Abstract:
An automated dispensing system and method for dispensing a viscous liquid material along an imperfect dispensing path. In a first scan, a scanning apparatus determines a dispensing path. A dispensing apparatus dispenses the viscous liquid material along the dispensing path. In a second scan, the scanning apparatus measures a dimension of the dispensed material. Object not meeting an acceptable liquid height are rejected.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates generally to an apparatus and method for dispensing a viscous liquid material onto a surface. More particularly, the present invention relates to providing a liquid gasket material onto a twisted, warped or displaced surface.  
         BACKGROUND OF INVENTION  
         [0002]    Automatic liquid dispensing machines are used for dispensing materials, (e.g., mastics, sealants, gaskets, adhesives, etc.) onto a surface of an object. Problems arise when trying to automatically dispense material onto a non-repeatable surface of an object, in other words, a surface that is twisted, warped or displaced. Currently available robotic devices may not be able to follow variations created by the twisting, warping or displacement.  
         SUMMARY OF THE INVENTION  
         [0003]    The present invention provides an automated dispensing system for dispensing a liquid onto a non-repeatable surface of an object. The object may include any suitable object (e.g., cap, cover, radiator end tank cover, etc.), that requires a liquid material (e.g., mastic, sealant, gasket, adhesives, etc.) to be applied along an irregular dispensing path. In a first scan, a scanning apparatus of a robotic apparatus maps and determines a first contour profile, then determines the dispensing path. A dispensing apparatus of the robotic apparatus then dispenses the viscous liquid material along the dispensing path. In a second scan, the scanning system of the robotic apparatus measures and maps a height of the dispensed material. Objects not meeting an acceptable dispensed material height are rejected. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0004]    The features of the present invention will best be understood from a detailed description of the invention selected for the purposes of illustration and shown in the accompanying drawings in which:  
         [0005]    [0005]FIG. 1 illustrates a plan view of a robotic motion apparatus;  
         [0006]    [0006]FIG. 2 illustrates a front view of a robotic motion apparatus;  
         [0007]    [0007]FIG. 3 illustrates a side view of the robotic motion apparatus;  
         [0008]    [0008]FIG. 4 illustrates a front and side view of the dispensing apparatus and the scanning apparatus;  
         [0009]    [0009]FIG. 5 illustrates a scanning path of the scanning apparatus for determining a contour profile of each object;  
         [0010]    [0010]FIG. 6 illustrates a plan view of a dispensing path along a top rail of each object;  
         [0011]    [0011]FIG. 7 illustrates a cross-sectional view of a bead of material dispensed on the object; and  
         [0012]    [0012]FIG. 8 illustrates a front view of a display device of a robotic controller.  
         [0013]    [0013]FIG. 9 illustrates a cross section view of a scanning window around the object rails.  
     
    
     DESCRIPTION OF THE INVENTION  
       [0014]    Although certain embodiments of the present invention will be shown and described in detail, it should be understood that various changes and modifications may be made without departing from the scope of the appended claims. The scope of the present invention will in no way be limited to the number of constituting components, the materials thereof, the shapes thereof, the relative arrangement thereof, etc. The features of the present invention are illustrated in detail in the accompanying drawings, wherein like reference numerals refer to like elements throughout the drawings. Although the drawings are intended to illustrate the present invention, the drawings are not necessarily drawn to scale.  
         [0015]    [0015]FIG. 1 illustrates a plan view of a robotic motion apparatus  10 , a scanning apparatus  40 , a data acquisition system  12 , a computer processing system  13 , a dispensing apparatus  41 , and a robotic controller  14 . The electronics being enclosed in an electrical enclosure  11 .  
         [0016]    [0016]FIG. 2 illustrates a front view of the robotic motion apparatus  10 . FIG. 3 illustrates a an side view of the robotic motion apparatus  10 , and FIG. 4 illustrates a front and side view of the scanning and dispensing apparatus  40  and  41 . FIGS.  5 , and  6  illustrate plan views of a pallet  42 . A plurality of objects  16 A,  16 B,  16 C, and  16 D are removably attached to the pallet  42  by clamping assemblies  24 A,  24 B,  24 C, and  24 D (FIG. 5). The clamping assemblies  24 A,  24 B,  24 C, and  24 D may be any suitable means (e.g., clamps, supports, removable fasteners, etc.) for removably attaching the objects  16 A,  16 B,  16 C, and  16 D to the pallet  42 . The clamping assemblies  24 A- 24 D rigidly locate and secure the objects  16 A- 16 D to the pallet  42 .  
         [0017]    FIGS.  4  illustrates a side and front view of the dispensing apparatus  41  and the scanning apparatus  40 . As illustrated in FIG. 4, the dispensing apparatus  41  includes a material supply reservoir  43 , material supply pumps  22 A and  22 B, a material control valve  44 , a solenoid  23 , and a nozzle  20 . The material supply reservoir  43  stores and supplies a material  38 . the material  38  may be any suitable material (e.g., mastic, sealant, liquid gasket, liquid silicon rubber, two-part liquid silicon rubber, etc.). The material supply reservoir  43  may supply the material  38  under pressure to the nozzle  20 . The material control valve  44  turns on or shuts off the flow of the material  38  to the nozzle  20 . The material  38  passes through the nozzle  20  and is dispensed onto a surface of the object  16 A.  
         [0018]    As illustrated in FIG. 2, the scanning apparatus  40  may include a displacement sensor  21 A and a displacement sensor  21 B. The displacement sensors  21 A,  21 B may be any suitable sensor (e.g., laser displacement sensor, light sensor, visual sensor, proximity sensor, etc.). The displacement sensors  21 A,  21 B are moved above and across the objects  16 A- 16 D by the robotic motion apparatus  10 A. The displacement sensors  21 A,  21 B repeatedly take measurements of the objects  16 A- 16 D. From these measurements, a first contour profile  36 A- 36 D of the objects  16 A- 16 D may be established (FIG. 4).  
         [0019]    [0019]FIG. 1 illustrates a calibration apparatus  17 . The calibration apparatus  17  is used to determine the X, Y, and Z offset  45  between the displacement sensors  21 A,  21 B of the scanning apparatus  40  and the nozzle  20  of the dispensing apparatus  41 . The nozzle  20  of the dispensing apparatus  41  is placed within the calibration apparatus  17  and the X, Y, and Z offset  45  is determined.  
         [0020]    As illustrated in FIGS.  1 , the scanning apparatus  40  and the dispensing apparatus  41  are attached to the robotic motion apparatus  10 . The robotic motion apparatus  10  includes an X-Y motion assembly  18 , and a Z motion assembly  19 . The X-Y motion assembly  18  provides motion in an X-Y direction and the Z motion assembly  19  provides motion in a Z direction. Therefore, the robotic motion apparatus  10  may move the scanning apparatus  40  and the dispensing apparatus  41  in any desired X, Y or Z direction. Optionally, other robotic motion apparatus may be used, such as, an arm robot, an n-axis motion machine (wherein n=2,3,4 . . . ),etc.  
         [0021]    The data acquisition system  12  (FIG. 1) acquires and stores measurement information provided by the scanning apparatus  40 . A computer processing system  13  reads the measurement information from the data acquisition system  12  and location “Z” and “X” information provided from the robotic motion controller  14 . The computer processing system  13  then determines the first contour profiles  36 A- 36 D of the objects  16 A- 16 D. The computer processing system  13  determines a dispense path  34 A- 34 D for objects  16 A- 16 D from the first contour profiles  36 A- 36 D. The computer processing system communicates the dispense path  34 A- 34 D information to the robotic motion controller  14 . The robotic motion controller  14  controls the robotic motion apparatus  10 , the scanning apparatus  40 , and the dispensing apparatus  41 . The computer processing system  13  may include a display device  15  and an input device  46  (FIG. 2). The display device  15  may include any suitable device (e.g., digital display, screen display, etc.), as illustrated in FIG. 2. The input device  46  allows an operator to input commands into the computer processing system  13 . The input device  46  may include any suitable device (e.g., keyboard, touch screen, computer mouse, etc.). The robotic motion apparatus  10  may include an emergency stop control system  47  (FIG. 2). The emergency stop control system  47  may include a “stop” button  48 . If an operator presses the “stop” button  48 , the emergency stop control system  47  stops the robotic motion apparatus  10 .  
         [0022]    In robotic motion apparatus  10 , the objects such as  16 A,  16 B,  16 C, and  16 D are attached to a pallet  42  as illustrated in FIG. 5. The pallet  42  is brought to a location under the robotic motion apparatus  10  (FIG. 1). The robotic motion apparatus  10  moves the scanning apparatus  40  above the objects  16 A- 16 D to map the objects  16 A- 16 D in a first scan. A first scanning path is illustrated in FIG. 5. The first scanning path  27  starts at  27  “Start” and ends at  27  “End”. The displacement sensors  21 A and  21 B take measurements in the “Z” direction between the sensors  21 A and  21 B and the objects  16 A- 16 D. The measurements are taken at 0.002 inch intervals as the robotic motion apparatus  10  moves the scanning apparatus  40  in the “Y” direction. Other intervals may be used depending on the accuracy required for any given application. The computer processing system  13  reads the measurements acquired from the data acquisition system  12 . The data is searched within a detection window  57  (FIG. 9) for the highest point  58 . The detection window  57  is stored in the computer processing system  13  by means of an input screen (FIG. 8). The computer processing system  13  then determines the edges  54  and  55  by comparing the highest point  58  and a point by which the height drops by more than a configured threshold (FIG. 8). Once the edges  54  and  55  are determined, the dispense point  56  is calculated. The computer processing system  13  compares the location information of the objects  16 A- 16 D with information stored by means of an input screen (FIG. 8) within the computer processing system  13 . If the computer processing system  13  determines that the “Y” or “Z” location for any given part  16 A- 16 D is out of acceptable limits, the computer processing system does not proceed with a dispense path  34 A- 34 D on the out of tolerance part  16 A- 16 D. The object  16 A- 16 D location information at points  25 A- 25 P,  26 A- 26 P is calculated by the computer processing system  13  to obtain a first contour profile  36 A- 36 D. The objects  16 A- 16 D may be radiator end tank covers, which include a side rail  32 B, a side rail  32 C, and end rail  32 A, and an end rail  32 D. The side rails  32 B and  32 C are typically twisted, warped or displaced in the “Y” direction and in the “Z” direction (see FIG. 5 for the directions). Additionally, the end rails  32 A,  32 D may be displaced in the “Z” direction. The number of times the scanning apparatus  40  is moved over the parts is configurable based on accuracy needs of the dispense path  34  and FIG. 5 is only representative in nature. The computer processing system calculates a dispense path  34 A- 34 D for the objects  16 A- 16 D based on the first contour profile 36 A- 36 D, the “X” and “Z” information from the robotic motion controller  14 , and the “XYZ” offsets  45 . The computer processing system  13  communicates the dispense path  34 A- 34 D information to the robotic motion controller  14 . The robotic motion controller  14  moves the dispensing apparatus  41  over the objects  16 A- 16 D along the dispense paths  34 A- 34 D. The nozzle  20  of the dispensing apparatus  41  moves over the objects  16 A- 16 D and material  38  is dispensed onto the objects  16 A- 16 D. The cross-sectional view in FIG. 7 illustrates a bead  35  of material  38  applied to the radiator end tank cover  16 A along the dispensing path  34 A. The height  33 A “H” of the bead  35 A of dispensed material  38  above the object  16 A is illustrated in FIG. 7.  
         [0023]    After the material  38  is dispensed onto each radiator end tank cover  16 A- 16 D, the robotic motion apparatus  10 A moves the scanning apparatus  40  above the radiator end tank covers  16 A- 16 D in a second scan of the radiator end tank covers  16 A- 16 D. The second scanning path  28  repeats the first scanning path  27 , starting at  27  “Start” and ending at  27  “End”. In a manner similar to the first scan, the displacement sensors  21 A and  21 B take measurements in the “Z” direction between the sensors  21 A and  21 B and the radiator end tank covers  16 A- 16 D. The data acquisition system  12  acquires and stores these measurements from the second scan and determines a second contour profile  37 A- 37 D. The computer processing system  13  calculates each bead height  33 A- 33 D by subtracting each first contour profile  36 A- 36 D from each second contour profile  37 A- 37 D. The computer processing system  13  compares the bead height  33 A- 33 D of the material  38  with a range of standard acceptable bead heights. If the bead height  33 A- 33 D for any radiator end tank cover  16 A- 16 D lies outside of the range of standard acceptable bead heights, then the computer processing  13  notes it. In addition to determining bead height, other bead characteristics (e.g., width, location, etc.). may be determined.