# US 12,216,184 B2 · Automated inspection for internal corrosion

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- Number: US 12,216,184 B2
- Document ID: US12216184B2
- Status: Granted
- Kind: B2
- Application number: 18/310,937
- Filed: 2023-05-02
- Published: 2023-08-31
- Granted: 2025-02-04
- Earliest claimed: 2019-03-22
- Assignees: Rtx Corporation
- Applicants: Raytheon Technologies Corporation
- Inventors: Andrew DeBiccari; Zhong Ouyang
- Web page: https://patentgrep.com/patent/US12216184B2

## CPC

- G01R 33/1223: {Measuring permeability, i.e. permeameters (G01R33/14 takes precedence)}
- G01M 15/14: Testing gas-turbine engines or jet-propulsion engines
- G01N 27/83: by investigating stray magnetic fields
- G01N 27/87: using probes
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

A system for magnetically inspecting a metallic component uses a manipulator configured to manipulate a relative position between a part fixture that holds the metallic component and a probe fixture that holds a magnetic probe, thereby causing the probe tip to trace an inspection route along the surface of the metallic component so that the probe tip contacts the metallic component such that an angular difference between the probe axis and a vector normal to the surface is less than a predetermined angle delta. The magnetic probe has a probe tip that measures magnetic permeability of the metallic component along the inspection route, which the controller receives. A method of performing the magnetic inspection is also disclosed.

## Claims

### Claim 1

A system for magnetically inspecting a metallic component having a surface, the system comprising:
a holder configured to hold the metallic component
a probe fixture configured to hold a magnetic probe having a probe tip aligned with a probe axis, the magnetic probe configured to measure a magnetic permeability of the metallic component;
a manipulator configured to manipulate a relative position between the holder and the probe fixture to put the probe tip in contact with the metallic component;
a controller configured to:
control the manipulator to trace an inspection route upon the surface of the metallic component along which the probe tip contacts the metallic component such that an angular difference between the probe axis and a surface tangent plane of the metallic component is 90±10 degrees; and
receive the magnetic permeability of the metallic component measured by the magnetic probe along the inspection route;
a mechanical biasing component, wherein the mechanical biasing component comprises a mechanically compressible component that is configured to maintain contact between the probe tip and the metallic component; and
a force transducer configured to produce a contact force signal that is indicative of a contact force between the probe tip and the metallic component.

### Claim 2 (depends on 1)

The system of claim 1, wherein the controller is further configured to calculate, based on a three-dimensional model of the metallic component, the inspection route.

### Claim 3 (depends on 1)

The system of claim 1, wherein the controller is further configured to:
determine a magnetic anomaly map based on the magnetic permeability of the metallic component;
determine a first corrosion element thickness based on the magnetic anomaly map;
determine a first remaining non-corrosion wall thickness based on a calculation using the first corrosion element thickness and a three-dimensional model of the metallic component; and
transmit the first remaining non-corrosion wall thickness to an operator via an input output interface.

### Claim 4 (depends on 1)

The system of claim 1, wherein the controller is further configured to generate, based on the magnetic permeability measured along the inspection route, a magnetic anomaly map and/or a corrosion map of the magnetic component.

### Claim 5 (depends on 1)

The system of claim 1, wherein:
tracing the inspection route defines a linear speed; and
the linear speed is within a target speed tolerance of a target speed.

### Claim 6 (depends on 5)

The system of claim 5, wherein the target speed ranges from 0.2-10 inches/second (0.5-25 cm/sec).

### Claim 7 (depends on 6)

The system of claim 6, wherein the target speed tolerance is ±5% of the target speed.

### Claim 8 (depends on 1)

The system of claim 1, wherein the controller is further configured to cause the manipulator to maintain the contact force within a contact force tolerance.

### Claim 9 (depends on 8)

The system of claim 8, wherein the contact force tolerance ranges from 0-1 pounds force (lbf) (0-4.4 Nt).

### Claim 10 (depends on 9)

The system of claim 9, wherein the contact force tolerance is ±20% of a target contact force of 0.2 lbf (0.89 Nt).

### Claim 11 (depends on 1)

The system of claim 1, wherein:
the manipulator is manipulatable with three, four, five, or six axes of movement; and
the manipulator comprises an actuator configured to manipulate the holder.

### Claim 12 (depends on 11)

The system of claim 11, further comprising a holder extension configured to separate the metallic component from the actuator by at least a critical separation distance.

### Claim 13 (depends on 12)

The system of claim 12, wherein:
the holder extension comprises a nonmetallic material defining a length; and
the length is at least 4 inches (10 cm).

### Claim 14 (depends on 1)

The system of claim 1, wherein the controller is further configured to:
determine a magnetic anomaly map based on the magnetic permeability of the metallic component;
determine a corrosion map based on the magnetic anomaly map;
determine a material remaining map based on a comparison of the corrosion map and a three-dimensional model of the metallic component; and
transmit the material remaining map to an operator via an input output interface.

### Claim 15 (depends on 1)

The system of claim 1, wherein the magnetic probe is stationary.

### Claim 16 (depends on 1)

The system of claim 1, wherein the metallic component is a blade of a gas turbine engine.

### Claim 17

A system for magnetically inspecting a metallic component having a surface, the system comprising:
a holder configured to hold the metallic component
a probe fixture configured to hold a magnetic probe having a probe tip aligned with a probe axis, the magnetic probe configured to measure a magnetic permeability of the metallic component;
a manipulator configured to manipulate a relative position between the holder and the probe fixture;
a controller configured to:
control the manipulator to trace an inspection route upon the surface of the metallic component along which the probe tip contacts the metallic component such that an angular difference between the probe axis and a surface tangent plane of the metallic component is 90±10 degrees; and
receive the magnetic permeability of the metallic component measured by the magnetic probe along the inspection route; and
a force transducer, wherein the force transducer comprises a piezoelectric cell that is configured to produce a contact force signal that is indicative of a contact force between the probe tip and the metallic component.

### Claim 18 (depends on 17)

The system of claim 17, further comprising:
a mechanical biasing component, wherein the mechanical biasing component comprises a spring that is configured to maintain the contact force within a desired contact force tolerance.