Patent ID: 8520929

Claim:
A method of sensing defects in the application of hot melt adhesive to a structure, comprising: using an infrared sensor to capture an infrared image of at least the location of the structure where an annular ring of the adhesive is supposed to have been applied; separately interrogating different areas of the image to detect the presence or absence of adhesive, wherein the interrogation comprises detecting a temperature within a preset annular boundary associated with the annular ring of adhesive and detecting a temperature outside of the preset annular boundary associated with the annular ring of adhesive; and using the results of the interrogation to determine whether or not the application of the adhesive is of acceptable quality, at least by: i) establishing the preset annular boundary as an area of the structure that is supposed to be covered by the adhesive; ii) establishing a minimum amount of the area of the structure that is supposed to be covered by the adhesive that must be covered by adhesive for the structure to be acceptable; iii) determining from the interrogation whether adhesive is present in at least the established minimum amount of the area of the structure that is supposed to be covered by the adhesive; iv) detecting when the temperature outside of the preset annular boundary associated with the annular ring of adhesive is greater than a preset threshold; v) rejecting the structure if adhesive is not present in at least the established minimum amount of the area of the structure that is supposed to be covered by the adhesive; and vi) rejecting the structure when the adhesive is present outside of the preset annular boundary in response to detecting of the temperature outside of the preset annular boundary associated with the annular ring of adhesive being greater than the preset threshold.