Patent Application
20140220249
The present disclosure concerns systems and methods for automatic spray coating of workpieces, and in particular robotically applied sprayed coatings of automotive workpieces such as partially assembled automobiles.
Sprayed coatings applied to partially assembled automobiles during manufacturing can include primer coats, base coats and clear coats. Such coats can be applied with different coating dispensers, such as various known types of air-powered sprayers. Different types of paint or coating dispensers can be implemented during the manufacturing process of a particular workpiece. For example, an air-powered spray gun can be used on interior surfaces of a workpiece such as the internal surfaces of trunks and engine compartments and the portions of car doors, engine hoods and trunk lids that interface with the car frame. Such surfaces can have more intricate shapes and can be more difficult to access with a sprayer than, for example, the exterior surface of the finished automobile. Coverage of these surfaces typically requires air-powered spray guns, which are able to achieve good coverage. However, air-powered spray guns result in greater coating consumption per unit area covered and also higher levels of coating overspray than other forms of sprayers. Excessive overspray from conventional air-powered sprayers can therefore require greater movement of temperature-regulated air through the booth to evacuate the over-sprayed coating present in the booth.
In contrast with the intricate shapes found on such internal surfaces, exterior surfaces such as the external surfaces of the passenger doors, car hood and trunk lid are commonly easier to access by sprayers. As such exterior surfaces can be satisfactorily coated with more efficient dispenser types, such as more efficient atomizers, which consume less coating per unit area on which coating is applied and have significantly less overspray than conventional air-powered sprayers.
In coating processes utilizing different coating dispensers, the finish characteristics, the amount of overspray and the amount of air consumption required during the coating process will differ depending on the type of dispenser used. Under certain circumstances, utilizing different dispenser types requires having separate spray areas, whether these areas are separated by sufficient distance on an assembly line or involve separate booths segregated by curtains or doors. Whichever coating dispenser technology or technologies are used, implementing separate spraying zones for different coating processes increases the overall resources required to implement the coating processes relative to implementing a coating process within a single, compact booth.
A system and method is disclosed including a coating booth and coating dispensing robots. The robots are mounted relative to the booth such that the robots' coating dispensers are operably disposed within the booth. The robots are in communication with at least one controller, which include computer readable instructions written on a computer memory that upon execution move one of the robots and dispenses coating on one or more of at least a portion of an engine compartment, trunk and internal surfaces of a bed of an automotive workpiece during a first time interval. The controller also moves the second robot over a second set of coordinates and causes the robot to dispense coating on one or more of at least a portion of an exterior surface of fenders and passenger doors of the workpiece over the first time interval.
The controller also moves the first robot over a third set of coordinates and causes the first robot to dispense coating on one or more of at least a portion of an exterior surface of a hood, roof, trunk lid and lift gate over a second time interval. The controller also moves the second robot over a fourth set of coordinates and causes the robot to dispense coating on one or more of at least a portion of the side door interiors over the second time interval.
In the accompanying drawings, structures and methods are illustrated that, together with the detailed description provided below, describe aspects of a system and method for interlaced coating application. It will be noted that a single component may be designed as multiple components or that multiple components may be designed as a single component.
Further, in the accompanying drawings and description that follow, like parts are indicated throughout the drawings and written description with the same reference numerals, respectively. The figures are not drawn to scale and the proportions of certain parts have been exaggerated for convenience of illustration.
The illustrated booth 102 has sufficient size to accept a single stationary workpiece 110. A booth having the minimum size sufficient to fit a single workpiece 110 minimizes the volume of air that must be moved through the booth per unit time to maintain optimum coating application conditions. Minimizing the size of the booth 102 can save resources such as energy spent heating and moving air through the booth 102 and the physical space required for installation of the booth 102, for example. However, such larger booths can also be implemented according to the present teachings, for example by having sufficient space to fit multiple workpieces, with or without additional coating dispensing robots 124 arranged similarly to those shown and described herein. According to one aspect of the present teachings, the housing is about 8 meters in length. According to yet other aspects, the housing length can range between about 6 and 10 meters in length. A booth having sufficient size to accept a single non-stationary workpiece 110 can also be implemented according to the present teachings. For example, by moving the workpiece 110 through the booth 102 during the coating process, coating can be applied within a window narrower than the length of the workpiece and still achieve complete coverage of the workpiece 110. For example, coating can be applied within a range of 3 to 4 meters, whereas the workpiece 110 can have a length greater than that range, for example 5 meters.
Coating dispensing robots 124a-d have bases 125a-d mounted adjacent to a right side wall 126 and left side wall 128 of the booth 102, respectively. The left and right sides of the booth 102 are separated by a central plane A extending along the length of the booth 102 from the entry door 106 and exit door 108 and vertically upward in a direction perpendicular to the floor of the booth 102. The central plane A is about equidistant from the side walls 126, 128 of the booth 102 and aligns with the central axis of the workpiece 110. The projection of central plane A on the floor of the booth 102 also defines a travel path of the workpiece 110 through the booth 102.
The robots 124a-d can be mounted in locations other than those illustrated. For example, one or more of the robots 124a-d can be mounted on the ceiling of the booth 102 or on tracks such that the robots 124a-d are moveable. According to one aspect of the present teachings, the coating dispensing robots 124a-d are equipped with coating dispensers 130 that are electrostatic rotational bell-type sprayers. According to another aspect of the present teachings, each of the coating dispensing robots 124a-d is equipped with the same type of coating dispensers 130, whether rotational bell-type sprayers, or other forms of sprayers. The robots 124a-d move the dispensers 130 within the booth 102 relative to the workpiece and can simultaneously apply coating to the workpiece 110 with the dispensers 130. The dispensers 130 are not limited to movement on the same side of the booth 102 on which their respective robots 124a-d are mounted, but rather can move across the central plane A to reach portions of the workpiece 110 on the side of A opposite to side on which their respective robots 124a-d are mounted. According to yet another aspect of the present teachings, a set of robots 124 mounted on one of the side walls 126, 128 may be implemented, for example where the vehicle size is small enough such that only a single pair of robots 124 is necessary, or where the vehicle is rotated such that opposing sides are coating in turn by a single pair of robots 124.
The robots 124a-d are each connected to a controller 136a-d via connection 137a-d, such as cabling capable of providing control signals and power to the robots 124a-d. The controllers 136a-d can include, for example, a central processing unit that executes computer-readable instructions stored on memory and a power supply for the individual robots and their corresponding dispensers 130. According to other aspects of the present teachings, the four illustrated robots 124a-d can be connected to a single controller that provides the functionality of the four individual controllers 136a-d illustrated in
As shown in
Opening and closing robots 174 are placed around the booth 102, allowing access of at least one of the robots 174 to the engine hood 112, passenger doors 122 and trunk lid 114. The opening and closing robots 174 open and close the engine hood 112, passenger doors 122 and trunk lid 114 at appropriate times during the application of coating on the workpiece 110. The opening and closing robots 174 can be controlled by dedicated controllers that can be put into communication with controllers 136 to synchronize the actions of the opening and closing robots 174 with the coating dispensing robots 124.
With reference to
As used herein, the term “internal surfaces” denotes surfaces of a workpiece that are typically not directly exposed to the external environment. However, a bed of a truck is also typically considered to be comprised of internal surfaces. Examples of such internal surfaces are the internal surface 150 of the engine compartment 151, the underside 152 of the engine hood 112, the underside 164 of the trunk lid 114 and the internal surface 166 of the trunk 168, the interior surfaces 158 and frame interfacing surfaces 170 of the passenger doors 122 facing the passenger compartment, the internal surface 166 of the trunk 168 and the door interfacing surface of the frame 172 shown in connection with workpiece 110 shown in
As used herein, the term “external surfaces” denotes those surfaces that face the external environment, such as the exterior surface 156 of the front fenders 118 and rear fenders 120, the external surfaces 160 of the passenger doors 122, the external surface 162 of the trunk lid 114, external surface 154 of the engine hood 112 and the roof 116. Several of these features are also present in the workpiece 410 shown in
With reference to
The controller 136a is connected to robot 124a through electrical connection 137a, such as one or more cables. A robot interface 612 manages communication between the robot 124a and controller 136a, transmitting electrical signals and optionally operating power to the robot. According to one aspect of the present teachings, upon execution of the instructions 603 stored on at least one of the RAM 604 or storage 606 by the CPU 602, the CPU 602 provides signals to the robot interface 612 through the bus 614 that cause to the robot interface 612 to communicate signals to the robot 124a though connection 137a. The signals provided by robot interface 612 in turn cause the robot 124a to move and dispense coating as directed by the CPU 602. The robot interface 612 can, for example, cause the robot 124a to move to a particular position or move with a particular velocity. According to one aspect of the present teachings, the controller 136a can cause the robot 124a having a coating dispenser 130 to undertake motion wherein the robot 124a follows a particular path with a predefined velocity and with the coating dispenser 130 oriented toward the workpiece 110 in a direction defined by a set of coordinates corresponding to the degrees of freedom of the robot 124a. The path thus includes information about each of the degrees of freedom of the robot 124a. Where the robots each have six degrees of freedom, the path taken by the robot 124a and dispenser 130 can be represented by Φk, where k=1 to 6, accounting for the 6 degrees of freedom. It should be noted that robots having less than or more than six degrees of freedom is possible. Additional degrees of freedom, such as 7, 8, 9 or more, are possible by, for example, including additional joints to the robot. Less degrees of freedom may compromise the flexibility afforded by robots having 6 degrees of freedom. For example, having 5 or 4 degrees of freedom can be implemented where 6 degrees of freedom are not requires due to, for example, the shape of the workpiece not requiring movement of the dispenser while coating the workpiece.
A user input/output (I/O) 616 such as a keyboard or remote control can be used to input instructions 603 into controller 136a. The user I/O 616 communicates with the user I/O interface 618 through connection 620. The user I/O 616 can be used to input instructions 603 into the controller 136a. According to one aspect of the present teachings, the user I/O 616 can be used to input a travel path, which can be defined by the coordinates Φk, where k=1 to 6 accounting for the 6 degrees of freedom, that will be followed by the robots 124a-d during the coating process, a speed and coating flow rate along the path Φk, k=1 to 6, and storing the path, speed and flow rate to at least one of the RAM 604 or storage 606. According to another aspect of the present teachings, the RAM 604 or storage 606 can have instruction 603 written upon them to execute coating processes described herein with regard to
A network interface 622 permits connection between controller 136a and a network 624. Additional controllers 136b-d are also connected to the network 624 though connections 137b-d allowing the controllers 136a-d to be in communication and further allowing the controllers 136a-d to synchronize their actions during application of coating on a workpiece such as workpieces 110 or 410. It should be noted that the aspects of controllers 136 described herein can be distributed, such as by providing computing resources and memory through a computer workstation, and providing the robot interface within a separate unit that communicates with the workstation through a communication linkage such as a wireless connection or suitable cabling.
In step 708, a second robot 124b moves a second coating dispenser along a second path over a timespan denoted t=(t3, t4), during which time the second robot 124b dispenses a selected coating on one or more of the external surfaces of the front fenders, rear fenders and external surfaces of the passenger doors. According to one aspect of the present teachings, the timespans (t1, t2) and (t3, t4) both occur during a first time interval, which starts prior to the earliest of t1 and t3, and ends after the latest of t2 and t4. According to another aspect of the present teachings, at least half of at least one of the timespans (t1, t2) and (t3, t4) overlap with the other of the two. For example, in arbitrary units of time, where t1=1, t2=4, t3=3 and t4=5, fifty percent of the timespan (t3, t4) overlaps with timespan (t1, t2). According to another aspect of the present teachings, at least 75 percent of at least one of the timespans (t1, t2) and (t3, t4) overlap with the other timespan. According to yet another aspect of the present teachings, t1=t3 and t2=t4, so that timespans (t1, t2) and (t3, t4) are the same. The timespans (t1, t2) and (t3, t4) can be coextensive with the first time interval, but need not be.
In step 710, the engine hood and trunk lid are closed by operation of opening and closing robot such as opening and closing robots 174 shown in
In step 714, the passenger doors are opened by operation of opening and closing robot 174. In step 716, the second robot 124b moves its coating dispenser along a fourth path over a fourth timespan denoted t=(t7, t8), during which time the second robot 124b dispenses coating on one or more of the interior surfaces of the front and rear passenger doors. In step 718, the passenger doors are closed by operation of opening and closing robot 174. According to one aspect of the present teachings, the timespans (t5, t6) and (t7, t8) overlap at least partially. According to one aspect of the present teachings, the timespans (t5, t6) and (t7, t8) both occur during a second time interval, which starts prior to the earliest of t5 and t7, and ends after the latest of t6 and t8. According to another aspect of the present teachings, at least half of at least one of the timespans (t5, t6) and (t7, t8) overlap with the other timeframe. According to yet another aspect of the present teachings, at least 75 percent of at least one of the timespans (t5, t6) and (t7, t8) overlap with the other timespan. According to yet another aspect of the present teachings, t5=t7 and t6=t8, so that timespans (t5, t6) and (t7, t8) are the same. The timespans (t5, t6) and (t7, t8) can be coextensive with the second time interval, but need not be. According to a further aspect of the present teachings, the second time interval can start after the first time interval ends.
According to yet other aspects of the present teachings, the order of the coating processes performed during the first and second time intervals can be ordered differently within the first and second time intervals. For example, the ordering of which surfaces are coated can be such that the interiors of the engine compartments and trunk can be coated prior to, during or after the front fender, rear fender and passenger door exterior are coated. As another example, the exterior of the engine hood, roof and trunk lid can be coated prior to, during or after the interiors of the passenger doors. Further, the second time interval and corresponding coating processes described herein as occurring during the second time interval can occur prior to the first time interval and corresponding coating processes. In step 720, the workpiece 110 is removed from the spray booth 102.
In another aspect of the present teachings, third and fourth coating robots can be mounted within the spray booth that can, for example, follow mirror image paths to the first and second robots, respectively, described in connection with
For the purposes of this disclosure and unless otherwise specified, “a” or “an” means “one or more.” To the extent that the term “includes” or “including” is used in the specification or the claims, it is intended to be inclusive in a manner similar to the term “comprising” as that term is interpreted when employed as a transitional word in a claim. Furthermore, to the extent that the term “or” is employed (e.g., A or B) it is intended to mean “A or B or both.” When the applicants intend to indicate “only A or B but not both” then the term “only A or B but not both” will be employed. Thus, use of the term “or” herein is the inclusive, and not the exclusive use. See, Bryan A. Garner, A Dictionary of Modern Legal Usage 624 (2d. Ed. 1995). Also, to the extent that the terms “in” or “into” are used in the specification or the claims, it is intended to additionally mean “on” or “onto.” As used herein, “about” will be understood by persons of ordinary skill in the art and will vary to some extent depending upon the context in which it is used. If there are uses of the term which are not clear to persons of ordinary skill in the art, given the context in which it is used, “about” will mean up to plus or minus 10% of the particular term. From about A to B is intended to mean from about A to about B, where A and B are the specified values.
While the present disclosure illustrates various embodiments, and while these embodiments have been described in some detail, it is not the intention of the applicant to restrict or in any way limit the scope of the claimed invention to such detail. Additional advantages and modifications will be apparent to those skilled in the art. Therefore, the invention, in its broader aspects, is not limited to the specific details and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of the applicant's claimed invention. Moreover, the foregoing embodiments are illustrative, and no single feature or element is essential to all possible combinations that may be claimed in this or a later application.
