Robotic sealant dispensing and scraping applicator and process

Abstract

A sealant dispensing tool for a robot. The tool includes a rod having a first end and a second end, the rod including a chamber extending from the first end to the second end. The tool also includes a scraper coupled to the first end of the rod, wherein the scraper includes an opening and a hollow portion in communication with the opening and a chamber in the rod. The tool further includes a dispensing nozzle positioned within an opening in the scraper; and an applicator coupled to the nozzle and extending through the hollow portion of the scraper and the chamber in the rod.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of the filing date of U.S. Provisional Application No. 63 / 589,730, filed on October 12, 2023, entitled “ROBOTIC SEALANT DISPENSING AND SKAW APPLICATOR AND PROCESS.” Technical Field

[0003] The present disclosure relates generally to a tool for simultaneously dispensing and scraping a material, and more particularly to a robotic tool for simultaneously dispensing and scraping a sealant, wherein the tool includes a scraper having a nozzle for dispensing the sealant, and wherein the nozzle dispenses the sealant in a pulsed manner. Background Art

[0004] Various components require seals. One of these components is a vehicle. For example, a vehicle typically requires seals around certain vehicle components, such as windshields, rear windows, lamp covers, etc., to prevent moisture and smoke from intruding into the vehicle passenger compartment. Current vehicle paint shop sealing processes typically require a human operator to lay down a viscous sealant, such as a liquid polyvinyl chloride (PVC) sealant. The current process requires a human operator to wipe (scrape or brush) the sealant off the seam and leave a small amount of sealant in the seam, which is a very labor intensive process and wastes excess sealant, thus being costly. This process is required for components that are assembled on a sealed vehicle body.

[0005] During the vehicle manufacturing process, gauge holes set in the floor pan or subframe of the vehicle are used as key reference points for building the body structure. The subassemblies and panels of the vehicle are assembled using the gauge holes as a baseline. As the vehicle is assembled, key body features that are important to the appearance of the vehicle must be maintained. In order to achieve the dimensional requirements of the exterior of the vehicle body, the seams of the body panels are used to adjust the key body features. This creates seam drift, where the seams are constantly moving in size to compensate for the key body features. The seams of the vehicle require small beads of sealant to meet the process requirements. Known systems use vision sensors to measure the seam drift of the process or fixed sensors. This vision process is very time consuming.

[0006] PVC sealants are manufactured in large batch mixers, which creates viscosity variations between batches. Additionally, PVC sealants are pre-catalyzed and therefore are very sensitive to aging, which also affects the viscosity of the material. This variation in viscosity causes variations in the sealant applied to the seam, which causes variations in the width of the bead seam of sealant applied to the seam. A sealant bead that is too narrow can allow water to leak into the vehicle, causing warranty claims. A sealant bead that is too wide can cause assembly problems, where the subassembly cannot be assembled to the vehicle without removing the large bead of sealant from the interference point, resulting in the need for manual repairs to the production vehicle. The current correct action for the end user is to manually adjust the pre-pressure of each bead / seam to compensate for the variation in material viscosity. This manual adjustment process is very time consuming.

[0007] Modern vehicle assembly employs robots to perform a variety of tasks, such as body welding and painting. The tasks performed by vehicle assembly robots have become more complex and intricate. Dispensing sealants into intricate vehicle locations is one of those areas where robots have become more useful. However, in certain areas of the vehicle, such as in the taillight area, the seams are dimensionally unstable, which makes the robotic application of sealants more difficult. Summary of the invention

[0008] The following discussion discloses and describes a sealant dispensing and scraping tool for a robot. The tool includes a rod having a chamber extending therethrough. The tool also includes a scraper coupled to one end of the rod, wherein the scraper includes an opening and a hollow portion communicating with the opening and the chamber in the rod. The tool also includes a dispensing nozzle positioned within the opening of the scraper, and an applicator coupled to the nozzle and extending through the hollow portion of the scraper and the chamber in the rod.

[0009] Additional features of the present disclosure will become apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a diagram of an assembly line for applying sealant to a vehicle;

[0011] Figure 2 is a cutaway isometric view of a robot including a precision seal applicator attached to a robotic arm;

[0012] Figure 3 is an illustration of a manufacturing system showing a vehicle component receiving a sealant and a robot having a scraping tool assembly having a sealant dispensing nozzle;

[0013] Figure 4 yes Figure 3 A cutaway isometric view of a scraper assembly is shown with one scraper extended;

[0014] Figure 5 is a cutaway isometric view of a sealant dispensing and scraping applicator for a robot for simultaneously applying and scraping sealant;

[0015] Figure 6 is an isometric view of a scraper cleaner;

[0016] Figure 7 yes Figure 6 a front view of the shaving cleaner shown, showing the internal filter and waste collection container; and

[0017] Figure 8 is an isometric view of a scraping solvent washing cleaner. DETAILED DESCRIPTION

[0018] The following discussion of embodiments of the present disclosure directed to a sealant dispensing and scraping tool for a robot is merely exemplary in nature and is in no way intended to limit the present disclosure or its application or uses.

[0019] Figure 1 is an illustration of an assembly line 10 for applying sealant to a vehicle 12 moving along the assembly line 10. The assembly line 10 includes a stopping station 14 at which sealant is dispensed into a seam on the vehicle 12 currently stopped at the stopping station 14. The assembly line 10 also includes a stopping station 16 at which excess sealant is removed from a seam on the vehicle 12 currently stopped at the stopping station 16. In alternative embodiments, the stopping station 14 and / or the stopping station 16 may provide both sealant dispensing and scraping, as will become apparent from the following discussion.

[0020] The stop station 14 includes two robots 18 and 20 that can slide on the track 22, two vision sensors 24 and 26 positioned on one side of the vehicle 12, two robots 28 and 30 that can slide on the track 32, and two vision sensors 34 and 36 positioned on the other side of the vehicle 12. Similarly, the stop station 16 includes two robots 40 and 42 that can slide on the track 44, two vision sensors 46 and 48 positioned on one side of the vehicle 12, two robots 50 and 52 that can slide on the track 54, and two vision sensors 56 and 58 positioned on the other side of the vehicle 12. The number of robots at the stop stations 14 and 16 is shown by way of example, and any reasonable number of robots may be employed for a particular operation. Each of the robots 18, 20, 28, and 30 includes a vision sensor 60 mounted on the robot that locates each seam on the vehicle 12. Vision controller 62 represents all vision control devices necessary to control vision sensors 60 on robots 18, 20, 28, 30, 40, 42, 50 and 52, as well as vision sensors 24, 26, 34, 36, 46, 48, 56 and 58, consistent with the discussion herein where multiple controllers and devices will be required.

[0021] The vehicle 12 is equipped with apertures (not shown) on each quadrant of the body of the vehicle 12 that provide a reference position on the vehicle 12. The apertures are imaged by the vision sensors 24, 26, 34, and 36, and the vision controller 62 uses those images to identify the location and position of the vehicle 12 in space. After the apertures are imaged and the position of the vehicle 12 when it stops at the stop station 14 is mathematically identified by the vision controller 62, the vision sensors 60 on the robots 18, 20, 28, and 30 provide images to the vision controller 62, which identifies the position or offset of the seams on the vehicle 12 relative to the apertures to which the robots 18, 20, 28, and 30 apply sealant. In particular, the vision sensors 60 on the robots 18, 20, 28, and 30 provide seam drift position measurements and changes. The robot paths are modified for seam drift changes, and the robots 18, 20, 28, and 30 apply sealant to the various seams on the vehicle 12 stopped at the station 14 using appropriate sealant applicators. As will be discussed below, the seam drift offset is sent from station 14 to station 16 to be used by robots 40 , 42 , 50 , and 52 to perform a scraping operation to remove excess sealant from a vehicle 12 parked at station 16 .

[0022] Conventionally, this process of identifying the offset of the seam or some other feature on the vehicle 12 is performed at each stop station 14 and 16. The present disclosure proposes that the mathematical offset between the seam and the hole or other feature is determined at the first stop station (here, stop station 14), and those offsets are passed or sent to the downstream stop station (such as stop station 16), so that the offsets at the downstream stop station do not need to be recalculated, which reduces the cycle time. In addition, if the offset does not need to be recalculated at the downstream stop station, the robot at those stop stations may not need the vision sensor 60, which reduces hardware. The vision system at those downstream stop stations still needs to identify the location of the hole on the vehicle 12. Once the location of the hole is identified, the offset that has been received from the upstream stop station is used to identify the location of the seam. In other embodiments, it may be desirable to have a first stop station that only determines the offset between the hole and the feature on the vehicle and then sends it to the downstream stop station.

[0023] Typically, a positive displacement metering system is used to maintain a constant flow rate of sealant to the sealant applicator on the robot. As generally discussed above, when the viscosity of the material changes, the amount of pre-pressure used when starting to dispense the sealant bead is constant and causes the sealant bead to begin to change as the viscosity of the sealant changes. As the material viscosity decreases, upon initial opening of the sealant applicator, the bead size will initially increase, which produces a larger bead than desired. As the material viscosity increases upon initial opening of the sealant applicator, a smaller sealant bead than desired is produced.

[0024] The present disclosure proposes using a vision system and control algorithms, such as vision sensors 24, 26, 34 and 36, vision sensor 60, vision controller 62 and sealant dispensing controller to adjust the dispensing system pre-pressure of the sealant applicator on, for example, robots 18, 20, 28 and 30 to compensate for changes in the viscosity of the sealant as it is dispensed. The vision system measures critical areas of the seam, typically the starting point of the bead width on each vehicle 12. The vision controller 62 provides the bead width data back to the sealant dispensing controller associated with each robot 18, 20, 28 and 30. The vision system also measures multiple points on the seam to provide individual seam width data and very precise metal sheet seam location, such as less than 0.5 mm seam location accuracy. Using the control algorithm, the dispensing controller adjusts the pre-pressure up or down to compensate for the changing viscosity of the sealant.

[0025] The present disclosure also proposes a robotic sealant applicator that includes robotic vision and a precision applicator tip to precisely place sealant on a joint, eliminating or reducing the labor-intensive manual scraping process. In one embodiment, a small sealant bead width of 3 mm to 12 mm is dispensed to a precise location on the joint to eliminate or reduce the need for manual or robotic scraping. The precision sealant applicator is designed to fit into tight areas, such as the taillight area of ​​a vehicle.

[0026] Figure 2 is a cutaway isometric view of a precision robotic end or arm tool 70 including a precision sealant applicator 72 and a material / air line swivel 74 suitable for the purposes discussed herein. The applicator 72 includes an applicator body 80 and an optional camera 76 attached to the swivel 74, the applicator body having three nozzles 82, 84, and 86 extending therefrom, and the three nozzles are oriented 120° relative to each other. Nozzle 82 includes a straight nozzle end 88 oriented at 0°, nozzle 84 includes a curved nozzle end 90 oriented at 45°, and nozzle 86 includes a curved nozzle end 92 oriented at 90°. Thus, nozzles 82, 84, and 86 provide a compact design with optimized angles to accurately dispense sealant into tight or complex locations with minimal waste, for example, sealant bead widths ranging from 2 mm to 8 mm. In other designs, a different number of nozzles may be provided.

[0027] The present disclosure also includes a discussion of a robotic process in which one or more robots utilize precision tools to dispense sealant onto and scrape sealant off one or more seams of a vehicle. The robotic applicator includes one or more precision applicator tips to precisely place the sealant onto the seam to facilitate robotic scraping, thereby eliminating the labor-intensive manual scraping process. A small bead of sealant is dispensed into a precise location on the seam, and then one or more scrapers located on the tool scrape off excess material to leave a very flat sealed seam in which components such as window glass or other subassemblies can be assembled over the sealed joint without interfering with the seal of the glass to the vehicle body.

[0028] Figure 31 is a cutaway isometric view of a manufacturing system 100 including a robotic arm 102 having an end effector 104 showing such a design in which the end effector is coupled to the robotic arm. The end effector 104 includes a nozzle 106 from which a viscous sealant (e.g., liquid PVC) is dispensed. The nozzle 106 is attached to various devices 108, including a sealant dispensing controller that controls the nozzle 106 to dispense the sealant. The end effector 104 also includes a scraping assembly 112 having three scrapers 114, 116, and 118 rigidly attached to and extending from a coupling 120 on a rod 124, wherein the scrapers 114, 116, and 118 are positioned in a circle and spaced 120° relative to each other. Figure 4 1 is a cutaway isometric view of the end effector 104 with the nozzle 106 and the device 108 removed. In one non-limiting embodiment, the scrapers 114, 116 and 118 are triangular paddles made of a rubber compound. The scrapers 114, 116 and 118 are formed to have a cup-shaped portion 122 that allows the scrapers 114, 116 and 118 to retain a certain amount of sealant during the scraping operation. During the scraping operation, one of the scrapers 114, 116 and 118 extends on the rod 124, and the scraper 114, 116 or 118 is used to remove excess sealant. When changing the scraper, the scrapers 114, 116 and 118 and the rod 124 are keyed to maintain the scraping position. Figure 4 The extended scraper 116 is shown. When the cup 122 of the scraper 114, 116 or 118 is full, the scraper 114, 116 or 118 is retracted, the coupling 120 is rotated, and another scraper 114, 116 or 118 is extended to continue the scraping operation. When the cup 122 of all scrapers 114, 116 and 118 is full of sealant, the sealant is removed from the cup 122 and the scrapers 114, 116 and 118 are cleaned, as will be discussed in detail below.

[0029] In this embodiment, manufacturing assembly 100 includes a vehicle component 130, specifically a rear window frame of a truck, to receive sealant. Robot arm 102 is controlled so that nozzle 106 is positioned in a suitable position close to component 130. Robot arm 102 moves nozzle 106 along component 130 so that when sealant is dispensed from nozzle 106, sealant is deposited on component 130 as a sealant bead 132. After sealant bead 132 is deposited on component 130, robot arm 102 is controlled to position one of scrapers 114, 116, and 118 over the sealant and move the selected scraper 114, 116, or 118 along bead 132 to remove excess sealant. Component 130 is then placed in oven 134 to heat and cure the sealant to provide a desired seal.

[0030] Figure 5 1 is a cutaway isometric view of a robotic sealant system 150 that includes an end effector 152 that can be configured to be attached to a robotic arm 102, rather than the end effector 104 in an alternative embodiment. The system 150 includes a sealant tool 154 having a hollow stem 156 secured at one end to the end effector 152. The tool 154 also includes a scraper 160 attached to the stem 156 opposite the end effector 152. The scraper 160 has a shape, size, and material similar to the scrapers 114, 116, and 118, but also includes a hollow upper portion 162 having an opening 164. A nozzle 166 is secured in the opening 164 and faces downwardly at a lower end 168 of the scraper 160. An applicator 170 is attached to the nozzle 166 inside the hollow portion 162 and passes upward through the stem 156 and is attached to a dispensing system 174 that includes a sealant source. The system 174 also includes a valve through which the sealant is dispensed and a metering device that selectively dispenses the appropriate amount of sealant. In one embodiment, the dispensing system 174 controls the valve to spray the sealant in a pulsed manner using, for example, pulse width modulation (PWM), so that the nozzle 166 does not deposit the sealant continuously, but deposits the sealant as sealant dots in a pulsed manner, which saves sealant material. The controller 176 represents all control devices necessary to control the position of the tool 154 and the operation of the dispensing system 174.

[0031] The tool 154 is positioned, for example, relative to the component 130 so that the nozzle 166 is in position to place the sealant bead 132. The controller 176 controls the dispensing system 174 to pump the sealant down to the applicator 170 to be dispensed by the nozzle 166 as a continuous sealant stream 178 or in pulses. The controller 176 moves the tool 154 so that the nozzle 166 dispenses the sealant stream 178 to form the bead 132 and simultaneously the scraper 160 removes excess sealant as it is laid down on the component 130.

[0032] As mentioned above, the scrapers 114, 116, and 118 require periodic cleaning in order to remove collected sealant therefrom. Figure 6 is an isometric view of a scraper cleaner 180 for removing sealant from scrapers 114, 116, and 118, and Figure 71 is a front view thereof. The scraper cleaner 180 can also clean the scraper 160. The cleaner 180 includes a rectangular frame 182 having an open bottom 184 that allows a collection bucket 186 to be positioned within the frame 182. The cleaner 180 also includes a top plate 190 that supports a scraper front / rear wiping structure 192 having a frame 194 and an opening 196 that is shaped to receive the scrapers 114, 116, and 118. When the cup-shaped portion 122 of each of the scrapers 114, 116, and 118 is full, in this embodiment, the robot arm 102 moves the scraper assembly 112 to the scraper cleaner 180. One of the scrapers 114, 116, and 118 extends and is inserted into the opening 196 so that the sealant in the cup-shaped portion 122 is scraped off on the edge of the opening 196. The extended scraper 114, 116, or 118 is then placed in the air wiping device 200, which blows air onto the extended scraper 114, 116, or 118 to remove any residual sealant on the extended scraper 114, 116, or 118. While the air wiping device 200 blows air onto the extended scraper 114, 116, or 118, the actuator 202 extends the cleaning arm 204 into the structure 192, which pushes the sealant collected in the frame 194 into the bucket 186. The scraper 114, 116, or 118 is then retracted, and the other scrapers 114, 116, or 118 are cleaned in the same manner. A media filter 208 is attached to the frame 182.

[0033] Eventually, a film will form on the scrapers 114, 116, and 118 which cannot be cleaned by the scraper cleaner 180 but needs to be removed. Figure 8is an isometric view of a scraper solvent wash cleaner 210 for removing this film from the scrapers 114, 116, and 118. The wash cleaner 210 includes a frame 212 that supports a tank 214 containing a cleaning solvent and a strategically positioned brush (not shown), and has a top opening 216 extending through a top plate 218 on the frame 212, with a cover 220 slidably mounted to the plate 218 to cover the opening 216 when the cleaner 210 is not in use and to open the opening 216 when the cleaner 210 is in use. A pump and circulation system 222 provides solvent to the tank 214 and removes solvent from the tank. After the scrapers 114, 116, and 118 have been cleaned by the scraper cleaner 180 as described above, the robot arm 102 moves the scraper assembly 112 to the cleaning cleaner 210, extends all the scrapers 114, 116, and 118, and moves the scraper assembly 112 through the opening 216 and into the tank 214 to clean the film off the scrapers 114, 116, and 118. The robot arm 102 rotates and swings the scraper assembly 112 up and down while it is in the tank 214 to rub the scrapers 114, 116, and 118 against the brush to help remove the film. The scraper assembly 112 is then removed from the tank 214, and the scrapers 114, 116, and 118 are retracted. In an alternative embodiment, the brush can be movable, and the scrapers 114, 116, and 118 can be fixed.

[0034] Solvent cleaner 210 may also have many features. For example, a brush may be configured to clean both the front and rear of the scraper and may be configured to be removed and replaced without the use of tools. Tank 214 may have a fluid level sensor to indicate the solvent level therein and may have simple drain and replacement features. Solvent cleaner 210 may have a closed design to minimize steam and solvent evaporation and a closed recirculation system to maintain solvent levels. Opening 216 may be covered with a lid that opens and closes automatically. A filter reservoir may be provided to clean and maintain solvent levels.

[0035] A cleaner may also be provided to clean the applicator 72 including nozzles 82, 84 and 86. This cleaner may have air nozzles for sealant blow-off, a design to manage airflow to eliminate overspray on the vision equipment, and independent air nozzle controls to optimize cleaning.

[0036] The various sealant dispensing and scraping devices and systems discussed herein can provide many advantages and features, many of which have been discussed above. For example, as described above, the bead size of the dispensed sealant can be measured by a visual system to adjust the dispensing pressure, thereby dynamically adjusting the bead size. In addition, the component gap size can be measured, the robot speed can be changed, and / or the dispensing parameters can be adjusted to increase or decrease the sealant bead size. The sealant dispensing nozzle can be accurately positioned, and the amount of the dispensed sealant can be minimized to reduce the sealant waste volume, wherein too much sealant leads to more waste, sealing defects and the need to provide additional scraping. A visual system can be used to independently locate each sealed joint to adjust the changes in the metal sheet body structure. The scraper can be keyed to facilitate the precise positioning of each scraper. The scraping assembly provides the ability to accurately install a replacement scraper. A position sensor can be used to identify the extended / retracted position of the scraper, and a visual system can be used to provide a joint offset to accurately arrange the scraper.

[0037] The foregoing discussion discloses and describes only exemplary embodiments of the present disclosure. Those skilled in the art will readily recognize from this discussion and from the accompanying drawings and claims that various changes, modifications and variations may be made therein without departing from the spirit and scope of the present disclosure as defined in the appended claims.

Claims

1. A material dispensing tool comprising: a rod having a first end and a second end, the rod further comprising a chamber extending from the first end to the second end; a scraper coupled to the first end of the rod, the scraper comprising an opening and a hollow portion in communication with the opening and the chamber in the rod; a dispensing nozzle positioned within said opening in said scraper; as well as An applicator is coupled to the nozzle and extends through the hollow portion of the scraper and the cavity in the stem.

2. The material dispensing tool according to claim 1 further includes a dispensing system, which is connected to the applicator and is configured to dispense material through the applicator and away from the dispensing nozzle, and the scraper and the nozzle are positioned to allow the scraper to collect some of the material when the nozzle dispenses the material.

3. The material dispensing tool of claim 2, wherein: The dispensing system dispenses the material in a pulsed manner such that the material is periodically dispensed by the dispensing nozzle.

4. The material dispensing tool of claim 2, wherein: The material is a sealant.

5. The material dispensing tool of claim 4, wherein: The sealant is liquid PVC.

6. The material dispensing tool of claim 1, wherein: The scraper is triangular in shape and includes a cup-shaped portion.

7. The material dispensing tool of claim 1, wherein: The scraper is made of a rubber compound.

8. The material dispensing tool of claim 1, wherein: The tool is configured to be coupled to a robotic arm.

9. The material dispensing tool of claim 8, wherein: The nozzle dispenses sealant onto the joint of the components, and the scraper removes some of the sealant while it is dispensed.

10. The material dispensing tool of claim 9, wherein: The component is a vehicle component.

11. A sealant dispensing tool configured to be coupled to a robotic arm for dispensing sealant onto a joint of a component, the sealant dispensing tool comprising: a rod having a first end and a second end, the rod further comprising a chamber extending from the first end to the second end; a scraper coupled to the first end of the rod, the scraper comprising an opening and a hollow portion in communication with the opening and the chamber in the rod; a dispensing nozzle positioned within said opening in said scraper; an applicator coupled to the nozzle and extending through the hollow portion of the scraper and the chamber in the stem; as well as A dispensing system is coupled to the applicator and configured to dispense the sealant through the applicator and out of the dispensing nozzle, the scraper and nozzle being positioned to allow the scraper to collect some of the sealant as it is dispensed by the nozzle.

12. The sealant dispensing tool of claim 11, wherein: The dispensing system dispenses the sealant in a pulsed manner such that the sealant is periodically dispensed by the dispensing nozzle.

13. The sealant dispensing tool of claim 11, wherein: The scraper is triangular in shape and includes a cup-shaped portion.

14. The sealant dispensing tool of claim 11, wherein: The component is a vehicle component.

15. A robot system comprising: Robotic arm; a dispensing tool coupled to the robotic arm for dispensing sealant, the dispensing tool comprising: a rod having a first end and a second end, including a chamber extending from the first end to the second end; a scraper coupled to the first end of the rod and including an opening and a hollow portion communicating with the opening and the chamber in the rod; a dispensing nozzle positioned within the opening; and an applicator coupled to the nozzle and extending through the hollow portion of the scraper and the chamber in the rod; and A dispensing system is coupled to the applicator and configured to dispense the sealant through the applicator and out of the dispensing nozzle, the scraper and nozzle being positioned to allow the scraper to collect some of the sealant as the nozzle dispenses the sealant.

16. The robot system according to claim 15, wherein: The dispensing system dispenses the sealant in a pulsed manner such that the sealant is periodically dispensed by the dispensing nozzle.

17. The robot system according to claim 15, wherein: The scraper is triangular in shape and includes a cup-shaped portion.

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