U.S. patent application number 11/322645 was filed with the patent office on 2006-11-23 for large-tow fiber-placement system.
This patent application is currently assigned to Zoltek Companies, Inc.. Invention is credited to Scott M. Cutler, Dennis Hegerhorst, Mark Liddiard, Paul C. Merrill, Trond R. Pedersen, David E. Rasmussen, Ronald R. Roser, Kirk J. Samowitz, Curtis Veit, Ken W. Warfield.
Application Number | 20060260106 11/322645 |
Document ID | / |
Family ID | 37446937 |
Filed Date | 2006-11-23 |
United States Patent
Application |
20060260106 |
Kind Code |
A1 |
Roser; Ronald R. ; et
al. |
November 23, 2006 |
Large-tow fiber-placement system
Abstract
A large-tow fiber placement system having (1) a creel, (2) a tow
feeding mechanism, (3) a tow cutting mechanism, and (4) a tow
consolidation system, wherein the creel shuttles a spool to
maintain a substantially fixed exit path of a large-tow exiting the
spool, the tow feeding mechanism has a head that is cooled by a
fluid to control integrity of the large-tow and the tow
consolidation system has interlocking shoes to provide a continuous
application of the head is disclosed.
Inventors: |
Roser; Ronald R.; (Salt Lake
City, UT) ; Rasmussen; David E.; (Sandy, UT) ;
Pedersen; Trond R.; (Murray, UT) ; Cutler; Scott
M.; (Sandy, UT) ; Warfield; Ken W.; (Holladay,
UT) ; Hegerhorst; Dennis; (Nampa, ID) ;
Merrill; Paul C.; (Bountiful, UT) ; Samowitz; Kirk
J.; (South Jordan, UT) ; Liddiard; Mark;
(Sandy, UT) ; Veit; Curtis; (Salt Lake City,
UT) |
Correspondence
Address: |
MORRISON & FOERSTER LLP
1650 TYSONS BOULEVARD
SUITE 300
MCLEAN
VA
22102
US
|
Assignee: |
Zoltek Companies, Inc.
St. Louis
MO
|
Family ID: |
37446937 |
Appl. No.: |
11/322645 |
Filed: |
January 3, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60640235 |
Jan 3, 2005 |
|
|
|
Current U.S.
Class: |
28/282 |
Current CPC
Class: |
D02J 1/18 20130101 |
Class at
Publication: |
028/282 |
International
Class: |
D02J 1/18 20060101
D02J001/18 |
Claims
1. A large-tow fiber placement system comprising (1) a creel, (2) a
tow feeding mechanism, (3) a tow cutting mechanism, and (4) a tow
consolidation system, wherein the creel shuttles a spool to
maintain a substantially fixed exit path of a large-tow exiting the
spool, the tow feeding mechanism comprises a head that is cooled by
a fluid to control integrity of the large-tow and the tow
consolidation system comprises interlocking shoes to provide a
continuous application of the head.
2. The large-tow fiber placement system of claim 1, wherein the
creel comprises a tow take-up mechanism to prevent slack of the
large-tow.
3. The large-tow fiber placement system of claim 1, wherein the
creel comprises staggered spindles to allow side-by-side alignment
of a plurality of the large-tows.
4. The large-tow fiber placement system of claim 1, wherein the tow
feeding mechanism comprises textured rollers.
5. The large-tow fiber placement system of claim 1, wherein the tow
feeding mechanism comprises multiple rollers.
6. The large-tow fiber placement system of claim 1, wherein the
feeding mechanism comprises a plurality of staggered cylinders to
maintain a desired gap between a plurality of the large-tows.
7. The large-tow fiber placement system of claim 1, wherein the
feeding mechanism is self-threading.
8. The large-tow fiber placement system of claim 1, wherein the
feeding mechanism comprises a modular side-drive assembly to allow
for an ease of maintenance.
9. The large-tow fiber placement system of claim 1, wherein the tow
cutting mechanism comprises a laser.
10. The large-tow fiber placement system of claim 9, wherein the
laser is mounted in a fixed position with the beam being directed
to the large-tow through telescoping optics.
11. The large-tow fiber placement system of claim 10, wherein a
shuttling head allows the laser to cut one or more large-tows from
a plurality of large-tows.
12. The large-tow fiber placement system of claim 10, wherein the
laser is contained beyond the large-tow with a monolithic carbon
trap.
13. The large-tow fiber placement system of claim 1, wherein the
tow consolidation system further comprises a wiper-blade to provide
smooth spreading and consolidation of the large-tow.
14. The large-tow fiber placement system of claim 1, wherein the
tow consolidation system pulls the large-tow straight onto an
application surface.
15. The large-tow fiber placement system of claim 1, wherein the
tow consolidation system prevents overlap of a plurality of the
large-tows on an application surface.
16. The large-tow fiber placement system of claim 1, wherein the
tow consolidation system eliminates the generation of catenaries at
an application point of an application surface.
17. The large-tow fiber placement system of claim 1, wherein the
tow consolidation system further comprises compaction cylinders and
the interlocking shoes are mounted on the ends of the compaction
cylinders.
18. The large-tow fiber placement system of claim 1, wherein the
interlocking shoes have a tangential swiveling capability.
19. The large-tow fiber placement system of claim 1, wherein the
fluid is a liquid.
20. The large-tow fiber placement system of claim 13, wherein the
wiper blade has a continuous, unbroken surface to contact a
plurality of the large-tows.
Description
REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to U.S. Provisional
Application No. 60/640,235, filed Jan. 3, 2005, the contents of
which are hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] The embodiments of the invention relate to a system for
large-tow fiber placement. This invention transcends several
scientific disciplines such as textiles, fibers, composites,
mechanical engineering, materials science, and chemistry.
BACKGROUND
[0003] The term "large-tow" refer to tows having filaments ranging
from 50K to 600K or more, for example 150K, which could be with or
without pre-impregnated resin. Currently, the placement of large
tow, particularly, resin pre-impregnated fibers, present a number
of challenges in handling and application in the fiber-placement
process. The subject invention embodies a practical process to
apply large-tow, preferably pre-impregnated, fibers to surfaces
through the use of specific tooling and process temperature
controls.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1: An embodiment of the shuttling-roller system.
[0005] FIG. 2: An embodiment of the tow tensioning assembly.
[0006] FIG. 3: An embodiment of the axial staggered mounting of the
material spools.
[0007] FIG. 4: An embodiment of the towpreg feeding system.
[0008] FIG. 5: An embodiment showing the arrangement of the laser
relative to the fiber band.
[0009] FIG. 6: An embodiment of the tow compaction system.
SUMMARY OF THE INVENTION
[0010] The embodiments of the invention relate to a large-tow fiber
placement system comprising (1) a creel, (2) a tow feeding
mechanism, (3) a tow cutting mechanism, and (4) a tow consolidation
system, wherein the creel shuttles a spool to maintain a
substantially fixed exit path of a large-tow exiting the spool, the
tow feeding mechanism comprises a head that is cooled by a fluid,
preferably a liquid, to control integrity of the large-tow and the
tow consolidation system comprises interlocking shoes to provide a
continuous application of the head. Preferably, the creel comprises
a tow take-up mechanism to prevent slack of the large-tow.
Preferably, the creel comprises staggered spindles to allow
side-by-side alignment of a plurality of the large-tows.
Preferably, the tow feeding mechanism comprises textured rollers.
Preferably, the tow feeding mechanism comprises multiple rollers.
Preferably, the feeding mechanism comprises a plurality of
staggered cylinders to maintain a desired gap between a plurality
of the large-tows. Preferably, the feeding mechanism is
self-threading. Preferably, the feeding mechanism comprises a
modular side-drive assembly to allow for an ease of maintenance.
Preferably, the tow cutting mechanism comprises a laser.
Preferably, the laser is mounted in a fixed position with the beam
being directed to the large-tow through telescoping optics.
Preferably, a shuttling head allows the laser to cut one or more
large-tows from a plurality of large-tows. Preferably, the laser is
contained beyond the large-tow with a monolithic carbon trap.
Preferably, the tow consolidation system further comprises a
wiper-blade to provide smooth spreading and consolidation of the
large-tow. Preferably, the tow consolidation system pulls the
large-tow straight onto an application surface. Preferably, the tow
consolidation system prevents overlap of a plurality of the
large-tows on an application surface. Preferably, the tow
consolidation system eliminates the generation of catenaries at an
application point of an application surface. Preferably, the tow
consolidation system further comprises compaction cylinders and the
interlocking shoes are mounted on the ends of the compaction
cylinders. Preferably, the interlocking shoes have a tangential
swiveling capability. Preferably, the wiper blade has a continuous,
unbroken surface to contact a plurality of the large-tows.
[0011] As will be realized, this invention is capable of other and
different embodiments, and its details are capable of modifications
in various obvious respects, all without departing from this
invention. Accordingly, the drawings and description are to be
regarded as illustrative in nature and not as restrictive.
DETAILED DESCRIPTION
[0012] As used in the specification and claims, the singular forms
"a", "an" and "the" include plural references unless the context
clearly dictates otherwise. The embodiments of the invention relate
to the following components of the large-tow fiber placement
system.
[0013] Creel: In the preferred embodiments, the creel has the
following features: (1) Axially shuttles a spool to maintain a
fixed towpreg centerline exit path. (2) Ablity to utilize large
material spools to minimize material change-outs. (3) Uses a
lightweight roller for payoff position feedback. (4) Tow take-up
mechanisms (individually and/or collectively) to prevent tow-slack
in the system. (5) Staggering of material spindles to allow
side-by-side tow alignment.
[0014] Tow Feed and Cut Mechanism: In the preferred embodiments,
the tow feed and cut mechanism has the following features: (1)
Textured rollers to provide superior tow pull. (2) Use of multiple
rollers to maximize feed pull-force. (3) Staggering (fore and aft)
of cylinders to minimize gap between tows. (4) Liquid cooling of
head to provide accurate cooling to control tow integrity. (5)
Design has self-threading feature. (6) Modular side drive assembly
design to allow for the ease of maintenance. (7) Cutting or
terminating of the tow feed could be done with an industrial laser
as required "on the fly".
[0015] Tow Consolidation System: In the preferred embodiments, the
tow consolidation system has the following features: (1) Individual
interlocking shoes to provide a continuous but compliant
application head. The interlocking shoes could also swivel to
provide a continuous consolidation force that conforms to
application surface. (2) A wiper-blade applicator to provide smooth
spreading and consolidation of tows. (3) Pulls tows straight onto
the application surface. (4) Prevents tow overlap on application
surface. (5) Eliminates the generation of catenaries at the
application point. (6) Single application-plane delivery.
[0016] The subject invention has been demonstrated to provide a
means to economically apply a wide band of large-tow, resin
pre-impregnated fiber to a surface to create a high strength,
lightweight, structure. The embodiments of the invention satisfy a
great need for such equipment and processes in the energy, and
transportation industries. Examples of applications include
manufacturing large wind turbine blades, aircraft and automotive
panels, etc.
EXAMPLES
[0017] Creel
[0018] In order to achieve manufacturing efficiency, the subject
machine could use towpreg and spools significantly larger than
those traditionally used. The spools typically used, for example,
are around 35 inches in length and, when loaded with material,
weigh approximately 90 lbs. The creel of the embodiments of the
invention could use spools of other sizes and weights. Grooved
rollers could be used to direct and route the tows into the
machine.
[0019] In order to maintain capture of the tows by guide rollers,
it is preferable that each tow feed off of their respective spools
substantially straight into a guided path. This is accomplished by
shuttling the material spool back and forth to keep the payoff
point aligned with the centerline of the appropriate guide roller.
A system was created using low-cost components, which minimizes the
amount of processing power required in closed-loop control. This
system was accomplished by a novel design of the shuttling
rollers--the first grooved roller the tows encounter as they leave
their spool. The shuttling roller is free to rotate about a shaft
as well as translate side to side. As each tow pays off its
respective spool, the pay off point moves axially with respect to
the spool. As it does so, the tow drags the shuttling roller along
with it axially. The axial movement of the shuttling roller is
constrained by blocks placed approximately 4 inches apart on the
roller shaft with the shuttling roller between these two
`set-point` blocks. A proximity sensor is mounted on each of the
two limiting blocks and interacts with the shuttling roller. As the
shuttling roller reaches the maximum allowed travel defined by the
position of a set-point block, a signal is produced by the
respective proximity sensor. This signal is noted by a controller
that then opens a valve supplying air to a pneumatic cylinder. The
pneumatic cylinder moves the towpreg spool in the proper direction
to re-position the payout point with the nominal centerline. As it
does so, the shuttling roller is dragged along with it and the
sensor signal is restored, the air to the pneumatic cylinder is
stopped, as is the movement of the towpreg spool. The towpreg spool
again remains axially stationary until the payout point has once
again dragged the shuttling spool to its set-point where the
closed-loop process begins again. This process continues until the
towpreg wrapping turn-around point is reached at which time the
unwinding of the towpreg drags to shuttling roller to the opposing
set-point block which then initiates a movement of the towpreg
spool in the opposite direction.
[0020] The operation of this system provides the ability of the
shuttling roller to move easily and freely. This is accomplished
through the use of very low friction bearings and the design of the
shuttling roller itself to be lightweight. Each roller has a
lead-in into its containment groove to insure that the tow is and
remains captured. Axial dragging of the shuttling roller is created
because of relatively high, straight walls on the sides of the
groove. The shuttling-roller system is illustrated in FIG. 1.
[0021] In order to prevent the tows from jumping out of the grooves
of the roller they pass over, and to prevent the tows from tangling
with each other, a slight tension needs to be maintained in each
tow. This is accomplished by two unique systems. The first system
uses springs and pneumatic cylinders to interact with each tow
individually. As the payout rate on each tow varies, an individual
pneumatic cylinder extends or retracts to take up the desired slack
and maintain the desired tension. Large excursions are handled by
the springs.
[0022] The other take-up system is used to take up slack created by
vertical movements of the head when tows are not being paid out.
The system uses linear actuators slaved to the vertical movement of
the head to take up slack in all the tows simultaneously. At the
end of a lay-down pass the head must be raised to position it for
the start of another pass. When this occurs, the above-mentioned
actuators extend a roller to take up the resulting slack in the
tows. At the beginning of the lay-down pass the head is lowered to
contact the mandrel surface. At this time the actuators retract the
roller and allow the tows to pay out. The actuators use the
lay-down rate to determine the retraction rate of the roller to
assure that no slack in introduced into the tows and allows the
roller to be completely retracted and ready for another cycle. The
tow tensioning assembly is shown in FIG. 2:
[0023] Another design feature of the creel is the axial staggering
of the material spool mounting. This allows side-by-side placement
of the tows as they feed into the fiber placement head. The axial
staggered mounting of the material spools is illustrated in FIG.
3.
[0024] Tow-Feed Mechanism
[0025] To start the towpreg lay-down process, the tows should
preferably be advanced to a nip point and back tension must be
relieved to facilitate the band start. Both of these functions are
accomplished by a tow-feeding mechanism that incorporates several
unique features.
[0026] Textured rollers are used to grip and feed the tows. This
type of roller provides a superior feeding force when compared to
simple rubber or coated rollers. Multiple rollers are used to
further increase the feeding force.
[0027] Another unique feature of this design is the fore and aft
staggering of the pneumatic cylinders used to pinch the tows
against the textured rollers. Because the tows on this design are
on a single plane (the same principle works with a staggered plane
delivery), it is desired to minimize the gap between the tows. In
order to provide maximum pull force it is desired to use the
largest pneumatic cylinders and pinch rollers possible. This is
accomplished by staggering the pneumatic cylinders.
[0028] In order to prevent sticking of the towpreg to components,
it is desired to cool the tows so that they are not tacky. One way
the cooling could be accomplished is through the use of cooled
gases. Another way the cooling could be accomplished is by using a
liquid coolant to control the temperature of surfaces in contact
with the tow.
[0029] The tow-feed mechanism incorporates a self-threading feature
to minimize the time required to set up the head. Tows can be
introduced at the back of the head and they are automatically fed
through the head to the nip point.
[0030] To facilitate maintenance, this design allows some or all
pinch rollers to be removed from the top and all textured rollers
to be removed from the side. The towpreg feeding mechanism is shown
in FIG. 4.
[0031] Tow-Cutting Mechanism
[0032] Tow-cutting is done with a laser during the fiber placement
process. An industrial power laser generator is mounted in a fixed
position with the laser beam being directed to location through
telescoping optics. A shuttling right angle head allows the common
laser to cut tows individually anywhere across the full bandwidth.
The focal point of the laser power is optically focused to be at
the point where it crosses the fiber path. Laser power is
sufficient to cut through a large tow such as 150K "on the fly"
during the fiber placement process. The laser beam beyond the fiber
tow is contained with a monolithic carbon trap. The laser beam trap
is cooled by a liquid cooled platen upon which it is mounted. FIG.
5 shows the arrangement of the laser relative to the fiber
band.
[0033] Tow Consolidation System
[0034] To ensure that the tows stay in place in the laminate, and
to eliminate voids, a compaction or consolidation system must be
used. The tow consolidation system for this design uses pneumatic
cylinders to provide the compaction force. Use of pneumatic
cylinders assures that the compaction force remains constant, as
long as the stroke of the cylinders is within their limits.
[0035] Compaction shoes are mounted on the ends of the compaction
cylinders. These shoes form a single tier and feature a unique
interlocking design to eliminate any across-the-bandwidth gaps in
compaction elements. This feature, along with the shoes tangential
swiveling capability, and position changes made possible by the
pneumatic cylinders, accommodates a varying-radius crowned
application surface.
[0036] Another unique feature of the compaction system is the use
of a wiper blade placed under the compaction shoes. This blade is
made of a low-friction, long-wearing material and is the element
that actually comes in contact with the towpreg. The use of a
sliding rather than a rolling element provides superior spreading
capability, smoothness of the laminate, and pulls the tows straight
in the lay-down process. The wiper blade also prevents tow overlap
and a band of fibers free of catenaries (loose fibers that stick to
and can roll up on rotating elements). The wiper blade presents a
continuous, unbroken surface to the towpreg so there are no cracks
or crevasses to catch or snag fibers during application. This makes
for a self-cleaning and highly reliable system. The wiper blade
tends to smooth out the distribution of the compaction force and
protects the compaction shoes from wear.
[0037] While the wiper blade is preformed to a desired mid-range
radius, it is compliant enough to allow conformance to other radii.
The wiper blade can be fabricated to help guide the tows to their
proper positions. The tow compaction system is shown in FIG. 6.
* * * * *