be associated with gear train 56, such that
roller 52 may only be selectively driven during driving of
compactor 48 and/or so that compactor 48 may be driven at least
partially independent of the rotation of roller 52.
[0039] A common mount 57 may be provided for compactor 48, roller
52, motor 51, and/or gear train 56. Mount 57 may include, among
other things, protruding arms 57a that extend to opposing ends of
compactor 48 and roller 52, one of arms 57a being located between
one of the ends and motor 51 and gear train 56. A guide 59 may be
connected to mount 57 at a location upstream of compactor 48. Guide
59 may have one or more guiding features (e.g., grooves, channels,
ribs, dividers, etc.) 61 that help to guide (e.g., align, separate,
converge, shape, etc.) the reinforcements to compactor 48.
[0040] As shown in FIGS. 3 and 4, a cutting mechanism 58 may be
integrated into roller 52. In these examples, cutting mechanism 58
embodies a blade that is normally recessed within roller 52, such
that the blade does not engage the reinforcements during normal
discharge. At select timings, the blade may be pushed radially
outward to protrude through or from an outer surface of roller 52,
thereby allowing the rotation of roller 52 to force the blade
through the reinforcements and against a compliant outer surface of
compactor 48. It is contemplated that the outer surface of
compactor 48 may require periodic replacement and/or that a
replaceable sleeve (not shown) may be positioned over compactor 48
to ensure that a desired texture of the deposited material is
maintained.
[0041] In one example, the blade of cutting mechanism 58 may be
pushed radially outward by fluid pressure. For example, an internal
bladder, piston, or other actuator (not shown) may be selectively
filled and drained of pressurized air, oil, or another fluid to
force the blade to slide outward (e.g., within side-located guides)
or be retracted, as needed. It is contemplated that cutting
mechanism 58 could alternatively be located inside of compactor 48
and selectively pushed radially outward toward roller 52, if
desired.
[0042] In another example, the blade of cutting mechanism 58 may
permanently protrude from roller 52. In this example, roller 52 may
selectively engage compactor 48 (e.g., via controlled swinging of
lever arm 55) only when cutting is desired.
[0043] It can be important, in some applications, to ensure that
severing of the reinforcement by cutting mechanism 58 has completed
successfully, before subsequent operations are initiated. An
exemplary arrangement that provides this confirmation is
illustrated in FIG. 3. As seen in this figure, spool 36 (or an
idler or feeder 32 located between spool 36 and compactor 48--shown
only in FIG. 2) may be fitted with indexing elements 41, and sensor
43 placed in close proximity. At this location, sensor 43 may be
configured to generate signals directed to controller 22 that are
indicative of reinforcement payout (e.g., of rotation of spool 36),
and controller 22 may utilize the signals to determine if
reinforcement is being pulled from head 16 at a time when no
reinforcement should be discharging from outlet 26. For example,
after severing of the reinforcement by cutting mechanism 58 and
during movement and/or restart of a new track of material, the
reinforcement should not be paying out from spool 36 or discharging
from outlet 26. However, if the reinforcement was not successfully
severed and head 16 attempts to move away from the severing
location, the remaining attachment to structure 12 might cause the
reinforcement to be inadvertently pulled from head 16. Sensor 43
may generate signals indicative of this undesired payout, and
controller 22 may respond in any number of different ways. For
example, controller 22 may cause movement of head 16 to halt (e.g.,
via corresponding signals directed to support 14--referring to FIG.
1), generate an error flag, shut down system 10, cause cutting
mechanism 58 to reattempt severing of the reinforcement, and/or
implement another corrective action.
INDUSTRIAL APPLICABILITY
[0044] The disclosed systems may be used to additively 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 cross-sectional sizes and shapes, and any number of
different matrixes of the same or different makeup. Operation of
system 10 will now be described in detail.
[0045] At a start of a manufacturing event, information regarding a
desired structure 12 may be loaded into system 10 (e.g., into
controller 22 that is responsible for regulating operations of
support 14 and/or head 16). 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.), desired weave patterns,
weave transition locations, reinforcement information (e.g., types,
sizes, shapes, performance characteristics, densities, and
trajectories), matrix information (e.g., type, cure requirements,
performance characteristics), 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.
[0046] To install the reinforcements, individual fibers, tows,
and/or ribbons may be passed through head 16 (e.g., through
reservoir 24 and/or reservoir 28, and outlet 26). In some
embodiments, the reinforcements may additional be passed between
roller 52 and compactor 48 (referring to FIGS. 3 and 4) and/or
attached to anchor point 18. Installation of the matrix material
may include filling matrix reservoir(s) 24 and/or 28, and/or
coupling of an extruder (not shown) to head 16.
[0047] The component information may then be used to control
operation of system 10. For example, particular reinforcements may
be pulled and/or pushed along with a particular matrix material
from head 16 in desired amounts and/or at desired rates. Support 14
may also selectively move head 16 and/or anchor point 18 in a
desired manner, such that an axis of the resulting structure 12
follows a desired three-dimensional trajectory. Cure enhancer(s) 20
may be selectively activated during material discharge, such that
the matrix cures at least enough to maintain a shape of structure
12. Once structure 12 has grown to a desired length, structure 12
may be severed from system 10 via cutting mechanism 58.
[0048] The disclosed system may have improved reinforcement wetting
and management. Wetting may be improved via precise control over
the matrix within a separate and upstream mechanism that is at
least partially isolated from (e.g., not axially aligned with)
outlet 26. Reinforcement management may be improved by monitoring
reinforcement travel through head 16 (e.g., fiber payout), and
selectively responding with corrective actions based on a
comparison with travel of head 16 caused by support 14.
[0049] 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. 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.
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