US20030134034A1 - Method for dispensing viscous liquid material - Google Patents

Abstract

An automated dispensing system and method for dispensing a viscous liquid material along a dynamic 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 an optional second scan, the scanning apparatus measures a dimension of the dispensed material. Object not meeting an acceptable liquid height are rejected.

Description

CROSS-REFERENCE TO RELATED APPLICATION
• This is a division of application Ser. No. 09/809,375 filed Mar. 15, 2000 still pending.[0001]
FIELD OF THE INVENTION
• 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.[0002]
BACKGROUND OF INVENTION
• 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.[0003]
SUMMARY OF THE INVENTION
• 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. Optionally, 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 may then be rejected.[0004]
BRIEF DESCRIPTION OF THE DRAWINGS
• 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]
• FIG. 1 illustrates a plan view of a robotic motion apparatus;[0006]
• FIG. 2 illustrates a front view of a robotic motion apparatus;[0007]
• FIG. 3 illustrates a side view of the robotic motion apparatus;[0008]
• FIG. 4 illustrates a front and side view of the dispensing apparatus and the scanning apparatus;[0009]
• FIG. 5 illustrates a scanning path of the scanning apparatus for determining a contour profile of each object;[0010]
• FIG. 6 illustrates a plan view of a dispensing path along a top rail of each object;[0011]
• FIG. 7 illustrates a cross-sectional view of a bead of material dispensed on the object; and[0012]
• FIG. 8 illustrates a front view of a display device of a robotic controller.[0013]
• FIG. 9 illustrates a cross section view of a scanning window around the object rails.[0014]
DESCRIPTION OF THE INVENTION
• 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]
• FIG. 1 illustrates a plan view of a[0016]robotic motion apparatus10, ascanning apparatus40, adata acquisition system12, acomputer processing system13, a dispensingapparatus41, and arobotic controller14. The electronics being enclosed in an electrical enclosure11.
• FIG. 2 illustrates a front view of the[0017]robotic motion apparatus10. FIG. 3 illustrates a an side view of therobotic motion apparatus10, and FIG. 4 illustrates a front and side view of the scanning and dispensingapparatus40 and41. FIGS.5, and6 illustrate plan views of a pallet42. A plurality ofobjects16A,16B,16C, and16D are removably attached to the pallet42 byclamping assemblies24A,24B,24C, and24D (FIG. 5). Theclamping assemblies24A,24B,24C, and24D may be any suitable means (e.g., clamps, supports, removable fasteners, etc.) for removably attaching theobjects16A,16B,16C, and16D to the pallet42. The clamping assemblies24A-24D rigidly locate and secure theobjects16A-16D to the pallet42.
• FIG. 4 illustrates a side and front view of the dispensing[0018]apparatus41 and thescanning apparatus40. As illustrated in FIG. 4, the dispensingapparatus41 includes amaterial supply reservoir43,material supply pumps22A and22B, amaterial control valve44, asolenoid23, and anozzle20. Thematerial supply reservoir43 stores and supplies a material38. the material38 may be any suitable material (e.g., mastic, sealant, liquid gasket, liquid silicon rubber, two-part liquid silicon rubber, etc.). Thematerial supply reservoir43 may supply the material38 under pressure to thenozzle20. Thematerial control valve44 turns on or shuts off the flow of the material38 to thenozzle20. The material38 passes through thenozzle20 and is dispensed onto a surface of theobject16A.
• As illustrated in FIG. 2, the[0019]scanning apparatus40 may include adisplacement sensor21A and a displacement sensor21B. Thedisplacement sensors21A,21B maybe any suitable sensor (e.g., laser displacement sensor, light sensor, visual sensor, proximity sensor, etc.). Thedisplacement sensors21A,21B are moved above and across theobjects16A-16D by the robotic motion apparatus10A. Thedisplacement sensors21A,21B repeatedly take measurements of theobjects16A-16D. From these measurements, afirst contour profile36A-36D of theobjects16A-16D may be established (FIG. 4).
• FIG. 1 illustrates a[0020]calibration apparatus17. Thecalibration apparatus17 is used to determine the X, Y, and Z offset45 between thedisplacement sensors21A,21B of thescanning apparatus40 and thenozzle20 of thedispensing apparatus41. Thenozzle20 of the dispensingapparatus41 is placed within thecalibration apparatus17 and the X, Y, and Z offset45 is determined.
• As illustrated in FIG. 1, the[0021]scanning apparatus40 and the dispensingapparatus41 are attached to therobotic motion apparatus10. Therobotic motion apparatus10 includes anX-Y motion assembly18, and aZ motion assembly19. TheX-Y motion assembly18 provides motion in an X-Y direction and theZ motion assembly19 provides motion in a Z direction. Therefore, therobotic motion apparatus10 may move thescanning apparatus40 and the dispensingapparatus41 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.
• The data acquisition system[0022]12 (FIG. 1) acquires and stores measurement information provided by thescanning apparatus40. Acomputer processing system13 reads the measurement information from thedata acquisition system12 and location “Z” and “X” information provided from therobotic motion controller14. Thecomputer processing system13 then determines thefirst contour profiles36A-36D of theobjects16A-16D. Thecomputer processing system13 determines adispense path34A-34D forobjects16A-16D from thefirst contour profiles36A-36D. The computer processing system communicates the dispensepath34A-34D information to therobotic motion controller14. Therobotic motion controller14 controls therobotic motion apparatus10, thescanning apparatus40, and the dispensingapparatus41. Thecomputer processing system13 may include adisplay device15 and an input device46 (FIG. 2). Thedisplay device15 may include any suitable device (e.g., digital display, screen display, etc.), as illustrated in FIG. 2. Theinput device46 allows an operator to input commands into thecomputer processing system13. Theinput device46 may include any suitable device (e.g., keyboard, touch screen, computer mouse, etc.). Therobotic motion apparatus10 may include an emergency stop control system47 (FIG. 2). The emergencystop control system47 may include a “stop”button48. If an operator presses the “stop”button48, the emergencystop control system47 stops therobotic motion apparatus10.
• In[0023]robotic motion apparatus10, the objects such as16A,16B,16C, and16D are attached to a pallet42 as illustrated in FIG. 5. The pallet42 is brought to a location under the robotic motion apparatus10 (FIG. 1). Therobotic motion apparatus10 moves thescanning apparatus40 above theobjects16A-16D to map theobjects16A-16D in a first scan. A first scanning path is illustrated in FIG. 5. Thefirst scanning path27 starts at27 “Start” and ends at27 “End”. Thedisplacement sensors21A and21B take measurements in the “Z” direction between thesensors21A and21B and theobjects16A-16D. The measurements are taken at 0.002 inch intervals as therobotic motion apparatus10 moves thescanning apparatus40 in the “Y” direction. Other intervals may be used depending on the accuracy required for any given application. Thecomputer processing system13 reads the measurements acquired from thedata acquisition system12. The data is searched within a detection window57 (FIG. 9) for thehighest point58. Thedetection window57 is stored in thecomputer processing system13 by means of an input screen (FIG. 8). Thecomputer processing system13 then determines theedges54 and55 by comparing thehighest point58 and a point by which the height drops by more than a configured threshold (FIG. 8). Once theedges54 and55 are determined, the dispensepoint56 is calculated. Thecomputer processing system13 compares the location information of theobjects16A-16D with information stored by means of an input screen (FIG. 8) within thecomputer processing system13. If thecomputer processing system13 determines that the “Y” or “Z” location for any givenpart16A-16D is out of acceptable limits, the computer processing system does not proceed with a dispensepath34A-34D on the out oftolerance part16A-16D. Theobject16A-16D location information atpoints25A-25P,26A-26P is calculated by thecomputer processing system13 to obtain afirst contour profile36A-36D. Theobjects16A-16D may be radiator end tank covers, which include aside rail32B, a side rail32C, and endrail32A, and an end rail32D. The side rails32B and32C are typically twisted, warped or displaced in the “Y” direction and in the “Z” direction (see FIG. 5 for the directions). Additionally, the end rails32A,32D may be displaced in the “Z” direction. The number of times thescanning apparatus40 is moved over the parts is configurable based on accuracy needs of the dispense path34 and FIG. 5 is only representative in nature. The computer processing system calculates a dispensepath34A-34D for theobjects16A-16D based on thefirst contour profile36A-36D, the “X” and “Z” information from therobotic motion controller14, and the “XYZ” offsets45. Thecomputer processing system13 communicates the dispensepath34A-34D information to therobotic motion controller14. Therobotic motion controller14 moves the dispensingapparatus41 over theobjects16A-16D along the dispensepaths34A-34D. Thenozzle20 of the dispensingapparatus41 moves over theobjects16A-16D and material38 is dispensed onto theobjects16A-16D. The cross-sectional view in FIG. 7 illustrates a bead35 of material38 applied to the radiatorend tank cover16A along the dispensingpath34A. Theheight33A “H” of thebead35A of dispensed material38 above theobject16A is illustrated in FIG. 7.
• After the material[0024]38 is dispensed onto each radiatorend tank cover16A-16D, the robotic motion apparatus10A moves thescanning apparatus40 above the radiator end tank covers16A-16D in a second scan of the radiator end tank covers16A-16D. Thesecond scanning path28 repeats thefirst scanning path27, starting at27 “Start” and ending at27 “End”. In a manner similar to the first scan, thedisplacement sensors21A and21B take measurements in the “Z” direction between thesensors21A and21B and the radiator end tank covers16A-16D. Thedata acquisition system12 acquires and stores these measurements from the second scan and determines asecond contour profile37A-37D. Thecomputer processing system13 calculates eachbead height33A-33D by subtracting eachfirst contour profile36A-36D from eachsecond contour profile37A-37D. Thecomputer processing system13 compares thebead height33A-33D of the material38 with a range of standard acceptable bead heights. If thebead height33A-33D for any radiatorend tank cover16A-16D lies outside of the range of standard acceptable bead heights, then thecomputer processing13 notes it. In addition to determining bead height, other bead characteristics (e.g., width, location, etc.). may be determined.

Claims (8)

I claim:

1. A method comprising:

a. Providing an object having a non-repeatable surface;

b. Performing a scan to determine a dispensing path; and

c. Dispensing a material onto the object along the dispensing path.

2. The method ofclaim 1, wherein the material is a viscous material.

3. The method ofclaim 2, wherein the viscous material is a liquid silicone rubber.

4. The method ofclaim 1, wherein the object is a radiator end tank.

5. The method ofclaim 1, wherein the scan is performed using a scanning apparatus.

6. The method ofclaim 1, further comprising analyzing the scan using a processing computer.

7. A method comprising:

a. Providing an object;

b. Performing a first scan of the object;

c. Calculating a dispensing path from the first scan;

d. Dispensing a material along the dispensing path; and

e. Performing a second scan of the object to determine a dimension, location or configuration of the material.

8. A method comprising:

a. Providing an object;

b. Determining a scanning window about the object;

c. Determining features of said object by defining thresholds; and

d. Calculating a desired dispense path point based on the features of the object.

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