U.S. patent application number 09/811152 was filed with the patent office on 2001-11-08 for process and apparatus for weakening an automotive trim piece for an airbag deployment opening.
Invention is credited to Nicholas, Antonios, Towler, Michael.
Application Number | 20010037998 09/811152 |
Document ID | / |
Family ID | 22702477 |
Filed Date | 2001-11-08 |
United States Patent
Application |
20010037998 |
Kind Code |
A1 |
Nicholas, Antonios ; et
al. |
November 8, 2001 |
Process and apparatus for weakening an automotive trim piece for an
airbag deployment opening
Abstract
A method and apparatus is disclosed for forming lines of
weakness in an automotive trim piece so as to enable formation of
an airbag deployment opening in the trim piece. A cutting beam,
such as a laser is directed at the trim piece surface to be scored
and a sensor emits a sensing beam, and a beam combining device
receives both the sensor beam and the laser beam and causes
downstream beam segments to be collinear with each other as they
impinge the trim piece surface. The scoring is thereby able to be
carried out in a single pass, and is precise, repeatable and
independent of cutting depth, angle of cutting, scoring patterns,
material inconsistency, material color, and surface grain
variability.
Inventors: |
Nicholas, Antonios; (Belle
Mead, NJ) ; Towler, Michael; (Farmington,
MI) |
Correspondence
Address: |
John R. Benefiel
Suite 100 B
280 Daines Street
Birmingham
MI
48009
US
|
Family ID: |
22702477 |
Appl. No.: |
09/811152 |
Filed: |
March 16, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60190719 |
Mar 17, 2000 |
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Current U.S.
Class: |
219/121.69 ;
219/121.83 |
Current CPC
Class: |
B23K 26/361 20151001;
B23K 2103/50 20180801; B23K 26/40 20130101; B29C 59/007 20130101;
B29L 2031/3008 20130101; B23K 2103/42 20180801; B29C 2791/009
20130101; B23K 26/0006 20130101; B23K 26/359 20151001; B23K 2103/38
20180801; B23K 26/389 20151001; B60R 21/2165 20130101; B23K 2103/30
20180801; B23K 2103/16 20180801; B23K 2103/34 20180801; B23K 26/042
20151001; B23K 26/032 20130101; B23K 2103/172 20180801 |
Class at
Publication: |
219/121.69 ;
219/121.83 |
International
Class: |
B23K 026/38 |
Claims
1. A process for forming lines of weakness in an automotive trim
piece covering an airbag installation, said airbag installation
including an airbag adapted to be inflated and deployed upon
detection of a collision, said weakening enabling formation of an
air bag deployment door opening, said trim piece having at least
one layer, comprising the steps of: scoring a surface of the trim
piece by directing a cutting beam onto to said surface and moving
said trim piece relative to a source of said cutting beam in a
predetermined scoring pattern; monitoring the scoring effect
produced by said scoring beam by sensor beams produced from a first
sensor and a second outer sensor respectively located on opposite
sides of said trim piece and directed towards the trim piece
location being by said cutting beam, said first sensor located on
the same side of said trim piece as said cutting beam source;
combining segments of said first sensor sensing beam with said
cutting beam to be collinear with each other when impinging said
trim piece surface so as to be continuously aimed at the same
points along said scoring pattern; controlling the extent of
material removed by said scoring beam at each point along said
predetermined pattern by controlling said scoring in correspondence
with feedback signals generated by said first and second sensors
during said scoring; and, moving said trim piece relative to said
scoring beam to score said trim piece along said predetermined
scoring pattern:
2. The process according to claim 1 wherein said cutting beam is a
laser.
3. The process according to claim 1 wherein said cutting beam
source is an ultrasonic generator.
4. The process according to claim 1 wherein said feedback signals
provided by said first and second sensors together correspond to
the material thickness remaining at each trim piece point being
scored.
5. The process according to claim 1 wherein said trim piece is held
in a fixture shaped to provide intimate contact with the outer
surface of said trim piece.
6. The process according to claim 1 wherein said feedback signals
produced from said sensors are used to also control the relative
movement of the trim piece and scoring beam.
7. A process for forming lines of weakening of automotive trim
piece covering an airbag installation, said airbag installation
including an airbag adapted to be inflated and deployed upon
detection of a collision, said lines of weakening enabling
formation of an air bag deployment door opening, said trim piece
having at least one layer, comprising the steps of: scoring a
surface of said trim piece by directing a cutting beam at said
inside surface from a cutting beam source, and relatively moving
said trim piece and said cutting beam source in a predetermined
scoring pattern after loading said trim piece onto a fixture where
a surface of said trim piece is in contact with a surface of said
fixture; monitoring the extent of scoring effected by said cutting
beam by feedback signals produced by a sensor located on the same
side of said trim piece as said cutting beam source, said sensor
having a sensor beam directed at said trim piece surface to be
scored; combining said sensor beam and said beam to have collinear
segments impinging said surface so that both beams impinge at the
same point on said trim piece; controlling the level of said
scoring effected by said cutting beam at each point along said
predetermined pattern in accordance with said feedback signals
provided by said sensor; and, moving said trim piece relative to
said scoring beam to score said trim piece along said predetermined
scoring pattern.
8. The process according to claim 7 wherein said cutting beam
source is a laser beam source.
9. The process according to claim 7 wherein said sensor beam is
electromagnetic radiation of a different wavelength than said
cutting beam which is also electromagnetic, and in said combining
step, said sensor and cutting beams are both directed at a
reflector which selectively transmits one beam and reflects the
other as a result of the difference in wavelengths to cause
downstream segments of said beams to be collinear.
10. The process according to claim 9 wherein said reflector is
inclined at 45.degree. and in said combining step one beam is
directed at a front face to be reflected and the other beam is
directed at a rear face of said reflector through which it is
transmitted.
11. The process according to claim 7 wherein said sensor beam is of
much smaller diameter than said cutting beam and wherein in said
combining step said cutting beam is directed at an inclined
reflector surface having a hole formed therein much smaller than
said cutting beam, and said sensor beam is directed through said
hole in a direction parallel to said cutting beam after being
reflected from said reflector.
12. A process for weakening an automotive trim piece covering an
airbag installation, said airbag installation including an airbag
adapted to be inflated and deployed upon detection of a collision,
said weakening enabling formation of an air bag deployment door
opening, said trim piece having at least one layer, comprising the
steps of: scoring an inside surface of the trim piece by directing
a cutting beam onto said inside surface and relatively moving said
trim and said cutting beam in a predetermined pattern; controlling
the level of said scoring effected by said scoring beam at each
point along said predetermined pattern; and, monitoring the scoring
produced by said scoring beam with feedback signals from a sensor
located on the same side of said trim piece as the said cutting
device, said sensor having a sensing beam combined in a collinear
relationship with said cutting beam and continuously impinging the
same point on said trim piece as the cutting beam.
13. The process according to claim 12 wherein said cutting beam
source is a laser beam source.
14. The process according to claim 12 wherein said cutting beam
source is an ultrasonic generator.
15. The process according to claim 12 wherein said trim piece is
attached to a fixture shaped to provide intimate contact with an
outer surface of said trim piece.
16. A process for weakening an automotive trim piece covering an
airbag installation, said airbag installation including an airbag
adapted to be inflated and deployed upon detection of a collision,
said weakening enabling formation of an air bag deployment door
opening, said trim piece having at least one layer, comprising the
steps of: scoring an inside surface of the trim piece by directing
a cutting beam at said inside surface and relatively moving said
trim piece and said cutting beam in a predetermined scoring
pattern; controlling the level of said scoring effected by said
cutting beam at each point along said predetermined pattern; and,
monitoring the extent of scoring effected by said cutting beam by
feedback signals produced from a sensor located on the same side of
said trim piece as said cutting beam, said sensor located next to
said cutting beam and directing a sensing beam at said trim piece,
said sensor beam collinear with said cutting beam.
17. The process according to claim 16 wherein said cutting beam is
a laser beam.
18. The process according to claim 16 wherein said cutting beam is
a beam of ultrasonic waves.
19. The process according to claim 16 wherein said trim piece is
held on to a fixture shaped to provide intimate contact with the
outer surface of said trim piece.
20. Apparatus for weakening an automotive trim piece covering an
airbag installation, said airbag installation including an airbag
adapted to be inflated and deployed upon detection of a collision,
said weakening enabling formation of an air bag deployment door
opening, said trim piece having at least one layer, comprising: a
source for a cutting beam able to score surface on one side of said
trim piece, said cutting beam directed at said surface of said trim
piece; a motion actuator imparting relative motion between said
source of said cutting beam and said trim piece in a predetermined
pattern; sensor means for monitoring the remaining material
thickness of said trim piece, said sensor means including a first
inner sensor and a second outer sensor located on opposite sides of
the said trim piece and directed towards each point on said trim
piece being scored by said cutting beam, said inner sensor located
on the same side of said trim piece as said cutting beam source; a
beam combiner combining said scoring beam and said first sensor
sensing beam in a collinear relationship, said collinear beams
continuously directed at the same point on said trim piece; control
means monitoring said scoring of said trim piece at each point
along said predetermined pattern, and adjusting the scoring effect
of said cutting beam to produce a predetermined thickness of trim
piece material remaining after said scoring along said
predetermined pattern.
21. The apparatus according to claim 20 wherein said cutting beam
source is a laser beam source.
22. The apparatus according to claim 20 wherein said cutting device
is a source of ultrasonic energy.
23. The apparatus according to claim 20 wherein said trim piece is
held in a fixture shaped to provide intimate contact with the outer
surface of said trim piece.
24. Apparatus for producing lines of weakening an automotive trim
piece covering an airbag installation, said airbag installation
including an airbag adapted to be inflated and deployed upon
detection of a collision, said lines of weakening enabling
formation of an air bag deployment door opening, said trim piece
having at least one layer, comprising: a source for a cutting beam
able to cut into said trim piece, said cutting beam directed at one
side of said trim piece; a motion actuator imparting relative
motion between said cutting beam and said trim piece along a
predetermined pattern; sensor for monitoring the extent of scoring
effected on said trim piece by said cutting beam, said sensor
located on the same side of said trim piece as said source of said
cutting beam and generating a sensing beam directed towards the
trim piece point being scored by said cutting beam; means for
combining downstream segments of said cutting beam and said sensing
beam to be a collinear with each other, said collinear beam
segments both continuously directed at the same point on said trim
piece; and, control means monitoring said scoring on said trim
piece at each point along said predetermined pattern, and adjusting
the scoring effected by said scoring beam to produce a
predetermined extent of scoring along said predetermined
pattern.
25. The apparatus according to claim 24 wherein said cutting beam
source is a laser beam source.
26. The apparatus according to claim 24 wherein said scoring beam
source is an ultrasonic generator.
27. The apparatus according to claim 24 wherein said trim piece is
held in a fixture shaped to provide intimate contact with the outer
surface of said trim piece.
28. Apparatus for forming lines of weakening in automotive trim
piece covering an airbag installation, said airbag installation
including an airbag adapted to be inflated and deployed upon
detection of a collision, said lines of weakening enabling
formation of an air bag deployment door opening, said trim piece
having at least one layer, comprising: a cutting beam source
producing a cutting beam able to score said trim piece, said
cutting beam source producing a cutting beam directed at one side
of said trim piece; a motion actuator imparting relative motion
between said cutting beam source and said trim piece in a
predetermined pattern; control means to produce said scoring along
said predetermined pattern; a sensor to monitor the extent of
material removal effected on said trim piece by said cutting beam,
said sensor producing a sensing beam directed towards said one side
of said trim piece; and, a beam combining device receiving both
said cutting and sensing beams, combining downstream segments of
the same in a collinear relationship, and directing the combined
beam segments at said one side of said trim piece.
29. The apparatus according to claim 28 wherein said cutting beam
source is a laser beam source.
30. The apparatus according to claim 29 wherein said sensor beam is
electromagnetic radiation of a different wavelength, said cutting
beam is also electromagnetic, and said sensing and cutting beams
are both directed at a reflector which selectively transmits one
beam and reflects the other as a result of the difference in
wavelengths to direct said beams into a collinear relationship with
each other.
31. The apparatus according to claim 30 wherein said reflector is
inclined at 45.degree. and said one beam is directed at a front
face thereof to be reflected and the other beam is directed at a
rear face of said reflector through which it is transmitted.
32. The apparatus according to claim 29 wherein said sensor beam is
of much smaller diameter than said cutting beam and wherein said
cutting beam is directed at an inclined reflector surface having a
hole formed therein of a much smaller diameter than said cutting
beam, and said sensor beam is directed through said hole in a
direction parallel to said cutting beam after being reflected from
said reflector.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. provisional
Serial No. 60/190,719, filed Mar. 17, 2000.
BACKGROUND OF THE INVENTION
[0002] This invention concerns forming lines of weakness in
portions of automotive trim pieces overlying airbag safety devices,
in order to allow one or more airbag deployment doors to be created
when an airbag is inflated.
[0003] Airbag safety systems are widely used in automotive vehicles
and generally comprise an inflatable cushion, referred to as an
"airbag", stored folded in a receptacle and then rapidly inflated
when a collision of the vehicle is detected by sensors.
[0004] The folded airbag is typically mounted behind an automotive
interior trim piece such as an instrument panel or a steering wheel
cover. One or more airbag deployment doors are forced open when the
airbag is inflated to allow deployment of the airbag through the
opening created by the deployment door movement.
[0005] During the last few years, airbag deployment doors that are
integrated into the trim piece overlying the airbag receptacle have
gained wide acceptance. As described in U.S. Pat. Nos. 5,082,310
and 5,744,776, these integrated doors employ a seamless or
invisible construction whereby the deployment door or doors,
although part of the trim piece, are not separately delineated
and/or visible from the passenger side of the trim piece.
[0006] For such integrated deployment doors to open during airbag
deployment necessitates weakening portions of the trim piece in
order to allow trim piece sections to break free and hinge open.
Weakening of the trim piece is carried out by creative lines of
weakness comprised of scored lines formed by removing material from
the trim piece from the back surface along a predetermined
deployment door pattern. A critical component of this process is
the amount of the trim piece material removed and /or remaining
after cutting the score line. Accurate control of this process is
critical to reliably producing proper airbag deployments.
[0007] A widely used method for determining the extent of material
removal during scoring involves the use of triangulation type
sensors as described in U.S. Pat. No. 5,883,356. These sensors,
however, due to their triangulation operating principle, are
limited in their ability to reach the bottom of the scoring
produced by the cutting device. This is particularly so for narrow,
deep penetrations which may be imparted by cutting devices such as
lasers and cutting knives. Furthermore, due to their offset
mounting, these sensors are not well suited to measure the varying
penetration depth that occurs during scoring at a specific
location. This is especially true if the scoring penetration is in
the form of partial perforations or slots. As such, the process
does not lend itself to scoring the trim piece in an adaptive
control mode, where both depth sensing and scoring are in registry
with each other to impinge the same point on the trim piece, during
the progression of scoring of the trim piece.
[0008] Accordingly it is an object of this invention to provide a
process and apparatus for scoring trim components overlying airbag
installations in a manner that provides accurate adaptive process
control, single-pass processing, improved airbag door deployment,
and lower manufacturing costs.
SUMMARY OF THE INVENTION
[0009] According to the invention, the scoring of the trim piece is
accomplished by the use of a controllable cutting means, such as a
laser beam, which, based on feedback from two sensors, is
controlled in intensity together with controlled relative movement
between the laser and the trim piece, producing a precise,
predetermined penetration into the trim piece along a predetermined
pattern.
[0010] In this process, the laser cutting beam and sensing beam
emitted from a first sensor are both directed at a surface on one
side of the trim piece. A second sensor may also be positioned on
the opposite side of the trim piece in opposition to the laser
beam. A beam combining device combines the laser and sensing beams
together to have into collinear segments with impinging the trim
piece surface so that they are continuously directed at exactly the
same point on the trim piece. The scoring of the trim piece is
carried out by the laser beam while the trim piece is moved in a
predetermined pattern relative to the laser to form one or more
deployment doors defined by the sections of the trim piece within
the pattern. The depth of scoring of the trim piece by the laser
beam is controlled by real time feedback signals corresponding to
the depth of the cut provided by the first sensor. To determine
material thickness remaining during scoring of each point along the
predetermined pattern, real time feedback from the second sensor
can be provided combined with the feedback signals from the first
sensor. The sensor feedback can also be utilized to control the
movement of the trim piece relative to the laser beam to enhance
the weakening process control.
[0011] This process, due to the collinear arrangement of the
impinging segments of the sensor and cutting beams, affords several
advantages, including single-pass adaptive processing, scoring
precision and superior part to part repeatability. The process is
also independent of cutting depth, angle of cutting, scoring
patterns, material inconsistency, material color, and surface grain
variations.
[0012] Relative motion between the trim piece and the cutting beam
to score the trim piece in a predetermined pattern, can be provided
by different means including robots and X-Y tables.
[0013] The trim piece can have a monolayer, multilayer, or
composite construction and could be scored on either side. The
scoring can be continuous, intermittent or be a combination of
both, and extend completely through one or more layers of the trim
piece. The trim piece can be a finished part or a component which
is subsequently integrated into a finished part.
DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a diagrammatic view of one form of the apparatus
according to the invention including two sensors
[0015] FIGS. 2, 2A and 2B are fragmentary enlarged views of several
alternative designs of the beam combining device incorporated in
the apparatus shown in FIG. 1.
[0016] FIG. 3 is an automotive instrument panel with an integrated
airbag deployment door formed by in a U pattern scoring carried out
by the apparatus and process of the present invention.
[0017] FIGS. 4 through 6 are cross sectional views of sample
monolayer and multilayer trim piece constructions on which various
types of trim piece weakening scorings have been made.
[0018] FIG. 7 is a diagrammatic view of one form of the apparatus
according to the invention incorporating only a single sensor.
[0019] FIG. 8 is a diagrammatic view of a second form of the
apparatus according to the invention incorporating only a single
sensor.
DETAILED DESCRIPTION
[0020] In the following detailed description, certain specific
terminology will be employed for the sake of clarity and particular
embodiments described, but it is to be understood that the same is
not intended to be limiting and should not be so construed inasmuch
as the invention is capable of taking many forms and variations
within the scope of the appended claims.
[0021] This invention describes an improved process and apparatus
for forming lines of weakness in an automotive trim piece for an
airbag door installation in a way that improves the accuracy of the
process, the trim piece quality, the airbag deployment performance,
and, also, reduces trim piece production costs. The process will be
described with respect to an instrument panel airbag door
installation, but it is also applicable to other automotive and
non-automotive installations, with or without an airbag. Typical
airbag installations include driver side airbags, front passenger
airbags, side impact airbags, headliner airbags, knee airbags, and
rear passenger airbags. The process will also be described in terms
of a laser beam, but is also applicable to other cutting beams as
described below.
[0022] FIG. 1 shows a first embodiment of a trim piece scoring
apparatus 10 according to the invention. This includes a cutting
beam source 12 which generates a cutting beam such as a laser beam
which is used to carry out controlled scoring of a surface 14 on
one side 14 of an instrument panel trim piece 16 that would overlie
an airbag installation when installed.
[0023] The trim piece 16 is positioned on a fixture 18. A first
sensor 20 is provided to determine the depth of scoring produced by
the laser cutting beam onto the surface 14 of the trim piece 16 to
weaken the same. The first sensor 20 and the cutting beam generator
12 are connected to a beam combining device 22. The beam combining
device 22 is designed to combine separately generated sensing beam
or beams emanating from the first sensor 20 and the laser cutting
beam downstream beam into segments an aligned collinear
relationship so as to direct the combined signal beam B and cutting
beam A to impinge the same precise spot on the trim piece surface
14. This beam combining device 22 will also redirect any reflected
returned beam or beams required for sensor operation from the trim
piece surface 14 back to the first sensor 20 in carrying out the
process.
[0024] The trim piece 16 is moved relative to the cutting beam
source 12, as well as the first sensor 20 and the beam combining
device 22 via a motion actuator 24 to cause tracing of a particular
scoring pattern and to achieve a precisely controlled rate of
scoring. The motion actuator 24 can directly move the trim piece 16
itself or move an optional fixture 18 onto which the trim piece 16
is mounted. Alternatively, the motion actuator 24 could be used to
move the laser beam source 12 and the first sensor 20 relative to
the trim piece 16.
[0025] A second sensor 26 may be located on the side of the trim
piece 16 opposite the first sensor 20, a second sensor beam
emanating therefrom, directed at the outer surface 28 of the trim
piece 16 and aligned opposite the same trim piece point as is the
laser cutting beam and the first sensor beam or beams are directed
in order to control the scoring cutting so as to produce a
programmed thickness of material remaining after scoring. This is
done by combining signals generated by both sensors 20, 26 to
create a feedback signal corresponding to the thickness of the
remaining material.
[0026] The apparatus 10 is operated via one or more industrial
controllers 30 that control the scoring effected by the laser
and/or the movement of the motion actuator based on a particular
program and feedback signals provided by the sensor 20, 26.
[0027] Lasers are particularly desirable for carrying out this type
of scoring processes and they can be of the carbon dioxide,
excimer, solid state, argon gas, or diode type. However, based on
the primary trim piece materials utilized (polymers, fabrics, wood,
leather), the carbon dioxide laser is likely to be the most
preferable in terms of operability, efficiency and cost. The laser
can be operated either continuously or in a pulsed mode.
[0028] Different type of sensors can be utilized to measure the
extent of material removed or remaining during scoring of the trim
piece. For the first sensor 20, connected to the beam combining
device 22, a preferred type is a closed loop device that sends and
receives a specific beam of electromagnetic radiation in order to
determine the depth of scoring effected by the laser. The Conoprobe
sensors offered by Optimet and based on the technique of conoscopic
holography, is one such sensor commercially available. In this type
of sensor, an emitted laser beam and reflected return beams of
visible light have segments also traveling in a collinear
relationship with each other and the laser beam. Another type of
sensor that could be utilized is one that detects reflected light
beams such as a high speed CCD camera. In this application, the
reflected beam will be reflected from the trim piece surface being
scored by the cutting beam.
[0029] For the second sensor 26 aimed at the outside surface of the
trim piece, which is generally smooth and accessible, there are
more numerous options including, infrared, laser, ultrasonic,
conoscopic, CCD camera, proximity and contact type sensors.
[0030] The signal spot size of the sensor selected can vary
significantly. Generally the smaller the spot size the better. For
the first sensor, the preferred size would be not to exceed the
size of the scoring produced on the trim piece by the cutting laser
beam. For the second sensor, if surface finish variations, so
called grain, are significant, its spot size should preferably not
exceed 300 microns.
[0031] The are numerous ways for combining the separately
originated laser beam and sensor beam to create collinear segments.
FIG. 2 shows the inner details of the beam combining device 22
which combines the separate the laser beam A and the first sensor
beam B to create collinear segments which impinge the trim piece
surface 14. The beam combining device 22 includes a reflector 32
having coatings causing reflection of light having the wavelength
of the sensor beam A from its inclined surface while allowing the
laser beam B to be transmitted.
[0032] Such coated selective reflectors are commercially available.
This of course requires that the laser and sensor beams be of
different wavelengths.
[0033] A side entrance tube 29 directed at the reflector 32 is
connected to the first sensor 20. The main tube 31 mounts the
reflector 32, main tube 31 having an end opening 33 directed at the
trim piece 16.
[0034] The segment of sensor beam A reflected from the reflector 32
aligned and coextensive with the laser beam 13 after, with both
collinear segments then impinging the surface 14 at the same
precise point.
[0035] FIG. 2A shows a second form of a beam combining device 22A
having an inclined reflector 32B having coatings causing reflection
of the wavelength of the laser beam B while allowing transmission
of the wavelengths of the sensor beam A to be transmitted
therethrough to reverse the relationship shown in FIG. 2.
[0036] FIG. 2B is a simplified diagrammatic view of another form of
the beam combining device 22B combining the laser beam B and the
first sensor beam A to produce collinear downstream segments. This
embodiment includes a simple mirror reflector 36 having a through
hole 34. The hole 34 is small in diameter relative to the diameter
of the laser beam B in order to minimize or eliminate the effect
that the presence of the hole 34 may have on reflecting the laser
beam from the mirror reflector 36 to redirect the laser beam A.
Such a mirror does not require coatings that are
wavelength-selective such as those shown in FIGS. 2 and 2A in order
to combine segments of the beams into a collinear relationship. In
this particular arrangement, the first sensor 20 could be a CCD
camera receiving beams reflected from the trim piece surface being
scored by the laser beam.
[0037] The trim piece can be any of many automotive parts including
instrument panels and/or their components (skins, substrates,
foams, scrims, etc.), driver side airbag covers, door panels, seat
covers, headliners, bumpers and seat belts. The scoring can be
applied on either side of the trim piece but is preferably applied
from the inside so that is substantially invisible from the outside
surface facing the passenger. As shown in FIG. 3, the scoring does
not penetrate the outer surface 28 of the trim piece 16 shown as an
instrument panel and would be essentially invisible to the
passenger. Different materials could be utilized in a trim piece
including metals, polymers (TPUs, TPOs, PVC, TPEs, etc.), leather,
fabrics, wood and wood composites. As shown in FIGS. 4 through 6,
the trim piece 16, 16A, 16B may consist of one or more layers of
similar or dissimilar materials. In multilayer constructions, the
scorings 40, 40A, 40B could be applied to any one layer or any
combination thereof as shown.
[0038] Manufacturing of the trim piece can be done in several ways
using different materials. Many of these materials can be formed in
a solid state or in a cellular state. Polymeric trim pieces can be
formed by processes such as extrusion, injection molding, low
pressure insert molding, blow molding, casting, thermoforming,
lamination and foaming.
[0039] The scoring applied can be in any shape, including a U, H,
I, T, X, W, S and Y pattern, required to form an opening for the
airbag to deploy. The opening could include one or more door
panels. The scoring can be either continuous or discontinuous
including grooves, blind holes and dashes. Furthermore, the cut
orientation can be straight or offset. For successful and
consistent airbag deployments, the degree of precision of cutting
is particularly important to ensure that the amount of material
remaining along the predetermined pattern is as intended. The
penetration or depth of scoring, for an invisible airbag door
application, can be up to about 95% of the trim piece
thickness.
[0040] In order to apply the complete scoring pattern, the trim
piece is preferably moved relative to the laser beam and/or the
sensors. The relative motion can be applied by a number of motion
actuators including robots and X-Y tables. During cutting, the
sensor thickness data can also be used to control the movement of
the motion device in order to apply the scoring along the
predetermined pattern. The trim piece may be held directly by the
motion device or be attached to a holding fixture held by the
motion device. The holding fixture may be shaped to match the shape
of the trim piece and/or be designed to register specific surface
features of the trim piece. Vacuum or clamps could also be applied
to the holding fixture to hold the trim piece surface in better
contact with the fixture 18. The fixture 18 can be designed to
allow the second sensor 26 to have physical and/or optical access
to the surface 26 of the trim piece (i.e., transparent fixture
wall, opening in fixture wall, etc.).
[0041] The process controller 30 is designed to control the
operation of the laser and/or motion actuator based on the feedback
signals provided by the two sensors 20, 26 which, from opposites
sides or surfaces of the trim piece 16, monitor the location being
scored. The two sensors 20, 26 working in tandem determine the
remaining thickness of the trim piece 16 at any point they are
directed to. During laser scoring at a given point, the two sensors
20, 26 provide signals from which a measurement of the material
thickness remaining after the scoring can be derived by the control
device 30. Based on this real-time thickness determination, the
control device 30 controls the operation of the cutting beam source
12 to effect only the desired extent of material removal intended
for any given point on the trim piece 16. The remaining thickness
data can also be used to control the motion actuator 24 to move the
trim piece to the next desired location along the predetermined
scoring pattern.
[0042] Due to the collinearity of the impinging segments of the
first sensor beam and the cutting beam, several advantages are
realized that could not be attained by any of the existing
processes. Since the first sensor beam and the laser beam are
always impinging on the same point of the trim piece, the process
becomes insensitive to a large number of key variables, including
the angle of cutting, the depth of the penetration, the trim piece
thickness, the configuration of the weakening pattern and, to a
large extent, the speed of cutting. Also, the combination of the
two sensors provides for a direct remaining thickness measurement,
superior scoring precision and excellent part to part
repeatability. In addition, the process enables the user to
overcome variations in trim piece thickness, material properties
such as density, color, voids and surface grain. These and other
benefits are obtained while operating with rapid adaptive control
in a single-pass mode.
[0043] A second embodiment of the apparatus 44 according to the
invention is shown in FIG. 7 where the outer surface 42 of the trim
piece 16 is in intimate contact with the inner fixture wall 46. In
this arrangement, the distance between the first sensor 48 and the
fixture inner wall 46, along the predetermined scoring pattern, can
be measured prior to starting the scoring operation. If this
distance can be maintained constant from pass to pass, then the
second outside sensor would not be necessary while still running
the process in a single-pass, adaptive control mode.
[0044] FIG. 8 shows another embodiment of the apparatus 50 where
the first sensor 52 is mounted immediately alongside the cutting
beam source 12 so that both beams A, B are substantially collinear
with each other to approximate the effect of using the beam
combining device 22 described.
[0045] The laser cutting beam may also function as the sensor. This
arrangement also maintains the collinear configuration as the
sensing signals and the laser beam are generated by the same laser.
Under this approach, the laser beam characteristics and control
would be manipulated to conduct sensing measurements during or
between cutting intervals (i.e., sensing after a preset number of
cutting pulses).
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