Note: Descriptions are shown in the official language in which they were submitted.
CA 02520378 2005-09-21
Our Reference: PTC-318-B PATENT
APPARATUS AND METHOD FOR APPLYING
A COATING TO A WINDSHIELD
FIELD OF THE INVENTION
[OOOI] The present invention is directed to a verification and coating
apparatus
and method for applying a material to a workpiece, and more particularly to a
verification and coating apparatus and method for applying a primer coating to
a
ultrasonically verified clear pre-primer coating on an edge of a v~indshield,
lights,
and/or back window.
BACKGROUND
[0002] Insulation of fixed windows in automotive vehicles previously required
manual installation of a glazing unit using suitable mechanical fasteners,
such as mete!
clips, for securing the glazing unit with respect to the vehicle body. Sealant
typically
was applied around the marginal edges of the glazing unit, prior to
positioning
decorative strips around the glazing unit to conceal the interface between the
marginal
edges of the glazing unit and the adjacent portions of the vehicle body.
Manual
assembly and installation of glazing units was inefficient, expensive, and not
amenable
to accommodate increased automotive production on an automated automobile
assembly line.
[0003] Unitary window assemblies were later developed to provide a sheet of
glass with an adjacent peripheral frame. A gasket of molded material extended
between the frame and the peripheral margin of the window to hold the glass
sheet
within the frame. Fasteners were provided at spaced locations along the frame
to
permit the entire assembly to be guided into position over an appropriate
opening in a
vehicle and to secure the entire assembly to the vehicle as a unit. While this
window
structure reduced the assembly time and simplified installation of the window
unit in a
vehicle opening, the labor required to manually assemble the frame and gasket
with
respect to the glass resulted in a relatively high cost per unit.
[0004] Individual sheets of glass or laminated glass units have been formed
with integral frame or gasket members molded and cured in situ by injection
molding.
These configurations seek to eliminate the manual assembly of the unit. The
assembly
has been referred to as an encapsulated glazing unit. The encapsulated glazing
units
require a minimum of manual labor for assembly and can be readily attached to
openings through the vehicle body during assembly on an automated production
line.
A predetermined portion of the marginal periphery of a sheet of transparent
material is
disposed within a mold structure during fabrication of the encapsulated
glazing unit.
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2
A polymeric gasket forming material is injected into the mold cavity and cured
in situ
on the sheet to encapsulate the marginal peripheral edge portion of the sheet.
The
resulting assembly is readily attachable to a periphery defining a window
opening
through a vehicle body during manufacturer and assembly of the vehicle.
(0005] It is known to be difficult to form a gasket material having a
permanent,
long term bond directly to a glass surface. The gasket materials can fail to
maintain
adhesion to the glass surface for a sufficient length of time to be consistent
with the
life of the vehicle. Exposure to environmental conditions can cause gasket
material to
loosen from the glass surface over time, and ultimately may separate entirely
from the
glass surface. It is known to apply a coating of a liquid primer material to
the effected
surface of the glass prior to formation of a gasket thereon in order to
improve the
adherence of a gasket material to the glass surface and to increase the
expected life of
the encapsulated glazing unit. A band of the primer material along the
appropriate
edge portion of the glass panel can be applied manually or through automated
processing equipment. The primer layer, typically a urethane material, is best
applied
as a uniform, continuous, relatively thin band in order to function properly.
The
primer layer may separate within an excessively thick layer along a cleavage
plane
resulting in failure ofthe bond. The primer layer may be ineffective for its
intended
purpose if not of su~cient thickness or of certain areas are not coated.
(0006] A programed robot or other motion device can be used to define a path
of travel coinciding with a perimeter or other path associated with a product
to be
coated. Applications can involve depositing primer material, paint material,
activator
material, adhesive material, or the like to aid in the attachment of foam
tapes, plastic
moldings, metal components, such as hinges, locks, and all types of
encapsulated
products.
[0007] Prior to the application of certain primer materials, it is known to be
advantageous to provide a pre-primer coating or surface treatment of a glass
surface
in order to better adhere the primer coating to the glass surface. Certain pre-
primer
coatings for glass surfaces clean or etch the glass surface in preparation for
the
application of the primer coating. The pre-primer coating or surface treatment
can
dry to a clear, transparent, virtually invisible, surface. In such
applications, it is
difficult to visually verify proper application of the pre-primer coating
prior to
application of the primer coating to the glass surface. Failure to properly
pre-prime
the glass surface can result in failure or unsatisfactory performance of the
primer
coating in performing its intended function. It would be desirable to provide
an
apparatus and method for verification of the presence and proper application
of the
pre-primer material prior to the application of the primer material layer.
CA 02520378 2005-09-21
SIJIY1NIARY
[0008] The verification and coating apparatus and method according to the
present invention will generally be described with regard to a particular
automotive
application, since one of the primary applications of the verification and
coating
apparatus and method is the automotive glass industry where a material
applicator is
used to apply various fluids to an edge of a windshield, side light, and/or a
backlight
glass. However, it should be understood that the present invention is also
suitable for
a wide range of other material applying applications. The automotive glass
application description is therefore by way of example and not limitation with
respect
to the possible applications of the present invention. The present invention
is
particularly adapted for the production of glazing units or window assemblies
for
automotive vehicles, although it will find utility generally in other material
application
fields as well.
[0009] The present invention provides an apparatus and process for applying a
material layer to a workpiece for a vehicle. By way of example and not
limitation, a
contoured glass workpiece can have a pre-primer material layer applied along a
predetermined path on a surface of the workpiece leaving a residual film. An
ultrasonic sensor can be provided for identifying a workpiece configuration,
and for
verifying presence, of the residual film of pre-primer material layer along
the
predetermined path on the surface of the workpiece. A first applicator can be
provided for applying a primer material layer over the pre-primer material
layer on a
surface of the workpiece, if presence of the residual film is verified by the
ultrasonic
sensor. A second applicator can be provided for applying a urethane sealant
material
layer over the primer material layer on the surface of the workpiece.
[0010] A process according to the present invention can be used for applying a
layer of material to a workpiece for a vehicle. By way of example and not
limitation,
the process according to the present invention can include the steps of
ultrasonically
verifying a residual film from a first material layer previously applied to a
surface of a
workpiece, and if verified, applying a second material layer over the first
material
layer on the surface of the workpiece. The first material layer can include a
pre-
primer material layer covering at least a portion of the surface of the
workpiece along
a predetermined path. The second material layer can include a primer material
applied
over the first material layer on the surface of the workpiece. A third
material layer
can be provided for application over the second material layer on the surface
of the
workpiece. By way of example and not limitation, the third material layer can
be a
urethane sealant material for connecting and sealing a contoured glass
workpiece to
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an opening in a vehicle body. If the residual film from the first material
layer is not
verified, the workpiece can be rejected as being defective prior to further
processing.
[00I1] According to the present invention, the apparatus and process
encompass different workstation configurations providing various degrees of
processing flexibility and production throughput. The apparatus and process
according to the present invention can also identify at least one of a
pattern, size, and
shape of a workpiece to be processed, and based on the identification can
select
material layers to be applied, in sequence of application of the material
layers, and a
path of applicator travel.
[0012] Other applications of the present invention will become apparent to
those skilled in the art when the following description of the best mode
contemplated
for practicing the invention is read in conjunction with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWTNGS
[0013) The description herein makes reference to the accompanying drawings
wherein like reference numerals refer to like parts throughout the several
views, and
wherein:
[0014] Figure 1 is a simplified schematic plan view of a black prime
application
to heated glass projected to be capable of processing 20 jobs per hour;
[0015] Figure 2 is a simplified schematic plan view of a red and black prime
application workstation projected to be capable of processing 65 jobs per
hour;
[0016] Figure 3 is a simplified schematic plan view of a red and black prime
application workstation projected to be capable of processing 130 jabs per
hour; and
[0017] Figure 4 is a simplified flow diagram illustrating various process
steps
according to one example of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0018] Referring now to Figure I, a workstation IO is illustrated including a
plurality of glass workpiece racks 12. At least one workpiece rack I2 can be
provided for workpieces to be processed, while at least one rack I2 can be
provided
for workpieces that have been processed. An operator load assist f xture 14
can be
provided with a bridge 16 and rails 18. The load assist fixture 14 can include
90
degrees of motion (horizontal to verticat). Hand controls can be provided for
manual
or automated motion of the fixture. Vacuum cups and control circuitry can be
provided connected to a source of vacuum for selectively engaging and dis-
engaging a
workpiece to be loaded and/or unloaded from the storage rack 12 for delivery
to and
from a glass nesting fixture 20. By way of example and not limitation, the
glass
nesting fixture 20 can include a 2 inch diameter tube frame construction with
leveling.
Vacuum cups and control circuitry can be provided for holding the workpiece in
place
CA 02520378 2005-09-21
within the nesting fixture Z0. Bumpers with threaded rod adjustment can also
be
provided for location of the workpiece with respect to the nesting future 20.
Part
present limit switches can be provided to signal the presence of a workpiece
within
the nesting fixture 20. Locators can also be provided for shifting the
workpiece into a
predetermined location with respect to the nesting fixture in response to
actuation of
the part present limit switches. At least one robot or other automated
material
application equipment 22 is provided for operative interaction with the
workpiece 12
mounted within the nesting fixture 20 at the workstation I0. The robot or
other
material application equipment is in fluid communication with material
dispense
equipment 24 for supplying the material to be applied to a surface ofthe
workpiece
12 held in the nesting fixture 20. One or more ventilation ducts 26 can be
provided
for ventilating the area of the workstation 10. A control panel 28 can be
provided for
controlling the robot or other material application equipment 22 in order to
apply the
appropriate material in the desired application sequence, and along a
programmable
path based on an identification of the pattern, size, and/or shape of the
workpiece to
be processed. The control panel 28 can include an emergency stop button 30. A
workstation control panel 32 can be provided for controlling the operation of
the
nesting fixture 20 and/or for controlling the operation of the load assist
fixture 14.
The workstation control panel 32 can include an emergency stop button 34. A
safety
run bar or switch 36 can be provided for dual handed operation by the loading
and
unloading operator to cycle the fixturing of the next workpiece to be
processed and
cycling the operation of the robot or material application equipment to
dispense the
appropriate selected material in the selected application sequence along a
programmed path based on an identification of the pattern, size, and/or shape
of the
workpiece to be processed. A main input/output enclosure panel 38 can be
provided
for the workstation. The main panel can route power and/or control lines to
and from
the workstation 10 with appropriate switches, breakers, and diagnostic lights
to
simplify proper operation of the workstation 10. A supplemental enclosure
panel 40
can also be provided if desired to interface power and/or control signals with
the
material dispense equipment 24 and to interact with the robot or material
application
equipment control panel 28.
[0019] In operation, a workstation operator uses the load assist fixture 14 to
remove an unprimed workpiece from the storage rack 12 and moves the workpiece
along the bridge and rails 16, 18 to a position to load the nesting fixture
20. After
loading the unprimed workpiece in the nesting fixture 20, the operator
activates the
run bar or switch 36 to activate the holding, and/or clamping and/or locating
components of the nesting fixture 20, and to activate an identification of the
CA 02520378 2005-09-21
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workpiece by pattern, size, and/or shape of the workpiece. An identification
signal is
sent to the control panel 28 for the robot or other material application
equipment ZZ
where the appropriate material is selected, the appropriate application
sequence is
selected, and a programmed path based on the identification signal of the
workpiece is
selected for automatic application of the material along the programmed path
for
applying material to a surface of the workpiece to be processed. The pattern,
size,
and/or shape of the workpiece can be identified in a variety of ways. By way
of
example and not limitation, the workpiece can be identified by operator input,
either
directly through a keypad entry or through a bar code scanning, or can be
identifced
with a computerized vision system. In the preferred configuration, an
ultrasonic
identification system can be used to identify the particular workpiece placed
in the
nesting fixture 20. The ultrasonic system can also be used to detect a
residual pre-
primer film on a surface of a workpiece positioned in the nesting fixture 20
of the
workstation I 0. If the pre-primer coating is detected as existing in the
desired area of
the surface of the workpiece, the robot or other material application
equipment 22 is
activated to apply a primer material layer over the residual film in
preparation for
subsequent application of a third material layer. By way of example and not
limitation, the third material layer can include a urethane sealant material
layer to be
applied over the primer material layer applied by the robot or other material
application equipment 22. If the residual pre-primer film is not detected on
the
surface of the workpiece, the robot can be prevented from applying the primer
layer
to the surface of the workpiece, and the control panel can signal a rejected
workpiece.
The robot or material application equipment 22 can be returned to a ready
position
allowing removal of the workpiece from the nesting fixture 20. The nesting
fixture 20
can be de-energized to release any clamps or suction cup vacuum holding the
workpiece in position within the nesting fixture 20, The Ioad/unload assist
fixture 14
can be manipulated along the bridge and rails 18 in order to operably engage
the
workpiece within the nesting fixture 20 in order to lift and move the
workpiece from
the nesting fixture 20 to a primed workpiece storage rack 12. The load/unload
assist
fixture 14 can include appropriate clamps and/or vacuum suction cups to
operably
engage and hold the workpiece during the transport procedure. After the primed
workpiece has been transported along the rails and across the bridge to an
appropriate
storage rack 12 and properly positioned therein, the assist fixture 14 can be
de-
energized to release any clamps and/or vacuum suction cups to transfer the
workpiece
from the assist fixture 14 to the storage rack 12. The assist fixture 14 can
then be
moved along the rail to an unprimed workpiece storage rack 12 where a
subsequent
unprimed workpiece is operably engaged for transport to the nesting fixture
20. The
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7
entire process is then repeated for the unprimed workpiece. If a workpiece has
been
rejected for failing to include a pre-primer coating in the appropriate areas
on the
surface of the workpiece, the workpiece can be removed from the nesting
fixture 20
with the assist fixture 14 for transportation to an appropriate rejected part
storage
rack 12.
[0020] By way of example and not limitation, suitable ultrasonic
identification
systems can be obtained from Quiss GmbH of Puchheim, Germany. The system can
check the width, position, and completeness of the pre-primer coating on the
surface
of the workpiece, as well as the width, position, and completeness of the
primer being
applied continuously during the application process. The system can be
equipped
with extremely fast algorithms so that inspection can be conducted in real
time at
production speeds. The system can be directly connected to the robot
controller, and
the sensor can be used with all conventional fuel bus systems. The
commercially
available system allows target values and tolerance ranges to be quickly
entered in the
programming device and the operating status can be displayed directly on the
robot
controller. The image processing software can be integrated in the sensor,
independent of the technology package installed on the robot controller to
enable the
sensor to be operated independently of the robot in use. The sensor can be
easily
integrated into any robot. The sensor can include a camera and lighting. The
sensor
can be mounted directly to a material application nozzle or other tool. The
basic
configuration can include a control cabinet and a visualization and control
unit. Any
number of cameras can be used depending on production conditions. The sensors
and
the components can be provided in a fixed position installation, or it can be
provided
in a mobile installation attached to the robot or other material application
equipment
for movement along the desired path of travel during application of the
material to the
surface of the workpiece. The result in parameter data can be displayed and
edited at
the workstation, or at a host computer, or at any authorized computer in a
network.
[0021] It has been estimated that a black prime application with heated glass
can be applied in a workstation according to the configuration illustrated in
Figure 1
at a rate of 20 jobs per hour. If increased production is desired with red and
black
prime application, the configuration illustrated in Figure 2 has been
estimated to
provide production at a rate of 65 jobs per hour. The configuration at
operation of
Figure 2 is identical to that previously described with respect to Figure 1
with the
exception of the addition of a two station index table 42 having 180 degree
oscillating
or rotary movement about a rotational axis. The table top frame allows first
and
second nesting fixtures 20a, 20b to be attached to diametrically opposite ends
of the
table for oscillating movement between first and second positions
corresponding to a
CA 02520378 2005-09-21
loading/unloading position, and a processing position. This allows the
workstation
operator to unload a primed workpiece from one nesting fixture 20a or 20b
while the
robot ar other material application equipment 22 applies material to the
workpiece
located at the processing position in the other nesting fixture 20b or 20a.
During the
time required for the robot to apply one or more layers of material to the
workpiece at
the processing location or position, the workstation operator can unload a
finished
piece from the other nesting fixture for transport to an appropriate coated
workpiece
storage rack 12, and load another uncoated workpiece from an appropriate
uncoated
workpiece storage rack I2 for delivery to the empty nesting fixture. After.
the
uncoated workpiece has been loaded into the nesting fixture, and after the
workpiece
has been coated in the processing location, the turntable can oscillate to
exchange the
two workpieces between the loading/unloading position and the processing
position
to repeat the sequence of steps for continued processing of workpieces. It
should be
recognized that the use of a turntable is considered to be the most efficient
configuration as illustrated in the configurations of Figures 2 and 3.
However, it
should be recognized by those skilled in the art that parts can be delivered
to the
processing position in any variety of forms, including various types of
workpiece
conveyors other than turntables. In the preferred configuration, the
ultrasonic
identif canon system can pattern match hundreds of different styles of
workpieces to
be processed through the workstation. The different styles are capable of
being held
stable within a nesting fixture having appropriately positioned vacuum cups.
The
ultrasonic vision system can identify the pattern, size, and/or shape of the
workpiece
in order to select the appropriate material to be applied, sequence of
application,
and/or path of application of the material to be applied. The ultrasonic
vision device
can also be used to detect a residual film or coating to verify its presence
in the
appropriate locations prior to applying another material over the residual
coating.
[0022] Referring now to Figure 3, if even greater production rates are
required,
the illustrated configuration is estimated to provide a production rate of
approximately 130 jobs per hour. The operation and configuration ofthe
workstation
illustrated in Figure 3 is identical to that previously described for Figures
1 and 2 with
the exception of a four station index table 44 is provided in place of the two
station
index table 42 illustrated in Figure 2. The four station index table can be
provided
with continuous rotation to move a part loaded into a first nest at a loading
station to
a first processing station, where a first robot or other material application
equipment
22a applies a first material layer to the workpiece along a desired path and
in a desired
sequence. While the workpiece in the first nest is being processed at the
first
processing station, a second nest is being loaded with a workpiece at the
loading
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9
station. When the turntable rotates again, the workpiece in the first nest is
delivered
to a second processing station, wMle the workpiece in the second nest is
delivered to
the first processing station, and a third nest is positioned at the loading
station for
receiving another workpiece. The workpiece in the second nest is processed in
the
same manner as described fox the workpiece in the first nest. The first
nesting fixture
now located at the second processing workstation is positioned within the work
zone
of a second robot or material application equipment 22b. The second robot or
material application equipment 22b then applies a second material layer to the
workpiece along the particular path and in the desired sequence for the
particular
workpiece as identified by the ultrasonic identification system. The
ultrasonic
identification system can determine whether the first material layer applied
to the
workpiece exists in the proper locations prior to application of the second
material
layer by the second robot or material application equipment 22b. If the first
material
layer is absent or does not exist in the appropriate locations within the
parameters set,
the workpiece can be rejected prior to application of the material by the
second
material application equipment or robot 22b. After completion of the
processing at
the first and second processing stations, and loading of a new part at the
loading
station into the third nesting fixture, the turntable can incrementally move
the
workpieces to the next workstation. In this position, the first nesting
fixture and the
workpiece located thereon is located at an unloading station where a
workstation
operator can remove the workpiece from the first nesting fixture for transport
by the
assist fixture along the rail and bridge to an appropriate workpiece storage
rack 12.
The workpiece located in the second nesting fracture has been moved from the
first
processing station to the second processing station for application of the
second
material layer. The workpiece located in the third nesting fixture has moved
from the
loading station to the first processing station for application for the first
material layer
by the first mater equipment or robot 22a. A fourth nesting fixture is now
located at
the loading station, where a workstation operator can remove an uncoated
workpiece
from an appropriate storage rack 12 for positioning using the assist fixture
for
movement along the rail and ridge to locate the workpiece in the fourth
nesting
fixture. While the configuration illustrated in Figure 3 depicts a turntable
configuration, it should be recognized by the those skilled in the art that
workpieces
can be moved between the four stations by any appropriate workpiece conveyor
system known to those skilled in the art.
[0023] Referring now to Figure 4, the present invention includes a process for
applying a layer of material to a workpiece for a vehicle. The process can
include the
step 100 of identifying a pattern, a size, and/or a shape of a workpiece to be
CA 02520378 2005-09-21
10
processed. The identification can be performed by any suitable process known
to
those skilled in the art, such as operator input, bar code scanning, vision
system
scanning, and/or ultrasonic scanning. In the preferred configuration,
identification of
the workpiece can be accomplished with ultrasonic verification of the pattern,
size,
and/or shape of a workpiece. Based on the identification of the workpiece, the
process continues to step I02 where the appropriate material is selected for
application to the particular identified workpiece, the application sequence
of the
material is selected based on the identification of the workpiece to be
processed,
and/or the path of the material application equipment or robot is selected
based on the
identification of the workpiece. After selection of the appropriate material,
sequence,
and/or path, the process continues to query 104 where it is determined
ultrasonically
whether a residual pre-primer film is detected on a surface of the workpiece
to be
processed. if the residual pre-primer film is not detected ultrasonically on a
surface of
the workpiece, the process branches to step 106 where the workpiece is
rejected. If
the residual pre-primer film is ultrasonically detected on a surface of the
workpiece,
the process continues to step 108 where the material applicaxion equipment or
robot
applies a primer material layer over the residual film in preparation for
subsequent
application of a urethane sealant material layer. The process can then
continue to step
110 where the material application equipment or robot can apply a urethane
sealant
material layer over the primer material layer previously applied. In other
words, the
process according to the present invention can include the steps of
ultrasonically
verifying a residual film from a first material layer previously applied to a
surface of a
workpiece, and if verified, applying a second material layer over the first
material
layer on the surface of the workpiece. The process can also include applying
the first
material layer to at least a portion of the surface of the workpiece using the
material
application equipment or robot at a workstation, and drying the first material
layer to
form a clear transparent surface. The first material layer can be provided as
a pre-
primer material for application to a least a portion of the surface of a
workpiece. The
process according to the present invention can also include applying a third
material
layer over the second material layer previously applied to the surface of a
workpiece.
The third material layer can be provided as a urethane sealant material for
application
to at least a portion of the surface of the workpiece. The second material
layer can be
provided as a primer material application to at least a portion of the surface
of the
workpiece.
T0024] The workpiece according to the present invention can include a
contoured glass member defining the workpiece to be processed. A pre-primer
material can be applied to at least a portion of the contoured glass member.
The first
CA 02520378 2005-09-21
11
material layer can be dried to form a clear transparent surface. A primer
material can
be provided for application on top of the first material layer located on the
surface of
the workpiece. A urethane sealant material can also be provided for
application on
top of the primer material layer located on the surface of the workpiece.
[0025] While the invention has been described in connection with what is
presently considered to be the most practical and preferred embodiment, it is
to be
understood that the invention is not to be limited to the disclosed
embodiments but,
on the contrary, is intended to cover various modifications and equivalent
arrangements included within the spirit and scope of the appended claims,
which
scope is to be accorded the broadest interpretation so as to encompass all
such
modifications and equivalent structures as is permitted under the law.
