Method and apparatus for measuring and adjusting a liquid spray pattern

• US 6,457,655 B1
• Filed: 09/01/2000
• Issued: 10/01/2002
• Est. Priority Date: 09/03/1999
• Status: Active Grant

• Current Assignee: Nordson Corporation
• Original Assignee: Nordson Corporation
• Inventors: Reighard, Michael A., Minnich, Jeffrey, van der Heijden, Mark, Byers, John P., Mycke, Jacques
• Primary Examiner(s): DOUGLAS, LISA ANN
• Application Number:
  US09/654,404
• Time in Patent Office: 760 Days
• Field of Search: 239/8, 239/1, 239/101, 239/70, 239/67-69, 239/73, 427/8
• US Class Current: 239/8
• CPC Class Codes: B05B 1/04 in flat form, e.g. fan-like, sheet-like
• CPC Class Codes: B05B 12/082 responsive to a condition of the discharged jet or spray, e.g. to jet shape, spray pattern or droplet size
• CPC Class Codes: B05B 15/50 Arrangements for cleaning; Arrangements for preventing deposits, drying-out or blockage; Arrangements for detecting improper discharge caused by the presence of foreign matter
• CPC Class Codes: H05K 3/0091 Apparatus for coating printed circuits using liquid non-metallic coating compositions

Abstract

A control system for use in a liquid dispensing system to measure and adjust a liquid spray pattern dispensed from the liquid dispensing system. The control system includes a sensor that detect edges of the liquid spray pattern and, from the detected positions of those edges, is operable to adjust the liquid spray pattern to a pattern width set by the operator. The control system is also operable to measure the width of the liquid spray pattern and the offset of the liquid spray pattern relative to a nozzle centerline of the liquid dispensing system and provide warnings to the operator if those measurements fall outside of acceptable ranges.

Claims

1. A method of measuring the width of a liquid spray pattern having a first and second edge using a liquid dispenser having a centerline, a first edge and a second opposite edge and a sensor, comprising:

dispensing the liquid spray pattern from the liquid dispenser;

moving the liquid spray pattern in one direction relative to the sensor;

detecting the first edge of the liquid spray pattern with the sensor;

associating the detected liquid spray pattern first edge with a first position;

moving the liquid spray pattern in an opposite direction relative to the sensor;

detecting the second edge of the liquid spray pattern with the sensor;

associating the detected liquid spray pattern second edge with a second position; and

calculating the width of the liquid spray pattern using the first and second positions.

2. The method of claim 1 further comprising the steps of:

determining a position of the sensor;

determining a position of the dispenser centerline;

associating the position of the dispenser centerline with the position the sensor; and

calculating an offset of the liquid spray pattern relative to the dispenser centerline using the first and second positions.

3. The method of claim 2 wherein the step of determining the position of the dispenser centerline comprises:

moving the dispenser in one direction relative to the sensor;

detecting the first edge of the dispenser with the sensor;

associating the detected dispenser first edge with a third position;

moving the dispenser in an opposite direction relative to the sensor;

detecting the second opposite edge of the dispenser with the sensor;

associating the detected dispenser second opposite edge with a fourth position; and

calculating the position of the dispenser centerline using the third and fourth positions.

4. The method of claim 1 wherein the step of detecting the first edge of the liquid spray pattern comprises:

transmitting a beam of light;

moving the liquid spray pattern through the beam of light; and

generating a signal in response to one of the presence or absence of the liquid spray pattern first edge within the beam of light.

5. The method of claim 4 wherein the step of detecting the second edge of the liquid spray pattern comprises:

continuing to move the liquid spray pattern through the beam of light; and

generating a signal in response to one of the presence or absence of the liquid spray pattern second edge within the beam of light.

6. A method of measuring the width of a liquid spray pattern having a first and second edge using a liquid dispenser having a centerline, a first edge and a second opposite edge, a sensor and a timer, comprising:

dispensing the liquid spray pattern from the liquid dispenser;

moving the liquid spray pattern in one direction relative to the sensor;

detecting the first edge of the liquid spray pattern with the sensor;

initiating the timer upon detecting the first edge of the liquid spray pattern;

moving the liquid spray pattern at a constant velocity in an opposite direction relative to the sensor;

detecting the second edge of the liquid spray pattern with the sensor;

terminating the timer upon detecting the second edge of the liquid spray pattern;

determining the elapsed time between said initiation of the timer and said termination of the timer; and

calculating a width of the liquid spray pattern using the elapsed time and the constant velocity.

7. The method of claim 6 further comprising the steps of:

associating the detected liquid spray pattern first edge with a first position;

associating the detected liquid spray pattern second edge with a second position;

determining a position of the sensor;

determining a position of the dispenser centerline;

associating the position of the dispenser centerline with the position of the sensor; and

calculating an offset of the liquid spray pattern relative to the dispenser centerline using the first and second positions.

8. The method of claim 7 wherein the step of determining the position of the dispenser centerline comprises:

moving the dispenser in one direction relative to the sensor;

detecting the first edge of the dispenser with the sensor;

associating the detected dispenser first edge with a third position;

moving the dispenser in an opposite direction relative to the sensor;

detecting the second opposite edge of the dispenser with the sensor;

associating the detected dispenser second opposite edge with a fourth position; and

calculating the position of the dispenser centerline using the third and fourth positions.

9. The method of claim 8 wherein the step of detecting the first edge of the liquid spray pattern comprises:

transmitting a beam of light;

moving the liquid spray pattern through the beam of light; and

generating a signal in response to one of the presence or absence of the liquid spray pattern first edge within the beam of light.

10. The method of claim 9 wherein the step of detecting the second edge of the liquid spray pattern comprises:

continuing to move the liquid spray pattern through the beam of light; and

generating a signal in response to one of the presence or absence of the liquid spray pattern second edge within the beam of light.

11. A method of adjusting the width of a liquid spray pattern using a liquid dispenser and a sensor, comprising:

positioning the liquid dispenser at a predetermined position relative to the sensor;

dispensing the liquid spray pattern from the liquid dispenser at a predetermined dispensing pressure;

detecting an absence of the liquid spray pattern with the sensor;

increasing the width of the liquid spray pattern by increasing the dispensing pressure until the liquid spray pattern is detected by the sensor.

12. A method of adjusting the width of a liquid spray pattern using a liquid dispenser and a sensor, comprising:

positioning the liquid dispenser at a predetermined position relative to the sensor;

dispensing the liquid spray pattern from the liquid dispenser at a predetermined dispensing pressure;

detecting a presence of the liquid spray pattern with the sensor;

decreasing the width of the liquid spray pattern by decreasing the dispensing pressure until an absence of the liquid spray pattern is detected by the sensor.

13. A liquid dispensing system for dispensing a variable width liquid spray pattern having a first and second edge, comprising:

a source of liquid material;

a dispensing nozzle connected to said source of liquid material and capable of dispensing said liquid material as a liquid spray pattern with a predetermined spray pattern width;

a pneumatically controlled pressure regulator operatively coupled to said source of liquid material and said dispensing nozzle to regulate a pressure at which said liquid material is dispensed by said dispensing nozzle; and

a control circuit coupled to said pressure regulator and capable of varying the regulated pressure at which said liquid material is dispensed by said dispensing nozzle to increase or decrease the width of the liquid spray pattern.

14. The liquid dispensing system of claim 13 further comprising a source of air operatively connected to said control circuit, wherein said pressure regulator comprises a pneumatically controlled fluid regulator having an air inlet coupled to said source of air and capable of increasing or decreasing the pressure at which said liquid material is dispensed by said dispensing nozzle by varying a pressure of air at said air inlet.

15. The liquid dispensing system of claim 14 wherein said control circuit is capable of varying the pressure of air at said air inlet of said pneumatically controlled fluid regulator to increase or decrease the pressure at which said liquid material is dispensed by said dispensing nozzle.

16. The liquid dispensing system of claim 14 further comprising a sensor coupled to said control circuit and capable of detecting one of the presence or absence of the first edge and second edge of the liquid spray pattern.

17. The liquid dispensing system of claim 16 wherein said sensor is capable of applying a signal to said control circuit in response to detecting one of the presence or absence of at least one of the first edge and second edge, and further wherein said control circuit is capable of varying the regulated pressure at which said liquid material is dispensed by said dispensing nozzle in response to receipt of said signal to increase or decrease the width of the liquid spray pattern.

18. The liquid dispensing system of claim 17 wherein said sensor comprises a light beam emitter and a light beam receiver.

19. The liquid dispensing system of claim 16 further comprising a fluid receptacle defined by a bottom wall, a pair of upstanding side walls and a pair of upstanding end walls and capable of receiving said liquid material dispensed from said dispensing nozzle, each of said side walls having a pair of resilient retaining members capable of releasably engaging therebetween said sensor.

20. The liquid dispensing system of claim 19 wherein each of said pair of resilient retaining members are formed in each of said fluid receptacle side walls.

21. The liquid dispensing system of claim 16 further comprising a shroud member mounted about said sensor to form an annular chamber thereabout, said shroud member having an air inlet connected to said annular chamber and to said source of air and being capable of emitting air toward the liquid spray pattern.