U.S. patent application number 13/566853 was filed with the patent office on 2013-01-24 for method for irradiation and removal of material from a surface of a structure.
This patent application is currently assigned to Loma Linda University Medical Center. The applicant listed for this patent is Paul E. Denney, Jay R. Eastman, Paul M. Fallara. Invention is credited to Paul E. Denney, Jay R. Eastman, Paul M. Fallara.
Application Number | 20130020296 13/566853 |
Document ID | / |
Family ID | 32996382 |
Filed Date | 2013-01-24 |
United States Patent
Application |
20130020296 |
Kind Code |
A1 |
Denney; Paul E. ; et
al. |
January 24, 2013 |
METHOD FOR IRRADIATION AND REMOVAL OF MATERIAL FROM A SURFACE OF A
STRUCTURE
Abstract
A method irradiates an interaction region of an inhabitable
structure with laser light to remove material from the structure.
The method includes releasably affixing an anchoring mechanism to
the structure by vacuum pressure. The method further includes
releasably affixing the anchoring mechanism to a laser head
configured to receive laser light from a laser generator, such that
the laser head is in a drilling position relative to the
interaction region. The method further includes receiving the laser
light from the laser generator and directing the laser light to the
interaction region of the structure. The method further includes
confining the material and removing the material from the
interaction region resulting from irradiating the structure with
the laser light.
Inventors: |
Denney; Paul E.; (Columbus,
OH) ; Eastman; Jay R.; (Westerville, OH) ;
Fallara; Paul M.; (Columbus, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Denney; Paul E.
Eastman; Jay R.
Fallara; Paul M. |
Columbus
Westerville
Columbus |
OH
OH
OH |
US
US
US |
|
|
Assignee: |
Loma Linda University Medical
Center
Loma Linda
CA
|
Family ID: |
32996382 |
Appl. No.: |
13/566853 |
Filed: |
August 3, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11363647 |
Feb 28, 2006 |
8258425 |
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13566853 |
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10803243 |
Mar 18, 2004 |
7038164 |
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11363647 |
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10690833 |
Oct 22, 2003 |
7880116 |
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10803243 |
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60456043 |
Mar 18, 2003 |
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60471057 |
May 16, 2003 |
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60496460 |
Aug 20, 2003 |
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Current U.S.
Class: |
219/121.72 |
Current CPC
Class: |
B23K 26/0643 20130101;
B23K 26/0884 20130101; B23K 26/206 20130101; B23K 26/127 20130101;
B23K 37/0217 20130101; B23K 26/0622 20151001; B23K 26/08 20130101;
B23K 26/1476 20130101; B23K 26/12 20130101; B23K 26/032 20130101;
B23K 26/128 20130101; B23K 2103/50 20180801; B23K 26/16 20130101;
B23K 26/40 20130101; B23K 26/123 20130101 |
Class at
Publication: |
219/121.72 |
International
Class: |
B23K 26/36 20060101
B23K026/36 |
Goverment Interests
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] This invention was funded, in part, by the Federal Emergency
Management Agency as part of the Robert T. Stafford Disaster Relief
and Emergency Assistance Act (42 U.S.C. .sctn.5121 et seq.).
Claims
1. A method of irradiating an interaction region of a structure
with laser light to remove material from the structure, the method
comprising: releasably affixing an anchoring mechanism to the
structure by vacuum pressure; releasably affixing the anchoring
mechanism to a laser head configured to receive laser light from a
laser generator, such that the laser head is in a drilling position
relative to the interaction region; receiving the laser light from
the laser generator; directing the laser light to the interaction
region of the structure; and confining the material and removing
the material from the interaction region resulting from irradiating
the structure with the laser light.
2. The method of claim 1, wherein directing the laser light
comprises reflecting the laser light by a first mirror and a second
mirror.
3. The method of claim 2, wherein the first mirror is mounted on a
first adjustable assembly in the housing, wherein alignment of the
laser light can be optimized by adjusting the first adjustable
assembly.
4. The method of claim 3, wherein the second mirror is mounted on a
second adjustable assembly in the housing, wherein alignment of the
laser light can be optimized by adjusting the second adjustable
assembly.
5. The method of claim 2, wherein the first mirror has a curvature
adapted to modify a beam profile of the laser light.
6. The method of claim 5, wherein the second mirror has a curvature
adapted to modify a beam profile of the laser light.
7. The method of claim 2, wherein the first mirror reflects the
laser light by a first non-zero angle and the second mirror
reflects the laser light by a second non-zero angle, wherein the
first non-zero angle is approximately equal to the negative of the
second non-zero angle.
8. The method of claim 1, wherein directing the laser light
comprises transmitting the laser light through a lens.
9. The method of claim 8, wherein the lens is mounted in an
adjustable assembly in the housing, wherein alignment and focus of
the laser light can be optimized by adjusting the assembly.
10. The method of claim 1, wherein releasably affixing the
anchoring mechanism to the laser head comprises releasably coupling
at least one recess of the anchoring mechanism to at least one
protrusion of the laser head.
11. The method of claim 1, wherein releasably affixing the
anchoring mechanism to the laser head comprises releasably coupling
at least one protrusion of the anchoring mechanism to at least one
recess of the laser head.
12. The method of claim 1, wherein releasably affixing the
anchoring mechanism to the laser head comprises releasably coupling
at least one rod of the anchoring mechanism to at least one collar
of the laser head, wherein the at least one collar is configured to
be releasably coupled to the at least one rod at a plurality of
locations along the at least one rod.
Description
CLAIM OF PRIORITY
[0001] This application is a divisional of U.S. patent application
Ser. No. 11/363,647, filed Feb. 28, 2006 which is incorporated in
its entirety by reference herein, which is a continuation from U.S.
patent application Ser. No. 10/803,243 filed Mar. 18, 2004 which is
incorporated in its entirety by reference herein and which is a
continuation-in-part from U.S. patent application Ser. No.
10/690,833, filed Oct. 22, 2003, which claims benefit under 35
U.S.C. .sctn.119(e) to U.S. Provisional Pat. Appl. No. 60/456,043,
filed Mar. 18, 2003, to U.S. Provisional Pat. Appl. No. 60/471,057,
filed May 16, 2003, and to U.S. Provisional Pat. Appl. No.
60/496,460, filed Aug. 20, 2003, each of which is incorporated in
its entirety by reference herein.
BACKGROUND
[0003] 1. Field of the Invention
[0004] The present invention relates to the field of material
processing, particularly, to an apparatus and method for drilling,
cutting, and surface processing of materials using energy
waves.
[0005] 2. Description of the Related Art
[0006] Those in the wide ranging materials processing industries
have long recognized the need for non-disruptive material
processing. In the past, virtually all material processing,
including drilling, cutting, scabbling, and the like have included
numerous disruptive aspects (e.g., noise, vibration, dust, vapors,
and fumes). Material processing generally includes mechanical
technologies such as drilling, hammering, and other power assisted
methods, and water jet based technologies. Demonstrative of the
problems of material processing, U.S. Pat. No. 5,085,026 is highly
illustrative. The '026 device requires mechanical drilling of
materials such as concrete or other masonry, and generates all the
disruptive aspects noted above.
SUMMARY
[0007] In certain embodiments, a laser head is adapted to irradiate
an interaction region of an inhabitable structure with laser light
to remove material from the structure. The laser head comprises a
housing. The laser head further comprises a connector coupled to
the housing and optically coupled to a laser generator. The
connector is adapted to transmit laser light from the laser
generator. The laser head further comprises at least one optical
element contained in the housing and optically coupled to the
connector. The optical element is adapted to receive laser light
from the connector. The laser head further comprises a containment
plenum coupled to the housing. The containment plenum is optically
coupled to the optical element to receive the laser light from the
optical element. The containment plenum is adapted to confine the
material and remove the material from the interaction region
resulting from irradiating the structure with the laser light.
[0008] In certain embodiments, a laser head is adapted to irradiate
an interaction region of an inhabitable structure with laser light
to remove material from the structure. The laser head comprises
means for connecting the laser head to a laser generator. The laser
head further comprises means for receiving the laser light from the
laser generator. The laser head further comprises means for guiding
the laser light to the interaction region. The laser head further
comprises means for confining the material and removing the
material from the interaction region.
[0009] In certain embodiments, a method irradiates an interaction
region of an inhabitable structure with laser light to remove
material from the structure. The method comprises connecting a
laser head to a laser generator. The method further comprises
receiving the laser light from the laser generator. The method
further comprises guiding the laser light to the interaction region
of the structure. The method further comprises confining the
material and removing the material from the interaction region.
[0010] In certain embodiments, a laser head is adapted to irradiate
an interaction region of an inhabitable structure with laser light
to remove material from the structure. The laser head comprises a
housing. The laser head further comprises a connector coupled to
the housing and optically coupled to a laser generator. The
connector is adapted to transmit laser light from the laser
generator. The laser head further comprises a first optical element
contained in the housing and optically coupled to the connector.
The first optical element is adapted to receive laser light from
the connector and to reflect the laser light from the connector
through a first non-zero angle. The laser head further comprises a
second optical element contained in the housing. The second optical
element is optically coupled to the first optical element. The
second optical element is adapted to receive laser light from the
first optical element and to reflect the laser light from the first
optical element through a second non-zero angle. The laser head
further comprises a containment plenum coupled to the housing. The
containment plenum is optically coupled to the second optical
element to receive the laser light from the second optical element.
The containment plenum is adapted to confine the material and to
remove the material from the interaction region resulting from
irradiating the structure with the laser light.
[0011] In certain embodiments, a laser head is adapted to irradiate
an interaction region of an inhabitable structure with laser light
to remove material from the structure. The laser head comprises
means for connecting the laser head to a laser generator. The laser
head further comprises means for connecting the laser head to an
anchoring mechanism. The laser head further comprises means for
receiving the laser light from the laser generator. The laser head
further comprises means for directing the laser light to the
interaction region. The laser head further comprises means for
confining the material and removing the material from the
interaction region.
[0012] In certain embodiments, a method irradiates an interaction
region of an inhabitable structure with laser light to remove
material from the structure. The method comprises connecting a
laser head to a laser generator. The method further comprises
positioning the laser head in a drilling position relative to the
interaction region. The method further comprises receiving the
laser light from the laser generator. The method further comprises
directing the laser light to the interaction region of the
structure. The method further comprises confining the material and
removing the material from the interaction region.
[0013] For purposes of summarizing the present invention, certain
aspects, advantages and novel features of the present invention
have been described herein above. It is to be understood, however,
that not necessarily all such advantages may be achieved in
accordance with any particular embodiment of the present invention.
Thus, the present invention may be embodied or carried out in a
manner that achieves or optimizes one advantage or group of
advantages as taught herein without necessarily achieving other
advantages as may be taught or suggested herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Without limiting the scope of the present invention as
claimed below and referring now to the drawings and figures:
[0015] FIG. 1 schematically illustrates an embodiment of an
apparatus for processing a surface of a structure;
[0016] FIG. 2 schematically illustrates a laser base unit
compatible with embodiments described herein;
[0017] FIG. 3A schematically illustrates a laser head in accordance
with embodiments described herein;
[0018] FIGS. 3B and 3C schematically illustrate two alternative
embodiments of the laser head;
[0019] FIG. 4 schematically illustrates a cross-sectional view of a
containment plenum in accordance with embodiments described
herein;
[0020] FIG. 5 schematically illustrates a laser head comprising a
sensor adapted to measure the relative distance between the laser
head and the interaction region;
[0021] FIGS. 6A and 6B schematically illustrate two opposite
elevated perspectives of an embodiment in which the laser
manipulation system comprises an anchoring mechanism adapted to be
releasably coupled to the structure and a positioning mechanism
coupled to the anchoring mechanism and coupled to the laser
head;
[0022] FIG. 7 schematically illustrates an embodiment of an
attachment interface of the anchoring mechanism;
[0023] FIG. 8 schematically illustrates an exploded view of one
embodiment of the positioning mechanism along with the attachment
interfaces of the anchoring mechanism;
[0024] FIG. 9 schematically illustrates an embodiment of a
first-axis position system;
[0025] FIG. 10 schematically illustrates an embodiment of a
second-axis position system;
[0026] FIGS. 11A and 11B schematically illustrate an embodiment of
an interface in two alternative configurations;
[0027] FIG. 12 schematically illustrates an embodiment of a laser
head receiver;
[0028] FIG. 13 schematically illustrates an embodiment of a support
structure coupled to the other components of the apparatus;
[0029] FIG. 14A schematically illustrates an embodiment of a
suspension-based support system coupled to the apparatus;
[0030] FIG. 14B schematically illustrates an embodiment of the
apparatus comprising suspension-based support connectors;
[0031] FIG. 15 schematically illustrates an embodiment of a
controller comprising a control panel, a microprocessor, a laser
generator interface, a positioning system interface, a sensor
interface, and a user interface;
[0032] FIG. 16 schematically illustrates a control pendant
comprising a screen and a plurality of buttons;
[0033] FIG. 17A illustrates an exemplary "MAIN SCREEN" display of
the control pendant;
[0034] FIG. 17B illustrates an exemplary "SELECT OPERATION SCREEN"
display of the control pendant;
[0035] FIG. 17C illustrates an exemplary "CIRCLE SETUP/OPERATION
SCREEN" display of the control pendant;
[0036] FIG. 17D illustrates an exemplary "PIERCE SETUP/OPERATION
SCREEN" display of the control pendant;
[0037] FIG. 17E illustrates an exemplary "CUT SETUP/OPERATION
SCREEN" display of the control pendant;
[0038] FIG. 17F illustrates an exemplary "SURFACE KEYING
SETUP/OPERATION SCREEN" display of the control pendant;
[0039] FIG. 17G illustrates an exemplary "FAULT SCREEN" display of
the control pendant;
[0040] FIG. 17H illustrates an exemplary "MAINTENANCE SCREEN"
display of the control pendant;
[0041] FIG. 18A schematically illustrates a detector compatible
with embodiments described herein;
[0042] FIG. 18B schematically illustrates a computer system adapted
to analyze the resulting spectroscopic data;
[0043] FIG. 19 shows a graph of the light spectrum of wavelengths
detected upon irradiating concrete with laser light and the light
spectrum detected upon irradiating concrete with embedded
rebar;
[0044] FIG. 20 schematically illustrates another configuration of a
laser head in accordance with embodiments described herein;
[0045] FIGS. 21A-21D schematically illustrate other anchoring
mechanisms in accordance with embodiments described herein; and
[0046] FIG. 22 is a flowchart of an exemplary method for
determining a spectral ratio in accordance with embodiments
described herein.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0047] Reducing the disruptive aspects of material processing has
long been a goal of those in materials processing industries,
particularly in industries that require materials processing within
or near occupied structures, such as is common in renovation and
many other applications. Such long-felt needs have been
particularly prevalent in seismically active areas of the earth,
where there is a pressing need for an effective and economical
means of retrofitting occupied structures to increase the safety of
these structures.
[0048] Prior technologies are plagued by disruptive
characteristics, thereby making them virtually unsuitable for
retrofitting occupied structures. Additionally, such material
processing technologies often present dangerous and costly "cut
through" dangers. "Cut through" dangers include instances such as a
worker unintentionally cutting an embedded object while drilling
through the subject material. For example, a construction worker
drilling a hole in an existing concrete wall may accidentally
encounter reinforcing steel or rebar, or embedded utilities, such
as live electrical conduit and conductors. Such an incident may
result in costly damage to tools or the subject material, as well
as potentially deadly consequences (e.g., electrocution) for
workers. Traditional drilling methods also can include "punch
through" dangers of unexpectedly punching through the material
drilled and damaging structures or personnel on the opposite side
of the material.
[0049] In addition, traditional material processing equipment has
been extremely burdensome to operate. Handheld power drilling and
hammering devices commonly weigh in excess of fifty pounds and are
often required to be held overhead by the operator for extended
period of time. Conventional devices also typically produce jarring
forces that the operator must absorb while holding the device.
Besides the potentially injurious jarring forces, sustained heavy
lifting, and "cut through" dangers, the operator and those in the
vicinity of the device may be exposed to falling or projectile
debris, as well as dust, fumes, vapors, vibration, and noise. This
level of noisome activity is unsuitable in general for occupied
structures, and is entirely unsuitable for structures used as
hospitals, laboratories, and the like, where noise and vibration
can be completely unacceptable.
[0050] What continues to be needed but missing from this field of
art is a non-disruptive material processing technology that
overcomes the drawbacks illustrated above. In certain embodiments
described herein, energy waves are directed toward the surface to
be processed to overcome some or all of such drawbacks. The energy
waves of certain embodiments are electromagnetic waves (e.g., laser
light, microwaves), while in other embodiments, they are acoustic
waves (e.g., ultrasonic waves). However, in certain embodiments,
such cutting units can be as bulky and often are as difficult to
maneuver as their mechanical counterparts. In addition, lasers can
be subject to the same "cut through" dangers as described above,
wherein objects hidden within the matrix of the material to be
processed can be inadvertently damaged. Lasers can also pose
additional dangers of "punch through" with danger to persons or
objects in the path of the laser beam. Lasers can also present
complexities in removing drilled material from a cut or a drilled
hole. In certain embodiments, the laser system would incorporate a
remote laser generator communicating with a portable processing
head that incorporates numerous non-disruptive and safety features
allowing the system to be utilized within or near occupied
structures.
[0051] Certain embodiments of the present invention provide fast
material processing while addressing many of the shortcomings of
prior technologies and allowing for heretofore unavailable benefits
(e.g., reduced disruption to activities within the structure). In
certain embodiments, the method and apparatus utilize fiber
connections between elements such that noisy, bulky, and heavy
elements can operate at a significant distance from the actual work
area. Certain embodiments are low in both noise and vibration
during operation, and effectively remove dust and debris. Certain
embodiments include a detection system to reduce the dangers of
"cut through" or "punch through." Certain embodiments enhance
worker safety by allowing workers to be located away from the work
area during material processing. Certain embodiments are separable
into man-portable pieces (e.g., less than 50 pounds) to facilitate
transportation to locations in proximity to or within the structure
being processed by providing easy and fast portability and
set-up.
[0052] Certain embodiments of the present invention provide a
method and apparatus for processing fragile structures which may be
damaged by conventional processing techniques. For example, using
conventional saws for processing concrete grain silos as part of a
retrofit or refurbishment process may result in vibrations damaging
to other portions of the silo. Using a laser to process the fragile
structure can reduce the collateral damage done to the structure
during processing. Furthermore, certain embodiments described
herein are easily assembled/disassembled, so they can be used in
otherwise inaccessible portions of the structures. While
embodiments described herein are disclosed in terms of processing
man-made structures, in still other embodiments, the present
invention can be useful for processing natural formations (e.g., as
part of a mining or drilling operation).
[0053] The method and apparatus described herein represent a
significant advance in the state of the art. Various embodiments of
the apparatus comprise new and novel arrangements of elements and
methods that are configured in unique and novel ways and which
demonstrate previously unavailable but desirable capabilities. In
particular, certain embodiments of the present invention provide a
material processing method that is quiet, substantially
vibration-free, and less likely to exude dust, debris, or noxious
fumes. Additionally, certain embodiments allow a higher rate of
material processing than do conventional technologies.
[0054] The detailed description set forth below in connection with
the drawings is intended merely as a description of various
embodiments of the present invention, and is not intended to
represent the only form in which the present invention may be
constructed or utilized. The description sets forth illustrated
embodiments of the designs, functions, apparatus, and methods of
implementing the invention. It is to be understood, however, that
the same or equivalent functions and features may be accomplished
by different embodiments that are also intended to be encompassed
within the spirit and scope of the invention.
[0055] FIG. 1 schematically illustrates an embodiment of an
apparatus 50 for processing a structure having a surface. The
apparatus 50 comprises a laser base unit 300, a laser manipulation
system 100, and a controller 500. The laser base unit 300 is
adapted to provide laser light to an interaction region and
includes a laser generator 310 and a laser head 200 coupled to the
laser generator 310. The laser head 200 is adapted to remove the
material from the interaction region. The laser manipulation system
100 includes an anchoring mechanism 110 adapted to be releasably
coupled to the structure and a positioning mechanism 121 coupled to
the anchoring mechanism 110 and coupled to the laser head 200. The
laser manipulation system 100 is adapted to controllably adjust the
position of the laser head 200 relative to the structure. The
controller 500 is electrically coupled to the laser base unit 300
and the laser manipulation system 100. The controller 500 is
adapted to transmit control signals to the laser base unit 300 and
to the laser manipulation system 100 in response to user input.
[0056] In certain embodiments, the laser head 200 is releasably
coupled to the laser generator 310 and is releasably coupled to the
positioning mechanism 121. In certain embodiments, the positioning
mechanism 121 is releasably coupled to the anchoring mechanism 110,
and the controller 500 is releasably coupled to the laser base unit
300 and the laser manipulation system 100. Such embodiments can
provide an apparatus 50 which can be reversibly assembled and
disassembled to facilitate transportation of the apparatus 50 to
locations in proximity to or within the structure being
processed.
Laser Base Unit
[0057] Certain embodiments of the laser base unit 300 are described
below. While the laser base unit 300 is described below as
comprising separate components, other embodiments can include
combinations of two or more of these components in an integral
unit.
[0058] Laser Generator
[0059] FIG. 2 schematically illustrates a laser base unit 300
compatible with embodiments described herein. In certain
embodiments, the laser base unit 300 comprises a laser generator
310 and a cooling subsystem 320. The laser generator 310 is coupled
to a power source (not shown) which provides electrical power of
appropriate voltage, phase, and amperage sufficient to power the
laser generator 310. The power source can also be portable in
certain embodiments, and can operate without cooling water, air, or
power from the facility at which the apparatus 50 is operating.
Exemplary power sources include, but are not limited to,
diesel-powered electric generators.
[0060] In certain embodiments, the laser generator 310 preferably
comprises an arc-lamp-pumped Nd:YAG laser, but may alternatively
comprise a CO.sub.2 laser, a diode laser, a diode-pumped Nd:YAG
laser, a fiber laser, or other types of laser systems. The laser
generator 310 can be operated in either a pulsed mode or a
continuous-wave mode. One exemplary laser generator 310 in
accordance with embodiments described herein includes a Trumpf
4006D, 4000-watt, continuous-wave laser available from Trumpf
Lasertechnik GmbH of Ditzingen, Germany. In other exemplary
embodiments, a Yb-doped fiber laser or an Er-doped fiber laser can
be used. Other types of lasers with other power outputs (e.g.,
2000-watt) are compatible with embodiments described herein.
Depending on the requirements unique to a given application of the
method and apparatus described herein, one skilled in the art will
be able to select the optimal laser for the purposes at hand.
[0061] In certain embodiments, the laser generator 310 can be
located within a shipping container for ease of transport and
storage. The laser generator 310 generates laser light which is
preferably delivered through a glass fiber-optic cable from the
laser generator 310 to the work location.
[0062] In certain alternative embodiments, the laser generator 310
comprises a gas-based CO.sub.2 laser which generates laser light by
the excitation of CO.sub.2 gas. Such lasers provide high power
output (e.g., .about.100 W-50 kW) at high efficiencies (e.g.,
.about.5-13%), and are relatively inexpensive. The laser light
generated by such gas-based CO.sub.2 lasers is typically delivered
by mirrors and by using a system of ducts or arms to deliver the
laser light around bends or corners.
[0063] In certain alternative embodiments, the laser generator 310
comprises a diode laser. Such diode lasers are compact compared to
gas and Nd:YAG lasers so they can be used in a direct delivery
configuration (e.g., in close proximity to the work site). Diode
lasers provide high power (e.g., .about.10 W-6 kW) at high power
efficiencies (e.g., .about.25-40%). In certain embodiments, the
laser light from a diode laser can be delivered via optical fiber,
but with some corresponding losses of power.
[0064] Embodiments using a Nd:YAG laser can have certain advantages
over embodiments with CO.sub.2 lasers or diode lasers. There is
long industrial experience with Nd:YAG lasers in the materials
processing industry and they provide high power (e.g., .about.100
W-6 kW). Additionally, the laser light from a Nd:YAG laser can be
delivered by optical fiber with only slight power losses (e.g.,
.about.12%) through a relatively small and long optical fiber. This
permits the staging of the laser generator 310 and support
equipment in locations relatively far (e.g., about 100 meters) from
the work area. Maintaining the laser generator 310 at a distance
from the surface being processed allows the remainder of the
apparatus 50 to be smaller and more portable.
[0065] Arc-lamp-pumped Nd:YAG lasers use an arc lamp to excite a
Nd:YAG crystal to generate laser light. Diode-pumped Nd:YAG lasers
use diode lasers to excite the Nd:YAG crystal, resulting in an
increase in power efficiency (e.g., .about.10-25%, as compared to
less than 5% for arc-lamp-pumped Nd:YAG lasers). This increased
efficiency results in the diode-pumped laser having a better beam
quality, and requiring a smaller cooling subsystem 320. An
exemplary arc-lamp-pumped Nd:YAG laser is available from Trumpf
Lasertechnik GmbH of Ditzingen, Germany.
[0066] Nd:YAG and other solid state lasers (e.g., Nd:YLiF.sub.4,
Ti:Sapphire, Yb:YAG, etc.) compatible with embodiments described
herein can be configured and pumped by a number of methods. These
methods include, but are not limited to, flash and arc lamps, as
well as diode lasers. Various configurations of the solid state
media are compatible with embodiments described herein, including,
but not limited to, rod, slab, and disk configurations. The
advantages of the different configurations and pumping methods will
impact various aspects of the laser generator 310, including, but
not limited to, the efficiency, the beam quality, and the
operational mode of the laser generator 310. An exemplary
diode-laser-pumped Nd:YAG disk laser is available from Trumpf
Lasertechnik GmbH of Ditzingen, Germany.
[0067] Fiber lasers use a doped (e.g., doped with ytterbium or
erbium) fiber to produce a laser beam. The doped fiber can be
pumped by other light sources including, but not limited to, arc
lamps and diodes. The fiber laser can be coupled into a delivery
fiber which carries the laser beam to the interaction location. In
certain embodiments, a fiber laser provides an advantageous
efficiency of approximately 15% to approximately 20%. Such high
efficiencies make the laser generator 310 more mobile, since they
utilize smaller chiller units. In addition, such high efficiency
laser generators 310 can be located closer to the processing area.
An exemplary fiber laser compatible with embodiments described
herein is available from IPG Photonics of Oxford, Mass.
[0068] Typically, the generation of laser light by the laser
generator 310 creates excess heat which is preferably removed from
the laser generator 310 by the cooling subsystem 320 coupled to the
laser generator 310. The amount of cooling needed is determined by
the size and type of laser used, but can be about 190 kW of cooling
capacity for a 4-kW Nd:YAG laser. The cooling subsystem 320 can
utilize excess cooling capability at a job site, such as an
existing process water or chilled water cooling subsystem.
Alternatively, a unitary cooling subsystem 320 dedicated to the
laser generator 310 is preferably used. Unitary cooling subsystems
320 may be air- or liquid-cooled.
[0069] In certain embodiments, as schematically illustrated in FIG.
2, the cooling subsystem 320 comprises a heat exchanger 322 and a
water chiller 324 coupled to the laser 310 to provide sufficient
circulatory cooling water to the laser generator 310 to remove the
excess heat. The heat exchanger 322 preferably removes a portion of
the excess heat from the water, and circulates the water back to
the water chiller 324. The water chiller 324 cools the water to a
predetermined temperature and returns the cooling water to the
laser generator 310. Exemplary heat exchangers 322 and water
coolers 324 in accordance with embodiments described herein are
available from Trumpf Lasertechnik GmbH of Ditzingen, Germany.
[0070] Laser Head
[0071] In certain embodiments, the laser head 200 is coupled to the
laser generator 310 and serves as the interface between the
apparatus 50 and the structure being irradiated. As schematically
illustrated by FIG. 1, an energy conduit 400 couples the laser head
200 and the laser generator 310 and facilitates the transmission of
energy from the laser generator 310 to the laser head 200. In
certain embodiments, the energy conduit 400 comprises an optical
fiber which transmits laser light from the laser generator 310 to
the laser head 200. In other embodiments, the energy conduit 400
comprises conductors that may include fiber-optic, power, or
control wiring cables.
[0072] FIG. 3A schematically illustrates a laser head 200 in
accordance with embodiments described herein. The laser head 200
comprises a connector 210, at least one optical element 220, a
housing 230, and a containment plenum 240. In certain embodiments,
the connector 210 is coupled to the housing 230, is optically
coupled to the laser generator 310 via the energy conduit 400, and
is adapted to transmit laser light from the laser generator 310.
The optical element 220 can be located within the connector 210,
the housing 230, or the containment plenum 240. FIG. 3A illustrates
an embodiment in which the optical element 220 is within the
housing 230. In embodiments in which the conduit 400 provides laser
light to the laser head 200, the laser light is transmitted through
the optical element 220 prior to impinging on the structure being
irradiated.
[0073] Laser Head: Extended Configuration
[0074] FIG. 3B schematically illustrates one configuration of a
laser head 200 in accordance with embodiments described herein. The
housing 230 comprises a distal portion 232, an angle portion 234,
and a proximal portion 236. As used herein, the terms "distal" and
"proximal" have their standard definitions, referring generally to
the position of the portion relative to the interaction region. The
connector 210 is coupled to the distal portion 232, which is
coupled to the angle portion 234, which is coupled to the proximal
portion 236, which is coupled to the containment plenum 240.
Configurations such as that illustrated by FIG. 3B can be used for
drilling and scabbling the surface of the structure (e.g., concrete
wall). Various components of the laser head 200 are available from
Laser Mechanisms, Inc. of Farmington Hills, Mich.
[0075] In certain embodiments in which the energy conduit 400
comprises an optical fiber, the connector 210 receives laser light
transmitted from the laser generator 310 through the optical fiber
to the laser head 200. In certain such embodiments, the connector
210 comprises a lens 212 which collimates the diverging laser light
emitted by the conduit 400. The lens 212 can comprise various
materials which are transmissive and will refract the laser light
in a desired amount. Such materials include, but are not limited
to, borosilicate crown glass (BK7), quartz (SiO.sub.2), zinc
selenide (ZnSe), and sodium chloride (NaCl). The material of the
lens 212 can be selected based on the quality, cost, and stability
of the material. Borosilicate crown glass is commonly used for
transmissive optics with Nd:YAG lasers, and zinc selenide is
commonly used for transmissive optics with CO.sub.2 lasers.
[0076] The lens 212 can be mounted in a removable assembly in
certain embodiments to facilitate cleaning, maintenance, and
replacement of the lens 212. In addition, the mounting of the lens
212 can be adjustable (e.g., using thumbscrews or Allen hex screws)
so as to optimize the alignment and focus of the light beam. In
certain embodiments, the lens 212 can provide additional
modification of the beam profile (e.g., focussing, beam shape).
[0077] The collimated laser light of certain embodiments is then
transmitted through the laser head 200 via other optical elements
within the laser head 200. In certain embodiments, the distal
portion 232 comprises a generally straight first tube through which
laser light propagates to the angle portion 234, and the proximal
portion 236 comprises a generally straight second tube through
which the laser light from the angle portion 234 propagates. In
certain embodiments, the distal portion 232 contains a lens 233,
and the angle portion 234 contains a mirror 235 which directs the
light through the proximal portion 236 and the containment plenum
240 onto the structure. In other embodiments, other devices (e.g.,
a prism) can be used in the angle portion 234 to direct the light
through the proximal portion 236 and the containment plenum 240
onto the structure.
[0078] The lens 233 can be mounted in a removable assembly in
certain embodiments to facilitate cleaning, maintenance, and
replacement of the lens 233. In addition, the mounting of the lens
233 can be adjustable (e.g., using thumbscrews or Allen hex screws)
so as to optimize the alignment and focus of the light beam. In
certain embodiments, the lens 233 focuses the light received from
the lens 212, while in other embodiments, the lens 233 can provide
additional modification of the beam profile (e.g., beam shape).
Exemplary lenses 233 include, but are not limited to, a 600-mm
focal length silica plano-convex lens (e.g., Part No.
PLCX-50.8-309.1-UV-1064 available from CVI Laser Corp. of
Albuquerque, N. Mex.). The lens 233 can comprise various materials
which are transmissive and will refract the laser light in a
desired amount. Such materials include, but are not limited to,
borosilicate crown glass, quartz, zinc selenide, and sodium
chloride. Exemplary lens mounting assemblies include, but are not
limited to, Part Nos. PLALH0097 and PLFLH0119 available from Laser
Mechanisms, Inc. of Farmington Hills, Mich.
[0079] In the embodiment schematically illustrated by FIG. 3B in
which the distal portion 232 is substantially perpendicular to the
proximal portion 236, the mirror 235 reflects the light through an
angle of approximately 90 degrees. Other embodiments are configured
to reflect the light through other angles. The mirror 235 can be
mounted on a removable assembly in certain embodiments to
facilitate cleaning, maintenance, and replacement of the mirror
235. In addition, the mounting of the mirror 235 can be adjustable
(e.g., using thumbscrews or Allen hex screws) so as to optimize the
alignment and focus of the light beam. In certain embodiments, the
mirror 235 can also have a curvature or otherwise be configured so
as to focus the light beam or otherwise modify the beam profile
(e.g., beam shape). Exemplary mirrors 235 include, but are not
limited to, metal mirrors such as copper mirrors (e.g., Part Nos.
PLTRG19 and PLTRC0024 from Laser Mechanisms, Inc. of Farmington
Hills, Mich.), and gold-coated copper mirrors (e.g., Part No.
PLTRC0100 from Laser Mechanisms, Inc.). In other embodiments,
dielectric-coated mirrors can be used.
[0080] FIG. 3C schematically illustrates another configuration of a
laser head 200 in accordance with embodiments described herein. The
housing 230 comprises the distal portion 232, a first angle portion
234, a second angle portion 234', and the proximal portion 236. The
connector 210 is coupled to the distal portion 232, which is
coupled to the first angle portion 234, which is coupled to the
second angle portion 234', which is coupled to the proximal portion
236, which is coupled to the containment plenum 240. Configurations
such as that illustrated by FIG. 3C can be used for cutting the
structure in spatially constrained regions (e.g., cutting off
portions of a concrete wall near a corner or protrusion).
[0081] As described above, in certain embodiments, the connector
210 comprises a lens 212 and the distal portion 232 is tubular and
contains a lens 233. The first angle portion 234 of the embodiment
illustrated by FIG. 3C contains a first mirror 235 which directs
the light to the second angle portion 234' which contains a second
mirror 235'. The second mirror 235' directs the light through the
proximal portion 236, which can be tubular, and through the
containment plenum 240 onto the structure. In certain embodiments,
as described more fully below with respect to the containment
plenum 240, the light is transmitted through a window 243 and a
nozzle 244 to the interaction region. In certain embodiments, the
laser head 200 comprises the window 243 and the nozzle 244, while
in other embodiments, the window 243 and the nozzle 244 are
components of the containment plenum 240.
[0082] In the embodiment schematically illustrated by FIG. 3C, the
first mirror 235 reflects the light through an angle of
approximately 90 degrees and the second mirror 235' reflects the
light through an angle of approximately -90 degrees such that the
proximal portion 236 is substantially parallel to the distal
portion 232. In such embodiments, the light emitted by the
containment plenum 240 is substantially parallel to, but displaced
from, the light propagating through the distal portion 232. Other
embodiments have the first mirror 235 and the second mirror 235'
configured to reflect the light through other angles. Certain
embodiments comprise a straight tubular portion between the first
angle portion 234 and the second angle portion 234' to provide
additional displacement of the light emitted by the containment
plenum 240 from the light propagating through the distal portion
232.
[0083] In certain embodiments, the coupling between the distal
portion 232 and the first angle portion 234 is rotatable. In
certain other embodiments, the coupling between the first angle
portion 234 and the second angle portion 234' is rotatable. These
rotatable couplings can comprise swivel joints which can be locked
in position by thumbscrews. Such embodiments provide additional
flexibility in directing the light emitted by the containment
plenum 240 in a selected direction. In certain embodiments, the
selected direction is non-planar with the light propagating through
the distal portion 232.
[0084] As described above, one or both of the first mirror 235 and
the second mirror 235' can be mounted on a removable assembly in
certain embodiments to facilitate cleaning, maintenance, and
replacement. In addition, the mountings of the first mirror 235
and/or the second mirror 235' can be adjustable (e.g., using
thumbscrews or Allen hex screws) so as to optimize the alignment
and focus of the light beam. In certain embodiments, one or both of
the first mirror 235 and the second minor 235' can also have a
curvature or otherwise be configured so as to focus the light beam
or otherwise modify the beam profile (e.g., beam shape).
[0085] In certain embodiments, one or more of the optical elements
220 within the laser head 200 (e.g., lens 212, lens 233, mirror
235, mirror 235') are water-cooled or air-cooled. Cooling water can
be supplied by a heat exchanger located near the laser head 200 and
dedicated to providing sufficient water flow to the laser head 200.
In certain such embodiments, the conduits for the cooling water for
each of the optical elements 220 can be connected in series so that
the cooling water flows sequentially in proximity to the optical
elements 220. In other embodiments, the conduits are connected in
parallel so that separate portions of the cooling water flow in
proximity to the various optical elements 220. Exemplary heat
exchangers include, but are not limited to a Miller Coolmate.TM. 4,
available from Miller Electric Manufacturing Co. of Appleton, Wis.
The flow rate of the cooling water is preferably at least
approximately 0.5 gallons per minute.
[0086] Laser Head: Compact Configuration
[0087] FIG. 20 schematically illustrates another configuration of a
laser head 1200 in accordance with embodiments described herein.
Certain embodiments of the laser head 1200 are adapted to be
movable and placed in position relative to the surface to be
irradiated by a single person. In certain such embodiments, the
combination of the laser head 1200 and certain embodiments of the
anchoring mechanism 1110, discussed below, weighs less than fifty
pounds.
[0088] The embodiment illustrated by FIG. 20 is generally adapted
for drilling holes in the surface to be irradiated, and is
generally of smaller size and weight than the embodiments of FIGS.
3B and 3C, thereby providing an apparatus which is adapted to
access more constrained spaces. In addition, the embodiment of FIG.
20 is generally more simple and more robust than the embodiments of
FIGS. 3B and 3C, thereby providing an apparatus which is adapted to
withstand rough handling and non-ideal operating conditions.
[0089] The laser head 1200 in certain embodiments comprises a
generally rectangular housing 1230. The other components of the
laser head 1200 are positioned on the housing 1230 or within the
housing 1230. The housing 1230 of certain embodiments comprises a
connection structure (not shown) which is adapted to be releasably
coupled to an anchoring mechanism 1110 which, as described further
below, is adapted to position the laser head 1200 relative to the
surface to be irradiated. In an exemplary embodiment, the housing
1230 has a length of approximately 12 inches, a height of
approximately 8 inches, and a width of approximately 4 inches.
Other shapes and dimensions of the housing 1230 are compatible with
embodiments described herein.
[0090] In certain embodiments, the laser head 1200 further
comprises a connector 1210 which is adapted to be coupled to the
conduit 400 carrying laser light from the laser generator 310 to
the laser head 1200. In certain embodiments, the connector 1210
comprises a lens (not shown) which collimates the diverging laser
light emitted by the conduit 400. As described above in relation to
the extended configuration, the lens of various embodiments can
comprise various materials, can be removably mounted to the housing
1230, can be adjustably mounted to the housing 1230, and can
provide additional modification of the beam profile.
[0091] In certain embodiments, the laser head 1200 further
comprises a first mirror 1235 adapted to reflect light from the
connector 1210 through a first non-zero angle, and a second mirror
1235' adapted to reflect light from the first mirror 1235 through a
second non-zero angle to a nozzle 1244 which is adapted to be
coupled to the containment plenum 240. In certain embodiments, as
schematically illustrated in FIG. 20, the first non-zero angle is
approximately equal to the negative of the second non-zero angle.
Such two-mirror configurations are sometimes called "folded optics"
configurations since reflecting the light between the mirrors
effectively "folds" a propagation path having a length into a
smaller space. Certain embodiments of the laser head 1200 comprise
additional optical components adapted to modify the beam profile of
the laser light.
[0092] As described above in relation to the extended
configuration, at least one of the first mirror 1235 and the second
mirror 1235' is mounted in the housing 1230 on a removable and
adjustable assembly. In addition, at least one of the first mirror
1235 and the second mirror 1235' of certain embodiments has a
curvature or is otherwise configured to modify the beam profile. At
least one of the first mirror 1235 and the second mirror 1235' of
certain embodiments is cooled by either air or water provided by
cooling conduits. In certain embodiments, the cooling conduits are
contained within the housing 1230, thereby facilitating transport
and placement of the laser head 1200 by making the laser head 1200
less unwieldy and making the laser head 1200 more robust.
[0093] In certain embodiments, as shown in FIG. 21C, the laser head
1200 comprises a laser head handle 1240 coupled to the housing
1230. The laser head handle 1240 is adapted to facilitate
transporting and positioning the laser head 1200 at a selected
location. Other configurations of the laser head handle 1240 are
compatible with other embodiments described herein. The laser head
1200 of certain embodiments further comprises a coupler 1250
adapted to releasably couple the laser head 1200 to the anchoring
mechanism 1110. Other configurations of the laser head 1200 are
compatible with embodiments described herein.
[0094] In certain embodiments, the compact configuration of the
laser head ("compact laser head") 1200, such as shown in FIGS.
21A-21C, is advantageously used in certain applications rather than
the extended configuration of the laser head ("extended laser
head") 200 as shown in FIGS. 3B and 3C. For example, when drilling
holes in the structure, there may be areas in which the extended
laser head 200 may not have access due to its length or other
constraints (e.g., rigidity of the coupling between the energy
conduit 400 and the connector 210). The compact laser head 1200 has
a smaller volume, thereby allowing access to smaller areas.
[0095] In addition, in certain embodiments, the compact laser head
1200 is used in conjunction with an energy conduit 400 comprising a
pivoting collimator head (not shown) adapted to provide a
rotational coupling between the energy conduit 400 and the laser
head 1200. In such embodiments, the pivoting collimator head
provides additional flexibility by allowing the laser head 1200 to
access smaller areas. The collimator head can be straight, or can
have an angle (e.g., 90 degrees). Using collimator heads with
different orientations advantageously permits various orientations
of the energy conduit 400 for providing access to constrained
areas. Exemplary collimator heads compatible with embodiments
described herein are available from Trumpf Lasertechnik GmbH of
Ditzingen, Germany.
[0096] Furthermore, in certain embodiments, the compact laser head
1200 also incorporates the various sensors, proximity switches, and
flow meters of the laser head 1200 within the housing 1230. Such
embodiments are generally more simple and more robust than the
extended laser head 200, thereby providing an apparatus which is
adapted to withstand rough handling and non-ideal operating
conditions, and is less likely to be damaged.
[0097] Laser Head: Lightweight Configuration
[0098] FIG. 21D schematically illustrates a combination of a
lightweight laser head 2200 with an anchoring mechanism 1110. In
certain embodiments, the laser head 2200 has a 140-millimeter focal
length and is commercially available, e.g., a D35 90-degree focus
head with cooling and observation port available from Trumpf
Lasertechnik GmbH of Ditzingen, Germany (Catalog No. 35902090). The
laser head 2200 of certain embodiments is adapted for drilling
relatively shallow holes. In certain embodiments, the laser
head/anchoring mechanism combination weighs less than 10 pounds,
while in other embodiments, the combination weighs approximately 8
pounds.
[0099] Laser Head: Containment Plenum
[0100] In certain embodiments, the laser head 200 comprises a
containment plenum 240 coupled to the proximal portion 236 and
which interfaces with the structure. In certain embodiments, the
containment plenum 240 is adapted to confine material (e.g., debris
and fumes generated during laser processing) removed from the
structure and remove the material from the interaction region. The
containment plenum 240 can also be further adapted to reduce noise
and light emitted from the interaction region out of the
containment plenum 240 (e.g., into the nominal hazard zone ("NHZ")
of the laser). One goal of the containment plenum 240 can be to
ensure that no laser radiation in excess of the accessible emission
limit ("AEL") or maximum-permissible exposure ("MPE") limit reaches
the eye or skin of any personnel.
[0101] FIG. 4 schematically illustrates a cross-sectional view of a
containment plenum 240 in accordance with embodiments described
herein. The containment plenum 240 of FIG. 4 comprises a plenum
housing 242, a window 243, a nozzle 244, a resilient interface 246,
an extraction port 248, and a compressed gas inlet 249. The plenum
housing 242 can be coupled to a source of laser light (e.g., the
proximal portion 236 of the laser head 200) and can provide
structural support for the other components of the containment
plenum 240. Exemplary materials for the plenum housing 242 include,
but are not limited to, metals (e.g., aluminum, steel) which can be
in the form of thin flexible sheets, ceramic materials, glass or
graphite fibers, and fabric made from glass or graphite fibers. In
certain embodiments, the plenum housing 242 is either air-cooled or
water-cooled to reduce heating of the plenum housing 242. Coolant
conduits for the plenum housing 242 can be coupled in series or in
parallel with the coolant conduits for other components of the
laser head 200.
[0102] The window 243 of certain embodiments is positioned upstream
of the nozzle 244 and within the propagation path of the laser
light from the proximal portion 236 to the structure. As used
herein, the terms "downstream" and "upstream" have their ordinary
meanings referring to the propagation direction of the laser light
and to the direction opposite to the propagation direction of the
laser light, respectively. In such embodiments, the light
propagating through the containment plenum 240 reaches the window
243 prior to reaching the nozzle 244. In such embodiments in which
the light propagates downstream through the window 243, the window
243 is substantially transparent to the laser light. The window 243
can be mounted within the plenum housing 242 to transmit the laser
light in the downstream direction. The window 243 can have a number
of shapes, including, but not limited to, square and circular.
Exemplary windows 243 include, but are not limited to, a silica
window (e.g., Part No. W2-PW-2037-UV-1064-0 available from CVI
Laser Corp. of Albuquerque, N. Mex.).
[0103] Dust and/or dirt on the optical elements of the laser head
200 can absorb an appreciable fraction of the laser light,
resulting in nonuniform heating which can damage the optical
elements. In certain embodiments, the window 243 is mounted within
the plenum housing 242 to provide a barrier to the upstream
transport of dust, smoke, or other particulate matter generated by
the interaction of the laser light and the structure. In this way,
the window 243 can facilitate protection of the upstream optical
elements within the other portions of the laser head 200.
[0104] The window 243 can be mounted in a removable assembly in
certain embodiments to facilitate cleaning, maintenance, and
replacement of the window 243. In certain embodiments, the window
243 focuses the light received from the proximal portion 236, while
in other embodiments, the window 243 can provide additional
modification of the beam profile (e.g., beam shape). In such
embodiments, the mounting of the window 243 can be adjustable
(e.g., using thumbscrews or Allen hex screws) so as to optimize the
alignment and focus of the light beam. Exemplary window mounting
assemblies include, but are not limited to, Part Nos. PLALH0097 and
PLFLH0119 available from Laser Mechanisms, Inc. of Farmington
Hills, Mich. In certain embodiments, the window 243 is either
air-cooled or water-cooled.
[0105] The laser light transmitted through the window 243 is
emitted through the nozzle 244 towards the interaction region of
the structure. The laser light can be focussed near the opening of
the nozzle 244. Exemplary materials for the nozzle 244 include, but
are not limited to metals (e.g., copper). In certain embodiments,
the nozzle 244 is either air-cooled or water-cooled to reduce
heating of the nozzle 244. Coolant conduits for the nozzle 244 can
be coupled in series or in parallel with the coolant conduits for
other components of the laser head 200.
[0106] The laser light propagating through the nozzle 244
preferably does not impinge the nozzle 244 (termed "clipping") to
avoid excessively heating and damaging the nozzle 244. Improper
alignment of the laser light through the laser head 200 can cause
clipping. The opening of the nozzle 244 can be sufficiently large
so that the laser light does not appreciably interact with the
nozzle 244. In certain embodiments, the nozzle 244 is approximately
0.3 inches in diameter.
[0107] In certain embodiments, the resilient interface 246 of the
containment plenum 240 is adapted to contact the structure and to
substantially surround the interaction region, thereby facilitating
confinement and removal of material from the interaction region. In
addition, the resilient interface 246 can facilitate blocking light
and/or sound from escaping outside the containment plenum 240.
Exemplary resilient interfaces 246 include, but are not limited to,
a wire brush.
[0108] In certain embodiments, the extraction port 248 of the
containment plenum 240 is adapted to extract an appreciable portion
of the material (e.g., gas, vapor, dust, and debris) generated
within the interaction region during operation. The extraction port
248 can be coupled to a vacuum generator (not shown) which creates
a vacuum to pull material (e.g., airborne particulates, gases, and
vapors) from the interaction region. In this way, the extraction
port 248 can provide a pathway for removal of the material from the
containment plenum 240.
[0109] In certain embodiments, the compressed gas inlet 249 is
adapted to provide compressed gas (e.g., air) to the containment
plenum 240. In certain embodiments, the compressed gas inlet 249 is
fluidly coupled to the nozzle 244 which is adapted to direct a
compressed gas stream to the interaction region. In certain
embodiments, compressed gas flows coaxially with the laser light
through the nozzle 244. The window 243 of certain embodiments
provides a surface against which the compressed gas exerts
pressure. In this way, the compressed gas can flow through the
nozzle 244 to the interaction region at a selected pressure and
velocity.
[0110] The compressed gas flowing from the compressed gas inlet 249
through the nozzle 244 can be used to deter dust, debris, smoke,
and other particulate matter from entering the nozzle 244. In this
way, the compressed gas can facilitate protection of the window 243
from such particulate matter. In addition, the compressed gas can
be directed by the nozzle 244 to the interaction region so as to
facilitate removal of material from the interaction region. The
nozzle 244 can be used in this manner in embodiments in which the
structure includes concrete with a high percentage of Si, so that
the resultant glassy slag is sufficiently viscous and more
difficult to remove from the interaction region.
[0111] In certain embodiments, the compressed air is substantially
free of oil, moisture, or other contaminants to avoid contaminating
the surface of the window 243 and potentially damaging the window
243 by nonuniform heating. An exemplary source of instrument
quality ("IQ") compressed air is the 300-IQ air compressor
available from Ingersoll-Rand Air Solutions Group of Davidson, N.C.
The source of compressed air preferably provides air at a
sufficient flow rate determined in part by the length of the hose
delivering the air, and the number of components using the air and
their requirements.
[0112] In certain embodiments, the air compressor can be located
hundreds of feet away from the laser head 200. In such embodiments,
the source of compressed air can comprise an air dryer to reduce
the amount of moisture condensing in the air conduits or hoses
between the air compressor and the laser head 200. An exemplary air
dryer in accordance with embodiments described herein is the 400
HSB air dryer available from Zeks Compressed Air Solutions of West
Chester, Pa.
[0113] In certain embodiments, as schematically illustrated in FIG.
5, the laser head 200 comprises a sensor 250 adapted to measure the
relative distance between the laser head 200 and the interaction
region. FIG. 5 schematically illustrates an embodiment in which the
containment plenum 240 comprises the sensor 250, although other
locations of the sensor 250 are also compatible with embodiments
described herein. As material is removed from the structure, the
interaction region extends into the structure. The sensor 250 then
provides a measure of the depth of the interaction region from the
surface of the structure. The sensor 250 can use various
technologies to determine this distance, including, but not limited
to, acoustic sensors, infrared sensors, tactile sensors, and
imaging sensors. In certain embodiments in which laser scabbling or
machining is performed, a sensor 250 comprising a diode laser and
utilizing triangulation could be used to determine the distance
between the laser head 200 and the surface being processed. Such a
sensor 250 can also provide a measure of the amount of material
removed from the surface.
[0114] In certain embodiments, the sensor 250 is coupled to the
controller 500, and the controller 500 is adapted to transmit
control signals to the laser base unit 300 in response to signals
from the sensor 250. The laser base unit 300 can be adapted to
adjust one or more parameters of the laser light in response to the
control signals. In this way, the depth information from the sensor
250 can be used in real-time to adjust the focus or other
parameters of the laser light.
[0115] In other embodiments, the controller 500 is adapted to
transmit control signals to the laser manipulation system 100 in
response to signals from the sensor 250. The laser manipulation
system 100 is adapted to adjust the relative distance between the
laser head 200 and the interaction region in response to the
control signals. In addition, the laser manipulation system 100 can
be adapted to adjust the position of the laser head 200 along the
surface of the structure in response to the control signals. In
this way, the depth information from the sensor 250 at a first
location can be used in real-time to move the laser light to
another location along the surface once a desired depth at the
first location is achieved.
[0116] In other embodiments, the sensor 250 is used in conjunction
with statistical methods to determine the depth of the interaction
region. In such embodiments, the sensor 250 is first used in a
measurement phase to develop statistical data which correlates
penetration depths with certain processing parameters (e.g.,
material being processed, light intensity). During the measurement
phase, selected processing parameters are systematically varied for
processing a test or sample surfaces indicative of the surfaces of
the structure to be processed. The sensor 250 is used in the
measurement phase to determine the depth of the interaction region
corresponding to these processing parameters. In certain such
embodiments, the sensor 250 can be separate from the laser head
200, and can be used during the processing of the structure or
during periods when the processing has been temporarily halted in
order to measure the depth of the interaction region. Exemplary
sensors 250 compatible with such embodiments include, but are not
limited to, calipers or other manual measuring devices which are
inserted into the resultant hole to determine the depth of the
interaction region.
[0117] In certain embodiments, the controller 500 contains this
resulting statistical data regarding the correlation between the
processing parameters and the depth of the interaction region.
During a subsequent processing phase, the structure is processed,
but rather than using the sensor 250 at this time, the controller
500 can be adapted to determine the relative distance by accessing
the statistical data corresponding to the particular processing
parameters being used. Such an approach represents a reliable and
cost-effective approach for determining the depth of the
interaction region while processing the structure.
[0118] In alternative embodiments, the sensor 250 is adapted to
provide a measure of the distance between the laser head 200 and
the surface of the structure. In such embodiments, the sensor 250
can be adapted to provide a fail condition signal to the controller
500 upon detection of the relative distance between the laser head
200 and the structure exceeding a predetermined distance. Such a
fail condition may result from the apparatus 50 inadvertently
becoming detached from the structure. The controller 500 can be
adapted to respond to the fail condition signal by sending
appropriate signals to the laser base unit 300 to halt the
transmission of energy between the laser base unit 300 and the
laser head 200. In certain embodiments, the transmission is
preferably halted when the laser head 200 is further than one
centimeter from the surface of the structure. In this way, the
apparatus 50 can utilize the sensor 250 to insure that laser light
is not emitted unless the containment plenum 240 is in contact with
the structure. In certain embodiments, the sensor 250 comprises a
proximity switch which contacts the surface of the structure while
the apparatus 50 is attached to the structure.
Laser Manipulation System (LMS)
LMS: Combined Anchoring Mechanism and Positioning Mechanism
[0119] In certain embodiments, the laser manipulation system 100
serves to accurately and repeatedly position the laser head 200 in
relation to the structure so as to provide articulated robotic
motion generally parallel to the surface to be processed. To do so,
the laser manipulation system 100 can be releasably affixed to the
structure to be processed, and can then accurately move the laser
head 200 in proximity to that surface. FIGS. 6A and 6B
schematically illustrate two opposite elevated perspectives of an
embodiment in which the laser manipulation system 100 comprises an
anchoring mechanism 110 adapted to be releasably coupled to the
structure and a positioning mechanism 121 coupled to the anchoring
mechanism 110 and coupled to the laser head 200. In certain
embodiments, the laser manipulation system 100 can be
advantageously disassembled and reassembled for transport, storage,
or maintenance.
[0120] Anchoring Mechanism
[0121] Certain embodiments of the laser manipulation system 100
comprise an anchoring mechanism 110 to releasably affix the laser
manipulation system 100 to the structure to be processed. The
anchoring mechanism 110 can be adapted to be releasably coupled to
the structure and can comprise one or more attachment interfaces
111.
[0122] In the embodiment schematically illustrated in FIG. 6B, the
anchoring mechanism 110 comprises a pair of attachment interfaces
111. Each attachment interface 111 comprises at least one resilient
vacuum pad 112, at least one interface mounting device 114, at
least one vacuum conduit 116, at least one mounting connector 118,
and a coupler 119 adapted to couple the attachment interface 111 of
the anchoring mechanism 110 to the positioning mechanism 121. While
the embodiment schematically illustrated in FIGS. 6A and 6B have
two vacuum pads 112 for each of the two attachment interfaces 111,
other embodiments utilize any configuration or number of attachment
interfaces 111 and vacuum pads 112.
[0123] In the embodiment illustrated by FIG. 7, two vacuum pads 112
are coupled to the interface mounting device 114. In certain
embodiments, each vacuum pad 112 comprises a circular rubber pad
which forms an effectively air-tight region when placed on the
structure. Each vacuum pad 112 is fluidly coupled to at least one
vacuum generator (not shown) via a vacuum conduit 116 (e.g., a
flexible hose). The vacuum generator may use fluid power (e.g.,
compressed air) to generate the vacuum, or it may use an external
vacuum source. The vacuum generator draws air out from the
air-tight region between the vacuum pad 112 and the structure via
the vacuum conduit 116, thereby creating a vacuum within the
air-tight region. Atmospheric pressure provides a force which
reversibly affixes the vacuum pad 112 to the structure.
[0124] The interface mounting device 114 comprises a rigid metal
support upon which is mounted the vacuum pads 112, the mounting
connector 118, and the coupler 119. In certain embodiments, the
mounting connector 118 can comprise a ground-based support
connector 118a adapted to be releasably attached to a ground-based
support system 700, as described more fully below. In other
embodiments, the mounting connector 118 can comprise at least one
suspension-based support connector 118b adapted to be releasably
attached to a suspension-based support system 800, as described
more fully below. The coupler 119 is adapted to releasably couple
the interface mounting device 114 to the positioning mechanism 121.
In certain embodiments, the coupler 119 comprises at least one
protrusion which is connectable to at least one corresponding
recess in the positioning mechanism 121.
[0125] In alternative embodiments, the anchoring mechanism 110 can
comprise other technologies for anchoring the apparatus 50 to the
structure to be processed. These other technologies include, but
are not limited to, a winch, suction devices (e.g., cups,
gekkomats, or skirts) affixed to the apparatus 50 or on quasi-tank
treads, mobile scaffolding suspended from the structure, and a
rigid ladder. These technologies can also be used in combination
with one another in certain embodiments of the anchoring mechanism
110.
[0126] Positioning Mechanism
[0127] Certain embodiments of the laser manipulation system 100
comprise a positioning mechanism 121 to accurately move the laser
head 200 while in proximity to the structure to be processed. FIG.
8 schematically illustrates an exploded view of one embodiment of
the positioning mechanism 121 along with the attachment interfaces
111 of the anchoring mechanism 110. The positioning mechanism 121
of FIG. 8 comprises a first-axis position system 130, a second-axis
position system 150, an interface 140, and a laser head receiver
220. The first-axis position system 130 is releasably coupled to
the attachment interfaces 111 of the anchoring mechanism 110 by at
least one coupler 132. The interface 140 (comprising a first piece
140a and a second piece 140b in the embodiment of FIG. 8)
releasably couples the second-axis position system 150 to the
first-axis position system 130. The laser head receiver 220 is
releasably coupled to the second-axis position system 150, and is
adapted to be releasably coupled to the housing 230 of the laser
head 200.
[0128] In certain embodiments, the first-axis position system 130
comprises at least one coupler 132 having a recess which is
releasably connectable to at least one corresponding protrusion of
the coupler 119 of the anchoring mechanism 110. Such embodiments
are advantageously disassembled and reassembled for transport,
storage, or maintenance of the positioning mechanism 121. Other
embodiments can have the first-axis position system 130 fixedly
coupled to the anchoring mechanism 110.
[0129] In certain embodiments, the first-axis position system 130
moves the laser head 200 in a first direction substantially
parallel to the surface of the structure. In the embodiment
schematically illustrated by FIG. 9, the first-axis position system
130 further comprises a first rail 134, a first drive 136, and a
first stage 138. The first stage 138 is movably coupled to the
first rail 134 under the influence of the first drive 136. The
first piece 140a of the interface 140 is fixedly coupled to the
first stage 138 so that the first drive 136 can be used to move the
interface 140 along the first rail 134. In certain embodiments, the
first-axis position system 130 further comprises sensors, limit
switches, or other devices which provide information regarding the
position of the first stage 138 along the first rail 134. This
information can be provided to the controller 500, which is adapted
to transmit control signals to the first drive 136 or other
components of the laser manipulation system 100 in response to this
information.
[0130] Exemplary first drives 136 include, but are not limited to,
hydraulic drives, pneumatic drives, electromechanical drives, screw
drives, and belt drives. First rails 134, first drives 136, and
first stages 138 compatible with embodiments described herein are
available from Tol-O-Matic, Inc. of Hamel, Minn. Other types and
configurations of first rails 134, first drives 136, and first
stages 138 are also compatible with embodiments described
herein.
[0131] In certain embodiments, the second-axis position system 150
moves the laser head 200 in a second direction substantially
parallel to the surface of the structure. The second direction in
certain embodiments is substantially perpendicular to the first
direction of the first-axis position system 130. In the embodiment
schematically illustrated by FIG. 10, the second-axis position
system 150 comprises a second rail 152, a second drive 154, and a
second stage 156. In certain embodiments, the first-axis position
system 130 and the second-axis position system 150 provide linear
movements of the laser head 200. In other embodiments, the
first-axis position system 130 and the second-axis position system
150 provide circular and axial movements of the laser head 200,
respectively.
[0132] In certain embodiments, the second stage 156 is movably
coupled to the second rail 152 under the influence of the second
drive 154. The laser head receiver 220 is releasably coupled to the
second stage 156 so that the second drive 154 can be used to move
the laser head receiver 220 along the second rail 152. In certain
embodiments, the second-axis position system 150 further comprises
sensors, limit switches, or other devices which provide information
regarding the position of the second stage 156 along the second
rail 152. This information can be provided to the controller 500,
which is adapted to transmit control signals to the second drive
154 or other components of the laser manipulation system 100 in
response to this information.
[0133] Exemplary second drives 154 include, but are not limited to,
hydraulic drives, pneumatic drives, electromechanical drives, screw
drives, and belt drives. Second rails 152, second drives 154, and
second stages 156 compatible with embodiments described herein are
available from Tol-O-Matic, Inc. of Hamel, Minn. Other types and
configurations of second rails 152, second drives 154, and second
stages 156 are also compatible with embodiments described
herein.
[0134] In certain embodiments, the second rail 152 is fixedly
coupled to the second piece 140b of the interface 140. The second
piece 140b can comprise at least one recess which is releasably
connectable to at least one corresponding protrusion of the first
piece 140a of the interface 140. Such embodiments are
advantageously disassembled and reassembled for transport, storage,
or maintenance of the positioning mechanism 121. In other
embodiments, the interface 140 can be made of a single piece which
is releasably coupled to one or both of the first stage 138 and the
second rail 152. Other embodiments are not configured for
convenient disassembly (e.g., having an interface 140 made of a
single piece and that is fixedly coupled to both the first stage
138 and the second rail 152).
[0135] In certain embodiments, the interface 140 comprises a tilt
mechanism 144 to adjust the relative orientation between the first
rail 134 and the second rail 152. As schematically illustrated in
FIG. 11A, the first piece 140a of the interface 140 is coupled to
the first stage 138 on the first rail 134, and comprises a pair of
protuberances 142 adapted to couple with corresponding recesses of
the second piece 140b of the interface 140. The tilt mechanism 144
comprises a first plate 145, a hinge 146, a second plate 147, and a
pair of support braces 148. The first plate 145 is fixedly mounted
to the first stage 138 and is substantially parallel to the surface
upon which the anchoring mechanism 110 is mounted. The second plate
147 is pivotally coupled to the first plate 145 by the hinge 146,
and can be locked in place by the support braces 148.
[0136] In FIG. 11A, the tilt mechanism 144 is configured so that
the first plate 145 and the second plate 147 are substantially
parallel to one another. In this configuration, the plane of
movement defined by the first direction and the second direction of
the laser head 200 is substantially parallel to the surface upon
which the anchoring mechanism 110 is coupled. In FIG. 11B, the tilt
mechanism 144 is configured so that the second plate 147 is at a
non-zero angle (e.g., 90 degrees) relative to the first plate 145.
In this configuration, the plane of movement defined by the first
direction and the second direction of the laser head 200 is at a
non-zero angle relative to the surface upon which the anchoring
mechanism 110 is coupled.
[0137] In certain embodiments, the laser head receiver 220 is
releasably coupled the housing 230 of the laser head 200. FIG. 12
schematically illustrates a laser head receiver 220 compatible with
embodiments described herein. The laser head receiver 220 is
coupled to the second stage 156 and comprises a releasable clamp
222 and a third-axis position system 224. The clamp 222 is adapted
to hold the housing 230 of the laser head 200. The third-axis
position system 224 is adapted to adjust the relative distance
between the laser head 200 and the structure being processed. In
certain embodiments, the third-axis position system 224 comprises a
screw drive which moves the clamp 222 substantially perpendicularly
to the second rail 152. In certain embodiments, as schematically
illustrated by FIG. 12, the screw drive is manually actuated by a
handle 226, which can be rotated to move the clamp 222. In other
embodiments, the screw drive is automatically controlled by
equipment responsive to control signals from the controller
500.
[0138] Ground-Based Support System
[0139] In certain embodiments, the apparatus 50 can be utilized
with a ground-based support system 700 which is releasably coupled
to the apparatus 50. The interface mounting devices 114 can each
comprise a ground-based support connector 118a adapted to
releasably couple to the ground-based support system 700. The
ground-based support system 700 advantageously attaches to various
types of external boom systems, such as commercially-available
lifting- or positioning-type systems, which can support some of the
weight of the apparatus 50, thereby reducing the weight load
supported by the anchoring mechanism 110. The ground-based support
system 700 can be used to facilitate use of the apparatus 50 on
substantially vertical surfaces (e.g., walls) or on substantially
horizontal surfaces (e.g., ceilings).
[0140] In certain embodiments, the ground-based support system 700
includes a support structure 710 such as that schematically
illustrated in FIG. 13. The support structure 710 of FIG. 13
comprises a boom connector 712, a rotational mount 714, a spreader
member 716, a pair of primary posts 718, and a pair of auxiliary
posts 720. The boom connector 712 is adapted to attach to a
selected external boom system. The rotational mount 714 is adapted
to be rotatably coupled to the boom connector 712 and fixedly
coupled to the spreader member 716 so that the boom connector 712
can be advantageously rotated relative to the support structure
710.
[0141] The primary posts 718 are coupled to the spreader member 716
and are substantially parallel to one another. Each of the primary
posts 718 is adapted to be coupled to one of the ground-based
support connectors 118a of the interface mounting devices 114. The
primary posts 718 can each be coupled to the spreader member 716 at
various positions so that they are aligned with the ground-based
support connectors 118a. Each primary post 718 is also coupled to,
and is substantially perpendicular to, an auxiliary post 720. In
such embodiments, rather than having the primary posts 718 coupled
to the ground-based support connectors 118a, the auxiliary posts
720 can be coupled to the ground-based support connectors 118a,
thereby effectively rotating the support structure 710 by 90
degrees relative to the anchoring mechanism 110. Such embodiments
advantageously provide adjustability for processing various
configurations of structures and to permit alternative
configurations best suited for particular applications.
[0142] Suspension-Based Support System
[0143] Alternatively, the apparatus 50 can be utilized with a
suspension-based support system 800 which is releasably coupled to
the apparatus 50. The interface mounting devices 114 can each
comprise at least one suspension-based support connector 118b
adapted to releasably couple to the suspension-based support system
800. The suspension-based support system 800 advantageously
supports some of the weight of the apparatus 50, thereby reducing
the weight load supported by the anchoring mechanism 110. The
suspension-based support system 800 can be used to facilitate use
of the apparatus 50 on substantially vertical surfaces (e.g.,
outside walls).
[0144] In certain embodiments, as schematically illustrated in FIG.
14A, the suspension-based support system 800 comprises a winch 810,
a primary cable 812, and a pair of secondary cables 814. The winch
810 is positioned on the roof or other portion of a structure to be
processed. The winch 810 is coupled to the primary cable 812, which
is coupled to the secondary cables 814. The secondary cables 814
are each coupled to a suspension-based support connector 118b of
the interface mounting device 114 of the anchoring mechanism 110.
FIG. 14B schematically illustrates one embodiment of the apparatus
having the suspension-based support connectors 118b. The apparatus
50 can then be lowered or raised by utilizing the winch 810 to
shorten or lengthen the working length of the primary cable 814. In
alternative embodiments, the ground-based support connectors 118a
can be configured to serve also as the suspension-based support
connectors 118b.
LMS: Simplified Anchoring Mechanism
[0145] FIGS. 21A-21D schematically illustrate other anchoring
mechanisms 1110 in accordance with embodiments described herein.
The anchoring mechanism 1110 comprises a resilient vacuum pad 1112
adapted to be releasably coupled to the structure, a coupler 1114
adapted to be releasably attached to the laser head 1200, and a
handle 1116. Rather than the above-described laser manipulation
system 100 which comprises a four-vacuum-pad anchoring mechanism
110 and a multiple-axis positioning mechanism 121, the anchoring
mechanism 1110 provides a simplified mechanism to releasably hold
the laser head 1200 of FIG. 20 at a selected position in relation
to the structure being irradiated.
[0146] In certain embodiments, the vacuum pad 1112 comprises a
circular rubber membrane (not shown) which forms an effectively
air-tight region when placed on the structure. The vacuum pad 1112
is fluidly coupled to at least one vacuum generator (not shown) via
a vacuum conduit (not shown), such as flexible rubber hose. By
drawing air out from the air-tight region between the rubber
membrane and the structure via the vacuum conduit, the vacuum
generator creates a vacuum within the air-tight region. Atmospheric
pressure provides a force which reversibly affixes the anchoring
mechanism 1110 to the structure. Removal of the anchoring mechanism
1110 from the surface is achieved by allowing air back into the
air-tight region between the rubber membrane and the structure.
Vacuum pads 1112 compatible with embodiments described herein are
available from a variety of sources. An exemplary vacuum pad 1112
is provided by the 376281-DD-CR-1 Complete Core Rig Stand from
Hilti Corporation of Schaan in the Principality of
Liechtenstein.
[0147] In certain embodiments, the coupler 1114 comprises a
structure which mates with a corresponding laser head coupler 1250
of the laser head 1200. For the anchoring mechanism 1110
schematically illustrated by FIG. 21A, the coupler 1114 comprises
at least one protrusion 1115 which is attached to the vacuum pad
1112. The coupler 1114 is connectable to the laser head coupler
1250 which comprises at least one corresponding recess 1116. In
other embodiments, the coupler 1114 comprises a recess and the
laser head coupler 1250 comprises a corresponding protrusion. In
still other embodiments, the coupler 1114 comprises a collar 1117
which is adapted to hold the laser head 2200, as schematically
illustrated by FIG. 21D.
[0148] As schematically illustrated by FIG. 21C, in still other
embodiments, the connector 1114 comprises at least one rod 1118 and
the coupler 1250 of the laser head 1200 comprises at least one
collar 1119. In the exemplary embodiment of FIG. 21C, the coupler
1114 comprises two rods 1118a, 1118b and the laser head coupler
1250 comprises two collars 1119a, 1119b. Each collar 1119 is
releasably coupled to the corresponding rod 1118 such that the
laser head 1200 can be adjustably positioned at various locations
along the length of the rod 1118. In certain such embodiments, the
collar 1119 can be adjustably rotated with respect to the rod 1118
to allow the laser head 1200 to be rotated about the rod 1118. For
example, in the embodiment schematically illustrated by FIG. 21C,
one collar 1119a can be detached from its corresponding rod 1118a,
and the other collar 1119b can be rotated about its corresponding
rod 1118b. Such embodiments provide the capability to rotate the
laser head 1200 away from its drilling position so that visual
inspection can be made of the hole being drilled. Once visual
inspection has been made, the laser head 1200 can then be replaced
back into the drilling position by rotating the laser head 1200
back and recoupling the collar 1119a to its corresponding rod
1118a.
[0149] In certain embodiments, the handle 1116 is adapted to
facilitate transporting and positioning the anchoring mechanism
1110 at a desired location. Other configurations of the handle 1116
besides that schematically illustrated by FIGS. 21A-21D are
compatible with other embodiments described herein.
[0150] Such simplified anchoring mechanisms 1110, as described
above, can be used when the apparatus is used to only drill or
pierce holes into the structure. In certain such embodiments, the
anchoring mechanism 1110 can be releasably affixed to the structure
so that the laser head 1200 is positioned to irradiate the
structure to drill a hole at a selected location. To drill a second
hole at a second selected location in such embodiments, the
anchoring mechanism 1110 is removed from the structure and moved so
that the laser head 1200 is repositioned to irradiate the structure
at the second selected location. By simplifying the anchoring
mechanism 1110 (as compared to the anchoring mechanism 110 of FIGS.
6A, 6B, 7, and 8) and avoiding the use of a positioning mechanism
121, such simplified embodiments provide a lighter weight
alternative which is movable and positionable by a single person.
In addition, such simplified embodiments are more robust than those
described in relation to FIGS. 6A, 6B, 7, and 8.
Controller
[0151] In certain embodiments, the controller 500 is electrically
coupled to the laser base unit 300 and is adapted to transmit
control signals to the laser base unit 300. In other embodiments,
the controller 500 is electrically coupled to both the laser base
unit 300 and the laser manipulation system 100, and is adapted to
transmit control signals to both the laser base unit 300 and the
laser manipulation system 100. FIG. 15 schematically illustrates an
embodiment of a controller 500 in accordance with embodiments
described herein. The controller 500 comprises a control panel 510,
a microprocessor 520, a laser generator interface 530, a
positioning system interface 540, a sensor interface 550, and a
user interface 560.
[0152] In certain embodiments, the control panel 510 includes a
main power supply, main power switch, emergency power off switch,
and various electrical connectors adapted to couple to other
components of the controller 500. The control panel 510 is adapted
to be coupled to an external power source (not shown in FIG. 15)
and to provide power to various components of the apparatus 50.
[0153] In certain embodiments, the microprocessor 520 can comprise
a Programmable Logic Controller microprocessor (PLC). PLCs are
rugged, reliable, and easy-to-configure, and exemplary PLCs are
available from Rockwell Automation of Milwaukee, Wis., Schneider
Electric of Palatine, Ill., and Siemens AG of Munich, Germany. In
alternative embodiments, the microprocessor 520 comprises a
personal computer microprocessor, or PC/104 embedded PC modules
which provide easy and flexible implementation. The microprocessor
520 can be adapted to respond to input signals from the user (via
the user interface 560), as well as from various sensors of the
apparatus 50 (via the sensor interface 550), by transmitting
control signals to the other components of the apparatus 50 (via
the laser generator interface 530 and the positioning system
interface 540) to achieve the desired cutting or drilling
pattern.
[0154] The microprocessor 520 can be implemented in hardware,
software, or a combination of the two. When implemented in a
combination of hardware and software, the software can reside on a
processor-readable storage medium. In addition, the microprocessor
520 of certain embodiments comprises memory to hold information
used during operation.
[0155] In certain embodiments, the laser generator interface 530 is
coupled to the laser base unit 300 and is adapted to transmit
control signals from the microprocessor 520 to various components
of the laser base unit 300. For example, the laser generator
interface 530 can transmit control signals to the laser generator
310 to set desired operational parameters, including, but not
limited to, laser power output levels and laser pulse profiles and
timing. In addition, the laser generator interface 530 can transmit
control signals to the cooling subsystem 320 to set appropriate
cooling levels, the source of compressed gas coupled to the
compressed gas inlet 249 of the containment plenum 240, or to the
vacuum generator coupled to the extraction port 248.
[0156] In certain embodiments, the positioning system interface 540
is coupled to the positioning mechanism 121 of the laser
manipulation system 100 and is compatible with the first-axis
position system 130 and second-axis position system 150, as
described above. In certain such embodiments, the positioning
system interface 540 comprises servo-drivers for the first-axis
position system 130 and the second-axis position system 150. The
servo-drivers are preferably responsive to control signals from the
microprocessor 520 to generate driving voltages and currents for
the first drive 136 and the second drive 154. In this way, the
controller 500 can determine how the laser head 200 is scanned
across the surface of the structure. In certain embodiments, the
servo-drivers receive their power from the control panel 510 of the
controller 500. In embodiments in which the positioning mechanism
121 further comprises a third-axis position system, the positioning
system interface 540 further comprises an appropriate servo-driver
so that the controller 500 can determine the relative distance
between the laser head 200 and the structure surface being
processed.
[0157] In certain embodiments, the sensor interface 550 is coupled
to various sensors (not shown in FIG. 15) of the apparatus 50 which
provide data upon which operation parameters can be selected or
modified. For example, as described above, the laser head 200 can
comprise a sensor 250 adapted to measure the relative distance
between the laser head 200 and the interaction region. The sensor
interface 550 of such embodiments receives data from the sensor 250
and provide this data to the microprocessor 520. The microprocessor
520 can then adjust various operational parameters of the laser
base unit 300 and/or the laser manipulation system 100, as
appropriate, in real-time. Other sensors which can be coupled to
the controller 500 via the sensor interface 550 include, but are
not limited to, proximity sensors to confirm that the laser head
200 is in position relative to the surface being processed,
temperature or flow sensors for the various cooling, compressed
air, and vacuum systems, and rebar detectors (as described more
fully below).
[0158] In certain embodiments, the user interface 560 adapted to
provide information regarding the apparatus 50 to the user and to
receive user input which is transmitted to the microprocessor 520.
In certain embodiments, the user interface 560 comprises a control
pendant 570 which is electrically coupled to the microprocessor
520. As schematically illustrated in FIG. 16, in certain
embodiments, the control pendant 570 comprises a screen 572 and a
plurality of buttons 574.
[0159] The screen 572 can be used to display status information and
operational parameter information to the user. Exemplary screens
572 include, but are not limited to, liquid-crystal displays. The
buttons 574 can be used to allow a user to input data which is used
by the microprocessor 520 to set operational parameters of the
apparatus 50. Other embodiments can use other technologies for
communicating user input to the apparatus 50, including, but not
limited to, keyboard, mouse, touchpad, and potentiometer knobs
and/or dials. In certain embodiments, the control pendant 570 is
hard-wired to the apparatus 50, while in other embodiments, the
control pendant 570 communicates remotely (e.g., wirelessly) with
the apparatus 50.
[0160] In certain embodiments, the control pendant 570 further
comprises an emergency stop button and a cycle stop button. Upon
pressing the emergency stop button, the apparatus 50 immediately
ceases all movement and the laser irradiation is immediately
halted. Upon pressing the cycle stop button, the apparatus 50
similarly ceases all movement and halts laser irradiation
corresponding to the cutting sequence being performed, but the user
is then provided with the option to return to the beginning of the
cutting sequence or to re-start cutting at the spot where the
cutting sequence was stopped. In certain embodiments, the control
pendant 570 further comprises a "dead man switch," which must be
manually actuated by the user for the apparatus 50 to perform. Such
a switch provides a measure of safety by ensuring that the
apparatus 50 is not run without someone actively using the control
pendant 570.
[0161] FIGS. 17A-17H illustrate a set of exemplary screen displays
of the control pendant 570. The function of each of the buttons 574
along the left and right sides of the screen 572 is dependent on
the operation mode of the apparatus 50. Each of the screen displays
provides information regarding system status along with relevant
information regarding the current operation mode.
[0162] The "MAIN SCREEN" display of FIG. 17A comprises a "Machine
Status" field, a "System Status" field, and label fields
corresponding to the functions of some or all of the buttons 574 of
the control pendant 570. The "Machine Status" field includes a text
message which describes what the apparatus 50 is doing and what the
user may do next.
[0163] The "System Status" field includes a box which shows the
operational mode of the apparatus 50. In the example illustrated by
FIG. 17A, the apparatus is in "maintenance mode." The "System
Status" field also includes a plurality of status boxes which
indicate the status of various components of the apparatus 50,
including, but not limited to, the vacuum pads 112 of the anchoring
system 110, the air or vacuum pressure, the first-axis position
system 130, and the second-axis position system 150. The "System
Status" field also indicates whether there are any faults sensed
with the laser base unit 300. In certain embodiments, nominal
status of a component is shown with the corresponding status box as
green. The ready state of the apparatus 50 is illustrated by having
all the system status boxes appear as green. If the status of one
of these components is outside operational parameters, the
corresponding status box is shown as red, and the system interlocks
are enabled, preventing operation of the apparatus 50. Upon
startup, the system interlocks are enabled and must be cleared
prior to operation of the apparatus 50. The text messages of the
"Machine Status" field provide information regarding the actions to
be performed to place the apparatus 50 within operational
parameters and to clear the system interlocks. Upon clearing all
the system interlocks, the "Machine Status" field will indicate
that the apparatus 50 is ready to be used.
[0164] The "SELECT OPERATION SCREEN" display of FIG. 17B comprises
the "Machine Status" field, the "System Status" field, and the
label fields corresponding to the functions of some or all of the
buttons 574. The "System Status" field includes information
regarding the position of the laser head 200 along the first-axis
position system 130 (referred to as the long axis) and the
second-axis position system 150 (referred to as the short axis).
Some of the buttons 574 are configured to enable various
operations. For example, four buttons 574 are configured to enable
four different operations: circle, pierce, straight cut, and
surface keying, as illustrated in FIG. 17B.
[0165] FIG. 17C shows a "CIRCLE SETUP/OPERATION SCREEN" display
which provides information regarding the circle operation of the
apparatus 50 in which the laser head 200 moves circularly to cut a
circular pattern to a desired depth into the surface of the
structure to be processed. In certain embodiments, the circle
operation can be used for "trepanning," whereby a solid circular
core is cut and removed from the surface, leaving a circular
hole.
[0166] A "Circle Status" field provides information regarding the
status of the circle operation and corresponding instructions to
the user. The starting position of the laser head 200 along the
first-axis position system 130 and the second-axis position system
15.0 are provided in the "System Status" field. A "Circle
Parameters" field provides information regarding various parameters
associated with the cutting of a circular pattern, including, but
not limited to, the number of revolutions around the circular
pattern, the diameter, time period that the cutting will be
performed, the speed of motion of the laser head 200 around the
circle, and the laser base unit (LBU) program number. In certain
embodiments, the LBU program number corresponds to operational
parameters of the laser head 200 including, but not limited to,
beam focus and intensity.
[0167] In certain embodiments, the various parameters can be
changed by touching the parameter on the screen 572, upon which a
numerical keypad will pop up on the screen 572 so that a new value
can be entered. For each parameter, the "set point" value
corresponds to the value currently in memory and the last value
that was entered. The "status" value corresponds to the current
value being selected. Upon saving the new parameter value, the
"status" and "set point" values are the same. Pressing the button
574a labeled "Auto/Dry Run" will initiate the circular movement of
the laser head 200 without activating the laser beam, to ensure the
desired motion. Pressing the button 574b labeled "Cycle Start" will
initiate the cutting of the circular pattern, including both the
movement of the laser head 200 and the activation of the laser
beam. Pressing the button 574c labeled "Cycle Stop" will halt or
pause the cutting and movement, with the option to re-start the
cutting and movement where it was halted. Pressing the button 574d
labeled "Machine Reset" will place the apparatus 50 in a neutral
condition. Pressing the button 574e labeled "Next" upon completion
of the cutting will return to the "SELECT OPERATION SCREEN."
[0168] FIG. 17D shows a "PIERCE SETUP/OPERATION SCREEN" display
which provides information regarding the pierce operation of the
apparatus 50 in which the laser head 200 drills a hole to a desired
depth into the surface of the structure to be processed. A "Pierce
Status" field provides information regarding the status of the
pierce operation and corresponding instructions to the user. The
starting position of the laser head 200 along the first-axis
position system 130 and the second-axis position system 150 are
provided in the "System Status" field. A "Pierce Parameters" field
provides information regarding various parameters associated with
the drilling of a hole. The laser parameters can include, but are
not limited to, the laser power, the laser spot size, and the time
period for drilling (each of which can influence the diameter of
the resultant hole which is formed in the structure), and the LBU
program number. The parameters can be changed as described above.
The buttons 574 labeled "Auto/Dry Run," "Cycle Start," "Cycle
Stop," "Machine Reset," and "Next" operate as described above.
[0169] FIG. 17E shows a "CUT SETUP/OPERATION SCREEN" display which
provides information regarding the straight cutting operation of
the apparatus 50 in which the laser head 200 makes a straight cut
to a desired depth in the surface of the structure to be processed.
The straight cut is preferably along one of the axes of the
apparatus 50. A "Cut Status" field provides information regarding
the status of the cut operation and corresponding instructions to
the user. The starting position of the laser head 200 along the
first-axis position system 130 and the second-axis position system
150 are provided in the "System Status" field. A "Cut Parameters"
field provides information regarding various parameters associated
with the cutting, including, but not limited to, the speed of
motion of the laser head 200, the length of the cut to be made, and
the LBU program number. The parameters can be changed as described
above. The buttons 574f, 574g labeled "Long Axis" and "Short Axis"
are used to select either the first axis or the second axis
respectively as the axis of motion of the laser head 200. The
buttons 574 labeled "Auto/Dry Run," "Cycle Start," "Cycle Stop,"
"Machine Reset," and "Next" operate as described above.
[0170] FIG. 17F shows a "SURFACE KEYING SETUP/OPERATION SCREEN"
display which provides information regarding the surface keying
operation of the apparatus 50 in which the laser head 200 cuts an
indentation or key into the surface of the structure to be
processed. The surface keying operation includes scanning the laser
beam across the surface to create an indentation or "key" in the
surface with a desired depth and with a generally rectangular area.
In certain embodiments, the surface keying operation can be used to
perform "scabbling" of the surface, whereby the surface is
roughened by interaction with the laser beam across an area (e.g.,
rectangular).
[0171] A "Surface Keying Status" field provides information
regarding the status of the surface keying operation and
corresponding instructions to the user. The starting position of
the laser head 200 along the first-axis position system 130 and the
second-axis position system 150 are provided in the "System Status"
field. A "Surface Keying Parameters" field provides information
regarding various parameters associated with the cutting,
including, but not limited to, the speed of motion of the laser
head 200, the length of the key to be made along the first axis and
along the second axis, the offset length that the apparatus 50 will
increment between movement along the first axis and the second
axis, and the LBU program number. The parameters can be changed as
described above. The buttons 574f, 574g labeled "Long Axis" and
"Short Axis" are used to select either the first axis or the second
axis respectively as the axis of motion of the laser head 200. The
buttons 574 labeled "Auto/Dry Run," "Cycle Start," "Cycle Stop,"
"Machine Reset," and "Next" operate as described above.
[0172] FIG. 17G shows a "FAULT SCREEN" display which provides
information regarding detected operation faults. A fault occurs
when a sensor (e.g., flowmeters, temperature sensors, safety
switches, emergencies stops) of the monitored systems detects a
non-operational condition, and can occur while the apparatus 50 is
any of the operational modes and while any of the screens are being
displayed. When a fault occurs, a scrolling message indicating the
fault is preferably provided at the bottom of the current screen
being displayed. In addition, the "Machine Status" field will
indicate to the user to clear the faults. The "FAULT SCREEN" can be
accessed from any of the other screens by pressing an appropriate
button 574. As illustrated in FIG. 17G, in certain embodiments, the
"FAULT SCREEN" displays the detected faults in a table with the
relevant data, including, but not limited to, the date and the type
of fault. To prepare the apparatus 50 for operation, the detected
faults are preferably cleared by the user. After clearing the
detected faults, the user can press an appropriate button 574
(e.g., "Acknowledge All") to acknowledge the faults. If the faults
are not cleared, the user can press an appropriate button 574
(e.g., "Machine Reset") to return to the screen being displayed
when the fault occurred. Pressing the "Machine Reset" button 574
again will return the user to the "MAIN SCREEN" from where the
apparatus 50 can be reset.
[0173] FIG. 17H shows a "MAINTENANCE SCREEN" display which provides
information regarding the apparatus 50. The maintenance mode can be
accessed from the "MAIN SCREEN" display by pressing an appropriate
button 574. In the maintenance mode, the system interlocks are
bypassed, therefore the user preferably practices particular care
to avoid damaging the apparatus 50 or people or materials in
proximity to the apparatus 50. The "MAINTENANCE SCREEN" can display
an appropriate warning to the user.
[0174] The maintenance mode provides an, opportunity for the user
to check the operation of various components of the apparatus 50
independent of the fault status of the apparatus 50. For example,
by pressing appropriate buttons 574 in the maintenance mode, the
vacuum system can be turned on and off, the compressed air can be
turned on and off via a solenoid valve, and the first drive 136 and
second drive 154 can be turned on and off. In addition, the default
jog speed of the first axis and second axis can be changed by
pressing the screen 572 to pop up a numerical keypad display, as
described above.
[0175] The "System Status" field also includes a plurality of
status boxes which indicate the status of various components of the
apparatus 50, including, but not limited to, the vacuum pads 112 of
the anchoring system 110, the air or vacuum pressure, the
first-axis position system 130, and the second-axis position system
150. The "System Status" field also indicates whether there are any
faults sensed with the laser base unit 300. In certain embodiments,
nominal status of a component is shown with the corresponding
status box as green. The ready state of the apparatus 50 is
illustrated by having all the system status boxes appear as green.
If the status of one of these components is outside operational
parameters, the corresponding status box is shown as red.
[0176] The "MAINTENANCE SCREEN" can also provide the capability to
move the laser head 200 along the first axis and second axis, as
desired. A set of three buttons 574 are configured to move the
laser head 200 along the first axis to a home position, in a
forward direction, or in a backward direction, respectively.
Similarly, another set of three buttons 574 are configured for
similar movement of the laser head 200 along the second axis. The
label field for these sets of buttons can include information
regarding the position of the laser head 200 along these two
axes.
[0177] Detector
[0178] In certain embodiments, the controller 500 is coupled to a
detector 600 adapted to detect embedded material in the structure
while processing the structure, and to transmit detection signals
to the controller 500. In certain embodiments, the controller 500
is adapted to avoid substantially damaging the embedded material by
transmitting appropriate control signals to the laser base unit 300
or to both the laser base unit 300 and the laser manipulation
system 100. In certain embodiments, the detector 600 is adapted to
utilize light emitted by the interaction region during processing
to detect embedded material.
[0179] Various technologies for detecting embedded material are
compatible with embodiments of the present invention. Spectral
analysis of the light emitted by the interaction region during
processing can provide information regarding the chemical
constituents of the material in the interaction region. By
analyzing the wavelength and/or the intensity of the light, it is
possible to determine the composition of the material being heated
and its temperature. Using spectroscopic information, the detection
of embedded materials in certain embodiments relies on monitoring
changes in the light spectrum during processing. With the
differences in composition of embedded materials, by way of example
and not limitation, such as rebar (e.g., steel) embedded in
concrete, variations in the melting and boiling temperatures for
the diverse materials will produce noticeable changes in the amount
of light, and/or the wavelength of the light when the laser light
impinges and heats the embedded material.
[0180] FIG. 18A schematically illustrates an exemplary detector 600
compatible with embodiments described herein. The detector 600
comprises a collimating lens 610, an optical fiber 620, and a
spectrometer 630. The spectrometer 630 of certain embodiments
comprises an input slit 631, an optical grating 632, a collection
lens 633, and a light sensor 634. The collimating lens 610 is
positioned to receive light emitted from the interaction region,
and to direct the light onto the optical fiber 620. The optical
fiber 620 then delivers the light to the spectrometer 630, and the
light is transmitted through the input slit 631 to the optical
grating 632 of the spectrometer 630. The optical grating 632
separates the light into a spectrum of wavelengths. The separated
light having a selected range of wavelengths can then be directed
through the collection lens 633 onto the light sensor 634 which
generates a signal corresponding to the intensity of the light in
the range of wavelengths.
[0181] In certain embodiments, at least a portion of the detector
600 is mounted onto the laser head 200. In embodiments in which the
collimating lens 610 is part of the laser head 200, the collimating
lens 610 can be positioned close to the axis of the emitted laser
light so as to receive light from the interaction region. In such
embodiments, the collimating lens 610 can be behind the nozzle 244
and protected by the compressed air from the compressed air inlet
249, as is the window 243. In certain embodiments, the collimating
lens 610 is coaxial with the laser beam, while in other
embodiments, the collimating lens 610 is located off-axis.
Exemplary collimating lenses 610 include, but are not limited to,
UV-74 from Ocean Optics of Dunedin, Fla.
[0182] In certain embodiments, the optical fiber 620 comprises a
material selected to provide sufficiently low attenuation of the
light intensity transmitted from the laser head 200 to the
spectrometer 630. Exemplary materials for the optical fiber 620
include, but are not limited to, silica and fused silica. In
certain embodiments, the optical fiber 620 comprises a pure fused
silica core, a doped fused silica cladding, and a polyimide buffer
coating. In addition, the optical fiber 620 of certain embodiments
is protected by an outer jacket (e.g., Teflon.RTM., Tefzel.RTM.,
Kevlar.RTM., and combinations thereof) and a stainless steel
sheath. In addition, the optical fiber 620 of certain embodiments
is connectable to the laser head 200 using a right-angle fiber
mount. Other types of optical fibers 620 and mounting
configurations are compatible with embodiments described herein.
Exemplary optical fibers 620 include, but are not limited to,
P400-2-UV/VIS from Ocean Optics of Dunedin, Fla.
[0183] In certain embodiments, the spectrometer 630 comprises an
adjustable input slit 631. The input slit 631 of certain
embodiments has a height of approximately 1 millimeter and a width
in a range between approximately 5 microns and approximately 200
microns. The input slit 631 determines the amount of light entering
the spectrometer 630. The width of the input slit 631 affects the
resolution of the light sensor 634. For example, in certain
embodiments, an input slit width of approximately 5 microns
corresponds to a resolution of approximately 3 pixels, while an
input slit width of approximately 200 microns corresponds to a
resolution of approximately 24 pixels. The width of the input slit
631 is advantageously selected to provide sufficient light
transmittance as well as sufficient resolution.
[0184] The optical grating 632 of certain embodiments receives
light from the input slit 631 and diffracts the various wavelength
components of the light by corresponding angles dependent on the
wavelength of the light. In this way, the optical grating 632
separates the various wavelength components of the light. In
certain embodiments, the angle between the optical grating 632 and
the light from the input slit 631 is scanned (e.g., by moving the
optical grating 632), thereby scanning the wavelength components
which reach the light sensor 634. Exemplary spectrometers 630
utilizing an optical grating 632 include, but are not limited to,
USB2000(VIS/UV) from Ocean Optics of Dunedin, Fla.
[0185] In certain embodiments, the collection lens 633 of the
spectrometer 630 is adapted to increase the light reception
efficiency of the light sensor 634. In certain embodiments, the
collection lens 633 comprises a cylindrical lens affixed onto the
light sensor 634. Such embodiments of the collection lens 633 are
advantageously useful with large diameter entrance apertures
(limited by the width of the input slit 631 or the size of the
optical fiber 620) and with low-light-level applications. In
addition, in certain embodiments, the collection lens 633 improves
the efficiency of the spectrometer 630 by reducing the amount of
stray light which reaches the light sensor 634. Other spectrometers
630 with other configurations of the input slit 631, the optical
grating 632, and the collection lens 633 are compatible with
embodiments described herein.
[0186] In certain embodiments, the detection system 600 comprises a
computer system 640 coupled to the spectrometer 630, as
schematically illustrated by FIG. 18B. The computer system 640 is
adapted to analyze the resulting spectroscopic data. The computer
system 640 of certain embodiments comprises a microprocessor 641, a
memory subsystem 642, and a display 643. To provide more robustness
to the computer system 640, the microprocessor 641 and the memory
subsystem 642 can be mounted within a National Electrical
Manufacturers Association (NEMA)-rated enclosure 644 with input and
output power and signal connections on one or more side panels of
the enclosure for easy access. In certain embodiments, the computer
system 640 is powered by 110 V from a wall outlet, while in certain
embodiments, the computer system 630 further comprises a battery
backup power supply (not shown) to ensure functionality in the
event of power loss.
[0187] In certain embodiments, the microprocessor 641 comprises a
Pentium-200 microprocessor chip, while in other embodiments, the
microprocessor 641 comprises a Pentium-III 850-MHz microprocessor
chip. In certain embodiments, the memory subsystem 642 comprises a
hard disk drive. Other types of microprocessors 641 and memory
subsystems 642 are compatible with embodiments described
herein.
[0188] In certain embodiments, the display 643 comprises a
thin-film-transistor (TFT) touch screen display. Besides being used
to display spectroscopic results to a user, such a touch screen
display can be used to provide user input to the detector 600 to
modify various operation parameters.
[0189] The spectrometer 630 can monitor specific wavelengths that
are associated with various embedded materials in the structure. In
certain embodiments, the spectrometer 630 can monitor the relative
intensity of the light at, or in spectral regions in proximity to,
these wavelengths. Additionally, at least one neutral density
filter may be employed to decrease the light reaching the
spectrometer 630 to improve spectral analysis performance.
[0190] In certain embodiments, the spectrometer 630 monitors the
intensity at a specific wavelength and the intensities on both
sides of this wavelength. The spectrometer 630 of certain
embodiments also monitors the reduction of the intensities
resulting from the increased depth of the hole being drilled. FIG.
19 shows an exemplary graph of the light spectrum detected upon
irradiating concrete with laser light and the light spectrum
detected upon irradiating an embedded rebar. The spectrum from
concrete shows an emission peak at a wavelength of approximately
592 nanometers. The spectrum from rebar does not have this emission
peak, but instead shows an absorption dip at approximately the same
wavelength. Thus, the emission spectrum at about 592 nanometers can
be used to provide a real-time indication of whether an embedded
rebar is being cut by the laser light. For example, in certain
embodiments in which the detector 600 assumes that either a valley
or a peak exists in the spectrum at 592 nanometers, by sampling the
emission spectrum at about 588.5 nanometers, 592 nanometers, and
593 nanometers, and calculating the ratio:
(2.times.I.sub.592)/(I.sub.593+I.sub.588.5), the detector 600 can
determine whether the emission spectrum has a dip corresponding to
concrete or a peak corresponding to embedded rebar. Other
spectroscopic data can be used in other embodiments.
[0191] In certain embodiments, the detector 600 examines a spectral
region defined by an upper cutoff wavelength (e.g., 582 nanometers)
and a lower cutoff wavelength (e.g., 600 nanometers) and determines
a spectral ratio R characteristic of the detection or non-detection
of embedded rebar. FIG. 22 is a flowchart of an exemplary method
2500 for determining the spectral ratio R in accordance with
embodiments described herein. The method 2500 does not address
changes in the light from the interaction region as the hole
becomes deeper.
[0192] In certain embodiments, the method 2500 comprises an
operational block 2510 in which the data within the spectral region
is compared to a selected amplitude range. If any of the data fall
outside the amplitude range, the spectrum is deemed to correspond
to non-detection of embedded rebar.
[0193] In certain embodiments, the method 2500 further comprises
analyzing the data of the spectral region to determine the
existence of a valley and two peaks. In certain embodiments, this
analysis comprises determining whether the data of the spectral
region comprises a valley in an operational block 2520. If a valley
is determined to exist, then a valley value V is calculated in an
operational block 2530 and the spectral region is analyzed to
determine whether the data of the spectral region comprises two
peaks in an operational block 2540. In certain embodiments, the
valley value V corresponds to the amplitude of the data at the
valley. In certain other embodiments, calculating the valley value
V comprises determining a minimum value of the data in a first
portion of the spectral region. In certain embodiments, the first
portion of the spectral region corresponds to a range of
wavelengths between approximately 588 nanometers and approximately
594 nanometers.
[0194] If the data of the spectral region is determined to contain
two peaks, then a peak value P is calculated in the operational
block 2550 and the spectral ratio R is calculated by dividing the
valley value V by the peak value P in an operational block 2560. In
certain embodiments, the peak value P is calculated by averaging
the values of the two peaks. If the spectral ratio R is greater
than or equal to one, then the spectrum is deemed to correspond to
detection of embedded rebar.
[0195] If the data of the spectral region is determined to not
contain two peaks, then in certain embodiments, a first maximum
value M1 is calculated from the data of a second portion of the
spectral region in an operational block 2570 and a second maximum
value M2 is calculated from the data of a third portion of the
spectral region in an operational block 2580. In certain
embodiments, the second portion of the spectral region corresponds
to a range of wavelengths from approximately 582 nanometers to
approximately 588 nanometers, and the third portion of the spectral
region corresponds to a range of wavelengths from approximately 594
nanometers to approximately 600 nanometers. In certain embodiments,
the first maximum value M1 corresponds to a maximum data amplitude
in the second portion of the spectral region and the second maximum
value M2 corresponds to a maximum data amplitude in the third
portion of the spectral region. In certain embodiments, the peak
value P is calculated by averaging the first maximum value M1 and
the second maximum value M2 in an operational block 2590. In such
embodiments, the spectral ratio R is calculated by dividing the
valley value V by the peak value P in an operational block 2600. If
the spectral ratio R is greater than or equal to one, then the
spectrum is deemed to correspond to detection of embedded
rebar.
[0196] If a valley is determined to not exist in the data of the
spectral region, a peak value P' is calculated in an operational
block 2610 and the peak value P' is compared to a predetermined
threshold value T in an operational block 2620. In certain
embodiments in which the spectral region comprises one or more
peaks, calculating the peak value P' comprises averaging the
intensity values of any peaks detected in the spectral region. If
the peak value P' is less than the threshold value T, then the
spectrum is deemed to correspond to detection of embedded
rebar.
[0197] An alternative technology for detecting embedded materials
uses high speed shutter monitoring. This approach utilizes advances
in Coupled Capacitance Discharge (CCD) camera systems to monitor
discrete changes in the interactions between the material to be
processed and the laser light. Newer CCD cameras have systems that
can decrease the time the shutter is open to about 0.0001 second.
At this speed, it is possible to see many features of the
interaction between the laser light and the material being
processed. Additionally, neutral density filters may be employed to
decrease the glare observed from the incandescent interaction of
the laser light and the material to be processed and to better
image the interaction region.
[0198] Numerous alterations, modifications, and variations of the
various embodiments disclosed herein will be apparent to those
skilled in the art and they are all anticipated and contemplated to
be within the spirit and scope of the instant invention. For
example, although specific embodiments have been described in
detail, those with skill in the art will understand that the
preceding embodiments and variations can be modified to incorporate
various types of substitute and/or additional or alternative
materials, relative arrangement of elements, and dimensional
configurations. Accordingly, even though only few variations of the
present invention are described herein, it is to be understood that
the practice of such additional modifications and variations and
the equivalents thereof, are within the spirit and scope of the
invention as defined in the following claims.
[0199] The corresponding structures, materials, acts, and
equivalents of all means or step plus function elements in the
claims below are intended to include any structure, material, or
acts for performing the functions in combination with other claimed
elements as specifically claimed.
* * * * *