System and method for inspection of parts with an eddy current probe

• US 7,994,780 B2
• Filed: 09/14/2007
• Issued: 08/09/2011
• Est. Priority Date: 09/14/2007
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Wang, Changting, Sun, Haiyan, McKnight, William Stewart
• Primary Examiner(s): Patidar; Jay M
• Application Number:
  US11/855,816
• Publication Number:
  US 20090072822A1
• Time in Patent Office: 1,425 Days
• Field of Search: None
• US Class Current: 324/240
• CPC Class Codes: G01N 27/9046 by analysing electrical signals
• CPC Class Codes: H01F 17/062 Toroidal core with turns of coil around it
• CPC Class Codes: H01F 3/14 Constrictions; Gaps, e.g. air-gaps in magnetic shunt paths H01F3/12
• CPC Class Codes: H01F 5/003 Printed circuit coils
• CPC Class Codes: Y10T 29/49071 by winding or coiling

Abstract

An inspection system for detecting a flaw in a part is provided. The inspection system includes a generally C-shaped core having an opening for receiving the part. The system also includes a driver coil wrapped around the core for creating a magnetic field in the opening. The system further includes at least one single element or multiple element eddy current sensor disposed in the opening.

Claims

1. An inspection system for detecting a flaw in a part comprising:

a generally C-shaped core having an opening for receiving the part;

a driver coil wrapped around the core for creating a magnetic field in the opening;

a driving circuit configured to apply a plurality of excitation signals in the driver coil to induce a plurality of eddy current signals in the part;

at least one single element or multiple element eddy current sensor disposed in the opening, wherein the eddy current sensor is configured to detect a disruption in the plurality of eddy current signals; and

a control circuit configured to analyze the plurality of eddy current signals by performing a multifrequency phase analysis subsequent to multifrequency mixing of the plurality of eddy current signals, to inspect the part for the presence of the flaw.

2. The inspection system of claim 1, wherein the sensor is operable in an absolute mode.

3. The inspection system of claim 1, wherein the sensor is operable in a differential mode.

4. The inspection system of claim 3, wherein the sensor comprises two generally rectangular coils.

5. The inspection system of claim 1, wherein the generally C-shaped core comprises a circular C-shaped core.

6. The inspection system of claim 1, wherein the generally C-shaped core comprises a ferrite core.

7. The inspection system of claim 1, wherein the opening comprises a pair of curved sides.

8. An inspection system for detecting a flaw in a part comprising:

a generally C-shaped core having an opening for receiving the part;

a driver coil wrapped around the core for creating a magnetic field in the opening;

at least one single element or multiple element eddy current sensor disposed in the opening;

a driving circuit configured to apply a plurality of excitation signals in the driver coil to induce a plurality of eddy current signals in the part;

a detection circuit configured to detect a disruption in the plurality of eddy current signals; and

a control circuit configured to analyze the plurality of eddy current signals by performing a multifrequency phase analysis subsequent to multifrequency mixing of the plurality of eddy current signals, to inspect the part for the presence of the flaw.

9. The inspection system of claim 8, wherein the driving circuit and the detection circuit are further configured to:

regulate the plurality of excitation signals from the driving circuit at selective frequencies; and

receive a plurality of eddy current signals from the detection circuit.

10. The inspection system of claim 8, wherein the a control circuit is further configured to control a scan of the eddy current sensor and rotation of the part.

11. The inspection system of claim 8, further comprising a display monitor configured to display an indication of a presence of at least one flaw in the part based upon the plurality of eddy current signals.

12. The inspection system of claim 8, wherein the sensor is operable in an absolute mode.

13. The inspection system of claim 8, wherein the sensor is operable in a differential mode.

14. The inspection system of claim 13, wherein the sensor comprises two generally rectangular coils.

15. The inspection system of claim 8, wherein the generally C-shaped core comprises a circular C-shaped core.

16. The inspection system of claim 8, wherein the generally C-shaped core comprises a ferrite core.

17. The inspection system of claim 8, wherein the opening comprises a pair of curved sides.

18. The inspection system of claim 8, wherein the flaw detected is in a surface or a sub-surface of the part.

19. A method of manufacturing an inspection system comprising:

disposing a driver coil around a generally C-shaped core;

coupling a driving circuit to the driver coil, wherein the driving circuit is configured to apply a plurality of excitation signals in the driver coil to induce a plurality of eddy current signals in a part;

disposing at least one single element or multiple element eddy current sensor inside an opening of the core wherein the eddy current sensor is configured to detect a disruption in the eddy current signals; and

coupling a control circuit to the at least one single element or multiple element eddy current sensor, wherein the control circuit is configured to analyze the plurality of eddy current signals by performing a multifrequency phase analysis subsequent to multifrequency mixing of the plurality of eddy current signals, to inspect the part for the presence of the flaw.

20. The method of claim 19, wherein the disposing at least one single element or multiple element eddy current sensor comprises attaching the sensor to the core via an adhesive epoxy.