U.S. patent application number 09/252744 was filed with the patent office on 2001-05-24 for method and apparatus for trimming shaped plastic workpieces.
Invention is credited to HARDGROVE, WILLIAM H., SWARTZ, MICHAEL A., YORDE, ANDREW G..
Application Number | 20010001516 09/252744 |
Document ID | / |
Family ID | 22957348 |
Filed Date | 2001-05-24 |
United States Patent
Application |
20010001516 |
Kind Code |
A1 |
HARDGROVE, WILLIAM H. ; et
al. |
May 24, 2001 |
METHOD AND APPARATUS FOR TRIMMING SHAPED PLASTIC WORKPIECES
Abstract
A method and apparatus for laser trimming a shaped plastic
workpiece use a laser beam positioned and directed by a robotic arm
traveling along a pre-programmed path to trim the edges of a
workpiece held against a positioning block. Preferably, the
positioning block includes a laser beam capturing channel
comprising suction holes for removing smoke generated by the
ablation and burning of the plastic so as to minimize the risk of
smoke damage to the workpiece and to remove soot and vapors from
the work area. At the same time, laser beams are inhibited form
reflecting back off the block onto the workpiece by positioning the
channel under the workpiece and along the predetermined cutting
path.
Inventors: |
HARDGROVE, WILLIAM H.;
(ENGLEWOOD, OH) ; SWARTZ, MICHAEL A.; (BROOKVILLE,
OH) ; YORDE, ANDREW G.; (BROOKVILLE, OH) |
Correspondence
Address: |
BIEBEL AND FRENCH
35 EAST FIRST STREET
DAYTON
OH
45402
|
Family ID: |
22957348 |
Appl. No.: |
09/252744 |
Filed: |
February 19, 1999 |
Current U.S.
Class: |
264/400 ;
219/121.67; 219/121.68; 219/121.69; 264/102 |
Current CPC
Class: |
B23K 26/351
20151001 |
Class at
Publication: |
264/400 ;
219/121.67; 219/121.68; 219/121.69; 264/102 |
International
Class: |
B29C 035/08; B23K
026/16; B23K 026/38 |
Claims
1. A method of trimming a paint film laminate workpiece to
correspond to predetermined dimensions comprising: a) placing said
paint film laminate on a work platform; b) trimming said laminate
to said predetermined dimensions; and c) venting volatiles and
particulates that may be formed by said trimming away from said
work platform.
2. A method as recited in claim 1 further comprising providing a
port proximate said work platform, and wherein said venting
comprises applying a source of suction through said port to thereby
vent said vapors and particulates.
3. A method as recited in claim 2 wherein said trimming comprises
cutting said laminate with a laser.
4. A method as recited in claim 3 wherein said work platform
comprises a convex shaped positioning block, said block having said
port mounted therein.
5. A method of trim cutting a thin film laminate work piece
comprising: a) placing said thin film laminate on a work platform;
b) moving said platform to an enclosed housing; and c) laser
trimming said laminate along a predetermined cutting path to
predetermined dimensions while in said enclosed housing, and d)
providing a laser beam capturing groove adjacent said cutting path
and under said thin film laminate.
6. Method as recited in claim 5 further comprising d) venting
volatiles and particulates from said laser trimming step.
7. Method as recited in claim 6 further comprising venting said
volatiles and particulates through said groove.
8. Method as recited in claim 7 further comprising moving said
platform after said laser trimming step c) to an unloading
station.
9. Method as recited in claim 8 further comprising placing
apertures in said platform in communication with said channel.
10. Method as recited in claim 9 further comprising providing a
convex positioning block on said work platform, said apertures
provided in said positioning block and wherein said placing a)
comprises placing said thin film laminate on said positioning
block.
11. A method for trimming a workpiece defining a concave workpiece
contour, said method comprising the steps of: a) positioning said
workpiece on a convex positioning block having a block contour
complementary to said workpiece contour; b) projecting a laser beam
onto a surface of said workpiece to trim said workpiece; c)
providing suction ports in said convex positioning block; and d)
drawing at least a partial vacuum through suction ports to vent
particulates and volatiles away from said workpiece.
12. A method for trimming a workpiece defining a concave workpiece
contour having a re-entrant section, said method comprising the
steps of: a) positioning said workpiece on a convex positioning
block, said positioning block having a groove; b) programming a
controller to define a path of travel lying proximate said groove;
c) positioning a projector to direct a laser beam onto said
workpiece at said home position on said path of travel; d) moving
said projector to induce said laser beam to trace said path of
travel on said workpiece; and e) drawing at least a partial vacuum
through suction ports communicating with said groove.
13. Apparatus for trimming a paint film laminate workpiece to
correspond to a predetermined dimensional configuration,
comprising: a) a work platform having said workpiece mounted
thereon; b) trimming means in operative association with said work
platform for cutting said laminate so that said laminate
corresponds to said predetermined dimensional configuration; c) a
channel communicating with said work platform; and d) means for
drawing a draft through said channel to thereby vent particulate
and volatiles that may be formed by said trimming means b) away
from said work platform.
14. Apparatus as recited in claim 13 wherein said platform
comprises a convex positioning block and wherein said laminate is
placed on said positioning block, said block comprising at least
one opening therein in communication with said channel.
15. Apparatus as recited in claim 14 wherein said trimming means b)
comprises a laser cutting.
16. Apparatus as recited in claim 13 further comprising means for
moving said platform to an enclosed housing and wherein said
trimming means b) is located in said enclosed housing.
17. Apparatus for trimming a workpiece comprising: a convex
positioning block for positioning the workpiece thereon, said
convex positioning block having a block contour complementary to a
contour of said workpiece; a projector for directing a laser beam
onto the workpiece when the workpiece is positioned on said
positioning block; a robotic arm having a distal end, said
projector being supported near a distal end of said robotic arm for
movement along a path of travel; and a programmable controller for
inducing said robotic arm to move said projector so that said laser
beam traces said path of travel.
18. The apparatus as recited in claim 17 wherein said positioning
block includes a vacuum source for drawing at least a partial
vacuum and a plurality of suction ports communicating with said
vacuum source, said plurality of suction ports being arranged along
said path of travel.
19. The apparatus as recited in claim 17 wherein said positioning
block is convex, defining a groove along said path of travel for
receiving a re-entrant portion of said workpiece; and wherein said
suction ports open through said groove.
20. The apparatus as recited in claim 17 wherein said positioning
block includes a plurality of hold-down ports positioned within
said path of travel and communicating with said vacuum source, each
of said suction ports being larger than any of said hold-down
ports.
21. The apparatus as recited in claim 17 including a laser light
source and an optical conduit for conducting laser light between
said optical source and said projector.
22. The apparatus as recited in claim 17 including a wrist portion
supported near said distal end of said robotic arm for rotatably
mounting said projector.
23. The apparatus as recited in claim 17 including a boom pivotally
mounting said robotic arm.
24. The apparatus as recited in claim 23 including a base pivotally
mounting said boom.
25. The apparatus as recited in claim 17 wherein said controller is
a microprocessor electrically communicating with a plurality of
electric motors for controlling movement of said robotic arm and
said projector.
26. Apparatus for trimming a concave plastic workpiece comprising:
a convex positioning block having a block contour complementary to
a workpiece contour; said convex positioning block defining a
plenum and a plurality of hold-down ports communicating with said
plenum; a vacuum source communicating with said plenum for drawing
at least a partial vacuum through said hold-down ports; a laser
source for generating a laser beam; a projector optically
communicating with said laser source for directing said laser beam
toward said convex positioning block; a spar defining a spar
proximal end and a spar distal end; a wrist portion mounted near
said spar distal end, said wrist portion including a first robot
electric motor for pivoting said projector along a first pivot axis
and a second electric motor for pivoting a direction of said first
pivot axis; a boom having a boom proximal end and a boom distal
end, said boom pivotally supporting said spar proximal end near
said boom distal end; a third robot electric motor for pivoting
said spar relative to said boom; a base pivotally mounting said
boom proximal end; a fourth robot electric motor for pivoting said
boom relative to said base; a fifth robot electric motor for
pivoting said boom relative to said base; and a controller
programmed to recognize a path of travel along said convex
positioning block, said controller being in electrical
communication with said first, second, third, fourth and fifth
robot electric motors to induce movement of said projector so that
said laser beam traces said path of travel; said convex positioning
block including a groove extending along said path of travel and a
plurality of suction ports communicating between said plenum and
said re-entrant groove, said suction ports being larger than said
hold-down ports.
27. Apparatus for trimming a point film laminate workpiece along a
predetermined cutting path, comprising a) a work platform adapted
for mount of a workpiece thereon; b) laser beam trimming means in
operative association with said work platform for cutting said
workpiece along said predetermined path; and c) a channel adjacent
said predetermined path and underneath said workpiece dimensioned
to capture laser beams cutting through said workpiece while
inhibiting reflection of said laser beam from said work platform
onto said workpiece.
Description
FIELD OF THE INVENTION
[0001] The present invention pertains to a method and apparatus for
trimming a shaped plastic workpiece such as a paint film laminate
that is to be used to form an injection molded automotive or truck
part. The method uses a laser beam positioned and directed by a
robotic arm along a pre-programmed path to trim the edges of the
paint film laminate workpiece as the workpiece is held against a
positioning block.
BACKGROUND OF THE INVENTION
[0002] A variety of injection molded parts are made and used for
automobile body and trim parts. For example, bumpers, spoilers,
body panels, doors, filler panels, wheel covers, dashboards, arm
rests and other parts are commonly made by the injection molding of
thermoplastic materials.
[0003] In order to provide a painted or other decorative surface
for injection molded plastic trim parts, film lamination techniques
are commonly employed. A paint film laminate is insert molded or,
as it is sometimes referred to, co-molded, with the desired
thermoplastic to fuse the film over the injection molded substrate.
The resulting injection molded film-plastic part is ready for
assembly without subsequent painting.
[0004] The paint film laminate used in these insert molding
techniques may comprise a backing sheet to which paint, other
pigment-containing, or clear layers are adhered. Typically, the
backing sheet comprises an extruded thermoplastic sheet. The paint
or pigment layer may contain colored pigments or reflective flake
pigments such as aluminum or mica flakes to provide for example a
metallic finish.
[0005] The paint film may consist of a monocoat; a clear coat over
a base coat; or a clear coat and a base coat with interposed print
or design. The paint film, including base coat, clear coat and
print or design, if desired, may range from about 0.5-4 mil.
(13-100 .mu.m) in thickness.
[0006] Laminated paint films are well known in the art and are
available, for example, from Avery Dennison Decorative Films Div.
of Schererville, Ind., or Rexham Decorative Products of Charlotte,
N.C. For example, laminated paint films are described in U.S. Pat.
No. 5,514,427, the disclosure of which is incorporated herein by
reference. The films are typically provided in a roll, unwound and
then "preformed" to a size and shape approximating that of the
final injection molded film-plastic part.
[0007] The paint film laminate preform is next usually trimmed and
placed along the cavity side of an injection mold with the painted
side or "show" side thereof facing the mold cavity surface.
Trimming may be accomplished by hand or in some instances by the
use of heavy stamping machines that require the use of expensive
tooling.
[0008] After trimming, the paint film laminate preform is ready for
the molding process where it may be placed along the core side of
the mold. The mold is then clamped and the desired molten resin is
injected into the mold cavity. Heat and pressure conditions in the
mold partially melt the backing sheet and a melt bonding or fusion
of the injected resin and the backing sheet of the film occur.
Injection molds used for these processes are rear or edge gated so
that the molten resin is directed along the backside of the
film.
[0009] Techniques for preforming paint film laminates and insert
molding film-plastic parts are disclosed in U.S. Pat. Nos.
5,599,608; 5,759,477; and 5,783,287. The disclosure of these
patents is incorporated herein by reference.
[0010] While the prior art process described above has proven
effective in many respects, there is a need in the art to improve
upon the trimming step for the paint film laminate so that this
operation can be conducted economically and more accurately. At the
same time, it is desirable to minimize the use of heavy stamping or
cutting machines that require large spatial areas and expensive
cutting tools and dies.
[0011] It is even more desirable to provide a laser trimming
operation wherein operation of the laser is conducted in an
enclosed atmosphere, shielding workers from the laser beam and from
soot and vapors that emanate from the cutting operation. Another
desirable goal is to provide an automated laser trimming apparatus
wherein soot and vapors from the laser cutting area are immediately
removed from the trimming area to a bag house or other filter
mechanism and wherein the trimmed workpiece does not contain burned
or charred areas surrounding the laser trimming line.
SUMMARY OF THE INVENTION
[0012] These and other objects are met by the paint film laminate
trimming apparatus and process of the present invention. Basically,
the apparatus comprises a rotatable wall carrying a work platform
with the platform including a plurality of convex positioning
blocks mounted thereon. Each positioning block is contoured to
correspond in shape and dimension to a desired work piece such as
an automobile or truck trim part.
[0013] In a first work station, the operator, which can include
manual or robotic means, loads a plurality of "preformed" and
roughly trimmed paint laminate films over each of the positioning
blocks. The roughly trimmed paint films are dimensioned so that
they snugly fit over the corresponding positioning blocks. After
all of these paint films are properly positioned over their
corresponding positioning blocks, the wall and associated platform
are rotated to an enclosed work chamber wherein a laser performs a
final, highly accurate trimming of the paint laminate films.
[0014] In the laser cutting operation, X, Y, and Z coordinates of
the desired cutting pattern are contained in the memory of a
microprocessor. The microprocessor then provides this information
to a laser controller which in turn moves the laser along the
desired cutting pattern to finally trim the paint film laminates,
each of which is positioned on its associated positioning
block.
[0015] The positioning blocks each include a plurality of suction
ports positioned along the path of travel of the laser. These ports
communicate with a manifold and plenum chamber so that a suction
source in operative association with the manifold and plenum
chamber draws particulates and vapors from the laser cutting area
to a bag house or other effective filter mechanism. This suction
action also helps to grip or secure the paint film laminate to the
positioning blocks.
[0016] The laser includes a source that generates a laser beam
which is used to cut the workpiece along the path of travel. The
projector is in optical communication with the laser source,
preferably through a flexible or jointed optical conductor, so that
the projector receives the laser beam from the laser source and
projects it onto the workpiece positioned on one of the convex
positioning blocks.
[0017] The robot positions and orients the projector to direct the
laser beam toward the convex positioning block and workpiece
mounted thereon. A channel or groove is formed in the positioning
block and extends substantially parallel to the desired cutting
line. The laser photons pass through the workpiece providing a
clear cut therein and then terminate in the channel without
reflecting out of the channel onto the back of the workpiece.
[0018] Most preferably, the robot includes a first arm or spar
having proximal and distal ends. The spar includes a wrist portion
near its proximal end on which the projector is mounted. The robot
also includes a second arm or boom having a proximal end pivotally
supported by a base. The boom has a distal end near which the boom
pivotally supports the proximal end of the spar.
[0019] The controller electrically communicates with robot electric
motors positioned near the wrist portion as well as near the
proximal ends of the spar and the boom to enable the robot to move
the projector so that the laser beam traces the path of travel
programmed into the controller. Most preferably, the controller
signals the robot electric motors to orient the projector so that
the laser beam remains normal to the tangent of the path of travel
and maintains a constant angle with a plane containing that path as
the laser beam traces the path.
[0020] The invention will be further described in conjunction with
the attached drawings and in the ensuing detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a side elevational view of a rotatable laser
cutting unit according to the present invention;
[0022] FIG. 2 is a perspective view of a convex positioning block
for the laser cutting unit of FIG. 1, partially cut away along the
line 2-2 in FIG. 1 to show suction ports opening through the
surface of the block;
[0023] FIG. 3 is a schematic view showing a laser projector for use
with the laser cutting unit of FIG. 1 mounted on a robotic arm;
[0024] FIG. 4 is a schematic view of the laser projector of FIG. 3
trimming a paint film laminate workpiece;
[0025] FIG. 4a is a magnified schematic view of the cutting area
showing the laser photons cutting the workpiece and then
terminating in the channel formed in the positioning block;
[0026] FIG. 5 is a block diagram showing the preferred system for
controlling the movement of the laser in accordance with the
invention;
[0027] FIG. 6 is a partially cut away top plan view showing the
rotatable wall and work platform in the open or loading position
wherein the operator may manually load pretrimmed paint film
laminate parts onto the positioning blocks; and
[0028] FIG. 7 is a partially cut away top plan view showing the
rotatable wall and work platform positioned in the safety enclosure
ready for operation of the laser-trimming position.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
[0029] As shown in FIG. 1, a laser cutting unit 10 in accordance
with the invention includes a metallic work platform 16 carrying a
plurality of convex positioning blocks 22, 24, 26, 28, 30 and 32
thereon. The work platform 16 is attached to rotatable wall 40 by
horizontal truss members 42, 44 with mounting brackets 52, 54
respectively formed in the trusses for fixed mounting of the bottom
portion of work platform 16 therein.
[0030] The work platform 16 and wall 40 may be rotated by rotatable
shaft 60 that is driven by electric motor 62. As shown in FIG. 1,
the proximal ends of the trusses 42, 44, in this position, rest
upon stationary legs 46, 48 that are in turn fixed to stationary
base 50. Accordingly, the entire wall 40, associated work platform
16, and trusses 42, 44 are positioned for rotation between: (1) a
loading and unloading station and (2) a laser trimming station, as
shall be explained hereinafter.
[0031] The unit 10 includes an air manifold 20 (best shown in FIG.
2) formed by the interior housing of platform 16. The manifold
communicates with chamber 70, with both the manifold and chamber
being operatively connected to a vacuum source (not shown). Air,
gases and soot that are present near the platform are drawn via the
action of the vacuum source, through the manifold and chamber to a
bag house or other air cleaning device (not shown).
[0032] Each of the convex positioning blocks 22, 24, 26, 28, 30, 32
has an outer contour complementary to the contour of the concave
workpiece 80 which it is desired to trim. As shown in FIG. 2, the
block 22 includes a peripheral groove 90; a series of hold down
ports 92 and a series of suction ports 94 communicating with a
plenum 96, the manifold 20 and ultimately with chamber 70. Each
convex positioning block 22, 24, 26, 28, 30, 32 is provided with an
associated plenum 96 that in turn communicates with the manifold
20.
[0033] The hold down ports serve primarily to secure the workpiece
80 against the block 22. The suction ports 94 serve primarily to
draw gases and soot evolved from the burning or ablation of the
workpiece 80 into the plenum 96. The suction ports 94 preferably
are larger in diameter than the hold down ports 92 so as to draw a
greater volume flow of air from into the plenum 96 from the
vicinity of the groove 90.
[0034] When the rotatable wall and associated work platform are
rotated to the laser trimming station, the workpiece 80 is trimmed
by means of a laser beam which is generated by a laser source 110
(FIG. 3) and projected against the workpiece 80 by means of a
projector 112 (FIG. 3). As shown in FIG. 3, the projector 112 is
mounted on a robot 114. The robot 114 is programmed to move the
projector 112 so that the laser beam projected by the projector 112
traces a path of travel near the periphery of the workpiece 80.
[0035] The preferred laser source 110 is a 200 W laser available
from Synrad, Inc. of Mukilteo, Wash. Preferably, the source 110
itself remains stationary on a shelf (not shown) positioned above
the laser cutting unit 10 (FIG. 1). The laser beam generated by the
source 110 is transmitted to an optical conduit 120 which, in turn,
conducts the beam to the projector 112. The optical conductor 120
includes a series of pivotally coupled sections 122, 124 and 126
which allow the robot 114 to translate and re-orient the projector
112 so as to direct the laser beam onto the workpiece 80 (FIG.
2).
[0036] The preferred robot 114 is available from FANUC Robotics
Corp. of Auburn, Mich. It includes a spar or first robotic arm
(shown in phantom at 130) having a proximal end 132 and a distal
end 134. A wrist portion 136 near the distal end 134 of the spar
130 supports the projector 112 for pivotal movement around a first
pivot axis 138 and a second pivot axis 140. The robot 114 also
includes a boom or second robotic arm 150 (shown in phantom) having
a proximal end 152 and a distal end 154. The boom 150 supports the
proximal end 132 of the spar 130 near its distal end 154 for
pivotal movement around a third pivot axis 156. In addition, the
robot 114 includes a base 160 (shown in phantom) which supports the
proximal end 152 of the boom 150 for pivotal movement around a
fourth pivot axis 162 and a fifth pivot axis 164, which intersect
at a pivot point 166.
[0037] The wrist portion 136 includes a pair of blocks 170 and 172;
a link 174; a first robot electric motor 176; a yoke 178 affixed to
the spar 130 and a second electric motor (shown schematically at
180). The projector 112 is directly supported by the block 170. The
blocks 170, 172 are connected by the link 174 eccentrically to the
first pivot axis 138. The block 172 is mounted on a drive shaft
(not shown) of the first robot electric motor 176 so as to cause
the first robot electric motor 176 to pivot the projector 112; the
blocks 170, 172; and the link 174 as a unit relative to the first
pivot axis 138. The projector 112 itself includes an elbow 190 to
direct the laser beam at an angle transverse (preferably
perpendicular) to the first pivot axis 138.
[0038] The first robot electric motor 176 itself is supported by
the yoke 178. The second robot electric motor 180 is housed within
the yoke 178 so as to enable the second robot electric motor 180 to
pivot the first electric motor 176 (and the direction of the first
pivot axis 138) relative to the second pivot axis 140.
[0039] A third robot electric motor (shown schematically at 200) is
housed within the distal end 154 of the boom 150 to cause the spar
130 to pivot relative to the third pivot axis 156. Fourth and fifth
robot electric motors (shown schematically at 202 and 204) are
housed within the base 160 to cause the boom 150 to pivot relative
to the fourth and fifth pivot axes 162, 164, that is, relative to
the pivot pint 166.
[0040] A controller 210, which is preferably a microprocessor, is
in electrical communication through means well known to those of
ordinary skill in the art with the robot electric motors 176, 180,
200, 202, 204 so as to induce the robot electric motors 176, 180,
200, 202, 204 to move the projector 112 so that the laser beam
traces a path of travel (212 in FIG. 4) programmed into the
controller 210.
[0041] Referring next to FIG. 4, a preferred method for trimming a
plastic workpiece 80 begins by mounting the workpiece 80 on one or
more of the convex positioning blocks (only block 22 shown in FIG.
4) so the path 212 along which the workpiece 80 is to be trimmed
lies adjacent the peripheral groove 90. At least a partial vacuum
is drawn through the plenum 96 (FIG. 2) and the hold down ports 92
(FIG. 2) of the block 22 to secure the workpiece 80 to the block
22. Next, the path of travel 212 is programmed into the controller
230 (FIG. 3). The controller 230 induces the robot electric motors
176, 180, 200, 202, 204 to move the projector so that the laser
beam traces the path of travel 212 to separate a first portion 214
of the workpiece 80 from a second (scrap) portion 216. Preferably,
the laser beam is directed normally to a tangent of the path of
travel 212 and at a constant angle with the plane of the work
platform 16. As the laser beam cleanly cuts the workpiece 80, gases
and soot generated by the process are removed through the suction
ports 94 (FIG. 2). When the first and second portions 214, 216 of
the workpiece 80 have been completely separated, the vacuum drawn
through the plenum 96 is released so that the first portion 214 of
the workpiece 80 can be removed.
[0042] FIG. 4A schematically depicts another important aspect of
the invention and shows an example of how the invention helps to
minimize burned or charred areas that in some prior art methods may
be left along the laser cut line. Here, the laser beam L is shown
penetrating the workpiece 80, typically a paint film as the film is
positioned over the block 22. The laser beam impinges on the film
at an approximate right angle, passes through the workpiece to
provide a clean cut, and extends into the depth of the peripheral
groove 90 formed in block 22. The depth of the groove 90 is
dimensioned so that the photons or beams L are totally captured
within the groove 90 and do not rebound off the block 22 back into
the underside of the workpiece 80. In contrast, in some prior art
methods that do not employ a photon capturing groove 90 contiguous
to the cut line, the laser photons bounce off a background
substrate and re-enter the workpiece adjacent the cut line
resulting in charring or burning of the part.
[0043] FIG. 5 provides a simplified block diagram showing the
manner in which the laser is ultimately driven along the desired
path to perform its accurate cutting operation on the plurality of
paint film laminate workpieces each of which is positioned on its
associated convex positioning block.
[0044] In accordance with conventional techniques, X, Y, and Z
cutting coordinates for the desired cut or trim are provided as
input and are digitized. This information is fed as memory to a
microprocessor unit that, in turn, provides this information to
controller 210 that in turn provides drive input for motors 176,
180, 200, 202, 204 (see FIG. 3).
[0045] The manner in which the laser drive is controlled is not an
essential part of the invention and, accordingly, the provision of
coordinates for the desired cutting pattern and correlated laser
drive can be provided by a variety of conventional techniques.
Examples of suitable laser control methods are detailed for example
in U.S. Pat. Nos. 5,698,121 (Kosaka et al.); 4,918,611 (Shyu et
al.) and 5,466,909 (Nihei et al). The disclosures of these patents
are incorporated by reference herein.
[0046] FIGS. 6 and 7 illustrate a preferred embodiment of the
invention in which the wall 14, associated platform 16 and support
trusses 42, 44 can be rotated between: (1) a loading and unloading
station and (2) the laser trimming station with operation at the
laser trimming station proceeding as set forth above. With
reference first to FIG. 6, the wall 14 and associated platform 16
are positioned at the loading and unloading station 526. As shown,
the assembly is housed by said wall members 502, 504 and end wall
member 506, the latter of which defines the end-wise boundary for
the laser trimming station 524. The housing is open ended at the
loading and unloading zone 526. Roof 510 extends over the assembly
from the middle of the side walls to the end wall 506. Accordingly,
a closed chamber is provided in the laser trimming station 524. In
FIGS. 6 and 7, the roof member 510 is partially broken away. This
is necessary to reveal the positioning of the wall and platform in
the laser trimming station 524 shown in FIGS. 7 and 8.
[0047] In accordance with the inventive methods, the wall 14,
platform 16 and associated trusses 42, 44 are first caused to
rotate so that the platform 16 is presented in the position shown
in FIG. 6. Here, an operator places the preformed and roughly
trimmed paint film laminate workpieces over the corresponding
convex positioning blocks that are mounted on the work platform.
Then, the platform 16 and its associated support mechanisms
including the wall 14 and trusses 42, 44 are rotated so that the
platform 16 is positioned in the laser trimming station 524 with,
as aforementioned, the laser trimming station being enclosed by
wall members 502, 504, 506 and roof 510.
[0048] While in the enclosed chamber, the laser cutting of the
paint film laminate workpieces is performed. As aforementioned,
gases and particulates are drawn through the positioning blocks
through manifold 20 and chamber 70 to a bag house or other air
cleaning station. Accordingly, the entire laser cutting operation
is performed in an enclosure so as to shield the work force from
the laser beam and the gases and particulates that are formed as an
undesirable byproducts of the cutting operation.
[0049] After the laser cutting operation is performed, the platform
16 and its associated support mechanisms are rotated back to the
position shown in FIG. 6. The operator then unloads the accurately
dimensioned laser cut workpieces from the platform, and provides
preformed roughly trimmed workpieces over the positioning blocks so
that the precise laser trimming cycle can be again commenced.
[0050] While this invention has been described with respect to
particular embodiments thereof, it is apparent that numerous other
forms and modifications of this invention will be obvious to those
skilled in the art. The appended claims and this invention
generally should be construed to cover all such obvious forms and
modifications which are within the true spirit and scope of the
present invention.
* * * * *