U.S. patent application number 10/829270 was filed with the patent office on 2005-10-27 for backing film and method for ply materials.
This patent application is currently assigned to The Boeing Company. Invention is credited to Evans, Richard B..
Application Number | 20050238892 10/829270 |
Document ID | / |
Family ID | 35136825 |
Filed Date | 2005-10-27 |
United States Patent
Application |
20050238892 |
Kind Code |
A1 |
Evans, Richard B. |
October 27, 2005 |
Backing film and method for ply materials
Abstract
A layered material includes a ply material and a backing film to
support the ply material. The backing film includes a polyester
film. The layered material is generated by disposing the backing
film upon the ply material. A composite layup is generated by
tacking the layered material to a tool, disposing the layered
material upon the tool along a path, and removing the backing
film.
Inventors: |
Evans, Richard B.; (Maple
Valley, WA) |
Correspondence
Address: |
BAKER & HOSTETLER LLP
Suite 1100
Washington Square
1050 Connecticut Avenue
WASHINGTON
DC
20036
US
|
Assignee: |
The Boeing Company
|
Family ID: |
35136825 |
Appl. No.: |
10/829270 |
Filed: |
April 22, 2004 |
Current U.S.
Class: |
428/458 ;
428/323; 428/447; 428/480 |
Current CPC
Class: |
B32B 7/06 20130101; Y10T
156/1705 20150115; Y10T 156/1052 20150115; Y10T 156/1062 20150115;
B32B 9/007 20130101; B32B 27/12 20130101; B32B 2037/148 20130101;
Y10T 428/31529 20150401; Y10T 156/12 20150115; Y10T 428/31681
20150401; B32B 9/045 20130101; B32B 38/0004 20130101; Y10T 428/25
20150115; Y10T 428/31663 20150401; Y10T 428/269 20150115; Y10T
428/31786 20150401; B32B 15/09 20130101; B32B 27/36 20130101 |
Class at
Publication: |
428/458 ;
428/480; 428/447; 428/323 |
International
Class: |
B32B 009/00; B32B
027/36 |
Claims
What is claimed is:
1. A layered material comprising: a ply material; and a backing
film disposed upon the ply material, the backing film comprising a
polyester film.
2. The layered material according to claim 1, wherein the backing
film further comprises: a release coating to facilitate removal of
the backing film from the composite ply material.
3. The layered material according to claim 2, wherein the release
coating comprises silicone.
4. The layered material according to claim 1, wherein the backing
film is about 0.001 to about 0.004 inches thick.
5. The layered material according to claim 4, wherein the backing
film is about 0.001 to about 0.002 inches thick.
6. The layered material according to claim 1, wherein the backing
film is substantially transparent.
7. The layered material according to claim 1, wherein the backing
film comprises polyethylene terephthalate.
8. The layered material according to claim 1, wherein the backing
film is heat stabilized.
9. The layered material according to claim 1, wherein the ply
material comprises graphite fibers.
10. The layered material according to claim 1, wherein the ply
material comprises a metal foil.
11. The layered material according to claim 10, wherein the ply
material comprises a titanium foil.
12. The layered material according to claim 11, wherein the ply
material comprises a titanium graphite composite.
13. The layered material according to claim 1, wherein the backing
film is recyclable.
14. An apparatus for generating backed ply material, the apparatus
comprising: means for disposing a polyester film upon a ply
material; and means for generating a roll of the backed ply
material by wrapping the backed ply material about a spool.
15. The apparatus according to claim 14, wherein the polyester film
is substantially transparent.
16. An apparatus for generating a composite layup, the apparatus
comprising: means for tacking a ply material having a polyester
backing film to a tool; means for disposing the ply material upon
the tool along a path; and means for removing the polyester backing
film.
17. The apparatus according to claim 16, further comprising: means
for cutting the ply material in response disposing the ply material
at an end of the path.
18. A method of generating a backed ply material, the method
comprising: disposing a polyester film upon a ply material.
19. The method according to claim 18, further comprising:
generating a roll of the backed ply material by wrapping the backed
ply material about a spool.
20. The method according to claim 18, wherein the polyester film is
substantially transparent.
21. A method of generating a composite layup, the method
comprising: tacking a ply material having a polyester backing film
to a tool; disposing the ply material upon the tool along a path;
and removing the polyester backing film.
22. The method according to claim 21, further comprising: cutting
the ply material in response disposing the ply material at an end
of the path.
23. The method according to claim 21, further comprising: recycling
the polyester backing film in response to the removing step.
Description
FIELD OF THE INVENTION
[0001] The present invention generally relates to backing materials
for sheet and roll stock. More particularly, the present invention
pertains to an improved backing material for pre-impregnated ply
material.
BACKGROUND OF THE INVENTION
[0002] Composite structures are typically constructed from multiple
layers or plies. These plies may include a variety of materials
such as carbon fiber, various other fibers, metal foils, and the
like. In addition, the plies may be pre-impregnated with a resin
and are often dispensed from a roll or spool. In roll form, the ply
material is referred to as "tape" and typically includes a paper
backing film. This backing film generally prevents pre-impregnated
ply material (prepreg) from adhering to itself and aids in handling
the ply as the ply is applied to the tool and the layup. In
particular, at the beginning and end of each ply placement, the ply
material is generally cut to match the profile of the layup while
the backing film is left intact. In this manner, the intact backing
film is utilized to guide the severed ply on to the layup. During
the layup process, the backing film is removed prior to placement
of any subsequent ply.
[0003] A disadvantage associated with conventional backing film
material is that the backing film rips or tears. In particular,
cuts in the backing film, introduced during the ply cutting
procedure, often serve as a starting point for a tear. As the
backing film is removed, torn backing film may remain on the ply,
may foul the ply placement head, and/or may lead to breakage of the
backing film.
[0004] Another disadvantage associated with conventional backing
film is that it is usually a relatively thick calendered claycote
type paper. The weight and thickness of this paper reduce the
yardage of ply material that may be placed on a spool of a given
diameter. Reducing the thickness of the conventional backing film
in an effort to place more backed ply material on a spool, however,
increases the tendency of the backing film to tear.
[0005] Yet another disadvantage associated with conventional
backings films is the opaque nature of the paper. This opacity
precludes visual inspection of the ply placement until the backing
film is removed. Once the backing film is removed from the ply, the
handling characteristics of the ply are negatively impacted so, it
is difficult or impossible to adjust the ply placement.
[0006] Accordingly, it is desirable to provide a backing film for
pre-impregnated ply material that is capable of overcoming the
disadvantages described herein at least to some extent.
SUMMARY OF THE INVENTION
[0007] The foregoing needs are met, to a great extent, by the
present invention, wherein in some embodiments an improved backing
film for pre-impregnated ply material is provided.
[0008] An embodiment of the present invention relates to a layered
material. The layered material includes a ply material and a
backing film disposed upon the ply material. The backing film
includes a polyester film.
[0009] Another embodiment of the present invention pertains to an
apparatus for generating backed ply material. The apparatus
includes a means for disposing a polyester film upon a ply material
and a means for generating a roll of the backed ply material by
wrapping the backed ply material about a spool.
[0010] Yet another embodiment of the present invention relates to
an apparatus for generating a composite layup. The apparatus
includes a means for tacking a ply material having a polyester
backing film to a tool. The apparatus further includes a means for
disposing the ply material upon the tool along a path and a means
for removing the polyester backing film.
[0011] Yet another embodiment of the present invention pertains to
a method of generating a backed ply material. In this method, a
polyester film is disposed upon a ply material.
[0012] Yet another embodiment of the present invention relates to a
method of generating a composite layup. In this method, a ply
material having a polyester backing film is tacked to a tool, the
ply material is disposed upon the tool along a path, and the
polyester backing film is removed.
[0013] There has thus been outlined, rather broadly, certain
embodiments of the invention in order that the detailed description
thereof herein may be better understood, and in order that the
present contribution to the art may be better appreciated. There
are, of course, additional embodiments of the invention that will
be described below and which will form the subject matter of the
claims appended hereto.
[0014] In this respect, before explaining at least one embodiment
of the invention in detail, it is to be understood that the
invention is not limited in its application to the details of
construction and to the arrangements of the components set forth in
the following description or illustrated in the drawings. The
invention is capable of embodiments in addition to those described
and of being practiced and carried out in various ways. Also, it is
to be understood that the phraseology and terminology employed
herein, as well as the abstract, are for the purpose of description
and should not be regarded as limiting.
[0015] As such, those skilled in the art will appreciate that the
conception upon which this disclosure is based may readily be
utilized as a basis for the designing of other structures, methods
and systems for carrying out the several purposes of the present
invention. It is important, therefore, that the claims be regarded
as including such equivalent constructions insofar as they do not
depart from the spirit and scope of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is perspective view of ply material according to an
embodiment of the invention.
[0017] FIG. 2 is a simplified side view of a tape laying head
suitable for use with the ply material according to FIG. 1.
[0018] FIG. 3 is a perspective view of a contour tape lamination
machine suitable for use with the ply material according to FIG.
1.
[0019] FIG. 4 is a flow diagram of a method of placing plies to
produce a composite structure or product according to an embodiment
of the invention.
[0020] FIG. 5 is a flow diagram of a method to generate a backed
ply material according to FIG. 1.
DETAILED DESCRIPTION
[0021] The present invention provides, in some embodiments, a
backing material, a backed composite ply material, and a method of
generating a backed ply material. An embodiment of the invention
will now be described with reference to the drawing figures, in
which like reference numerals refer to like parts throughout. As
shown in FIG. 1, a backed ply material 10 includes a ply material
12 and a backing 14. In various embodiments of the invention, the
ply material 12 may include any suitable sheet stock. Examples of
suitable sheet stocks include: woven fiber fabric; oriented strand
tape; metal foil such as aluminum alloy and titanium foil;
composite materials such as titanium graphite composites; and the
like. In a particular embodiment, the ply material 12 is a graphite
fiber tape pre-impregnated with an epoxy resin (pre-preg). In
another particular embodiment, the ply material 12 is an epoxy
resin coated titanium foil.
[0022] In general, the backing 14 lends support to the ply material
12 and aids in handling the ply material 12. As described herein,
the backed ply material 10 is typically rolled on to a spool in
preparation for dispensing. For a given thickness of the ply
material 12 rolled into a given diameter spool, the thickness of
the backing 14 has an inversely proportional relationship with the
length of ply material 12 that may be placed on the spool. That is,
the thinner the backing 14, the more ply material 12 will fit onto
the spool. Longer lengths of ply material 12 are generally
preferred due to the decreased number of splices that must be
prepared, reduced downtime as a result of the decreased number of
splices, and reduced number of spool change operation to be
performed. Thus, it is preferable that the backing 12 is thin. In
addition, the thickness of this backing 14 is varied depending upon
the particular application. For example, according to various
embodiments of the invention, for typical composite layup
applications, the thickness of the backing 14 is from about 0.001
inches (1 mil) to about 0.004 inches (4 mil). More preferably, the
thickness of the backing 14 is about 1 mil to about 2 mil. However,
in other embodiments, the thickness of the backing 14 is less than
1 mil. For example, when constructing relatively small and/or
convoluted items such as, hand held or smaller devices, it may be
advantageous that the ply material 12 be approximately 1 mil thick
or less and the backing 14 be approximately 0.1 mil thick or less.
In yet other embodiments, the thickness of the backing 14 is
greater than 4 mil. For example, when constructing items with
relatively thick (3 millimeters or more) or otherwise difficult to
handle ply material 12, the backing 14 may be 10 or more mil
thick.
[0023] During layup operations, the backing 14 is typically
removed. To reduce down time, it is also preferable that the
backing 14 is tear-resistant. For example, the backing 14 may
include a polymeric or otherwise tough resilient material.
According to an embodiment of the invention, the backing 14
includes a suitable polyester film. Suitable polyester films
include at least polyethylene terephthalate (PET) and heat
stabilized PET. In this regard, when applying heat during layup
operations, it may be advantageous to utilize a heat stabilized
PET. To further facilitate removal of the backing 14 from the ply
material 12, the backing 14 optionally includes a suitable release
agent. Suitable release agents include at least silicone release
agents applied by Tribex Corp. of Rocklin Calif., USA. Optionally,
the backing 14 is substantially transparent to facilitate
inspection of seams between abutting plies. For example, a 2 mil
film of PET is essentially transparent.
[0024] FIG. 2 is a simplified side view of a tape laying head 18
suitable for use with the backed ply material 10 according to FIG.
1. As shown in FIG. 2, the tape laying head 18 includes a supply
spool 20, take-up reel 22, a shoe or compaction roller 24, cutting
assembly 26, heater assembly 28, material feeder 30, and guide
chute 32. The tape laying head 18 dispenses the ply material 12
upon a tool 34 as it moves in direction A relative to the tool 34.
More particularly, the supply spool 20 and the take-up reel 22
rotate in the respectively indicated directions to cause backed ply
material 10 to advance through the tape laying head 18 as
indicated. The supply spool 20 and/or the take-up reel 22 are
optionally controlled to rotate via the action of, for example, one
or more servo axis motors. Following application of the ply
material 12 upon the tool 34, the backing 14 is removed and
collected by, for example, the take-up reel 22. However, the
take-up reel 22 is optional and thus, the backing 14 may be removed
in any suitable manner such as, for example, manually, a backing
removal device, or the like. Depending upon the particular
application, the placement of the ply material 12 may be inspected
prior to removal of the backing 14. In this regard, it is an
advantage of some embodiments of the invention that the backing 14
is substantially transparent and thus, the placement of the ply
material 14 may be plainly visible through the backing 14.
[0025] The cutting assembly 26 may employ any known cutting device
such as various bladed devices, abrasive cutters, high pressure
jets, lasers, and the like. In a specific example, the cutting
assembly 26 includes an ultrasonic knife that is caused to vibrate
by an ultrasonic transducer and controlled to rotate by the action
of a motor. The ultrasonic knife is further controlled to traverse
the full width of the backed ply material 10 or any portion thereof
by the action of a motor configured to rotate a jackscrew.
Furthermore, the cutting assembly 26 may employ more than one
cutting device. For example, the cutting assembly 26 of an
embodiment of the invention includes two cutting devices controlled
to perform cutting operations in a substantially simultaneous
manner.
[0026] When utilizing specific materials and/or operating
conditions in which heating of the material is advantageous, the
heater assembly 28 is configured to impart thermal energy upon the
backed ply material 10. In this regard, any known device operable
to heat the backed ply material 10 in a suitable manner may be
utilized by various embodiments of the invention. For example, the
heater assembly 28 may include a diverter valve configured to
control the flow of heated air directed onto the backed ply
material 10. In addition, to the heater assembly 28, the tape
laying head 18 may include various supplemental heaters such as,
for example, a guide chute heater, a heater following the
compactions roller 24, and the like.
[0027] FIG. 3 is a perspective view of a contour tape lamination
machine (CTLM) 38 suitable for use with the backed ply material 10
according to FIG. 1. As shown in FIG. 3, the CTLM 38 is of a
gantry-type and, as such, includes a gantry 40, the tape laying
head 18, and the tool 34. The gantry 40 is configured to control
the movement of the tape laying head 18 in relation to the tool 34
and the ply material 12 laid upon the tool 34. In an embodiment of
the invention, the gantry 40 is configured to control ten axis of
movement (five axis of the gantry and five axis of the tape laying
head 18). However, it is to be understood that the specific number
of axis may depend upon the particular operating condition and
thus, the number of axis controlled is not critical to the
invention.
[0028] FIG. 4 illustrates steps involved in a method 44 of placing
plies to produce a composite structure or product. Prior to the
initiation of the method 44, a composite product is designed and a
series of computer readable instructions specifying attributes of
the composite product is generated. These instructions are utilized
to control the operations of the CTLM 38 and construct a form such
as the tool 34. This form is further positioned within the
operational area of the CTLM 38.
[0029] At step 46, the method 44 is initiated by turning on the
various components of the CTLM 38 described herein above and
executing the computer readable instructions.
[0030] At step 48, the backed ply material 10 is advanced to an
initial point. For example, the take up reel 22 and/or the supply
spool 20 may be controlled to advance the backing 14 through the
tape laying head 18 until an end of the ply material 12 is
positioned between the compaction roller 24 and the tool 34. In
another example, the rollers of the material feeder 30 may engage
the backed ply material 10 and advance the ply through the tape
laying head 18 until the backed ply material 10 is positioned to be
applied to the tool 34, referred to as being tacked. To ensure the
backed ply material 10 has advanced a suitable amount, a sensor
and/or operator may sense the position of the backed ply material
10. In addition, the location on the tool 34 is determined based
upon the series of computer readable instruction and/or the
location of a previously positioned ply material 12. Furthermore,
prior to tacking the ply material 12 to the substrate at step 50,
the end of the ply material 12 is, optionally, cut based upon the
series of computer readable instruction, the orientation of a
previously positioned ply material 12, and/or the location of a
previously positioned ply material 12. In a particular example,
cutting of the ply material 12 may be performed at a controlled
depth of cut so as to substantially sever the ply material 12 while
leaving the backing 14 substantially uncut.
[0031] At step 50, the backed ply material 10 is tacked to the
substrate. In an embodiment of the invention, the backed ply
material 10 is tacked by positioning the tape laying head 18 with
the CTLM 38 such that the compaction roller 24 or a shoe is
controlled to press the backed ply material 10 on to the substrate
with sufficient force so as to cause the backed ply material 10 to
adhere to the substrate.
[0032] At step 52, the backed ply material 10 is dispensed along a
path across the tool 34. In order to minimize deformations in the
backed ply material 10 (e.g., wrinkles), this path is typically
calculated to coincide with a "natural path" based upon any
contours in the tool 34. As the tape laying head 18 is controlled
along the path across the tool 34, the compaction roller 24 is
caused to exert sufficient pressure so as to adhere the ply
material 12 to the tool 34. As the tape laying head 18 moves along
the path, the backed ply material 10 is drawn out of the tape
laying head 18 and consolidated on to the tool 34. In this regard,
composite layups typically include multiple layers of ply material.
Thus, in subsequent applications of the ply material 12, backed ply
material 10 is dispensed upon previously applied ply material.
[0033] At step 54, the placement of the backed ply material 10 on
the tool 34 is evaluated. For example, a sensor or an operator may
sense the relative position of the backed ply material 10 and a
previously positioned backed ply material 10 and determine if the
distance between these plies is within a predetermined tolerance.
If the distance between these plies is not within the predetermined
tolerance, an error may be generated at step 56. If the distance
between these plies is within the predetermined tolerance, it is
determined if the supply is sufficient at step 58. In addition, in
some embodiments of the invention, the backing 14 is removed from
the backed ply material 10 following placement evaluation. However,
the backing 14 need not be removed prior to step 58, but rather,
the backing 14 may be removed at essentially any time prior to
placement of a subsequent ply upon the backed ply material 10.
Furthermore, it is an advantage of embodiments of the invention
that the backing 14 is recyclable. That is, the backing 14 may be
collected and submitted to a recycling facility where the PET
constituent of the backing 14 may be processed to generate
products. For the purpose of this disclosure, the term, "recycling"
is defined as the act of collecting the backing 14 for submission
to a recycling facility and/or the reprocessing of the backing
14.
[0034] At step 58, it is determined whether the supply of ply
material is sufficient. For example, if it determined that the
supply spool 20 contains ply material then, it is determined that
sufficient ply material remains. If it is determined that then is
an insufficient amount of remaining ply material, the supply spool
20 is replaced at step 60. If it is determined that a sufficient
amount of ply material remains then, it is determined if the end of
the path has been reached at step 62.
[0035] At step 60 the supply spool 20 is replaced. For example, a
spent supply spool 20 is removed from the tape laying head 18 and a
substantially full supply spool 20 may be disposed within the tape
laying head 18. Following replacement of the supply spool 20, a
splice is optionally formed at step 64. For example, if the supply
of ply material is exhausted during the placement of a ply, the ply
material 12 for the uncompleted path may be removed or, optionally,
spliced to the ply material 12 from the new supply spool 20. If the
splice is performed, the particular steps performed is dependent
upon the ply material utilized and the product being laid up.
However, in general, the trailing edge of the uncompleted ply and
the starting edge of the new ply material are cut to match. These
cut edges are abutted and quality control procedure procedures are
performed.
[0036] An advantage of embodiments of the invention over
conventional backed ply material is that, due to the relative
thinness of the backing 12, a relatively greater amount of ply
material fits on the spool and thus, fewer spool change and tape
splicing operations need be performed.
[0037] At step 62, it is determined if the end of the path has been
reached. If, based on the series of computer readable instruction,
it is determined the tape laying head 18 has not advanced to the
end of the path, additional backed ply material 10 is dispensed at
step 52. If, it is determined the tape laying head 18 has advanced
to the end of the path, the backed ply material 10 is cut at step
66.
[0038] At step 66, the end of the ply material 12 may be cut based
upon the series of computer readable instruction, the orientation
of a previously positioned ply material 12, and/or the location of
a previously positioned ply material 12.
[0039] At step 68, it is determined if the placement of the ply
material 12 on the tool 34 has been completed. For example, if all
of the computer readable instructions have been completed, it may
be determined that the placement of plies for the composite product
has been completed and the CTLM 38 may idle until another series of
computer readable instructions is initiated. If is determined the
placement of plies 12 for the composite product is not completed,
an additional ply material 12 placement may proceed at step 48.
[0040] Following the method 44, the composite product may be cured
in any suitable manner. In the aerospace industry, thermoset resins
are generally utilized to pre-impregnate ply material. These
thermoset resins are typically cured by being held at an elevated
temperature for a predetermined amount of time. Times and
temperatures may be selected depending on the resin used, the size
and thickness of the composite product, and the like.
[0041] Although an example of the tape laying head 18 is shown
utilizing the backed ply material 10 for composite products in the
airline industry, the backed ply material 10 can also be used in
other industries that construct composite product. These industries
include, but are not limited to, automobile, marine, spacecraft,
building, and consumer products.
[0042] FIG. 5 is a flow diagram of steps performed in a method 70
to generate the backed ply material 10 according to FIG. 1. As
shown in FIG. 5, the method 70 is initiated in response to a press
or other such device being turned on. Prior to initiation of the
method 70 a variety of tasks may be performed. These tasks include,
in no particular order: secure a supply of the ply material 12
within the press; secure a supply of the backing 14 within the
press; mount an essentially empty spool downstream of the press;
and the like.
[0043] At step 72 the ply material 12 and the backing 14 are
introduced into the press.
[0044] At step 74 sufficient force and/or heat are applied to the
ply material 12 and the backing 14 so as to cause the ply material
12 and the backing 14 to adhere.
[0045] At step 76 the backed ply material 12 is taken up by the
spool. In addition, in response to a sufficient amount of backed
ply material 12 being placed upon the spool, the backed ply
material 12 is cut, the essentially full spool is removed, and a
substantially empty spool is optionally put in its place.
[0046] The many features and advantages of the invention are
apparent from the detailed specification, and thus, it is intended
by the appended claims to cover all such features and advantages of
the invention which fall within the true spirit and scope of the
invention. Further, since numerous modifications and variations
will readily occur to those skilled in the art, it is not desired
to limit the invention to the exact construction and operation
illustrated and described, and accordingly, all suitable
modifications and equivalents may be resorted to, falling within
the scope of the invention.
* * * * *