U.S. patent application number 16/892065 was filed with the patent office on 2021-12-09 for systems and methods for deposition and high-frequency microwave inspection of uncured fiber-reinforced polymeric materials.
The applicant listed for this patent is The Boeing Company. Invention is credited to Gary E. Georgeson, Morteza Safai.
Application Number | 20210379843 16/892065 |
Document ID | / |
Family ID | 1000004901015 |
Filed Date | 2021-12-09 |
United States Patent
Application |
20210379843 |
Kind Code |
A1 |
Safai; Morteza ; et
al. |
December 9, 2021 |
SYSTEMS AND METHODS FOR DEPOSITION AND HIGH-FREQUENCY MICROWAVE
INSPECTION OF UNCURED FIBER-REINFORCED POLYMERIC MATERIALS
Abstract
Disclosed herein is a system that comprises a deposition head
configured to deposit multiple tows in a stacked configuration one
layer at a time. Each tow of the multiple tows is a
currently-applied tow when the tow is a most-recently deposited tow
of the multiple tows and a tow of the multiple tows is a covered
tow when the tow is directly covered by the currently-applied tow.
The system also comprises a probe head, configured to move along
and be spatially offset from the currently-applied tow after
deposition of the currently-applied tow. The probe head is further
configured to transmit an incident microwave beam into the
currently-applied tow as the probe head moves along the
currently-applied tow. The incident microwave beam has a frequency
low enough to pass entirely through the currently-applied tow and
high enough to pass entirely through no more than the
currently-applied tow and the covered tow.
Inventors: |
Safai; Morteza; (Newcastle,
WA) ; Georgeson; Gary E.; (Tacoma, WA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
The Boeing Company |
Chicago |
IL |
US |
|
|
Family ID: |
1000004901015 |
Appl. No.: |
16/892065 |
Filed: |
June 3, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29C 70/54 20130101;
B29C 70/384 20130101; G01N 22/02 20130101 |
International
Class: |
B29C 70/54 20060101
B29C070/54; B29C 70/38 20060101 B29C070/38; G01N 22/02 20060101
G01N022/02 |
Claims
1. A system, comprising: a deposition head, configured to deposit
multiple tows of uncured fiber-reinforced polymeric material in a
stacked configuration one layer at a time, wherein each tow of the
multiple tows is a currently-applied tow when the tow is a
most-recently deposited tow of the multiple tows and a tow of the
multiple tows is a covered tow when the tow is directly covered by
the currently-applied tow; and a probe head, configured to move
along and be spatially offset from the currently-applied tow after
deposition of the currently-applied tow, wherein: the probe head is
further configured to transmit an incident microwave beam into the
currently-applied tow as the probe head moves along the
currently-applied tow; and the incident microwave beam has a
frequency low enough to pass entirely through the currently-applied
tow and high enough to pass entirely through no more than the
currently-applied tow and the covered tow.
2. The system according to claim 1, wherein the frequency of the
incident microwave beam is between 50 GHz and 100 GHz.
3. The system according to claim 1, wherein the frequency of the
incident microwave beam is high enough to pass entirely through no
more than the currently-applied tow and a stack interface between
the currently-applied tow and the covered tow.
4. The system according to claim 1, wherein: the probe head
comprises a linear phased array of microwave transmitters; each one
of the microwave transmitters generates a microwave signal; the
incident microwave beam comprises a combination of the microwave
signals generated by the linear phased array of microwave
transmitters; the linear phased array is configured to phase shift
the generation of the microwave signals; and the probe head is
configured to move the incident microwave beam laterally across a
width of the currently-applied tow, in a direction substantially
perpendicular to movement of the probe head along the
currently-applied tow, by selectively controlling the linear phased
array to change the phase shift of the generation of the microwave
signals.
5. The system according to claim 4, wherein: the probe head further
comprises at least one edge detector, which is configured to detect
at least one edge of the currently-applied tow as the probe head
moves along the currently-applied tow; and the probe head is
further configured to prevent movement of the incident microwave
beam beyond the at least one edge in response to detection of the
at least one edge of the currently-applied tow.
6. The system according to claim 5, wherein: the deposition head is
further configured to deposit multiple tows of uncured
fiber-reinforced polymeric material in a side-by-side arrangement
one layer at a time; the stacked configuration further comprises
multiple layers of tows in the side-by-side arrangement; the at
least one edge detector is further configured to detect the edge of
one currently-applied tow, of a currently-applied layer of tows in
the side-by-side arrangement, and the edge of another
currently-applied tow, of the currently-applied layer of tows in
the side-by-side arrangement; and the probe head is further
configured to prevent movement of the incident microwave beam
beyond the one edge of the one currently-applied tow, of the
currently-applied layer of tows in the side-by-side arrangement,
and the edge of the other currently-applied tow, of the
currently-applied layer of tows in the side-by-side arrangement, in
response to detection of the edge of the one currently-applied tow,
of the currently-applied layer of tows in the side-by-side
arrangement, and the edge of the other currently-applied tow, of
the currently-applied layer of tows in the side-by-side
arrangement.
7. The system according to claim 1, wherein the probe head further
comprises a laser profilometer configured to: transmit a laser beam
to the currently-applied tow; and determine profile characteristics
of the currently-applied tow based on a displacement of the laser
beam after impacting the currently-applied tow.
8. The system according to claim 1, wherein: the deposition head
moves along a deposition path to deposit the multiple tows of
uncured fiber-reinforced polymeric material in the stacked
configuration; and the probe head is non-movably affixed to the
deposition head such that the probe head moves along the deposition
path with the deposition head.
9. The system according to claim 1, further comprising a robot,
wherein: the deposition head is coupled to the robot such that the
deposition head is movable, to deposit the multiple tows in the
stacked configuration, by the robot; and the probe head is coupled
to the robot such that the probe head is movable, along each tow of
the of the multiple tows, by the robot.
10. The system according to claim 1, further comprising: a robot;
and a second robot, which is independently movable relative to the
robot; wherein: the deposition head is coupled to the robot such
that the deposition head is movable, to deposit the multiple tows
in the stacked configuration, by the robot; and the probe head is
coupled to the second robot such that the probe head is movable,
along each tow of the of the multiple tows, by the second
robot.
11. The system according to claim 1, wherein: the probe head is
further configured to detect a reflected microwave beam; and the
reflected microwave beam comprises at least a portion of the
incident microwave beam reflected from at least one of: the
currently-applied tow; or a stack interface between the
currently-applied tow and the covered tow.
12. The system according to claim 11, further comprising a
controller configured to determine a dielectric response of at
least one of the currently-applied tow or the stack interface based
on the reflected microwave beam.
13. The system according to claim 1, wherein the probe head further
comprises at least one of: an infrared camera configured to
generate a thermal image of the currently-applied tow based on
infrared radiation from the currently-applied tow; or a visual
camera configured to generate a visual image of the
currently-applied tow.
14. A probe head, comprising: a microwave sensor, configured to
transmit an incident microwave beam into a currently-applied tow,
forming part of a stacked configuration of multiple tows of uncured
fiber-reinforced polymeric material, as the microwave sensor moves
along the currently-applied tow, wherein: the incident microwave
beam has a frequency low enough to pass entirely through
currently-applied tow and high enough to pass entirely through no
more than the currently-applied tow and a covered tow on which the
currently-applied tow is directly stacked; the microwave sensor
further comprises a linear phased array of microwave transmitters;
each one of the microwave transmitters generates a microwave
signal; the incident microwave beam comprises a combination of the
microwave signals generated by the linear phased array of microwave
transmitters; the linear phased array is configured to phase shift
the generation of the microwave signals; and the microwave sensor
is configured to move the incident microwave beam laterally across
a width of the currently-applied tow, in a direction perpendicular
to movement of the probe head along the currently-applied tow, by
selectively controlling the linear phased array to change the phase
shift of the generation of the microwave signals; and at least one
edge detector, configured to detect at least one edge of the
currently-applied tow as the at least one edge detector moves along
the currently-applied tow, wherein the microwave sensor is further
configured to limit movement of the incident microwave beam beyond
the at least one edge in response to detection of the at least one
edge of the currently-applied tow.
15. The probe head according to claim 14, further comprising at
least one of: an infrared camera configured to generate a thermal
image of the currently-applied tow based on infrared radiation from
the currently-applied tow; or a laser profilometer configured to:
transmit a laser beam to the currently-applied tow; and determine
profile characteristics of the currently-applied tow based on a
displacement of the laser beam upon impacting the currently-applied
tow.
16. A method, comprising: depositing a currently-applied tow, made
of uncured fiber-reinforced polymeric material, onto an object or
onto a covered tow to form a stacked configuration with the covered
tow; transmitting an incident microwave beam into the
currently-applied tow at locations along the currently-applied tow
after deposition of the currently-applied tow, wherein the incident
microwave beam has a frequency low enough to pass entirely through
the currently-applied tow and high enough to pass entirely through
no more than the currently-applied tow and a stack interface
between the currently-applied tow and the covered tow; detecting a
reflected microwave beam, comprising at least a portion of the
incident microwave beam reflected from at least one of the
currently-applied tow or the stack interface; and determining a
dielectric response of the currently-applied tow or the stack
interface based on the reflected microwave beam.
17. The method according to claim 16, further comprising: moving
the incident microwave beam laterally across a width of the
currently-applied tow; detecting at least one edge of the
currently-applied tow at the locations along the currently-applied
tow; and preventing movement of the incident microwave beam beyond
the at least one edge in response to detecting the at least one
edge.
18. The method according to claim 16, wherein the step of
depositing the currently-applied tow and the step of transmitting
the incident microwave beam into the currently-applied tow are
performed concurrently.
19. The method according to claim 18, further comprising generating
a thermal image of the currently-applied tow concurrently with the
step of depositing the currently-applied tow and the step of
transmitting the incident microwave beam into the currently-applied
tow, wherein the thermal image of the currently-applied tow is
based on infrared radiation from the currently-applied tow.
20. The method according to claim 18, further comprising:
transmitting a laser beam to the currently-applied tow concurrently
with the step of depositing the currently-applied tow and the step
of transmitting the incident microwave beam into the
currently-applied tow; and determining profile characteristics of
the currently-applied tow based on a displacement of the laser beam
after impacting the currently-applied tow.
Description
FIELD
[0001] This disclosure relates generally to the manufacturing and
inspection of parts, and more particularly to depositing uncured
fiber-reinforced polymeric material and inspecting the uncured
fiber-reinforced polymeric material using high-frequency
microwaves.
BACKGROUND
[0002] The inspection of aerospace composite structures can be
costly and time-consuming. Some aerospace composite structures are
manufactured by the automated placement of fiber-reinforced
polymeric materials using various tape or ply lay-up processes.
Monitoring the fiber-reinforced polymeric material, including the
placement of the material, during the lay-up process to identify
and limit material and placement defects and to improve the overall
manufacturing process is needed.
[0003] Most monitoring techniques identify defects after the
fiber-reinforced polymeric material is cured. Some monitoring
techniques are used to identify and limit defects in the
fiber-reinforced polymeric material before the material is cured.
However, conventional monitoring techniques to identify and limit
defects in uncured fiber-reinforced polymeric material suffer from
several shortcomings, such as cost, speed, lack of sensitivity, and
edge effect issues.
SUMMARY
[0004] The subject matter of the present application provides
examples of systems and methods for depositing and inspecting
uncured fiber-reinforced polymeric materials that overcome at least
some of the above-discussed shortcomings of prior art techniques.
Accordingly, the subject matter of the present application has been
developed in response to the present state of the art, and in
particular, in response to shortcomings of conventional monitoring
techniques for identifying and limiting defects in uncured
fiber-reinforced polymeric material.
[0005] Disclosed herein is a system that comprises a deposition
head that is configured to deposit multiple tows of uncured
fiber-reinforced polymeric material in a stacked configuration one
layer at a time. Each tow of the multiple tows is a
currently-applied tow when the tow is a most-recently deposited tow
of the multiple tows and a tow of the multiple tows is a covered
tow when the tow is directly covered by the currently-applied tow.
The system also comprises a probe head that is configured to move
along and be spatially offset from the currently-applied tow after
deposition of the currently-applied tow. The probe head is further
configured to transmit an incident microwave beam into the
currently-applied tow as the probe head moves along the
currently-applied tow. The incident microwave beam has a frequency
low enough to pass entirely through the currently-applied tow and
high enough to pass entirely through no more than the
currently-applied tow and the covered tow. The preceding subject
matter of this paragraph characterizes example 1 of the present
disclosure.
[0006] The frequency of the incident microwave beam is between 50
GHz and 100 GHz. The preceding subject matter of this paragraph
characterizes example 2 of the present disclosure, wherein example
2 also includes the subject matter according to example 1,
above.
[0007] The frequency of the incident microwave beam is high enough
to pass entirely through no more than the currently-applied tow and
a stack interface between the currently-applied tow and the covered
tow. The preceding subject matter of this paragraph characterizes
example 3 of the present disclosure, wherein example 3 also
includes the subject matter according to any one of examples 1-2,
above.
[0008] The probe head comprises a linear phased array of microwave
transmitters. Each one of the microwave transmitters generates a
microwave signal. The incident microwave beam comprises a
combination of the microwave signals generated by the linear phased
array of microwave transmitters. The linear phased array is
configured to phase shift the generation of the microwave signals.
The probe head is configured to move the incident microwave beam
laterally across a width of the currently-applied tow, in a
direction substantially perpendicular to movement of the probe head
along the currently-applied tow, by selectively controlling the
linear phased array to change the phase shift of the generation of
the microwave signals. The preceding subject matter of this
paragraph characterizes example 4 of the present disclosure,
wherein example 4 also includes the subject matter according to any
one of examples 1-3, above.
[0009] The probe head further comprises at least one edge detector,
which is configured to detect at least one edge of the
currently-applied tow as the probe head moves along the
currently-applied tow. The probe head is further configured to
prevent movement of the incident microwave beam beyond the at least
one edge in response to detection of the at least one edge of the
currently-applied tow. The preceding subject matter of this
paragraph characterizes example 5 of the present disclosure,
wherein example 5 also includes the subject matter according to
example 4, above.
[0010] The deposition head is further configured to deposit
multiple tows of uncured fiber-reinforced polymeric material in a
side-by-side arrangement one layer at a time. The stacked
configuration further comprises multiple layers of tows in the
side-by-side arrangement. The at least one edge detector is further
configured to detect the edge of one currently-applied tow, of a
currently-applied layer of tows in the side-by-side arrangement,
and the edge of another currently-applied tow, of the
currently-applied layer of tows in the side-by-side arrangement.
The probe head is further configured to prevent movement of the
incident microwave beam beyond the one edge of the one
currently-applied tow, of the currently-applied layer of tows in
the side-by-side arrangement, and the edge of the other
currently-applied tow, of the currently-applied layer of tows in
the side-by-side arrangement, in response to detection of the edge
of the one currently-applied tow, of the currently-applied layer of
tows in the side-by-side arrangement, and the edge of the other
currently-applied tow, of the currently-applied layer of tows in
the side-by-side arrangement. The preceding subject matter of this
paragraph characterizes example 6 of the present disclosure,
wherein example 6 also includes the subject matter according to
example 5, above.
[0011] The probe head further comprises a laser profilometer
configured to transmit a laser beam to the currently-applied tow
and determine profile characteristics of the currently-applied tow
based on a displacement of the laser beam after impacting the
currently-applied tow. The preceding subject matter of this
paragraph characterizes example 7 of the present disclosure,
wherein example 7 also includes the subject matter according to any
one of examples 1-6, above.
[0012] The deposition head moves along a deposition path to deposit
the multiple tows of uncured fiber-reinforced polymeric material in
the stacked configuration. The probe head is non-movably affixed to
the deposition head such that the probe head moves along the
deposition path with the deposition head. The preceding subject
matter of this paragraph characterizes example 8 of the present
disclosure, wherein example 8 also includes the subject matter
according to any one of examples 1-7, above.
[0013] The system further comprises a robot. The deposition head is
coupled to the robot such that the deposition head is movable, to
deposit the multiple tows in the stacked configuration, by the
robot. The probe head is coupled to the robot such that the probe
head is movable, along each tow of the of the multiple tows, by the
robot. The preceding subject matter of this paragraph characterizes
example 9 of the present disclosure, wherein example 9 also
includes the subject matter according to any one of examples 1-8,
above.
[0014] The system further comprises a robot and a second robot,
which is independently movable relative to the robot. The
deposition head is coupled to the robot such that the deposition
head is movable, to deposit the multiple tows in the stacked
configuration, by the robot. The probe head is coupled to the
second robot such that the probe head is movable, along each tow of
the of the multiple tows, by the second robot. The preceding
subject matter of this paragraph characterizes example 10 of the
present disclosure, wherein example 10 also includes the subject
matter according to any one of examples 1-8, above.
[0015] The probe head is further configured to detect a reflected
microwave beam. The reflected microwave beam comprises at least a
portion of the incident microwave beam reflected from at least one
of the currently-applied tow or a stack interface. The preceding
subject matter of this paragraph characterizes example 11 of the
present disclosure, wherein example 11 also includes the subject
matter according to any one of examples 1-10, above.
[0016] The system further comprises a controller configured to
determine a dielectric response of at least one of the
currently-applied tow or the stack interface based on the reflected
microwave beam. The preceding subject matter of this paragraph
characterizes example 12 of the present disclosure, wherein example
12 also includes the subject matter according to example 11,
above.
[0017] The probe head further comprises at least one of an infrared
camera configured to generate a thermal image of the
currently-applied tow based on infrared radiation from the
currently-applied tow, or a visual camera configured to generate a
visual image of the currently-applied tow. The preceding subject
matter of this paragraph characterizes example 13 of the present
disclosure, wherein example 13 also includes the subject matter
according to any one of examples 1-12, above.
[0018] Further disclosed herein is a probe head. The probe head
comprises a microwave sensor that is configured to transmit an
incident microwave beam into a currently-applied tow, forming part
of a stacked configuration of multiple tows of uncured
fiber-reinforced polymeric material, as the microwave sensor moves
along the currently-applied tow. The incident microwave beam has a
frequency low enough to pass entirely through currently-applied tow
and high enough to pass entirely through no more than the
currently-applied tow and a covered tow on which the
currently-applied tow is directly stacked. The microwave sensor
further comprises a linear phased array of microwave transmitters.
Each one of the microwave transmitters generates a microwave
signal. The incident microwave beam comprises a combination of the
microwave signals generated by the linear phased array of microwave
transmitters. The linear phased array is configured to phase shift
the generation of the microwave signals. The microwave sensor is
configured to move the incident microwave beam laterally across a
width of the currently-applied tow, in a direction perpendicular to
movement of the probe head along the currently-applied tow, by
selectively controlling the linear phased array to change the phase
shift of the generation of the microwave signals. The probe head
also comprises at least one edge detector, configured to detect at
least one edge of the currently-applied tow as the at least one
edge detector moves along the currently-applied tow. The microwave
sensor is further configured to limit movement of the incident
microwave beam beyond the at least one edge in response to
detection of the at least one edge of the currently-applied tow.
The preceding subject matter of this paragraph characterizes
example 14 of the present disclosure.
[0019] The probe head further comprises at least one of an infrared
camera or a laser profilometer. The infrared camera is configured
to generate a thermal image of the currently-applied tow based on
infrared radiation from the currently-applied tow. The laser
profilometer is configured to transmit a laser beam to the
currently-applied tow and determine profile characteristics of the
currently-applied tow based on a displacement of the laser beam
upon impacting the currently-applied tow. The preceding subject
matter of this paragraph characterizes example 15 of the present
disclosure, wherein example 15 also includes the subject matter
according to example 14, above.
[0020] Additionally disclosed herein is a method that comprises
depositing a currently-applied tow, made of uncured
fiber-reinforced polymeric material, onto an object or onto a
covered tow to form a stacked configuration with the covered tow.
The method also comprises transmitting an incident microwave beam
into the currently-applied tow at locations along the
currently-applied tow after deposition of the currently-applied
tow. The incident microwave beam has a frequency low enough to pass
entirely through the currently-applied tow and high enough to pass
entirely through no more than the currently-applied tow and a stack
interface between the currently-applied tow and the covered tow.
The method further comprises detecting a reflected microwave beam,
comprising at least a portion of the incident microwave beam
reflected from at least one of the currently-applied tow or the
stack interface. The method additionally comprises determining a
dielectric response of the currently-applied tow or the stack
interface based on the reflected microwave beam. The preceding
subject matter of this paragraph characterizes example 16 of the
present disclosure.
[0021] The method further comprises moving the incident microwave
beam laterally across a width of the currently-applied tow. The
method also comprises detecting at least one edge of the
currently-applied tow at the locations along the currently-applied
tow. The method further comprises preventing movement of the
incident microwave beam beyond the at least one edge in response to
detecting the at least one edge. The preceding subject matter of
this paragraph characterizes example 17 of the present disclosure,
wherein example 17 also includes the subject matter according to
example 16, above.
[0022] The step of depositing the currently-applied tow and the
step of transmitting the incident microwave beam into the
currently-applied tow are performed concurrently. The preceding
subject matter of this paragraph characterizes example 18 of the
present disclosure, wherein example 18 also includes the subject
matter according to any one of examples 16-17, above.
[0023] The method further comprises generating a thermal image of
the currently-applied tow concurrently with the step of depositing
the currently-applied tow and the step of transmitting the incident
microwave beam into the currently-applied tow. The thermal image of
the currently-applied tow is based on infrared radiation from the
currently-applied tow. The preceding subject matter of this
paragraph characterizes example 19 of the present disclosure,
wherein example 19 also includes the subject matter according to
example 18, above.
[0024] The method further comprises transmitting a laser beam to
the currently-applied tow concurrently with the step of depositing
the currently-applied tow and the step of transmitting the incident
microwave beam into the currently-applied tow and determining
profile characteristics of the currently-applied tow based on a
displacement of the laser beam after impacting the
currently-applied tow. The preceding subject matter of this
paragraph characterizes example 20 of the present disclosure,
wherein example 20 also includes the subject matter according to
any one of examples 18-19, above.
[0025] The described features, structures, advantages, and/or
characteristics of the subject matter of the present disclosure may
be combined in any suitable manner in one or more examples,
including embodiments and/or implementations. In the following
description, numerous specific details are provided to impart a
thorough understanding of examples of the subject matter of the
present disclosure. One skilled in the relevant art will recognize
that the subject matter of the present disclosure may be practiced
without one or more of the specific features, details, components,
materials, and/or methods of a particular example, embodiment, or
implementation. In other instances, additional features and
advantages may be recognized in certain examples, embodiments,
and/or implementations that may not be present in all examples,
embodiments, or implementations. Further, in some instances,
well-known structures, materials, or operations are not shown or
described in detail to avoid obscuring aspects of the subject
matter of the present disclosure. The features and advantages of
the subject matter of the present disclosure will become more fully
apparent from the following description and appended claims, or may
be learned by the practice of the subject matter as set forth
hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] In order that the advantages of the subject matter may be
more readily understood, a more particular description of the
subject matter briefly described above will be rendered by
reference to specific examples that are illustrated in the appended
drawings. Understanding that these drawings depict only typical
examples of the subject matter, they are not therefore to be
considered to be limiting of its scope. The subject matter will be
described and explained with additional specificity and detail
through the use of the drawings, in which:
[0027] FIG. 1 is a schematic, elevation view of a system for
depositing multiple tows of uncured fiber-reinforced polymeric
material one layer at a time and inspecting the multiple tows one
layer at a time, according to one or more examples of the present
disclosure;
[0028] FIG. 2A is a schematic, perspective view of an applicator
and a probe head of the system of FIG. 1, shown depositing multiple
tows of uncured fiber-reinforced polymeric material in a stacked
configuration one tow at a time, according to one or more examples
of the present disclosure;
[0029] FIG. 2B is a schematic, perspective view of an applicator
and a probe head of the system of FIG. 1, shown depositing multiple
tows of uncured fiber-reinforced polymeric material in a stacked
configuration multiple tows at a time, according to one or more
examples of the present disclosure;
[0030] FIG. 3A is a schematic, cross-sectional, front view of a
probe head of the system of FIG. 1, shown scanning a first layer of
uncured fiber-reinforced polymeric material, according to one or
more examples of the present disclosure;
[0031] FIG. 3B is a schematic, cross-sectional, front view of a
probe head of the system of FIG. 1, shown scanning a second layer
of uncured fiber-reinforced polymeric material and an interface
between the second layer and a first layer of uncured
fiber-reinforced polymeric material, according to one or more
examples of the present disclosure;
[0032] FIG. 3C is a schematic, cross-sectional, front view of a
probe head of the system of FIG. 1, shown scanning a third layer of
uncured fiber-reinforced polymeric material and an interface
between the third layer and a second layer of uncured
fiber-reinforced polymeric material, according to one or more
examples of the present disclosure;
[0033] FIG. 4A is a schematic, cross-sectional, front view of a
probe head of the system of FIG. 1, shown with a linear phased
array of the probe head generating an incident microwave beam,
according to one or more examples of the present disclosure;
[0034] FIG. 4B is a schematic, cross-sectional, front view of a
probe head of the system of FIG. 1, shown with a linear phased
array of the probe head generating an incident microwave beam,
according to one or more examples of the present disclosure;
[0035] FIG. 5 is a schematic, cross-sectional, front view of a
probe head of the system of FIG. 1 having a microwave sensor and
edge detectors, according to one or more examples of the present
disclosure;
[0036] FIG. 6 is a schematic, cross-sectional, front view of a
probe head of the system of FIG. 1 having a microwave sensor, edge
detectors, an infrared camera, a laser profilometer, and a visual
camera, according to one or more examples of the present
disclosure;
[0037] FIG. 7 is a schematic, elevation view of a system for
depositing multiple tows of uncured fiber-reinforced polymeric
material one layer at a time and inspecting the multiple tows one
layer at a time, according to one or more examples of the present
disclosure;
[0038] FIG. 8 is a schematic, cross-sectional, front view of a
probe head and a controller of the system of FIG. 1, according to
one or more examples of the present disclosure; and
[0039] FIG. 9 is a schematic flow diagram of a method of depositing
multiple tows of uncured fiber-reinforced polymeric material one
layer at a time and inspecting the multiple tows one layer at a
time, according to one or more examples of the present
disclosure.
DETAILED DESCRIPTION
[0040] Reference throughout this specification to "one example,"
"an example," or similar language means that a particular feature,
structure, or characteristic described in connection with the
example is included in at least one example of the present
disclosure. Appearances of the phrases "in one example," "in an
example," and similar language throughout this specification may,
but do not necessarily, all refer to the same example. Similarly,
the use of the term "implementation" means an implementation having
a particular feature, structure, or characteristic described in
connection with one or more examples of the present disclosure,
however, absent an express correlation to indicate otherwise, an
implementation may be associated with one or more examples.
[0041] Disclosed herein is a system that deposits multiple tows of
uncured fiber-reinforced polymeric material, one layer at a time,
to form a stacked configuration of tows. Additionally, the system
inspects the tows of the stacked configuration as they are
deposited one layer at a time. The system transmits a
high-frequency incident microwave beam into a most-recently
deposited tow of the stacked configuration and determines the
presence of anomalies in the most-recently deposited layer of a tow
or tows, the interface between two tows of the most-recently
deposited layer if applicable, and/or the interface between one or
more tows of the most-recently deposited layer and one or more tows
onto which the most-recently deposited layer is deposited. The
system enables inspection of pre-cured (i.e., uncured) composite
materials as they are laid up in a stacked configuration. Moreover,
in some examples, the high range of the frequency of the incident
microwave beam ensures the incident microwave beam penetrates only
a portion of the stacked configuration up to a predetermined depth,
which allows a determination of particular characteristics (e.g.,
fiber orientation, foreign object debris, laps, gaps, disbands,
resin starvations, marcelling, and the like) associated with the
predetermined depth of the stacked configuration. The scanned
microwave reflection from successive layers of composite material
provide ply-by-ply information concerning potential flaw-creating
anomalies, which allows on-the-fly adjustments to the current
deposition process and/or machine learning for improving future
deposition processes.
[0042] Referring to FIG. 1, according to one example, a system 100,
for depositing multiple tows 130 of uncured fiber-reinforced
polymeric material one layer at a time and inspecting the multiple
tows 130 one layer at a time, includes a deposition head 110 and a
probe head 120. In the example of FIG. 1, the probe head 120 is
non-movably affixed to the deposition head 110 such that the probe
head 120 moves as the deposition head 110 moves. In other words, in
some examples, the probe head 120 is co-movably coupled to the
deposition head 110.
[0043] The deposition head 110 is configured to deposit the
multiple tows 130 in a stacked configuration 142 one layer at a
time. The tows 130 are supplied from a tow supply 143 of the system
100. In some examples, the tow supply 143 includes one or more
spools containing an effectually continuous length of uncured
fiber-reinforced polymeric material having a set width W. The
continuous length of material from the tow supply 143 is cut to
length by the deposition head 110 to form the individual tows 130.
Alternatively, the tows 130 can be precut to length prior to being
introduced to the deposition head 110. Additionally, in certain
examples, the tows 130 can be formed from slit tape or include
other strips of precured-composite media.
[0044] The uncured fiber-reinforced polymeric material of the tows
130 includes fibers, such as carbon fibers, glass fibers, and/or
metal fibers, in some examples. The fibers can be unidirectional,
multi-directional, or interwoven. The fibers are embedded in a
polymeric material, such as resin or epoxy in an uncured (i.e.,
precured state), to form the tow 130. For example, the tow 130 may
be a pre-impregnated carbon fiber tape. Accordingly, each tow 130
may include impregnated fibers with preimpregnated resin. The resin
may be a thermoset or thermoplastic material. In one example, the
resin is a thermoset resin made of, for example, polyurethanes,
polyester, vinylester, epoxy, and the like. In another example, the
resin is a thermoplastic resin, such as a polyetheretherketone
(PEEK) or polyetherketoneketone (PEKK) material in some examples.
In certain examples, the tows 130 have some degree of "tack" or
stickiness. In some examples, each tow 130 has a width W of between
0.125 inches, inclusively, and 0.5 inches, inclusively. For
example, each tow 130 may have a width W of 0.125 inches, 0.25
inches, or 0.5 inches. In other examples, the tows 130 can have a
width W that is less than 0.125 inches or more than 0.5 inches.
[0045] According to some examples, the system 100 includes an
automated fiber placement system for delivering tows 130 onto a
surface 141 of an object 140. The automated fiber placement system
includes the deposition head 110 and a robot 102. The deposition
head 110 is coupled to and movable by the robot 102. Accordingly,
the deposition head 110 functions as an end effector in some
examples. In other words, the deposition head 110 is movable by the
robot 102, relative to the robot 102, to deliver the tows 130 onto
the surface 141. The tow supply 143 can be fixed to the robot 102
and movable with the robot 102. Alternatively, the tow supply 143
physically separated from the robot 102.
[0046] The robot 102 can be any of various automated robots. In
some examples, the robot 102 includes a footing and multiple
articulating members, such as a base that is rotatable relative to
the footing about a vertical axis, a connecting arm that is
pivotable relative to the base about a horizontal axis, a support
arm that is pivotable relative to the connecting arm about a
horizontal axis, an end-effector extension arm that is rotatable
relative to the support arm about a support axis, an end-effector
coupler arm that is pivotable relative to the end-effector
extension arm, and an end-effector interface arm that is rotatable
and to which the deposition head 110 is co-movably fixed.
Accordingly, in some examples, the robot 102 is a 6-axis robot that
facilitates motion of the deposition head 110 with 6-degrees of
freedom. However, in other examples, the robot 102 can have fewer
or more than 6-degrees of freedom.
[0047] The surface 141 is the surface of any object 140 onto which
the application of the tow 130 is advantageous. In one example, the
object 140 is a die or mold and the surface 141 defines a shape of
a part to be formed by the die or mold. Accordingly, in certain
implementations, the tow 130 is a material tape that is laid up on
the surface 141 to form a layer of a stacked configuration 142 to
be formed into a part. For example, the surface 141 can be a layup
or forming mandrel with a contour representative of an aerodynamic
surface. In other examples, the object 140 is a part and the
surface 141 is a surface of the part. Accordingly, in certain
implementations, the tow 130 is applied directly onto the surface
of a part to form the stacked configuration 142 on the part.
Accordingly, multiple layers of a tow 130 or tows 130 are formed on
top of each other, in the stacked configuration 142, to ultimately
form a laminated part after curing the stacked configuration
142.
[0048] The deposition head 110 of the system 100 includes an
applicator 117 that is configured to apply a single tow 130 or
multiple tows 130 onto the surface 141 at a time. Accordingly, the
configuration of the applicator 117 is dependent on the material,
shape, and number of tows 130 being deposited on a single pass.
According to one example, each tow 130 includes material tape and
the applicator 117 is a compaction roller. The compaction roller is
rotatable about a roller axis to apply tows 130 onto the surface
141. The compaction roller compacts (e.g., compresses) the tows 130
against the surface 141, which facilitates deliverance of the tows
130 onto the surface 141. The robot 102 is operable to
translationally move the deposition head 110 in a deposition path
112 such that the applicator 117 also moves along the surface 141
in the deposition path 112. When the surface 141 is contoured, such
as shown in FIG. 1, the robot 102 is configured to adjust the
position (e.g., height and/or angle) of the applicator 117 to
continue moving in the application direction along the contoured
portion of the surface 141. Adjustment of the applicator 117 can be
made by tilting or raising or lowering the deposition head 110
using one or more articulating members of the robot 102.
[0049] The tow 130 or tows 130 are fed to the applicator 117 of the
deposition head 110 from the tow supply 143. Although not shown, to
help prevent interference (e.g., undesired contact) between the
tows 130, the robot 102, and deposition head 110, as the tows 130
are fed to the applicator 117, the tows 130 are threaded through a
tow standoff co-movably fixed to the deposition head 110.
[0050] Referring to FIG. 2A, the applicator 117 receives a tow 130
and deposits the tow 130 onto either the surface 141 of the object
140 or a previously deposited tow 130. Each deposited tow 130 in
FIG. 2A individually forms a layer of the stacked configuration
142, such that each layer of the stacked configuration 142 has a
width equal to the width W of a tow 130. As an example, the stacked
configuration 142 of FIG. 2A has four layers with each layer being
formed by a single tow 130.
[0051] Alternatively, as shown in FIG. 2B, the applicator 117
receives multiple tows 130 and concurrently deposits the multiple
tows 130, in a side-by-side arrangement, onto either the surface
141 of the object 140 or previously deposited tows 130. The
multiple tows 130 in FIG. 2B, deposited concurrently in the
side-by-side arrangement, collectively form a layer of the stacked
configuration 142. As used herein, the most recently applied layer
of a tow 130 or tows 130 is a currently-applied layer and the layer
covered by the currently-applied layer is a covered layer. Each
layer of the stacked configuration 142 has a width equal to the
number of side-by-side tows 130 multiplied by the width W of the
tows 130. As an example, the stacked configuration 142 of FIG. 2B
has four layers with each layer being formed by two side-by-side
tows 130. Accordingly, the stacked configuration 142 in FIG. 2B has
a width equal to two widths W of a tow 130 or 2W. Of course, in
other examples, more than two tows 130 can be concurrently
deposited in a side-by-side manner by the applicator 117 such that
each layer of the stacked configuration 142 has more than two tows
130 in a side-by-side arrangement. A side interface 164 is defined
between interior edges 137 of side-by-side ones of the tows 130.
The side interface 164 becomes a bonding interface between the
side-by-side ones of the tows 130 when the stacked configuration
142 is cured. Two tows 130 in a side-by-side arrangement that share
a side interface 164 can be considered laterally-adjacent tows.
[0052] Referring to FIGS. 3A-3C, a step-by-step illustration of one
example of depositing multiple tows 130 is shown. In FIG. 3A, the
deposition head 110 has laid down a first one of the tows 130
directly onto the surface 141 of the object 140. Because no other
tow 130 has been deposited onto the first tow 130 in FIG. 3A, the
tow 130 in FIG. 3A is a most-recently deposited tow and thus a
currently-applied tow 130B. Accordingly, as used herein, each tow
130 of the multiple tows 130 of a stacked configuration 142 is a
currently-applied tow 130B when the tow 130 is a most-recently
deposited tow of the multiple tows 130. A tow 130 is considered a
most-recently deposited tow when the tow 130 is currently being
deposited (e.g., only partially deposited) or is the most recently
fully deposited tow, as long as no other tow has been at least
partially deposited on the tow 130.
[0053] As shown in FIG. 3B, the deposition head 110 has laid down a
second one of the tows 130 directly onto the first one of the tows
130. As the second one of the tows 130 is being laid down onto the
first one of the tows 130, the first one of the tows 130, which was
the currently-applied tow 130B, becomes a covered tow 130A and the
second one of the tows 130 is considered the currently-applied tow
130B because it is the most-recently deposited tow. Accordingly, a
tow 130 of the multiple tows 130 is a covered tow 130A when the tow
130 is directly covered by the currently-applied tow 130B (i.e.,
when the currently-applied tow 130B is deposited onto the tow 130).
A stack interface 135 is defined between the currently-applied tow
130B and the covered tow 130A. The stack interface 135 becomes a
bonding interface between the currently-applied tow 130B and the
covered tow 130A when the stacked configuration 142 is cured. The
covered tow 130A can also be considered a vertically-adjacent
tow.
[0054] Now referring to FIG. 3C, the deposition head 110 has laid
down a third one of the tows 130 directly onto the second one of
the tows 130. As the third one of the tows 130 is being laid down
onto the second one of the tows 130, the second one of the tows
130, which was the currently-applied tow 130B, becomes a covered
tow 130A, the third one of the tows 130 is considered the
currently-applied tow 130B because it is the most-recently
deposited tow, and the first one of the tows 130, which was the
covered tow 130A, is considered a previously-covered tow 130C.
Another stack interface 135 is defined between the new
currently-applied tow 130B and the new covered tow 130A.
[0055] If a desired number of layers of the stacked configuration
142 is more than three, the process depicted in FIGS. 3A-3C
continues in a repetitive manner until a desired number of tows 130
are deposited in the stacked configuration 142. Of course, in
certain examples, the stacked configuration 142 has less than three
tows 130 forming the stacked configuration 142. In fact, in some
examples, as used herein, a stacked configuration 142 can be formed
of a single tow 130 defining a single layer of the stacked
configuration 142.
[0056] Referring to FIG. 4B, when the deposition head 110 is
configured to deposit multiple tows 130 at a time, such as shown in
FIG. 2B, the process of laying down the tows 130 is similar to that
depicted in FIGS. 3A-3C. However, instead of each layer of the
stacked configuration 142 being defined by a single tow 130, each
layer of the stacked configuration 142 is defined by two or more
tows 130. Moreover, instead of the edges of the stacked
configuration 142 being defined by the edges 132 (i.e., exterior
edges) of the same currently-applied tow 130B (see, e.g., FIG. 4A),
the edges of the stacked configuration 142 are defined by an
exterior one of the edges 132 of one currently-applied tow 130B and
an exterior one of the edges 132 of another currently-applied tow
130B forming the same layer of the stacked configuration (see,
e.g., FIG. 4B).
[0057] After the stacked configuration 142 is completed, the
stacked configuration 142 is formed into a part by curing the
fiber-reinforced polymeric material. Curing the fiber-reinforced
polymeric material involves heating the material up to at least a
curing temperature of the material and, in some cases, applying a
compressive force to the stacked configuration 142. Curing the
polymeric material irreversibly hardens the polymeric material.
Moreover, the polymeric material of each tow 130 forming the
stacked configuration 142 bonds with the polymeric material of at
least one adjacent tow 130 forming the stacked configuration 142
during the curing process such that all tows 130 of the stacked
configuration 142 are bonded together after the curing process.
[0058] Prior to curing the fiber-reinforced polymeric material of
the stacked configuration 142, the system 100 is configured to
inspect each tow 130 of the stacked configuration 142 as the tow
130 is added to the stacked configuration 142 or before another tow
130 is deposited onto the tow 130. The inspection of the tows 130,
as they are laid up prior to curing, helps to discover anomalies or
imperfections in the fibers or the polymeric material of the tows,
in the stack interfaces 135 between stacked ones of the tows 130,
and the side interfaces 164 between side-by-side ones of the tows
130 before the tows 130 are cured. Such anomalies or imperfections
that are discoverable or correctable in pre-cured tows 130 may not
be discoverable or correctable after the tows 130 are cured.
[0059] The probe head 120 of the system 100 facilitates the
inspection of each tow 130 of the stacked configuration 142 as the
tow 130 is added to the stacked configuration 142 or before another
tow 130 is deposited onto the tow 130. In some examples, the probe
head 120 is configured to move along and be spatially offset from
the currently-applied tow 130B after deposition of the
currently-applied tow 130B. According to one example, to be
spatially offset from the currently-applied tow 130B means to be
out of physical contact with or physically separated from the
currently-applied tow 130B. Moreover, in one example, as used
herein, the currently-applied tow 130B is considered to be
deposited when either any portion of the currently-applied tow 130B
is deposited or all of the currently-applied tow 130B is deposited.
However, the probe head 120 moves along and inspects deposited
portions of the currently-applied tow 130B, rather than
yet-to-be-deposited portions of the currently-applied tow 130B. For
example, as shown in FIGS. 2A and 2B, the probe head 120 follows
the applicator 117 of the deposition head 110 to be in position to
inspect those portions of the currently-applied tow 130B as they
are deposited by the applicator 117. As mentioned, the probe head
120 is co-movably fixed relative to the applicator 117, in some
examples, such that a distance between the probe head 120 and the
applicator 117 is fixed as the applicator 117 deposits the
currently-applied tow 130B.
[0060] Referring to FIG. 2A, the probe head 120 includes a
microwave sensor 120A that is configured to transmit an incident
microwave beam 122 into the currently-applied tow 130B, in a beam
direction 150, as the probe head 120 moves along the
currently-applied tow 130B. Because the probe head 120 moves along
and inspects deposited portions of the currently-applied tow 130,
the incident microwave beam 122 is transmitted into a deposited
portion of the currently-applied tow 130.
[0061] As described in more detail below, and referring to FIG. 8,
the microwave sensor 120A of the probe head 120 is further
configured to detect a reflected microwave beam 123 transmitted
from the stacked configuration 142. The reflected microwave beam
123 includes at least a portion of the incident microwave beam 122
reflected from at least one of the currently-applied tow 130B or
the stack interface 135 between the currently-applied tow 130B and
the covered tow 130A. The characteristics of the reflected
microwave beam 123 are analyzed to determine the presence of
anomalies or imperfections in the currently-applied tow 130B, the
stack interface 135, and/or the side interface 164. More
specifically, in certain examples, the controller 108 is configured
to determine a dielectric response of at least one of the
currently-applied tow 130B or the stack interface 135 or the side
interface 164 based on the characteristics of the reflected
microwave beam 123. Certain determinable characteristics of the
dielectric response are indicative of anomalies or imperfections in
the currently-applied tow 130B, the stack interface 135, and/or the
side interface 164. Using a microwave technique to inspect the
uncured fiber-reinforced polymeric material is advantageous because
the probe head 120 need not be in contact with the material under
inspection, as is the case with other types of inspection, such as
ultrasonic inspection. Accordingly, the uncured material can be
inspected in a contactless manner, which helps alleviate
contamination concerns.
[0062] The incident microwave beam 122 penetrates the stacked
configuration 142 to a depth D that is dependent on the frequency
of the incident microwave beam 122. As used herein, the depth D is
the distance from the outermost facing surface of the stacked
configuration 142, in a direction perpendicular to the outermost
facing surface of the stacked configuration 142, to the location
within the stacked configuration 142 associated with a maximum
penetration of the incident microwave beam 122 into the stacked
configuration 142. The outermost facing surface is the surface of
the stacked configuration 142 that is closest to the probe head 120
when the probe head 120 is generating the incident microwave beam
122.
[0063] In some examples, the incident microwave beam 122 has a
frequency low enough to pass entirely through the currently-applied
tow 130B and high enough to pass entirely through no more than the
currently-applied tow 130B and the stack interface 135 between the
currently-applied tow 130B and the covered tow 130A. An incident
microwave beam 122 with a frequency that is too low may penetrate
too much of the stacked configuration 142 (e.g., depth D is too
deep) such that the results of the analysis of the reflected
microwave beam 123 would be inconclusive of any single layer of the
stacked configuration 142. Moreover, should the frequency of the
incident microwave beam 122 be too low, the beam may penetrate
entirely through the stacked configuration 142 and reflect off the
backside of the stacked configuration 142, which would result in
erroneous data or false characteristics. Accordingly, for a stacked
configuration 142 with at least two tows 130, the frequency of the
incident microwave beam 122 is selected to penetrate the stacked
configuration up to, at most, a depth D that extends beyond the
stack interface 135, but not beyond the covered tow 130A. In this
manner, the data obtained from the reflected microwave beam 123 is
usable to provide conclusive results of just a single layer and/or
a single stack interface of the stacked configuration 142.
[0064] However, when inspecting the first deposited tow(s) 130 or
the tow(s) 130 deposited directly onto the surface 141 of the
object 140, the frequency is selected such that the depth D does
not penetrate beyond the first deposited tow(s) 130. Accordingly,
in some examples, the controller 108 is configured to select a
higher frequency for the incident microwave beam 122 when
inspecting the first deposited tow(s) 130 compared to the frequency
for inspecting subsequently deposited tows 130. Accordingly, the
controller 108 can be configured to track the number of layers of
tows 130 deposited onto the surface 141 of the object 140 and to
adjust the frequency of the incident microwave beam 122
accordingly.
[0065] The desired depth D is also dependent on the thickness t of
the tows 130, as well as the material properties of the tows 130.
Accordingly, within examples, the frequency of the incident
microwave beam 122 is selected based on the thickness t of the tows
130 and/or the material properties of the tows 130. For example,
the thicker the tows 130, the lower the frequency of the incident
microwave beam 122 needed to penetrate the stacked configuration to
the desired depth D. Similarly, the denser the material of the tows
130, the lower the frequency of the incident microwave beam 122
needed to penetrate the stacked configuration to the desired depth
D. Accordingly, based on known penetration depths of microwave
beams of various frequencies into a fiber-reinforced polymeric
material, the frequency of the incident microwave beam 122 can be
selected. For example, in one type of fiber-reinforced polymeric
material, a microwave beam with a frequency of 18.00 GHz penetrates
1.0 mm into a fiber-reinforced polymeric material and a microwave
beam with a frequency of 12.73 GHz penetrates 1.5 mm into a
fiber-reinforced polymeric material.
[0066] Generally, the frequency of the incident microwave beam 122
is considerably higher than those used in conventional microwave
inspection techniques. In one example, the frequency of the
incident microwave beam 122 is at least 15 GHz. According to some
examples, the frequency of the incident microwave beam 122 is
between 15 GHz and 25 GHz, inclusive. In other examples, the
frequency of the incident microwave beam 122 is between 25 GHz and
50 GHz, inclusive. In other examples, the frequency of the incident
microwave beam 122 is between 50 GHz and 100 GHz, inclusive.
[0067] Referring to FIG. 8, in some examples, the microwave sensor
120A of the probe head 120 includes a microwave transmitter 180 and
a microwave receiver 182. The microwave transmitter 180 is
configured to generate the incident microwave beam 122 and transmit
the incident microwave beam 122 into the currently-applied tow 130B
and, in some examples, the stack interface 135 and/or the side
interface 164. The microwave receiver 182 is configured to receive
the reflected microwave beam 123 from the stacked configuration 142
and communicate data concerning the reflected microwave beam 123 to
a controller 108 of the system 100. The data can include
characteristics of the reflected microwave beam 123. The controller
108 is configured to determine the presence of anomalies or
imperfections in the currently-applied tow 130B and, in some
examples, the stack interface 135 and/or the side interface 164
based on a comparison between the data concerning the reflected
microwave beam 123 and the known characteristics of the incident
microwave beam 122. For example, knowing the characteristics of the
incidence microwave beam 122, and assuming no anomalies or
imperfections, the reflected microwave beam 123 should have certain
expected characteristics. When the actual characteristics of the
reflected microwave beam 123, obtained from the data gathered and
transmitted by the microwave receiver 182, differ from the expected
characteristics, then the controller 108 is able to determine that
anomalies or imperfections are present.
[0068] In some examples, the microwave transmitter 180 and the
microwave receiver 182 are physically separate devices, such as one
or more transducers each specifically adapted to transmit
microwaves and one or more transducers each specifically adapted to
receive microwaves. However, according to certain examples, the
microwave transmitter 180 and the microwave receiver 182 are
combined into a single device, such as a microwave transceiver 184.
The microwave sensor 120A includes one or more microwave
transceivers 184 each specifically adapted to both transmit
microwaves and receive microwaves.
[0069] Referring to FIG. 4A, in some examples, the microwave sensor
120A of the probe head 120 includes a linear phased array 160 of
microwave transmitters 180. The microwave transmitters 180 are
integrated into microwave transceivers 184 in some examples. Each
one of the microwave transmitters 180 (or microwave transceivers
184) generates a microwave signal. The incident microwave beam 122
includes a combination of the microwave signals generated by the
linear phased array 160 of microwave transmitters 180 (or microwave
transceivers 184). In some examples, the linear phased array 160 is
configured to phase shift the generation of the microwave signals.
Phase shifting the generation of the microwave signals involves
progressively delaying the generation of microwave signals going up
the line of microwave transmitters 180 of the linear phased array
160. The progressive delaying of the microwave signals results in
the microwave signals constructively combining to form the incident
microwave beam 122 as a plane wave. In some examples, the linear
phased array 160 includes various electrical circuits, such as
phase shifters that each control the feed current supplied to a
corresponding one of the microwave transmitters 180. The phase
shifters are selectively controlled by the controller 108 to change
the phase shift of the generation of the microwave signals.
[0070] The beam direction 150 of the transmission of the incident
microwave beam 122, which is defined by an angle .theta. relative
to the currently-applied tow 130B at the inspection site, is
dependent on the phase shifts of the microwave signals. In other
words, the phase shifts or timing of the generation of the
microwave signals can change the direction of the transmission of
the incident microwave beam 122. By changing the phase shift or
timing, the beam direction 150 of the incident microwave beam 122,
or angle .theta., can be adjusted. The selective adjustment allows
the incident microwave beam 122 to be rastered or moved laterally
across the width W of the currently-applied tow 130B (or the widths
W of multiple side-by-side currently-applied tows 130B, in a first
lateral direction 124 or a second lateral direction 126
substantially perpendicular to the movement of the probe head 120,
as shown in FIGS. 2A and 2B.
[0071] Rastering the incident microwave beam 122 promotes a compact
probe head 120 because the linear phased array 160 can be smaller
relative to the size of the tow 130 or tows 130 being inspected.
Moreover, a compact probe head 120 facilitates the direct coupling
of the probe head 120 to the deposition head 110, which promotes
inspection of the tows 130 as they are being deposited or between
applications of successive layers.
[0072] In some examples, as shown in FIG. 1, the probe head 120 is
coupled to the same robot 102 to which the deposition head 110 is
coupled. According to certain examples, the probe head 120 is
affixed directly to, or integrated into, the deposition head 110.
When coupled to the same robot 102 or directly affixed to the
deposition head 110, the probe head 120 is movable along the
currently-applied tow 130B along with the deposition head 110 via
operation of the robot 102.
[0073] According to alternative examples, as shown in FIG. 7, the
system 100 further includes a second robot 102A. The second robot
102A is independently movable and controllable relative to the
robot 102. In such examples, the deposition head 110 is coupled to
the robot 102 and movable by the robot 102 along the deposition
path 112 to deposit the multiple tows 130 in the stacked
configuration 142. In contrast, the probe head 120 is coupled to
the second robot 102A and movable by the second robot 102A in an
inspection path 114 along the currently-applied tow 130B
independently of the deposition head 110. In some examples, the
second robot 102A moves the probe head 120 in the inspection path
114 along the currently-applied tow 130B at the same rate as and at
the same distance from the deposition head 110. According to other
examples, the second robot 102A move the probe head 120 in the
inspection path 114 along the currently-applied tow 130B at a
different rate or after the deposition head 110 has completed the
deposition of the entire currently-applied tow 130B.
[0074] In some examples, the incident microwave beam 122 is
rastered up to, but not beyond, the edges 132 of the
currently-applied tow 130B (see, e.g., FIG. 5). Directing a portion
of the incident microwave beam 122 beyond the edges 132 results in
an erroneous inspection (e.g., false positives) because the portion
is not reflected back to the probe head 120. When inspecting parts
with large surface areas, some conventional techniques do not
experience such edge effects due to the shear size of the surface
area. However, when inspecting features have smaller surface areas,
such as the tows 130, conventional techniques are not equipped to
account for or mitigate edge effects.
[0075] To help prevent erroneous inspection due to edge effects, as
shown in FIG. 5, certain examples of the probe head 120 include at
least one edge detector 120B. The probe head 120 of FIG. 5 includes
two edge detectors 120B, each configured to detect a corresponding
one of two edges 132 of each layer of the stacked configuration
142. The edge detectors 120B flank the microwave sensor 120A, such
that the microwave sensor 120A is between the edge detectors 120B.
In some examples, the probe head 120 includes one edge detector
120B that is configured to detect both of the two edges 132 of each
layer. As described above, the edges 132 of each layer can be the
edges 132 of a single tow 130, when the deposition head 110
deposits one tow 130 at a time, or one edge 132 of one tow 130 and
one edge 132 of another tow 130, when the deposition head 110
deposits multiple tows 130 at a time in a side-by-side
arrangement.
[0076] In the illustrated example, the edge detector 120B includes
a camera that is configured to capture images of one or both of the
edges 132 based on visible light 170 reflected from the edge or
edges of the currently-applied tow 130B. The images are processed
by the controller 108 to detect the location of the edge 132 or
edges 132. In certain examples, the image processing technique
utilized by the controller 108 to detect the location of the edge
132 or edges 132 is one or more of a canny edge detection
technique, a sobel edge detection technique, or a sobel-canny edge
detection technique. According to alternative examples, the edge
detector 120B includes a line scan or line laser that utilizes
optical triangulation to detect the location of the edge 132 or
edges 132. The detected location of the edges 132 is utilized by
controller 108 to control the lateral movement of the incident
microwave beam 122 by the linear phased array 160 to limit the
movement to between the edges 132. In other words, the probe head
120 is controllable by the controller 108 to prevent movement of
the incident microwave beam 122 beyond the edges 132 (e.g.,
configured to limit movement of the incident microwave beam 122
beyond the at least one edge(s) 132) in response to the detected
location of the edge(s) 132.
[0077] In some examples, to enable multi-modal inspection of the
currently-applied tows 130B of the stacked configuration 142, the
probe head 120 includes additional inspection devices that
supplement the inspection capabilities of the microwave sensor
120A. According to one example, shown in FIG. 6, the probe head 120
additionally includes an infrared camera 120C. The infrared camera
120C is configured to generate a thermal image of the
currently-applied tow 130B based on infrared radiation 172 from the
currently-applied tow 130B. The thermal excitation of the
currently-applied tow 130B that is captured by the infrared camera
120C is generated by the application of heat to the
currently-applied tow 130B. In certain examples, the heat is
applied to the currently-applied tow 130B from the deposition head
110, which generates heat, as the deposition head 110 deposits the
currently-applied tow 130B. Additionally, or alternatively, in some
examples, heat is applied to the currently-applied tow 130B from an
external heat source, such as a hot air source or a heat lamp.
[0078] From the thermal image, the controller 108 is enabled to
determine surface and sub-surface characteristics (e.g., anomalies
and imperfections) of the currently-applied tow 130B, the stack
interface 135, and/or the side interface 164. The surface and
sub-surface characteristics determined from the thermal image
captured by the infrared camera 120C are compared with those
determined by the microwave sensor 120A to provide a more complete
analysis of the presence of anomalies and imperfections in the
currently-applied tow 130B, the stack interface 135, and/or the
side interface 164. For example, the controller 108 can be
configured to fuse together the characteristics determined from the
infrared camera 120C and the microwave sensor 120A into a composite
image from which further insights into the anomalies and
imperfections in the currently-applied tow 130B, the stack
interface 135, and/or the side interface 164 can be obtained.
[0079] According to another example, shown in FIG. 6, in addition
or alternative to the infrared camera 120C, the probe head 120
includes a laser profilometer 120D. The laser profilometer 120D is
configured to transmit a laser beam 174 to the currently-applied
tow 130B and determine profile characteristics of the
currently-applied tow 130B based on a displacement of the laser
beam 174 after impacting the currently-applied tow 130B. From the
profile characteristics, the controller 108 is enabled to determine
surface characteristics (e.g., anomalies and imperfections) of the
currently-applied tow 130B. The surface characteristics determined
by the laser profilometer 120D are compared with those determined
by the microwave sensor 120A (and optionally the infrared camera
120C) to provide a more complete analysis of the presence of
anomalies and imperfections in the currently-applied tow 130B, the
stack interface 135, and/or the side interface 164. For example,
the controller 108 can be configured to fuse together the
characteristics determined from the infrared camera 120C, the laser
profilometer 120D, and/or the microwave sensor 120A into a
composite image from which further insights into the anomalies and
imperfections in the currently-applied tow 130B, the stack
interface 135, and/or the side interface 164 can be obtained.
[0080] In yet another example, shown in FIG. 6, in addition or
alternative to the infrared camera 120C and/or the laser
profilometer 120D, the probe head 120 includes a visual camera
120E. The visual camera 120E is configured to generate a visual
image of the currently-applied tow 130B based on visible light 176
reflected from the currently-applied tow 130B. The controller 108
is configured to determine surface characteristics (e.g., anomalies
and imperfections) of the currently-applied tow 130B based on the
visual image generated by the visual camera 120E. The surface
characteristics obtained from the visual camera 120E are compared
with those determined by the microwave sensor 120A (and optionally
the infrared camera 120C and the laser profilometer 120D) to
provide a more complete analysis of the presence of anomalies and
imperfections in the currently-applied tow 130B, the stack
interface 135, and/or the side interface 164. For example, the
controller 108 can be configured to fuse together the
characteristics determined from the infrared camera 120C, the laser
profilometer 120D, the visual camera 120E, and/or the microwave
sensor 120A into a composite image from which further insights into
the anomalies and imperfections in the currently-applied tow 130B,
the stack interface 135, and/or the side interface 164 can be
obtained.
[0081] In some examples, the probe head 120 includes all of the
microwave sensor 120A, the edge detector 120B, the infrared camera
120C, the laser profilometer 120D, and the visual camera 120E.
However, in other examples, the probe head 120 includes the
microwave sensor 120A and some, but not all, of the edge detector
120B, the infrared camera 120C, the laser profilometer 120D, and
the visual camera 120E. In yet other examples, the probe head 120
includes the microwave sensor 120A and one other of the edge
detector 120B, the infrared camera 120C, the laser profilometer
120D, and the visual camera 120E. Of course, as described above, in
certain examples, the probe head 120 includes the microwave sensor
120A and none of the edge detector 120B, the infrared camera 120C,
the laser profilometer 120D, and the visual camera 120E.
[0082] Referring to FIG. 9, according to one example, a method 200
of depositing multiple tows 130 of uncured fiber-reinforced
polymeric material one layer at a time and inspecting the multiple
tows 130 one layer at a time, using the system 100, is disclosed.
The method 200 includes (block 202) depositing the
currently-applied tow 130B onto the object or onto a covered tow
130A, if a currently-applied tow 130B was previously applied, to
form a layer of a stacked configuration 142. Moreover, if the
currently-applied tow 130B is deposited onto the covered tow 130A,
the combination of the currently-applied tow 130B and the covered
tow 130A form the stacked configuration 142. In contrast, if the
currently-applied tow 130B is deposited onto the object 140, then
the currently-applied tow 130B does not yet form part of a stacked
configuration 142 because a stacked configuration 142 is not formed
until two or more tows 130 are stacked together. In some examples,
block 202 further includes depositing at least two
currently-applied tows 130B onto the object or onto at least two
covered tows 130A such that the at least two currently-applied tows
130B together form a layer of a stacked configuration 142.
[0083] The method 200 further includes (block 204) transmitting the
incident microwave beam 122 into the currently-applied tow 130B at
locations along the currently-applied tow 130B after deposition of
the currently-applied tow 130B. The incident microwave beam 122 has
a frequency low enough to pass entirely through the
currently-applied tow 130B and high enough to pass entirely through
no more than the currently-applied tow 130B and a stack interface
135 between the currently-applied tow 130B and the covered tow
130A. In some examples, the step of depositing the
currently-applied tow 130B at block 202 and the step of
transmitting the incident microwave beam 122 into the
currently-applied tow 130B at block 204 are performed
concurrently.
[0084] The method 200 also includes (block 206) detecting the
reflected microwave beam 123 and (block 208) determining a
dielectric response of the currently-applied tow 130B or the stack
interface 135 based on the reflected microwave beam 123. In some
examples, which include layers of laterally-adjacent tows 130 in a
side-by-side configuration, block 208 includes determining the
dielectric response of the side interface 164 between
laterally-adjacent tows 130.
[0085] According to some examples, the method 200 additionally
includes (block 210) moving the incident microwave beam 122
laterally across the width of the currently-applied tow 130B or
widths of the currently-applied tows 130B. The method 200 also
includes, in certain examples, (block 212) detecting one edge 132
or both edges 132 of the currently-applied tow 130B at the
locations along the currently-applied tow 30B. The method 200
further includes, in some examples, (block 214) preventing movement
of the incident microwave beam 122 beyond the edge(s) 132 in
response to detecting the edge(s) 132.
[0086] In some examples, the method 200 additionally includes
(block 216) generating the thermal image of the currently-applied
tow 130B concurrently with the step of depositing the
currently-applied tow 130B at block 202 and the step of
transmitting the incident microwave beam 122 into the
currently-applied tow 130B at block 204. Alternatively, or
additionally, the method 200 includes (block 218) transmitting the
laser beam 174 to the currently-applied tow 130B concurrently with
the step of depositing the currently-applied tow 130B at block 202
and the step of transmitting the incident microwave beam 122 into
the currently-applied tow 130B at block 204, and (block 220)
determining profile characteristics of the currently-applied tow
130B based on a displacement of the laser beam 174 after impacting
the currently-applied tow 130B.
[0087] In the above description, certain terms may be used such as
"up," "down," "upper," "lower," "horizontal," "vertical," "left,"
"right," "over," "under" and the like. These terms are used, where
applicable, to provide some clarity of description when dealing
with relative relationships. But, these terms are not intended to
imply absolute relationships, positions, and/or orientations. For
example, with respect to an object, an "upper" surface can become a
"lower" surface simply by turning the object over. Nevertheless, it
is still the same object. Further, the terms "including,"
"comprising," "having," and variations thereof mean "including but
not limited to" unless expressly specified otherwise. An enumerated
listing of items does not imply that any or all of the items are
mutually exclusive and/or mutually inclusive, unless expressly
specified otherwise. The terms "a," "an," and "the" also refer to
"one or more" unless expressly specified otherwise. Further, the
term "plurality" can be defined as "at least two."
[0088] Additionally, instances in this specification where one
element is "coupled" to another element can include direct and
indirect coupling. Direct coupling can be defined as one element
coupled to and in some contact with another element. Indirect
coupling can be defined as coupling between two elements not in
direct contact with each other, but having one or more additional
elements between the coupled elements. Further, as used herein,
securing one element to another element can include direct securing
and indirect securing. Additionally, as used herein, "adjacent"
does not necessarily denote contact. For example, one element can
be adjacent another element without being in contact with that
element.
[0089] As used herein, the phrase "at least one of", when used with
a list of items, means different combinations of one or more of the
listed items may be used and only one of the items in the list may
be needed. The item may be a particular object, thing, or category.
In other words, "at least one of" means any combination of items or
number of items may be used from the list, but not all of the items
in the list may be required. For example, "at least one of item A,
item B, and item C" may mean item A; item A and item B; item B;
item A, item B, and item C; or item B and item C. In some cases,
"at least one of item A, item B, and item C" may mean, for example,
without limitation, two of item A, one of item B, and ten of item
C; four of item B and seven of item C; or some other suitable
combination.
[0090] Unless otherwise indicated, the terms "first," "second,"
etc. are used herein merely as labels, and are not intended to
impose ordinal, positional, or hierarchical requirements on the
items to which these terms refer. Moreover, reference to, e.g., a
"second" item does not require or preclude the existence of, e.g.,
a "first" or lower-numbered item, and/or, e.g., a "third" or
higher-numbered item.
[0091] As used herein, a system, apparatus, structure, article,
element, component, or hardware "configured to" perform a specified
function is indeed capable of performing the specified function
without any alteration, rather than merely having potential to
perform the specified function after further modification. In other
words, the system, apparatus, structure, article, element,
component, or hardware "configured to" perform a specified function
is specifically selected, created, implemented, utilized,
programmed, and/or designed for the purpose of performing the
specified function. As used herein, "configured to" denotes
existing characteristics of a system, apparatus, structure,
article, element, component, or hardware which enable the system,
apparatus, structure, article, element, component, or hardware to
perform the specified function without further modification. For
purposes of this disclosure, a system, apparatus, structure,
article, element, component, or hardware described as being
"configured to" perform a particular function may additionally or
alternatively be described as being "adapted to" and/or as being
"operative to" perform that function.
[0092] The schematic flow chart diagrams included herein are
generally set forth as logical flow chart diagrams. As such, the
depicted order and labeled steps are indicative of one example of
the presented method. Other steps and methods may be conceived that
are equivalent in function, logic, or effect to one or more steps,
or portions thereof, of the illustrated method. Additionally, the
format and symbols employed are provided to explain the logical
steps of the method and are understood not to limit the scope of
the method. Although various arrow types and line types may be
employed in the flow chart diagrams, they are understood not to
limit the scope of the corresponding method. Indeed, some arrows or
other connectors may be used to indicate only the logical flow of
the method. For instance, an arrow may indicate a waiting or
monitoring period of unspecified duration between enumerated steps
of the depicted method. Additionally, the order in which a
particular method occurs may or may not strictly adhere to the
order of the corresponding steps shown.
[0093] The controller 108, which is an electronic controller,
described in this specification may be implemented as a hardware
circuit comprising custom VLSI circuits or gate arrays,
off-the-shelf semiconductors such as logic chips, transistors, or
other discrete components. The controller may also be implemented
in programmable hardware devices such as field programmable gate
arrays, programmable array logic, programmable logic devices or the
like.
[0094] The controller may also be implemented in code and/or
software for execution by various types of processors. An
identified module of code may, for instance, comprise one or more
physical or logical blocks of executable code which may, for
instance, be organized as an object, procedure, or function.
Nevertheless, the executables of the controller need not be
physically located together, but may comprise disparate
instructions stored in different locations which, when joined
logically together, comprise the controller and achieve the stated
purpose for the controller.
[0095] Indeed, code of the controller may be a single instruction,
or many instructions, and may even be distributed over several
different code segments, among different programs, and across
several memory devices. Similarly, operational data may be
identified and illustrated herein within the controller, and may be
embodied in any suitable form and organized within any suitable
type of data structure. The operational data may be collected as a
single data set, or may be distributed over different locations
including over different computer readable storage devices. Where
the controller or portions of the controller are implemented in
software, the software portions are stored on one or more computer
readable storage devices.
[0096] Any combination of one or more computer readable medium may
be utilized. The computer readable medium may be a computer
readable storage medium. The computer readable storage medium may
be a storage device storing the code. The storage device may be,
for example, but not limited to, an electronic, magnetic, optical,
electromagnetic, infrared, holographic, micromechanical, or
semiconductor system, apparatus, or device, or any suitable
combination of the foregoing.
[0097] More specific examples (a non-exhaustive list) of the
storage device would include the following: an electrical
connection having one or more wires, a portable computer diskette,
a hard disk, a random access memory (RAM), a read-only memory
(ROM), an erasable programmable read-only memory (EPROM or Flash
memory), a portable compact disc read-only memory (CD-ROM), an
optical storage device, a magnetic storage device, or any suitable
combination of the foregoing. In the context of this document, a
computer readable storage medium may be any tangible medium that
can contain, or store a program for use by or in connection with an
instruction execution system, apparatus, or device.
[0098] Code for carrying out operations for embodiments may be
written in any combination of one or more programming languages
including an object oriented programming language such as Python,
Ruby, Java, Smalltalk, C++, or the like, and conventional
procedural programming languages, such as the "C" programming
language, or the like, and/or machine languages such as assembly
languages. The code may execute entirely on the user's computer,
partly on the user's computer, as a stand-alone software package,
partly on the user's computer and partly on a remote computer or
entirely on the remote computer or server. In the latter scenario,
the remote computer may be connected to the user's computer through
any type of network, including a local area network (LAN) or a wide
area network (WAN), or the connection may be made to an external
computer (for example, through the Internet using an Internet
Service Provider).
[0099] The described features, structures, or characteristics of
the embodiments may be combined in any suitable manner. In the
above description, numerous specific details are provided, such as
examples of programming, software modules, user selections, network
transactions, database queries, database structures, hardware
modules, hardware circuits, hardware chips, etc., to provide a
thorough understanding of embodiments. One skilled in the relevant
art will recognize, however, that embodiments may be practiced
without one or more of the specific details, or with other methods,
components, materials, and so forth. In other instances, well-known
structures, materials, or operations are not shown or described in
detail to avoid obscuring aspects of an embodiment.
[0100] Aspects of the embodiments are described below with
reference to schematic flowchart diagrams and/or schematic block
diagrams of methods, apparatuses, systems, and program products
according to embodiments. It will be understood that each block of
the schematic flowchart diagrams and/or schematic block diagrams,
and combinations of blocks in the schematic flowchart diagrams
and/or schematic block diagrams, can be implemented by code. These
code may be provided to a processor of a general purpose computer,
special purpose computer, or other programmable data processing
apparatus to produce a machine, such that the instructions, which
execute via the processor of the computer or other programmable
data processing apparatus, create means for implementing the
functions/acts specified in the schematic flowchart diagrams and/or
schematic block diagrams block or blocks.
[0101] The code may also be stored in a storage device that can
direct a computer, other programmable data processing apparatus, or
other devices to function in a particular manner, such that the
instructions stored in the storage device produce an article of
manufacture including instructions which implement the function/act
specified in the schematic flowchart diagrams and/or schematic
block diagrams block or blocks.
[0102] The code may also be loaded onto a computer, other
programmable data processing apparatus, or other devices to cause a
series of operational steps to be performed on the computer, other
programmable apparatus or other devices to produce a computer
implemented process such that the code which execute on the
computer or other programmable apparatus provide processes for
implementing the functions/acts specified in the flowchart and/or
block diagram block or blocks.
[0103] The present subject matter may be embodied in other specific
forms without departing from its spirit or essential
characteristics. The described examples are to be considered in all
respects only as illustrative and not restrictive. All changes
which come within the meaning and range of equivalency of the
claims are to be embraced within their scope.
* * * * *