WO2003047767A1

WO2003047767A1 - Automated painting system and related methods

Info

Publication number: WO2003047767A1
Application number: PCT/US2002/032585
Authority: WO
Inventors: Andrew J. Bales
Original assignee: Bales Andrew J
Priority date: 2001-10-11
Filing date: 2002-10-11
Publication date: 2003-06-12
Also published as: AU2002351475A1; WO2003031081A1

Abstract

An automated painting system (10) for painting a workpiece, such as a sign, and related painting methods are disclosed. In one embodiment, the painting systemn (10) includes a paint supply or spray head capable of moving in at least three and preferably up to six axes, as well a movable gantry (14) and a workpiece support structure (16). An automated cutting device for cutting a mask applied to a surface of a workpiece is also disclosed, along with related inventions for facilitating locating and removing the cut mask.

Description

AUTOMATED PAINTING SYSTEM AND RELATED METHODS

This application claims thebenefit of U.S. Provisional Patent Ser. No. 60/328,635, filed October 11, 2001, the disclosure of which is incorporated herein by reference.

Technical Field

The present invention relates generally to the art of computer- controlled devices and, more particularly, to computer numerically controlled (CNC) multiple-axis painting and cutting devices and related methods for painting a workpiece or cutting a mask on a workpiece.

Background of the Invention

The process of hand painting a workpiece, such as for example a sign or similar display for conveying information to the public, is often a laborious and expensive undertaking, especially in cases where multiple colors are required, complex patterns are desired, or in mass production situations. Current automated sign painting techniques often require significant manual input and interaction by a user. Moreover, several machines are required to complete the desired painting tasks on a particular workpiece, such as a complex, multi-color sign using different hatch or fill patterns. The operation is particularly daunting in the case of an embossed workpiece, where paint must be applied essentially to a three-dimensional surface rather than merely a two-dimensional, fiat area. Accordingly, a need is identified for improved system and method for painting a workpiece such as a sign in an automated fashion to reduce the amount of labor and manual input by personnel and still achieve a high-quality finished product.

Computer numerically controlled (CNC) devices are currently used for a variety of automated machining applications, including lathes, routers, milling machines, cutting devices, welders, and the like. The typical CNC machine is controlled by a computer that is pre-programmed by the user with a series of instructions required to perform a particular sequence of movements or tasks (such as based on the particular location where each operation is to be performed, usually expressed in Cartesian coordinates). With the advent of improved robotics and sophisticated computer technology, modern CNC machines capable of highly complex multi-step operations have evolved.

Summary of the Invention

In accordance with a first aspect of the invention, a system for painting a workpiece, such as a sign, is disclosed. The system comprises a painting device including a paint supply head having a plurality of nozzles, each associated with a different color of paint; a first motive device for moving the paintmg device about or along at least a first axis; a second motive device for moving the paintmg device about or along a second axis generally perpendicular to the first axis; and a stable structure for supporting the workpiece relative to the painting device. During a painting operation, a first nozzle on the paint supply head applies a first color of paint to selected portions of the workpiece during a first pass and a second nozzle applies a second color of paint to selected portions during a second pass.

In one embodiment, the plurality of motive devices further comprise a third motive device for moving the paint supply head along a third axis perpendicular to the plane of the workpiece, a fourth motive device for rotating the paint supply head about said first axis, a fifth motive device for rotating the paint supply head about said second axis, and a sixth motive device for rotating the paint supply head about said third axis. Preferably, the painting device includes a first gantry for supporting the paint supply head adjacent to the stable support structure, wherein the first and second motive devices move both the spray head and the gantry along the first and second axes. A second gantry for supporting a cutting device for cutting a mask applied to the workpiece may also be provided. Alternatively, the painting device may include a cutter mechanism for cutting the mask to expose selected portions of the workpiece for paintmg. hi either case, the mask may be applied to the workpiece by at least one spray nozzle of the paint supply head.

In addition, a device for assisting in calibrating the position of the painting device relative to the workpiece may be provided. In one embodiment, the calibration device comprises at least one light source that generates and directs a light beam toward the workpiece. The light source is preferably a laser pointer. A controller may also be provided for automatically controlling the movement and operation of the paintmg device based on instructions previously provided by a user. The workpiece preferably includes at least two reference points at predeteraiined locations and the controller is capable of acquiring data regarding the locations of the reference points and then determining whether a corresponding adjustment to the instructions provided by the user is necessary to ensure that the workpiece is painted in the desired fashion. The controller may include a computer programmed to prompt the user for information or instructions used to create a digital job representative of the movement and operation of the painting device. Yet another option is for the stable support structure to include at least one vacuum or suction device for holding the workpiece in place during the pamtmg operation. Preferably, the stable structure supports the workpiece in a generally vertical orientation. h accordance with a second aspect of the invention, a system for intended use in cutting a mask or coating applied to at least one surface of a workpiece is disclosed. The system comprises a stable structure for supporting the workpiece; a cutting device positioned adjacent to the stable structure; a first motive device for moving the cutting device about or along at least a first axis; a second motive device for moving the cutting device about or along a second axis generally perpendicular to the first axis; a controller for controlling the first and second motive devices to move the cutting device about the surface of the sign to cut the mask in accordance with a predetermined pattern.

In one embodiment, the cutting device includes a gantry supported by the stable structure, with the first and second motive devices moving both the gantry and the cutting device. The cutting device may include a spring-loaded cutter element. A light source may also be mounted to the cutting device.

In accordance with a third aspect of the invention, a system for intended use in cutting a mask or coating applied to at least one surface of a workpiece is disclosed. The system comprises a stable structure for supporting the workpiece; a cutting device positioned adjacent to the stable structure for selectively cutting the mask on the workpiece; and a light source mounted to the cutting device for directing light towards the workpiece. The light source may be used to visually indicate the position of the cutting device relative to the workpiece. In one embodiment, the light source is a laser pointer and the system further includes a controller for controlling first and second motive devices for moving the cutting device along at least two axes for cutting the mask on the workpiece. The workpiece may include a reference point, in which case the controller is programmed with coordinates to initially position the cutting device over an expected location of the reference point on the workpiece. The system may further include an input device associated with the controller for manually controlling the movement of the cutting device, such that a user may move the light source on the cutting device over the reference point and generate a signal to the controller for storing an actual location of the reference point and calculating an offset amount. hi accordance with a fourth aspect of the invention, a system for intended use in cutting a mask or coating applied to at least one surface of a workpiece is disclosed. The system comprises a stable structure for supporting the workpiece; a cutting device positioned adjacent to the stable structure for selectively cutting the mask on the workpiece; and a light source for directing light towards the workpiece. The light source maybe used to visually indicate the portions of the mask cut by the cutting device. The system may further include a paintmg device positioned adjacent to the stable structure for painting the regions underlying the cut mask once removed. In accordance with a fifth aspect of the invention, a system for paintmg a workpiece, such as a sign, is disclosed comprising: (1) a movable painting device including a paint supply head; and (2) a stable structure for supporting the workpiece relative to the painting device. The stable structure includes at least one suction device. Preferably, the suction device includes a plurality of suction cups positioned on vertically extending struts or members forming part of the stable structure. The suction cups may further include check valves that open when contact is made with the workpiece.

In accordance with a sixth aspect of the invention, a system for cutting a mask or coating applied to one surface of a workpiece is disclosed. The system comprises a movable cutting device for cutting the mask on the workpiece and a stable structure for supporting the workpiece relative to the cutting device. The structure includes at least one suction device for supporting the workpiece therefrom. The suction device may include a plurality of suction cups positioned on vertically extending struts or members forming part of the stable structure, each suction cup including a check valve that opens when contact is made with the workpiece.

In accordance with a seventh aspect of the invention, a system for intended use in cutting a mask or coating applied to at least one surface of a workpiece is disclosed. The system comprises a stable structure for supporting the workpiece and a movable cutting device positioned adjacent to the stable structure. The cutting device includes a spring-loaded cutting element biased towards the workpiece for automatically providing the correct amount of cutting pressure for cutting the mask.

In accordance with an eighth aspect of the invention, a system for painting a workpiece including an embossed portion having a sidewall, such as a sign, is disclosed. The system comprises a painting device including a paint supply head having at least one nozzle positioned generally perpendicular to the workpiece and a first motive device for rotating the nozzle through an arc of up to 90° for painting the sidewall. In accordance with a ninth aspect of the invention, a system for painting a sign having a grip mask applied thereto is disclosed. The system comprises means for cutting the grip mask for removal and means for automatically paintmg the portions of a corresponding surface of the sign exposed when some or all of the portions of the grip mask cut by the cutting means are removed. The automatic painting means may include at least one paint source coupled to a spray nozzle by at least one supply line and the system further includes means for returning at least some of the paint in the supply line to the paint source.

In accordance with a tenth aspect of the invention, a painting system is disclosed comprising a workpiece; apainting device including apaint supply head; a first motive device for moving the painting device about or along at least a first axis; a second motive device for moving the pamtmg device about or along a second axis generally perpendicular to the first axis; a stable structure for supporting the workpiece relative to the painting device; and a controller for automatically controlling the movement and operation of the painting device based on instructions previously provided by a user. The workpiece includes at least two reference points at predetermined locations and the controller is capable of storing data regarding the locations of the reference point and then determining whether a corresponding adjustment to the instructions provided by the user is necessary to ensure that the workpiece is painted in the desired fashion. In accordance with an eleventh aspect of the invention, a method of compensating for variations in the position or size of a workpiece in an automated painting or cutting operation performed based on a series of pre-programmed instructions or information provided by a user is disclosed. The method comprises storing the location of a first reference point on the workpiece; comparing the stored location with an expected location of the first reference point provided in the preprogrammed instructions and detemiining an offset value; and applying the offset value to the pre-programmed instructions to modify the painting or cutting operation accordingly. The method may further include the step of locating the first reference point by directing a laser at the first reference point and the storing step includes recording the location of the laser in X and Y coordinates. The comparing step may comprise comparing at least the X-coordinate of the first reference point with the X- coordinate of the expected reference point to determine the offset value. The method may further include the steps of storing the location of a second reference point on the workpiece; calculating the parameters of a right triangle from the stored locations of the first and second reference points; comparing the calculated right triangle to a theoretical right triangle in the pre-programmed instructions; calculating a size correction factor, a rotation correction factor, or both based on the difference in size or orientation of the calculated and theoretical triangles; and applying one or both of the calculated correction factors to the instructions or information provided by the user to modify the paintmg or cutting operation accordingly.

In accordance with a twelfth aspect of the invention, a method of compensating for variations in the position or size of a workpiece in an automated painting or cutting operation performed based on a series of pre-programmed instructions or information provided by a user is disclosed. The method comprises storing the location of a first reference point on the workpiece; storing the location of a second reference point on the workpiece; calculating the parameters of a right triangle from the stored locations of the first and second reference points; comparing the calculated right triangle parameters to a theoretical right triangle in the preprogrammed instructions or information; calculating a size correction factor, an orientation correction factor, or both based on the difference in size or orientation of the calculated and theoretical triangles; and applying one or both of the calculated correction factors to the instructions or information provided by the user to modify the painting or cutting operation accordingly. hi accordance with a thirteenth aspect of the invention, a method of operating on two workpieces simultaneously is disclosed. The method comprises providing a first paintmg device adjacent to a stable structure for painting a first workpiece supported thereon and providing a second device for cutting or painting a second workpiece supported on the same stable structure as the first workpiece. h accordance with a fourteenth aspect of the invention, a method of operating on two workpieces simultaneously is disclosed. The method comprises cutting a mask or coating on a first workpiece supported on a stable support structure and cutting a mask or coating on a second workpiece supported on the stable support structure while at least a portion of the cut mask or coating is removed from the first workpiece. The method may further include the step of paintmg any areas on the first workpiece where the masking is removed and the step of removing only a portion of the masking corresponding to a color of paint to be applied during the paintmg step. In accordance with a fourteenth aspect of the invention, a method of operating on a workpiece is disclosed. The method comprises cutting at least a portion of a mask or coating on the workpiece supported on a stable support structure and illuminating at least a portion of the workpiece to facilitate locating and removing the cut portion of the mask. The illuminating step may comprise turning on a plurality of lights positioned adjacent to the stable support structure.

In accordance with a fifteenth aspect of the invention, a method of operating on a workpiece is disclosed. The method comprises cutting at least a portion of a mask or coating on the workpiece supported by a stable support structure using a computer-controlled cutting device and using the computer to automatically illuminate one or more lights positioned adjacent to the workpiece to facilitate locating and removing the cut portion of the mask.

In accordance with a sixteenth aspect of the invention, a method of operating on a workpiece is disclosed. The method comprises cutting at least a portion of a mask or coating on a first workpiece selected from a plurality of workpieces supported by a stable support structure and illuminating the first workpiece only to facilitate locating and removing the cut portion of the mask.

In accordance with a seventeenth aspect of the invention, a method of paintmg is disclosed. The method comprises the steps of: (1) providing a mask on at least one surface of a workpiece; and (2) using a controller to move a spring- loaded cutting device over the mask in accordance with a set of pre-programmed instructions to cut the mask.

In accordance with an eighteenth aspect of the invention, a method of evenly paintmg a workpiece, such as a sign, using an automated painting device is disclosed. The method comprises applying a first coat of a first color of paint to the sign during a plurality of first passes and applying a second coat of the first color of paint to the sign during a second plurality of passes. Each second pass is offset from the first passes by a predetermined distance. The predetermined distance may be calculated by dividing a distance between each pass by a number of coats to be applied to the workpiece.

In accordance with a nineteenth aspect of the invention, a method of evenly painting a workpiece, such as a sign, using an automated painting device is disclosed. The method comprises initiating the painting before the automated painting device is over the sign; and painting the sign using the automated painting device.

In accordance with a twentieth aspect of the invention, a method of evenly painting a workpiece, such as a sign, using an automated painting device is disclosed. The method comprises moving the automated painting device before the automated painting device is over the sign to reach a desired acceleration and applying paint to the sign once the desired acc'eleration is reached. The applying step is preferably completed during a first pass and the method further includes the steps of decelerating the automated painting device once the first pass is made and moving the automated painting device at a desired acceleration before a second pass is made. In accordance with a twenty-first aspect of the invention, a method of paintmg a workpiece for later undergoing embossment, such as a sign, is disclosed. The method comprises the steps of providing instructions to a controller regarding one or more areas of the workpiece to which paint is to be applied; providing an instruction regarding whether and the degree to which any of said one or more of said areas are to be embossed; and programming the controller to automatically adjust the size of the area to be painted at the embossment locations to compensate for distortion created during later embossing.

In accordance with a twenty-second aspect of the invention, a method of paintmg according to a preprogrammed set of instructions is disclosed. The method comprises the steps of providing a workpiece in the form of a sign; providing a painting device including a paint supply head having one or more nozzles; and moving the paint supply head and/or the nozzles about or along any of at least six axes in accordance with the preprogrammed instructions while selectively providing paint to at least one of the nozzles to paint the sign.

In accordance with a twenty-third aspect of the invention, a method of painting according to a preprogrammed set of instructions is disclosed. The method comprises the steps of providing a workpiece in the form of a sign; providing a painting device including a paint supply head having one or more nozzles; inputting the pre-programmed set of instructions to a controller; and using the controller to control the painting device. h accordance with a twenty- fourth aspect of the invention, a method of painting according to a set of instructions is disclosed. The method comprises the steps of providing a workpiece in the form of a sign; providing a painting device including a paint supply head having one or more nozzles; querying the user for instructions regarding a geometry of a shape to be painted on the workpiece and a color of the shape; creating the set of instructions; and using the controller to control the pamtmg device in accordance with the set of instructions. The method may further include querying the user for the location and depth or height of any embossments in the workpiece.

In accordance with a twenty-fifth aspect of the invention, a graphical user interface including a display and a user interface selection device is disclosed including a method of providing a tree view on the display comprising the steps of: displaying a branch representing a location for selecting a region of a workpiece and displaying a first sub-branch representing a location for selecting a color of paint for applying to the region displayed in the branch. The method may further include the step of displaying a second sub-branch including a menu listing a plurality of colors for applying to the region. h accordance with a twenty-sixth aspect of the invention, a computer system having a graphical user interface including a display and a user interface selection device is disclosed for performing a method of identifying a region to be painted on a workpiece comprising the steps of: displaying a representation of the workpiece; and displaying a tree view including a branch representing a location for selecting a region of a workpiece for undergoing painting and a sub-branch representing a location for selecting a color for applying to the region displayed in the branch.

In accordance with a twenty-seventh aspect of the invention, a computer-readable medium having computer-executable instructions for performing steps is disclosed. The steps comprise storing instructions for performing an automated painting or cutting operation on a workpiece, including an expected location of a first reference point; receiving an actual location the first reference point; comparing the actual location with the expected location to determine an offset value; and applying the offset value to the set of instructions. In accordance with a twenty-eighth aspect of the invention, a computer-readable medium having computer-executable instructions for performing steps is disclosed. The steps comprise storing instructions for performing an automated operation on a workpiece including a theoretical right triangle; receiving an actual location of first and second reference points on the workpiece; calculating the parameters of a right triangle from the actual locations of the first and second reference points; comparing the calculated right triangle to the theoretical right triangle; calculating a size correction factor, an orientation correction factor, or both based on the difference in size or orientation of the calculated and theoretical triangles. The method may further include applying one or both of the calculated correction factors to the instructions to modify the operation accordingly.

Additional aspects, advantages and other novel features of the invention will be set forth in part in the description that follows and in part will become apparent to those skilled in the art upon examination of the foregoing, or may be learned with the practice of the invention.

Brief Description of the Drawings

Figure 1 is a perspective view of one embodiment of the painting system of the present invention;

Figure la is a partially exploded perspective view of the system of Figure 1;

Figures lb, lc, and Id are top, side, and front views of the system of Figure 1 ;

Figure 2 is an enlarged, partially cutaway perspective view of the sprayer head forming part of the automated painting system of Figure 1; Figure 2a is a partially exploded view of a first motive device for moving the sprayer head;

Figure 2b is a partially exploded view of the sprayer head of Figure 2;

Figure 2c is a partially exploded view of the sprayer head of Figure 2; Figure 3 is an enlarged view of the sprayer head mounted in a hood;

Figure 4 is an enlarged view of the sprayer head of Figure 3 from a different perspective, also showing one example of a cutting device; Figure 5 is an enlarged, partially cutaway perspective view of the sprayer head forming part of the automated painting system of Figure 1;

Figure 6 is an enlarged, partially cutaway perspective view of the sprayer head forming part of the automated painting system of Figure 1; Figures 7a-7e are screen shots showing examples of possible graphical user interfaces that may be used on the computer or controller used to receive the instructions for controlling the painting operation;

Figure 8 is a schematic view showing the location of first and second reference points or dimples on a planar workpiece, such as a sign; Figure 9 is a perspective view of a second embodiment of an automated painting system including first and second gantries;

Figure 10 shows the painting system of Figure 9 including a plurality of lights for illuminating one or more workpieces to facilitate locating and removing the cut portions of a mask; Figure 11 illustrates a method of multi-pass painting; and

Figures 12 and 13 illustrate moving the painting device or sprayer head in a pattern that extends beyond the boundaries of the workpiece to compensate for initialization, acceleration, and deceleration problems.

Detailed Description of the Invention In one aspect, the present invention provides a computer numerically controlled (CNC) painting system 10 for painting a workpiece (not shown, but see Figure 10), such as a flexible or rigid, embossed or non-embossed, planar or semi- planar sign substrate. In a presently preferred embodiment, as depicted in Figures 1 and 2, the CNC painting system 10 comprises: (1) a gantry-style robot, including a sprayer head 12 including: (a) at least one, and preferably a plurality of spray nozzles 12a; and (b) a movable gantry 14; and (2) a workpiece support structure 16. As will be outlined further in the description that follows, the robot in the illustrated embodiment includes a plurality of motive devices that are capable or moving the sprayer head 12 relative to the workpiece in up to six different axes.

The workpiece support structure 16 maybe substantially rectangular in shape, with at least one, and preferably a plurality of struts 18 for supporting a workpiece (not shown). The structure 16 may further include at least one ground- engaging member 20 and at least one support rail 22 for determining the angle at which the workpiece is maintained, which is typically vertical or 90 degrees from a horizontal plane (but note the optional angular positioning in Figures lb, 1 c, and 1 d). The details of the construction of one possible support structure 16 are shown in Figures la and lb The workpiece support structure 16 further includes at least one means or device for assisting in supporting a workpiece in substantial juxtaposition thereto such that it is positioned adjacent to the sprayer head 12. In the illustrated embodiment, the means or device comprises a vacuum or suction device, such as a plurality of suction cups 24 forming a bed, and a support strut 26. Each suction cup 24 is preferably slidably mounted to the adjacent support structure 16, and thus may be adjusted for affixation to an appropriate portion of the workpiece (preferably, a planar (non-embossed) portion, as is typically found along the periphery or border, to ensure that a secure bond is established). The use of a vacuum or suction device is preferred to the use of mechanical fasteners, such as clamps or the like, since it provides stable support for the workpiece without interfering with the painting operation. Moreover, the use of a vacuum or suction device comprised of plural components, such as suction cups 24, helps to prevent the unintended or accidental repositioning of the workpiece on the workpiece support structure 16 during a painting operation. The use of a grid or array of vacuum suction cups 24 that include check valves (not shown) that automatically activate upon contact with the side of the workpiece not being painted. Most preferably, the suction device is one that uses positive pressure air to create the desired suction, since drawing a consistent vacuum through multiple devices using a single source of negative pressure can be problematic. Instead of or in addition to suction cups 24, conventional clamps may also be used to secure the workpiece to the support structure 16 (although this is less preferred because of the potential interference created).

It should be appreciated that any of a number of known CNC controlled devices maybe employed to direct movement of the sprayer head 12 along at least two axes relative to the workpiece. However, as noted above, in a preferred embodiment of the invention, a gantry-style robot capable of moving in up to six axes is utilized. The gantry 14 forming a part of the robot is depicted in greater detail in Figure 2, and includes motive devices for moving the sprayer head 12 along at least an X-axis (aligned with a plane parallel to the face of the workpiece), a Y-axis (aligned with a plane perpendicular to the face of the workpiece), and a Z-axis (vertical) relative to the workpiece support structure 16. The gantry 14 includes a first motive device 28 for positioning the sprayer head 12 along a Z-axis. The gantry 14 further includes a second motive device 30 (which is actually comprised of two motive devices, one positioned on each longitudinal side of the support structure 16) for positioning the sprayer head 12 along an X-axis. Finally, the gantry 14 includes a third motive device 32 for positioning the sprayer head 12 along a Y-axis. Examples of these three motive devices 28, 30, and 32 are shown in greater detail in Figure 2a.

Specifically, in Figure 2a, the first motive device 28 for positioning the sprayer head 12 along the Z-axis is shown as including a drive mechanism comprised of a motor 28a for driving an endless belt 28b that in turn frictionally engages the periphery of each of a pair of pulleys 28c. The pulleys 28c are com ected to axles (not numbered), which are in turn carry pinion gears or wheels 28d (see Figure 2). When the motor 28a is thus actuated in either direction, the pinion gears 28d engage an adjacent rack M of the gantry 14 in a corresponding direction, and thereby move the sprayer head 12 to and fro along the Z-axis. A cover C is also provided to prevent outside structures for interfering with the operation of the drive mechanism.

Still referring to Figure 2a, movement along the Y-axis is effected by the third motive device 32, which includes a drive mechanism comprised of a linear actuator, such as a ballscrew assembly 33 including a motor 33 a. This ballscrew assembly 33 engages and moves a support arm 34 coupled to the sprayer head 12 toward and away from the support structure 16 and, hence, the workpiece. hi particular, a support arm 34 includes a pair of C-shaped receivers 34a or linear guide bearings that receive and engage corresponding linear guides or tracks 35a positioned on an adjacent support plate 35 (which in turn may include a channel portion 35b for slidably engaging a support structure extending along the Z-axis adjacent to the gantry 14). Hence, when the motor 33a forming a part of the ballscrew assembly 33 is actuated in either direction, the arm 34 is moved toward or away from the stable support structure 16 and thus the workpiece when positioned thereon.

In Figure 2a, it is also noted that a spring-biased pin 29 is shown for coupling the motive device 28 to the plate 35. The motive device 28 also includes channels 28e that engage corresponding tracks 35c on the plate 35. Using this arrangement allows for the motive device 28 to move along the tracks 35c to overcome the biasing force provided by the spring-loaded pin 29. This facilitates movement of the wheels 28d relative to the plate 35 for placement over the tracks 35a, as well as to keep them in engagement as the robot traverses the workpiece. The spring also provides a limited shock-absorbing function. Referring back to Figure 2, the second motive device 30 is shown as being similar in construction to the first motive device 28, with the pinion gears or wheels (not shown) being rotated by a motor 28. The wheels roll along a second rack or track member (not shown) to move the sprayer head 12 to and fro along the X-axis. A similar spring-loaded arrangement may be provided for facilitating the placement of the corresponding wheels (not shown) over the second track member. A second, substantially similar motive device 30 is also provided at the distal end of the gantry 14 (see Figure lb). As is well-known in the art, power for these motive devices may be supplied from a remote location by "e-chains" (not shown) with links that articulate as the sprayer head 12 or gantry 14 traverses along the X and/or Z-axes, respectively.

It will be appreciated that inclusion of these motive devices 28, 30, 32 allow the sprayer head 12 to be positioned at any desired location along the X and Z- axes relative to a workpiece supported on the support structure 16, as well as along a Y-axis to a desired distance away from the workpiece. Instead of the arrangements described above, movement of sprayer head 12 (supported by gantry 14) by first motive device 28, second motive device 30, and third motive device 32 may be effected by any known structures, such as roller wheels for frictionally engaging a track, slide members, belt drives, ballscrews, leadscrews, and the like. Similarly, the motion may be controlled by known devices such as servomotors, stepper motors, pneumatic devices, hydraulic devices, or the like. The means chosen will likely depend on the particular application in which the robot is used.

The sprayer head 12 may also be rotated along three additional axes to maximize its flexibility in performing the painting operation. To do so, the system includes a fourth motive device 36 for rotating the head up to 90 degrees, thereby facilitating the painting of portions of the workpiece oriented in parallel to the plane of the Y-axis (e.g., an embossed portion having a sidewall). A fifth motive device 38 is also provided for rotating the sprayer head up to 360 degrees, thereby allowing the angle of the spray nozzles 12a to be kept in a perpendicular orientation to the axis along which the paint is being applied. Advantageously, the added ranges of motion provided allow for the painting of, for example, an inner surface of an embossment on an embossed workpiece or a sidewall of the workpiece projecting in a plane parallel to the Y-axis. It will be appreciated that the system 10 of this invention therefore allows automated painting of both two-dimensional planar surfaces and three-dimensional embossed surfaces without necessitating manual reconfiguration or re-calibration.

The multiple- axis sprayer head 12 forming a part of the system 10 of this invention is depicted in greater detail in Figures 3-5. As noted above, the sprayer head 12 preferably includes a plurality of spray nozzles 12a for directing the flow of paint onto a workpiece. In such as embodiment, a sixth motive device 42 may be included, thereby allowing a selected one of the spray nozzles 12a to be aligned to a known "home" or zero position relative to the workpiece. As perhaps best shown in Figures 1 and 5, a protective hood 44 may also be provided to reduce introduction of dust or other debris into the sprayer head 12, as well as to assist in capturing any errant or reflected paint spray.

With reference to Figures 2b and 2c, the fourth, fifth, and sixth motive devices 36, 38, and 42 that may form apart of the system 10 for rotating the sprayer head 12 about different axes are illustrated in detail. In the bottom portion of Figure 2b, the fourth motive device 36 for rotating the sprayer head 12 along a 90 degree arc relative to the Y-axis and about the X-axis is shown as including drive mechanism. This drive mechanism includes a motor 36a having a shaft that is coupled to a first pulley 36c that drives an endless belt 36b. A second pulley 36c is coupled or fixed to one end of a pivot pin 36d that extends through a hinge structure 36e formed between a plate 37 for supporting the sprayer head 12 and a plate (not numbered) forming apart of the fifth motive device 38. Hence, when the motor 36a is activated, the entire sprayer head 12 is caused to pivot toward and away from the workpiece support structure 16 about the X-axis and along a 90 degree arc to allow for the painting of embossed (inwardly or outwardly projecting) portions of the workpiece. A cover C is also provided for covering the belt 36b and pulleys 36c to prevent outside interference. An adjustable belt tensioner (not numbered) may also be provided to ensure that the belt 36b is properly tensioned.

Moving now to the top portion of Figure 2b, the fifth motive device 38 includes drive mechanism having a motor 38 a. The shaft of the motor 38a carries or is coupled to a first pulley 38b that engages an endless belt 38c. The belt 38c passes through a pair of spaced bearings 38d (which provide tensioning) and is entrained over and frictionally engages the periphery of an adjacent pulley 38e. The pulley 38e is in turn coupled or locked onto the periphery of a support 38f that includes an upstanding cylindrical portion and a portion of the hinge 36e to which the plate 37 is pivotably coupled. Hence, when the motor 38a is actuated, the endless belt 38c moves to rotate the pulley 38e, which in turn rotates the support 38f. Since the support 38f is coupled to the plate 37 supporting the sprayer head 12 via hinge 36e, it rotates the sprayer head 12 about the Z-axis up to 360 degrees. A tubular bushing B is also provided over the support 38f, and is prevented from moving along the Z-axis by a plate 38g supporting the drive mechanism. The underside of this bushing B provides a bearing function for an inwardly projecting portion of the support arm 34. A cover C may also be provided for preventing interference with the components of the drive mechanism of the motive device 38. Figure 2c is an exploded view of the sprayer head 12, including the nozzles 12a, and also illustrates one possible embodiment of a sixth motive device 42. This motive device 42 includes a drive mechanism having a motor 42a, the shaft of which projects through an aperture in plate 37 into engagement with a pulley 42b. An endless belt 42c is entrained over and frictionally engages the outer surface of this drive pulley 42b, as well as a second, adjacent driven pulley 42d. A cylindrical portion 37a projecting from the plate 37 provides a bearing surface for the pulley 42d, which is coupled to a structure 42e for supporting the nozzles 12a. Means for locking the support structure 42e to the projecting portion 37a is also provided, including a locking ring 42ft Hence, when the motor 42a is actuated, the spray nozzles 12a are caused to rotate about the centerline axis of the projecting portion 37a, which is generally parallel to the Z-axis when the sprayer head 12 is in the nominal position, as shown in Figures 1 , 2 and 3. Channels (not numbered) may also be provided in the support structure 42e that engage camming structures, such as pegs (not shown). These structures serve to define the maximum arc through which the sprayer head 12 may rotate about the Z-axis. A cover C having an aperture for allowing the support structure 42e to pass may also be provided.

It is further noted from Figure 2c that each spray nozzle 12a is pivotably supported by a finger 41 coupled to the support structure 42e. The end of each spray nozzle 12a opposite the nozzle portion includes a male receiver 40 for receiving a hose or tube (not shown) that supplies paint under pressure to the nozzle 12a. An adjustable thumb screw 40a allows for fine-tuning the positions of the nozzles 12a relative to the Z-axis.

Each hose may be coupled to a single paint source, or alternatively to a multiple position, solenoid operated valve V. The valve V is in turn coupled to multiple paint sources (not shown). As a result, color changes can be made by completing a nozzle cleaning operation (preferably automatic) using a cleaning fluid and then changing the position of the valve. For example, by providing a certain arrangement of valves, the system 10 maybe set-up such that any paint in remaining in a feed line upstream of a certain point is forced back to a holding tank (which is depressurized) for reuse, while the paint remaining in a downstream portion of the feed line is forced out of the corresponding nozzle to a disposal tank using the cleaning fluid (air, solvents, and most preferably, a combination thereof). Both operations may be computer controlled. The system 10 is also capable of determining the positioning of the workpiece and for calibrating the painting device to the position of the workpiece. In one embodiment, the determination is made in a non-contacting fashion using a light source in the form of a laser pointed generating a laser L, (see Figure 6) oriented so that it is aimed exactly along the axis of rotation of the fifth motive device 38 (i.e., perpendicular to the plane of the workpiece). An optional second laser L₂ emanating from a second light (laser) source may be located substantially adjacent to the first laser (not shown), but is oriented such that it projects at a 45 degree angle. The first and second lasers L_l3 L₂ maybe calibrated such that the intersection of the two light beams represents the desired distance of the sprayer head 12 from a particular workpiece. Accordingly, when the sprayer head is positioned too near or too far from the workpiece, two light points are visible, instead of one. Use of this feature is considered optional.

As perhaps best shown in Figures 2b and 4, the sprayer head 12 also includes a cutting assembly 50. The cutting assembly 50 may include a a cutter element 52 carried on or in a support 51. The cutter element 52 is preferably adjusted for positioning at a nominal elevation such that it makes contact with an upper surface of the workpiece when the sprayer head 12 is moved to a certain location along the Z-axis. This contact allows the cutter element to cut a structure on the surface of the workpiece, such as a previously applied masking (grip mask). The cutter element 52 is preferably spring-biased toward the workpiece (note springs 53 in Figure 4) to ensure that the correct amount of cutting force is evenly applied to remove the masking, without damaging the workpiece.

Any of a number of computer devices suitable for controlling CNC machines may be adapted to control the system 10 of this invention. In a presently preferred embodiment, a dual control arrangement is utilized wherein the predetermined job to be performed is input in a controller, which may comprise a centralized controller for receiving the input and a machine-side controller for controlling the painting operation (see Figure 1, which identified both by the same block labeled 70). Specifically, the machine-side controller may be a computer programmed to control such device-specific tasks as completion of the painting, cutting any mask (see below), the automated changing of paint colors, cleaning of spray nozzles and paint feeder lines (such as at a selected remote location relative to the support structure where the paint remaining in the lines and any cleaning fluid is collected for disposal), or others not specifically listed.

The centralized controller may also be a computer running software that either receives a digital job or develops instructions for a particular painting job and then provides these instructions to the machine controller on the basis of a series of questions which a user must answer (often referred to as a "wizard" by those of skill in the art). For example, the user is first asked to assign colors to particular spray nozzles 12a (which may require the proper mechanical hook-up to one or more remote paint sources using multiple position valves, as previously mentioned), which may be done using a graphical user interface like the one shown in Figure 7a. The software interface may also prompt the user to indicate whether to cut a pre-applied mask, such as using the cutting assembly 50, may prompt the user for information such as the knife feed rate (see Figure 7b) and may instruct the user to peel the mask once the cutting is complete (see Figure 7d). The user may also be prompted for more specific information regarding the painting operation, such as: (1) the number of coats of paint to be applied for specific categories of color (e.g., for white, for light colors, and for dark colors, see Figures 7a and 7b); (2) the number of passes to be made; (3) the stroke width and length; (4) the paint feed and supply rates (which may change depending on the portion of the workpiece being painted); and (5) the particular spray head assigned to each color. Using the interface described above, the user may also be shown a graphical "wire frame" representation of the workpiece on which the colors to be painted are represented (and may be inputted by the user to form the data or job file used in controlling the painting operation). As should be appreciated, this allows the user to dictate certain aspects of the painting operation in an intuitive manner, such as: (1) the selection and placement of a geometric shape for painting (including an alphanumeric character); and (2) the selection of a pamtmg pattern. As an example, after the color and the number of coats are selected, a shape may be outlined by the user, and then an indication as to whether it is to be painted solid (island fill) or painted in a hatch pattern may be made (or "shape" data in a vector-based file format may be provided). Then, the controller 70 may generate a screen visualizing the object to be painted and the selection of colors chosen (see, e.g. Figure 7c). The user may then select a particular pattern on the overall design being painted, assign a color, and if necessary assign an emboss depth to ensure accurate painting of all surfaces of an embossed workpiece regardless of location (Figure 7c). An aspect of the controller 70 of the present invention is the use of a

"tree view" feature in a graphical user display, which is advantageous for assisting in laying out the colors to be applied to different shapes on an adjacent wire frame, graphic representation of a sign. For example, Figure 7c shows the tree view 80 having a particular job 82 ("Sign #1") as a branch extending therefrom. Under this branch 82, a plurality of paint regions, shapes, or alphanumeric characters 84 may be identified by the user. A first sub-branch 86 from branch 82 is the particular color to be assigned to that region, which when highlighted or selected may provide a second or further sub-branch in the form of a pull down menu 88 providing a list of available color options. For example, "Paint Region 0," which may represent the letters in PAYROLL ADVANCE to be painted on the workpiece, may be assigned the color "forest" (green) on the menu 88, in which case a graphical representation of this selection is provided on the adjacent display. This allows the user to easily alter the colors of the particular regions to be painted (or to identify those where no paint is to be applied). To further enhance the ease of use, the headings under branch 82 may simply identify the different parts of the paint job (e.g., instead of "PaintRegion 0," the branch 84 could be called PAYROLL ADVANCE).

During operation, the machine-side portion of controller 70 automatically brings up painting jobs in the order assigned by the other side. The user inputs specific lists of paint colors to individual spray nozzles 12a, and assigns the order in which these multiple spray nozzles 12a are activated. The user may also control numerous functions of the paintmg system 10 using the machine-side controller, such as manual movement of sprayer head 12 to desired coordinates relative to aworkpiece, selection of a particular spray nozzle 12a, rotation of sprayer head 12 by the fifth motive device 38, purging paint lines and/or switching colors, cleaning spray nozzles 12a, controlling rate of paint and driving fluid (e.g., atomizer air) flow, and the like. In a presently preferred embodiment, the machine-side controller comprises a computer with an input device, such as a touch-screen interface. In the case where the mask is cut from the workpiece, the controller may also identify the areas of the mask that need to be removed to allow for painting. For example, as shown in Figure 7d, the controller is indicating on a graphical, wire frame representation of the workpiece that the highlighted portions of the mask 96 must be removed prior to painting. The controller may also prompt the user to request further input as to when the mask has been removed so that the painting operation may commence (see pop-up window requesting input in Figure 7d).

Another potentially advantageous feature of the controller is that it may display the status of the painting operation. For example, in Figure 7e, the paint job is graphically laid out on the left hand side of the display. On the right hand side, the headings representing the time required for knife cutting, the time required for spray painting each color, and the square footage to be covered are provided (which all may be determined or calculated by the controller).

Also disclosed is a manner of positioning the sprayer head 12 relative to a workpiece and the calibrating its relative location to allow for the computer controlled application of paint at desired locations, thereby allowing automated creation of even the most complex designs in a highly accurate manner with limited user input following the initial calibration and programming steps. The first step is to place coordinate markers representing at least two reference points at predetermined locations on the workpiece. In one example, at least a first and a second dimple 92, 94 are placed at predetermined locations, such as in opposite corners of a rectangular workpiece W (see Figure 8). The dimples 92, 94 may be formed by a variety of processes, such as by embossing them in the workpiece W during a vacuum forming fabrication process. By obtaining positional data regarding the location of one or both dimples 92, 94, it is then possible to determine any offset between the workpiece and the data in the digital job file containing the instructions inputted or created by the user. For example, the system may automatically move the laser L_j (such as by moving gantry 14) using a predefined computer software algorithm from a known home location (whichmaybe determined by providing sensors on both the gantry 14 and the support structure 16) to the location of a virtual representation of the dimple or marker relative to the physical machine provided in an inputted digital job file. The user then moves or jogs the laser L, along the X or Z-axes, respectively, as necessary to move it generally over the actual dimple or marker, such as dimple 92, in or on the corresponding face of the workpiece (such as by using a remote control, joystick, etc.). The user then indicates to the controller that the laser L, is positioned over the physical dimple or marker, such as by pressing a key on a keyboard or using a like input device, and the location is stored in memory (such as in the form of Cartesian Coordinates representing the location of the dimple along the X and Z axes).

The controller may then move the laser L, to the virtual representation of a second dimple, such as dimple 94, on the workpiece in the job file. As with the first dimple, the machine user jogs or moves the laser L, along the X and Z-axes, respectively, until it is over the second dimple in the workpiece and provides a corresponding signal to controller. Using the differences in the location between the virtual dimples and the physical dimples 92, 94, the controller 70 may then calculate various correction factors (such as offset amounts, values or ratios) by comparing the difference between the actual and expected location of the workpiece (offset) and any offset resulting from shrinkage and/or differences in the orientation of the physical workpiece resulting from rotation. For example, the controller may adjust (scale or shrink) the digital job file independently to match the ratio achieved by comparing the distance between X- coordinate of the first dimple 92 and the X-coordinate of the second dimple 94 with the distance between the X-coordinate of expected location of these dimples in the digital job file. Likewise, the controller may adjust the geometry of the job and scale (sl rink) the digital job file independently to match the ratio achieved through comparing the distance between Z-coordinate of the first dimple 92 to the second dimple 94 with the distance between the Z-coordinate of the expected location of these dimples. Using these correction factors, the controller may adjust the digital job file accordingly to ensure that the painting (and possibly cutting, see below) operations are carried out in a satisfactory manner. In the event that the workpiece does not have dimples or markers (such as a flexible sign, a vehicle (van) body, etc.), the controller may simply use the lower left and upper right limits (edges or corners) of the sign to determine the offset location and rotation of the physical sign and adjust the digital job file accordingly. A similar operation may also be used to determine the offset between the physical location of the workpiece and the known home position (but only the data (e.g., X and Z coordinates) from a single dimple needs to be stored for making this determination).

Another option is for the controller to create a right triangle from the acquired Cartesian coordinates of the first and second dimples. Once acquired, this right triangle is compared to a theoretical right triangle provided in a preprogrammed instructions, such as a digital job corresponding to the painting job being completed. The theoretical right triangle contained in the preprogrammed digital j ob is oriented substantially in parallel to the Cartesian X and Z axis created by the computer controller. The controller then rotates the theoretical right triangle contained in the pre-programmed digital job to align its 90 degree angle to that of the acquired right triangle (which is developed from the acquired Cartesian coordinates of the dimples on the workpiece) . The computer controller also compares the Cartesian coordinates of the two non-90 degree vertices of the theoretical and acquired right triangles.

Based on the differences in the coordinates, the correction factors are then calculated.

This invention further provides a method of painting a workpiece such as a sign utilizing the painting system 10. The method of this invention is suitable for automated painting of either a flat, substantially two-dimensional surface or an embossed surface providing a three-dimensional area. In one embodiment of the method of this invention, the first step comprises calibration of the painting system 10 as described above. Then, for more complex designs, a masking (e.g., grip mask) or removable coating maybe applied to the entire surface of the workpiece, such as through a first spray nozzle 12a. Any suitable masking substance capable of spraying, but easily removable from the surface of the workpiece, may be used. Alternatively, the masking may be pre-applied to the workpiece, either automatically or manually, including as part of the workpiece fabrication process. The desired pattern to be painted on the workpiece is then cut into the masking or coating using the cutter element of cutter assembly 50, in accordance with the commands of the preprogrammed digital job.

Next, portions of the pre-cut masking coating covering the area of the workpiece to be painted are removed. This may be accomplished manually, or by any suitable automated system. The desired color is then applied through a selected spray nozzle 12a. This process is repeated until the desired design has been painted onto the workpiece. In a preferred embodiment of painting a multi-colored design on a workpiece, the order of application is from darkest colors to lightest colors, with the final application being white for purposes of contrast. However, any desired order of color application may be programmed. As noted above, the multiple axes of rotation of which the sprayer head 12 is capable of painting of both flat, planar surfaces of the workpiece in two dimensions (X and Z-axes) and of embossed surfaces in three dimensions (X, Y, and Z-axes).

It should be appreciated that the method and system of this invention may be adapted for paintmg standard, flat workpieces, which will either remain flat or be embossed at a later time. The method of painting a flat workpiece requires controlling the paint and the pressure or flow rate of a driving fluid (pressurized air) as well as the distance of the selected spray nozzle 12a from the workpiece to maximize the pattern of the paint applied to a particular design. As noted, the painting system 10 of this invention is well-suited to this application. The particular pressure or flow required depends on a host of factors, including the type of paint, the texture of the workpiece, the distance between the nozzle 12a and the surface to be painted, the temperature, the humidity, etc.

For workpieces to be painted and then embossed, such as by using a vacuum molding machine with a die having the desired emboss, it is known that the embossing process results in distortion of the face of the workpiece. It is possible to estimate the extent of distortion of the workpiece during embossing, and to program the controller to automatically compensate for this distortion in the digital job file. When the workpiece is embossed, then painted, this may also be done by placing a reference point or marker on the workpiece, such as a dimple, the location of which will change as a result of the embossment (note embossed region R and reference point or dimple 92' in Figure 8). An expected location of the dimple or marker may be stored or programmed in the job file and the user may position a laser associated with the sprayer head 12 (or a cutting device, see below) over the actual location of the dimple on the embossed workpiece. The user may then instruct the software- driven controller to store this location, and it may then calculate the offset and apply it to the job file to correct for any distortion present.

Another embodiment of the painting system 110 is shown in Figure 9. This embodiment includes a workpiece support 116, a first gantry 114a for supporting and positioning a sprayer head 112 capable of moving along at least three axes (namely, the X, Y and Z axes as represented therein) and preferably six axes. A second gantry 114b, which may be substantially identical to gantry 114a, is provided for supporting a separate cutter assembly 150 used for cutting masking from the workpiece. The two gantries 114a, 114b move independently of each other and, as a result of being positioned in two different planes parallel to the X-axis, are capable of passing one another. The cutter assembly 150 includes a cutting element 152 at the distal end adapted for cutting a mask or the like applied to the adjacent surface of the workpiece (not shown). As with the gantry 114a supporting the sprayer head 112, the second gantry 114b includes motive devices (not shown) that may be similar to identical to motive devices 28, 30, 32 for moving and positioning the cutting assembly 150 in three different axes. The second gantry 114b may also support a sensor that corresponds to a sensor on the support structure 116 for defining a home position. Preferably, the second gantry 114b also supports the device that generates the laser L₍ used during calibration, as described above, and the location of the first gantry 114a relative to the second gantry 114b maybe determined by comparing the known distances from the same homing sensor. Both the first and second gantries 114a, 114b may also support cutter assemblies or cutting devices for cutting a mask applied to a surface of one or more workpieces. It should be appreciated from Figure 9 that, in this embodiment, the workpiece support 116 and the gantries 114a, 114b are generally vertically oriented (i.e., perpendicular to a horizontal plane). As described above, the workpiece support 116 may include a plurality of vertically-extending cross-members 118, which may support means, devices, or structures (such as the suction cups 24 of the first embodiment, not shown in Figure 9) for supporting the workpiece in a vertical orientation.

In accordance with another aspect of the invention, means for illuminating the workpiece may be provided for assisting a worker in locating and removing any masking applied thereto. Figure 10 shows the painting system 101 of Figure 9 with the dual gantries 114a, 114b contained in an optional painting booth 200 having exhaust vents 202. A plurality of lights 204 forming banks 206 are provided for illuminating one or more workpieces supported by the support structure 116 (which is shown including the suction cups 24 along the vertical members or struts 118 for engaging the non-painted surface of the workpiece). These lights 204 are used to selectively illuminate a workpiece or portions of the workpiece on which a cutting operation has been performed. This illumination not only helps a worker K to locate the proper workpiece requiring attention, but also makes it easier to locate the cut edges of and remove any masking present (note illuminated bank 206 in Figure 10 and the enhanced visibility of the cut portions of mask represented by the outline of the letters DEF in workpiece W₂). Preferably, the illumination is automatically controlled by the controller 70 such that, after cutting of the mask is completed, such as by using the cutting assembly 150 associated with gantry 114b, the corresponding lights 204 in a bank 206 are illuminated to direct the worker W to the proper location. The lights 204 may be located between the struts 118 as shown in Figure 10, but could also be formed integrally therewith (e.g., partially transparent struts with integral lights).

Instead of a cutting assembly 150, the second gantry 114b could also be positioned in the same plane as the first gantry 114a, provided with a second sprayer head 13, and used to paint one workpiece (W₃ in Figure 10) supported by the support structure 116 while the sprayer head 12 associated with the first gantry 114a is used to paint a different workpiece (W_[ in Figure 10). h this arrangement, multiple homing sensors would be provided for defining different home positions for the two gantries 114a, 114b. Optional stops could also be provided along the tracks or linear guides extending along the X-axis to prevent collisions. The gantries 114a, 114b could also be positioned such that when one is parked, the other may still paint multiple signs without creating any interference. A third gantry (not shown) in the same plane could also be provided using this same concept. Moreover, a third gantry for supporting a cutting device and light source (such as laser pointer) could also be positioned in a different plane (or a fourth gantry, when there is a third one supporting a third sprayer head). Note that, when at least two painting devices including gantries are used, as shown in Figure 10, the worker K is able to remove the mask on one workpiece W₂ while painting of the other two workpieces W,, W₂ is underway. A method of painting an object or workpiece, such as a sign is also disclosed herein. As background, when painting an opaque object, such as a piece of metal, minor differences in the thickness of the layers applied are insignificant. However, in the case where a workpiece is a translucent or transparent object, such as a sign later placed adjacent to an illumination source, variations in the thickness of the paint applied may create dark and light regions that detract from the overall appearance (and in severe cases, may also render the sign unsuitable for commercial use), h the past, workers have manually applied multiple coats of paint in a painstakingly slow manner to ensure that the application is even and level in all areas. However, this is of course an expensive, time consuming undertaking. The method disclosed herein overcomes these problems by using an automated sprayer to make multiple passes over the corresponding surface of the workpiece to be painted in an offsetting fashion to ensure that the application of paint is substantially even. For example, as shown in Figure 11, if the distance between horizontal passes of the sprayer head 12 is ten inches (see representative distance D), and four coats of paint are to be applied, the first pass for the first coat C_j travels at zero on the Z-axis, the second pass is at ten inches, the next at twenty, etc. Then, during application of the second coat C₂, the first pass is at 2.5 inches, the second at 12.5 inches, the third at 22.5 inches, etc. (which is essentially done by dividing the distance between passes by the number of coats and adding it to the nominal pass distance). The third coat C₃ is at 5 inches, 15 inches, and 25 inches, etc., and the fourth coat (not shown) is at 7.5 inches, 17.5 inches, 27.5 inches, etc. The same technique may also be used in painting two different colors on the sign, as represented by the letters ABC in Figure 11. Using this method advantageously results in an even application of paint to the corresponding surface of the workpiece.

As can be readily appreciated, automated painting is also complicated by the fact that the acceleration and deceleration of the automated sprayer (in this case, gantry 14 or 114 and sprayer head 12) as it traverses to and fro relative to the workpiece W. Moreover, when a painting operation is initiated, the paint first provided to the corresponding nozzle 12a on the sprayer head 12 may be admixed with air, solvents, or dried paint and is not well-suited for application to the workpiece. Thus, it is desirable to paint in an overpass pattern P as shown in Figures 11 - 13 in which the travel path of the sprayer head 12 (as represented by dash-dot lines in Figure 12 and solid lines in Figure 13) begins away from the workpiece W and generally extends a certain predetermined distance beyond the side, top, and bottom edges of the workpiece. Doing so also helps to ensure that the gantry 14, 144 or other device carrying the sprayer head 12 has sufficient distance to accelerate as it approaches the leading edge of the workpiece W, decelerate as it passes the opposite edge, and then reaccelerate for the next pass. The acceleration and deceleration zones are represented by the shaded portions of the path P in Figure 13.

The foregoing description of several aspects of the invention have been presented for purposes of illustration and description. The embodiments described are not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. For example, while the workpiece is shown as a sign for purposes of the preferred embodiment, it should be appreciated that the workpiece may comprise any structure requiring painting (although structures having substantially planar surfaces, with or without embossments, are preferred). Also, stops, such as upstanding pegs or an L-shaped channel, may also be strategically positioned at the ends of the support structure 16 to limit the motion of the robot as it traverses relative to the workpiece (see, e.g., Figure la and note X-axis stop 19). While a workpiece in the form of a rigid sign is contemplated, it should be appreciated that the workpiece could be at least partially flexible, and could even be an awning, banner, or the like. Moreover, the workpiece could be the a vehicle, such as a delivery van. Examples of source code for use with the present system form part of the provisional application and are part of a U.S. Copyright Registration Application for the work "Full-viMotion" listing the present inventor as the claimant. Any software used with the controller(s) may also be stored on a removable, computer-readable medium, such as a disk. The embodiments described were chosen to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention when interpreted in accordance with the breadth to which it is fairly, legally, and equitably entitled.

Claims

In the Claims:

1. A system for painting a workpiece, such as a sign, comprising: a painting device including a paint supply head having a plurality of nozzles, each associated with a different color of paint; a first motive device for moving the painting device about or along at least a first axis; a second motive device for moving the painting device about or along a second axis generally perpendicular to the first axis; and a stable structure for supporting the workpiece relative to the painting device; wherein a first nozzle on the paint supply head applies a first color of paint to selected portions of the workpiece during a first pass and a second nozzle applies a second color of paint to selected portions during a second pass.

2. The painting system of claim 1, wherein the plurality of motive devices further comprise: a third motive device for moving the paint supply head along a third axis perpendicular to the plane of the workpiece.

3. The painting system of claim 2, wherein the plurality of motive devices further comprise: a fourth motive device for rotating the paint supply head about said first axis; a fifth motive device for rotating the paint supply head about said second axis; a sixth motive device for rotating the paint supply head about said third axis.

4. The painting system of claim 1, wherein the painting device includes a first gantry for supporting the paint supply head adjacent to the stable support structure, wherein the first and second motive devices move both the spray head and the gantry along the first and second axes.

5. The painting system of claim 4, further including a second gantry for supporting a cutting device for cutting a mask applied to the workpiece.

6. The painting system of claim 1, wherein the workpiece includes a mask, and the paintmg device includes a cutter mechanism for cutting the mask to expose selected portions of the workpiece for painting.

7. The painting system of claim 6, wherein the mask is applied to the workpiece by at least one spray nozzle of the paint supply head.

8. The painting system of claim 1, further including a device for assisting in calibrating the position of the painting device relative to the workpiece, said calibration device comprising at least one light source that generates and directs a light beam toward the workpiece.

9. The painting system of claim 9, wherein the light source is a laser pointer.

10. The painting system of claim 1, further including a controller for automatically controlling the movement and operation of the painting device based on instructions previously provided by a user.

11. The painting system of claim 10, wherein the workpiece includes at least two reference points at predetermined locations and the controller is capable of acquiring data regarding the locations of said reference points and then determining whether a corresponding adjustment to the instructions provided by the user is necessary to ensure that the workpiece is painted in the desired fashion.

12. The painting system of claim 10, wherein the controller includes a computer programmed to prompt the user for information or instructions used to create a digital job representative of the movement and operation of the painting device.

13. The painting system of claim 1 , wherein the stable support structure includes at least one vacuum or suction device for holding the workpiece in place during the pamtmg operation.

14. The system according to claim 1 , wherein the stable structure supports the workpiece in a generally vertical orientation.

15. A system for intended use in cutting a mask or coating applied to at least one surface of a workpiece, comprising: a stable structure for supporting the workpiece; a cutting device positioned adjacent to the stable structure; a first motive device for moving the cutting device about or along at least a first axis; a second motive device for moving the cutting device about or along a second axis generally perpendicular to the first axis; and a controller for controlling the first and second motive devices to move the cutting device about the surface of the sign to cut the mask in accordance with a predetermined pattern.

16. The system according to claim 15, wherein the cutting device includes a gantry supported by the stable structure, wherein the first and second motive devices move both the gantry and the cutting device.

17. The system according to claim 15 , wherein the cutting device includes a spring-loaded cutter element.

18. The system according to claim 15, further including a light source mounted to the cutting device.

19. A system for intended use in cutting a mask or coating applied to at least one surface of a workpiece, comprising: a stable structure for supporting the workpiece; a cutting device positioned adjacent to the stable structure for selectively cutting the mask on the workpiece; and a light source mounted to the cutting device for directing light towards the workpiece, whereby the light source may be used to visually indicate the position of the cutting device relative to the workpiece.

20. The system according to claim 19, wherein the light source is a laser pointer and further including a controller for controlling first and second motive devices for moving the cutting device along at least two axes for cutting the mask on the workpiece.

21. The system according to claim 20, wherein the workpiece includes a reference point, the controller is programmed with coordinates to initially position the cutting device over an expected location of the reference point on the workpiece, and further including an input device associated with the controller for manually controlling the movement of the cutting device, wherein a user may move the light source on the cutting device over the reference point and generate a signal to the controller for noting an actual position of the reference point and calculating an offset amount.

22. A system for intended use in cutting a mask or coating applied to at least one surface of a workpiece, comprising: a stable structure for supporting the workpiece; a cutting device positioned adjacent to the stable structure for selectively cutting the mask on the workpiece; and a light source for directing light towards the workpiece, whereby the light source may be used to visually indicate the portions of the mask cut by the cutting device.

23. The system according to claim 22, further including a painting device positioned adjacent to the stable structure for painting the regions underlying the cut mask once removed.

24. A system for painting a workpiece, such as a sign, comprising: a movable painting device including a paint supply head; and a stable structure for supporting the workpiece relative to the painting device, said structure including at least one suction device.

25. The system according to claim 24, wherein the suction device includes a plurality of suction cups.

26. The system according to claim 25, wherein the suction cups are positioned on vertically extending struts or members forming part of the stable structure.

27. The system according to claim 25, wherein the suction cups include check valves that open when contact is made with the workpiece.

28. A system for cutting a mask or coating applied to one surface of a workpiece, comprising: a movable cutting device for cutting the mask on the workpiece; and a stable structure for supporting the workpiece relative to the cutting device, said structure including at least one suction device for supporting the workpiece therefrom.

29. The system according to claim 28, wherein the suction device includes a plurality of suction cups positioned on vertically extending struts or members forming part of the stable structure, each suction cup including a check valve that opens when contact is made with the workpiece.

30. A system for intended use in cutting a mask or coating applied to at least one surface of a workpiece, comprising: a stable structure for supporting the workpiece; and a movable cutting device positioned adjacent to the stable structure, the cutting device including a spring-loaded cutting element biased towards the workpiece for automatically providing the correct amount of cutting pressure for cutting the mask.

31. A system forpainting aworkpiece having an embossed portion having a sidewall, such as a sign, comprising: a painting device including a paint supply head having at least one nozzle positioned generally perpendicular to the workpiece; and a first motive device for rotating the nozzle through an arc of up to 90° for painting the sidewall.

32. A system for painting a sign having a grip mask applied thereto, comprising: means for cutting the grip mask for removal; means for automatically painting the portions of a corresponding surface of the sign exposed when some or all of the portions of the grip mask cut by the cutting means are removed.

33. The system of claim 32, wherein the automatic paintmg means include at least one paint source coupled to a spray nozzle by at least one supply line and the system further includes means for returning at le'ast some of the paint in the supply line to the paint source.

34. A painting system, comprising: a workpiece; a painting device including a paint supply head; a first motive device for moving the painting device about or along at least a first axis; a second motive device for moving the painting device about or along a second axis generally perpendicular to the first axis; a stable structure for supporting the workpiece relative to the painting device; and a controller for automatically controlling the movement and operation of the painting device based on instructions previously provided by a user; wherein the workpiece includes at least two reference points at predetermined locations and the controller is capable of storing data regarding the locations of the reference points and determining whether a corresponding adjustment to the instructions provided by the user is necessary to ensure that the workpiece is painted in the desired fashion.

35. A method of compensating for variations in the position or size of a workpiece in an automated painting or cutting operation performed based on a series of pre-programmed instructions or information provided by a user, comprising: storing the location of a first reference point on the workpiece; comparing the location of the first reference point on the workpiece with an expected location provided in the pre-programmed instructions and determining an offset value; and applying the offset value to the pre-programmed instructions to modify the painting or cutting operation accordingly.

36. The method according to claim 35, further including the step of locating the first reference point by directing a laser at the first reference point and the storing step includes recording the location of the laser in X and Y-coordinates.

37. The method according to claim 36, wherein the comparing step comprises comparing at least the X-coordinate of the first reference point location with the X-coordinate of the expected reference point location to determine the offset value.

38. The method according to claim 37, further including the steps of: storing the location of a second reference point on the workpiece; calculating the parameters of a right triangle from the stored locations of the first and second reference points; comparing the calculated right triangle to a theoretical right triangle in the pre-programmed instructions; calculating a size correction factor, an orientation correction factor, or both based on the difference in size or orientation of the calculated and theoretical triangles; and applying one or both of the calculated correction factors to the instructions or information provided by the user to modify the painting or cutting operation accordingly.

39. A method of compensating for variations in the position or size of a workpiece in an automated painting or cutting operation performed based on a series of pre-programmed instructions or information provided by a user, comprising: storing the location of a first reference point on the workpiece; storing the location of a second reference point on the workpiece; calculating the parameters of a right triangle from the stored locations of the first and second reference points; comparing the calculated right triangle to the theoretical right triangle parameters in the pre-programmed instructions or information; calculating a size correction factor, an orientation correction factor, or both based on the difference in size or orientation of the calculated and theoretical triangles; and applying one or both of the calculated correction factors to the instructions or information provided by the user to modify the painting or cutting operation accordingly.

40. A method of operating on two workpieces simultaneously, comprising: providing a first painting device adjacent to a stable structure for painting a first workpiece supported thereon; and providing a second device for cutting or painting a second workpiece supported on the same stable structure as the first workpiece.

41. A method of operating on two workpieces simultaneously, comprising: cutting a mask or coating on a first workpiece supported on a stable support structure; and cutting a mask or coating on a second workpiece supported on the stable support structure while at least a portion of the cut mask or coating is removed from the first workpiece.

42. The method according to claim 41, further including the step of painting any areas on the first workpiece where the masking is removed.

43. The method according to claim 42, further including the step of removing only a portion of the masking corresponding to a color of paint to be applied during the painting step.

44. A method of operating on a workpiece, comprising cutting at least a portion of a mask or coating on the workpiece supported on a stable support structure; and illuminating at least a portion of the workpiece to facilitate locating and removing the cut portion of the mask.

45. The method according to claim 44, wherein the illuminating step comprises turning on a plurality of lights positioned adjacent to the stable support structure.

46. A method of operating on a workpiece, comprising cutting at least a portion of a mask or coating on the workpiece supported by a stable support structure using a computer-controlled cutting device; and using the computer to automatically illuminate one or more lights positioned adjacent to the workpiece to facilitate locating and removing the cut portion of the mask.

47. A method of operating on a workpiece, comprising cutting at least a portion of a mask or coating on a first workpiece selected from a plurality of workpieces supported by a stable support structure; and illuminating the first workpiece only to facilitate locating and removing the cut portion of the mask.

48. A method of painting, comprising the steps of: providing a mask on at least one surface of a workpiece; and using a controller to move a spring-loaded cutting device over the mask in accordance with a set of pre-programmed instructions to cut the mask.

49. A method of evenly painting a workpiece, such as a sign, using an automated painting device, comprising: applying a first coat of a first color of paint to the sign during a plurality of first passes; applying a second coat of the first color of paint to the sign during a second plurality of passes; and wherein each second pass is offset from the corresponding first pass by a predetermined distance.

50. The method of claim 49, wherein the predetermined distance is calculated by dividing a distance between each pass by a number of coats to be applied to the workpiece.

51. A method of evenly painting a workpiece, such as a sign, using an automated painting device, comprising: initiating the painting before the automated painting device is over the sign; and painting the sign using the automated painting device.

52. A method of evenly painting a workpiece, such as a sign, using an automated painting device, comprising: moving the automated painting device before the automated painting device is over the sign to reach a desired acceleration; and applying paint to the sign once the desired acceleration is reached.

53. The method according to claim 52, wherein the applying step is completed during a first pass and further including the steps of: decelerating the automated painting device once the first pass is made; moving the automated painting device at a desired acceleration before a second pass is made.

54. A method of painting a workpiece for later undergoing embossment, such as a sign, comprising the steps of: providing instructions to a controller regarding one or more areas of the workpiece to which paint is to be applied; providing an instruction regarding whether and the degree to which any of said one or more of said areas are to be embossed; and programming the controller to automatically adjust the size of the area to be painted at the embossment locations to compensate for distortion created during later embossing.

55. A method of painting according to a preprogrammed set of instructions, comprising the steps of: providing a workpiece in the form of a sign; providing a painting device including a paint supply head having one or more nozzles; and moving the paint supply head and/or the nozzles about or along any of at least six axes in accordance with the preprogrammed instructions while selectively providing paint to at least one of the nozzles to paint the sign.

56. A method of painting according to a preprogrammed set of instructions, comprising the steps of: providing a workpiece in the form of a sign; providing a painting device including a paint supply head having one or more nozzles; inputting the pre-programmed set of instructions to a controller; and using the controller to control the painting device.

57. A method of painting according to a set of instructions, comprising the steps of: providing a workpiece in the form of a sign; providing a painting device including a paint supply head having one or more nozzles; querying the user for instructions regarding a geometry of a shape to be painted on the workpiece and a color of the shape; creating the set of instructions; and using the controller to control the painting device in accordance with the set of instructions.

58. The method according to claim 57, further including querying the user for the location and depth or height of any embossments in the workpiece.

59. hi a computer system having a graphical user interface including a display, a method of providing a tree view on the display comprising the steps of: displaying a branch representing a location for selecting a region of a workpiece; and displaying a first sub-branch representing a location for selecting a color of paint for applying to the region displayed in the branch.

60. The system having a graphical user interface according to claim 59, further comprising the step of displaying a second sub-branch including a menu listing a plurality of colors for applying to the region.

61. In a computer system having a graphical user interface including a display and a user interface selection device, a method of identifying a region to be painted on a workpiece comprising the steps of: displaying a representation of the workpiece; displaying a tree view including a branch representing a location for selecting a region of a workpiece for undergoing painting and a sub-branch representing a location for selecting a color for applying to the region displayed in the branch.

62. A computer-readable medium having computer-executable instructions for performing steps comprising: storing instructions for performing an automated painting or cutting operation on a workpiece, including an expected location of a first reference point; receiving an actual location the first reference point; comparing the actual location with the expected location and determining an offset value; and applying the offset value to the set of instructions.

63. A computer-readable medium having computer-executable instructions for performing steps comprising: storing instructions for performing an automated operation on a workpiece including a theoretical right triangle; receiving an actual location of first and second reference points on the workpiece; calculating the parameters of the right triangle from the actual locations of the first and second reference points; comparing the calculated right triangle to the theoretical right triangle; calculating a size correction factor, an orientation correction factor, or both based on the difference in size or location of the calculated and theoretical triangles; and applying one or both of the calculated correction factors to the instructions to modify the operation accordingly.