Systems and methods for inspecting coatings, surfaces and interfaces

• US 20050186327A1
• Filed: 11/12/2004
• Published: 08/25/2005
• Est. Priority Date: 07/29/2003
• Status: Active Grant

• Current Assignee: Toyota Motor Corporation, University Of Kentucky Research Foundation (University of Kentucky)
• Original Assignee: Toyota Motor Manufacturing North America Inc (Toyota Motor Corporation), University Of Kentucky Research Foundation (University of Kentucky)
• Inventors: Ali, Mohammed I. Hassan, Saito, Kozo, Sakakibara, Masahito, Suzuki, Toshikazu, Tanigawa, Yasuo, Omar, Mohammed A., Numasato, Akira
• Granted Patent: US 7,220,966 B2
• Time in Patent Office: Days
• US Class Current: 427/8
• CPC Class Codes: B05B 16/20 Arrangements for spraying in combination with other operations, e.g. drying; Arrangements enabling a combination of spraying operations
• CPC Class Codes: B05D 3/0263 with IR heaters
• CPC Class Codes: B05D 5/005 Repairing damaged coatings
• CPC Class Codes: G01N 25/72 Investigating presence of flaws

Abstract

A system for detecting defects in paint coatings includes a temperature manipulation apparatus configured to change the temperature of a surface and a coating applied to the surface. The system may further include an infrared sensor for measuring the change in temperature (over time) of the surface and coating and a processor to compare the measured change in temperature of the surface and coating to an expected change of temperature (over time) in order to determine anomalies in the coatings. A self-referencing method of determining defects is also disclosed, wherein surrounding pixels are utilized as a reference in the detection process for calculating the change in temperature of each pixel. In addition, application of the inventive aspects to inspection of adhesion interfaces is also disclosed.

Claims

1. A system for detecting defects in coatings comprising:

a) a temperature manipulation apparatus configured to change the temperature of a surface of a manufacturing part;

b) an infrared sensor configured to measure the temperature of said surface over time, wherein said infrared sensor is configured to provide a first temperature profile of said surface at a first time and second temperature profile of said surface at a second time, each of said profiles containing a plurality of temperature data for a plurality of individual localized areas of said surface; and

c) a processor configured to receive the first and second temperature profiles, to compare each of said profiles to a signature temperature profile, and to calculate a parameter representing the change in temperature over time for each localized area of each profile by comparing the temperature of each localized area with the temperatures of surrounding localized areas, wherein said processor is further configured to identify subsurface imperfections in said surface by comparing each of said temperature change parameters for each localized area to threshold levels.

2. The system of claim 1, wherein said system further comprises an application apparatus configured to apply a coating to said surface.

3. The system of claim 1, wherein said system further comprises multiple coating stations configured to apply a coating to said surface.

4. The system of claim 1, wherein said surface comprises a coating.

5. The system of claim 1, wherein said system further comprises a plurality of coating stations having associated sensors.

6. The system of claim 1, wherein said processor is further configured to compare radiation emitted by said surface to a thermal signature and an acceptable preexisting model profile.

7. The system of claim 1, wherein said processor is further configured to generate signals for transmission to an application apparatus to correct a detected defect.

8. The system of claim 1, wherein said processor is configured to vary the size of said surrounding areas for.

9. A method for detecting defects in coatings comprising the steps of:

a) measuring a thermal profile of a surface to create a thermal signature;

b) applying a first coating to said surface;

c) taking a first measurement of radiation emitted from said surface and said first coating as the temperature thereof is changing over time;

d) comparing said emitted radiation to said thermal signature;

e) applying a second coating to said first coating;

f) taking a second measurement of emitted radiation from said surface and said first and second coatings as the temperature thereof is changing over time;

g) comparing said first measurement to said second measurement;

h) calculating a thermal change for a plurality of pixel locations of at least one of said measurements by comparing the temperature for each pixel location to that of surrounding pixels; and

i) using the comparison and the calculation to identify a surface or subsurface defect.

10. The method for detecting defects in coatings as in claim 9, further comprising the steps of:

a) configuring an expected change of temperature;

b) manipulating the temperature of said surface and coatings;

c) measuring the change of temperature in said surface and coatings; and

d) comparing said measured change of temperature in said surface and coatings to said expected change of temperature.

11. The method for detecting defects in coatings as in claim 9, further comprising the step of comparing said first measurement of radiation emitted from said surface and said first coating to a first acceptable preexisting model profile.

12. The method for detecting defects in coatings as in claim 9, further comprising the step of comparing said second measurement of emitted radiation to a second acceptable preexisting model profile.

13. The method for detecting defects in coatings as in claim 9, further comprising the step of identifying the depth of said defect based upon said calculations.

14. The method for detecting defects in coatings as in claim 9, further comprising the step of correcting an identified defect.

15. A method for detecting defects in coatings comprising the steps of:

a) applying a plurality of coatings to a surface;

b) assigning a thermal effusivity value to each of said coatings;

c) configuring an expected change of temperature for said surface coatings;

d) manipulating the temperature of said surface and coatings;

e) calculating the change of temperature relative to time in said manipulated surface and coatings for a plurality of pixel locations by comparing the temperature of each location in a single thermal profile dataset to that of surrounding pixel locations;

f) comparing said calculated change of temperature for said pixel locations in said manipulated surface and coatings to said expected change of temperature; and

g) using the comparisons to identify a defect.

16. The method for detecting defects in coatings as in claim 15, further comprising the steps of:

a) measuring a thermal profile of said surface to create a thermal signature;

b) taking a first measurement of radiation emitted from said surface and a first of said coatings;

c) comparing said emitted radiation to said thermal signature;

d) taking a second measurement of emitted radiation from said surface and a second of said coatings; and

e) comparing said first measurement to said second measurement.

17. The method for detecting defects in coatings as in claim 15, further comprising the step of identifying the depth and planar location of said defect based upon said calculation.

18. The method for detecting defects in coatings as in claim 15, further comprising the step of correcting said defect.

19. The method for detecting defects in coatings as in claim 15, further comprising the step of implementing a change in the operation of an application apparatus to address one or more defects detected.

20. A method for detecting defects in coatings comprising the steps of:

a) measuring a thermal profile of a surface to create a thermal signature;

b) applying a first coating to said surface;

c) changing the temperature of said surface and said first coating;

d) taking a first measurement of amount of radiation emitted from said surface and said coating as their temperature changes over time;

e) comparing said radiation emitted to said thermal signature;

f) applying a second coating to said first coating;

g) changing the temperature of said surface and said first and second coating;

h) taking a second measurement of amount of radiation emitted from said surface and said first and second coatings as their temperature changes over time;

i) measuring change in temperature over time of said surface and said first and second coatings;

j) configuring an expected change of temperature over time;

k) comparing said first measurement to said second measurement;

l) comparing said measured change in temperature over time of said surface and said first and second coatings to said expected change of temperature over time;

m) calculating a change in temperature parameter for each of a plurality of localized areas in said first or second measurements by comparing the data for each localized area with that of surrounding areas; and

n) using the change in temperature parameter to identify the depth of a defect.

21. The method for detecting defects in coatings as in claim 20, further comprising the step of comparing said first measurement of radiation emitted from said surface and said first coating to a first acceptable preexisting model profile.

22. The method for detecting defects in coatings as in claim 20, further comprising the step of comparing said second measurement of radiation emitted from said surface and said first and second coatings to a second acceptable preexisting model profile.

23. The method for detecting defects in coatings as in claim 20, further comprising the step of comparing each change in temperature parameter for each localized area to a threshold level.

24. The method for detecting defects in coatings as in claim 20, further comprising the step of varying the number of the surrounding areas utilized in the calculation.

25. The method for detecting defects in coatings as in claim 20, further comprising the step of implementing a change in the operation of an application apparatus to address one or more defects detected.

26. A method for detecting defects in coatings comprising the steps of:

a) applying a first coating to a surface;

b) modifying the temperature of the surface and coating;

c) measuring a temperature parameter of said surface and said first coating for a plurality localized areas of said surface to create a thermal profile; and

d) for each localized area in said thermal profile, comparing said temperature parameter of said surface and said first coating to the temperature parameters for surrounding localized areas to determine a temperature change parameter;

e) identifying a defect based upon said temperature change parameters of said localized areas.

27. The method for detecting defects in coatings as in claim 26, further comprising the steps of:

a) measuring a thermal profile of said surface to create a thermal signature;

b) taking a first measurement of amount of radiation emitted from said surface and said first coating;

c) comparing said radiation emitted to said thermal signature;

d) creating a temperature differentiation between said surface, said first coating and a second coating;

e) applying a second coating to said first coating;

f) taking a second measurement of amount of emitted radiation from said surface and said first and second coatings; and

g) comparing said first measurement to said second measurement.

28. The method for detecting defects in coatings as in claim 26, further comprising the step of identifying the three-dimensional location of said defects based upon said comparison.

29. The method for detecting defects in coatings as in claim 26, further comprising the step of correcting a defect identified.

30. The method for detecting defects in coatings as in claim 26, further comprising the step of changing, in real time, the operation of an application apparatus upon identification of a defect.