automated dimensioning and ultrasonic inspection capability for … · 2011. 3. 1. · cleared for...

Cleared for Public Release Case No. 88ABW-10-2237

Automated Dimensioning and Ultrasonic

Inspection Capability within the TESI

Robotic Inspection System

James Sebastian, Victoria A. Kramb and Robert Olding

University of Dayton Research Institute

Under United States Air Force Contract F42620-00-D-0039

(RZ02)

The 53rd Annual ATA NDT Forum

Albuquerque, New Mexico

September 21, 2010


Inspection system requirements: – Embedded defect inspection system goal: life extension

of turbine engine components

– Depot/production environment

– Fully automated execution—including part pass/fail

decisions

– Demonstrate OEM mandated ultrasonic coverage and

sensitivity

– Satisfy reliability and repeatability requirements of USAF

TESI System Background—

Design Requirements

Build on lessons learned from previously

designed automated inspection systems!


System Requirements for Automated

Ultrasonic Inspections

Previous design experience with

fully automated depot level inspections—

Fully automated!

Operator/station independent!

Conventional industrial

ultrasonic inspection technology—

NOT automated!

NOT operator independent!


System Requirements for Automated

Ultrasonic Inspections

Learn from industrial successes—

Robotic manipulator, rotational water tank,

phased array ultrasound

Opportunities for improvement—

Operator making

defect decisions

Part loading

awkward

No modularity = Difficult to expand

Expensive, semi-custom mechanics

Submersible turntable = Maintainability problems


TESI Ultrasonic Inspection System

Design Highlights

• Designed with COTS components

• Six-axis Industrial Robotic Manipulator

• Open Architecture Robotic Controller

• Rotating Water Tank

• Integrated Vision System

• Phased Array Ultrasonics

• Windows XP Operating System

• Scan Plan Language (C++)

• Fully Automated

2001 2005


Design Requirements Implementation

• Reliability and repeatability—Use automation – All inspection commands contained within a single executable program

– All inspections run from a centralized server location

– All results stored on a centralized database

• Defect locating and sizing requirements—Inspections are part

specific – Inspections designed as a part specific ―scan plan‖

– Accounts for part-to-part dimensional variability

– Software displays/locates defects within actual component

• Inspection repeatability—verify probe performance – Verify probe positional accuracy

– Verify performance repeatability

• Detection sensitivity and coverage validation— – Verify coverage with geometrically correct specimens

– Conduct POD analysis with standardized targets


Reliability and Repeatability—

Through Automation

Off-line Scan plan creation:

• Same software package used to create all executable scan plans

• Tested through robotic motion simulation

• Based on part CAD drawings

Scan plan downloaded from database

• Station, probe S/N independent

• Results reviewed on-line or remotely


Defect Location and Sizing—

Account for Part and Probe Variability

Part dimensional variability due to service

• Scan plan created from CAD drawing—Adapt to part warpage

Measure current part dimensions

Recalculate robot motion

Stage Deviation from

CAD position

Rotational

Deviation

top

surface

bottom

surface

top

surface

bottom

surface

(mm) (mm) (mm) (mm)

1 -- -0.965 -- -0.279

2 0.508 0.9906 0.2794 0.1524

3 1.143 1.1176 0.127 0.1524

max.

allowed

3.81 3.81 1.905 1.905


Machined defects within actual component

• Used to demonstrate inspection Coverage, Repeatability, and

Reliability

Inspection results


Demonstrate with Actual Parts

1 2

3

5

6 7 8

Cross section

inspection surfaces

inspection

surface



Defect Position Variability

Inspection results Defects located within part geometry • Adapted for specific part dimensions


Inspection Repeatability— Probe Position Accuracy

Robotic positional accuracy:

– Highly accurate probe positioning:

turntable: 0.001 deg., robotic

repeatability: ±0.04 mm.

Probes positioned based on tool

offsets

– Allows for probe construction variability

– Daily checks allow for performance

verification


Inspection Repeatability—

Phased Array Implementation

Array Probe Features

• linear arrays provide beam

forming and steering capability

thus reducing the number of

transducer changes

• electronic scanning capability

provides for rapid inspection

execution

• flexible probe tool designs can

be customized for complicated

part geometries

electronic

scanning

electronic

scanning

5MHz linear array

z

y

x

10MHz

linear array



Verify Probe Performance

Routine System and Probe Alignment Check

– Ultrasonic probe positioning checked in all 6 degrees of freedom: x, y, z, yaw, pitch, roll

– prior to gain calibration, and after inspection

– alignment check the same for all ultrasonic

probes, and all inspection systems

– verifies probe offsets and robot accuracy

System and Probe Alignment Check:

Verifies Tool Offsets and Robot Accuracy

– independent of inspection application

– defining the inspection location based on

transducer face position

– positional accuracy checks done routinely,

not as periodic maintenance

roll

z, roll

x, pitch y, yaw

alignment block

electronic

scanning

z

y

x

10MHz

linear array




Probe Alignment Check • verify probe orientation

• yaw, pitch, roll

• verify probe positional accuracy

• values saved with inspections to monitor system performance

• monitor probe tool offsets or robot accuracy

Alignment check block

FBH

roll

pitchyaw

setup specimen

roll

pitchyaw

setup specimen

ultrasonic transducer


• Calibration repeatable

– ±1.1dB over 24 months with same probe

– Variability independent of inspection mode

• Monitor by channel, SDH, probe, station, TOF, mode

Phased Array Calibration Variability



Gain±1.1dB

TOF±2.4us

6/2006 through 6/2008


Inspection Coverage Verification

• Coverage confirmed with machined

targets

– embedded defects used to verify depth

coverage (#3RBH, #3FBH)

– notches used to verify surface area

coverage (0.003” X 0.003” X 0.028”)

• Sensitivity measured for different

inspection modes

– results compared to conventional

transducer response

• Defect locating capability checked

using known target locations turbine engine

component cross section

notches

drilled holes


• Inspection requirements include defect correlations

– Multi-mode interrogation approach requires amplitude

comparisons between multiple look angles

– RBHs provide multiple reflective surfaces for longitudinal and

shear modes

+45 shear

-45 shear

offset angle




1 2

3

5

6 7 8

Cross section

inspection surfaces

inspection

surface

RBH #1, 2, 3

RBH #5

RBH #6, 7, 8

EDM notches

Forward view

Longitudinal Scan

60 Shear Scan

Radial/Axial Scan

45 Shear Scan

Scan Segments Overlap

Area 1 Coverage

Area 4A Coverage

Longitudinal Scan

60 Shear Scan

Radial/Axial Scan

45 Shear Scan

Scan Segments Overlap

Coverage maps show actual inspection volume


• Comparisons show that phased array sensitivity is equal or

better than single element – no clear dependence on part geometry or depth

• Sensitivity measured for different inspection modes – no dependence observed

Hole

depth longitudinal +45 shear -45 shear +60 shear -60 shear

Hole # (inches) (amp., %) (amp., %) (amp., %) (amp., %) (amp., %)

1 0.25 63/51 85/52 78/44 40/31 62/21

2 0.5 63/34 58/24 26/-- -- --

3 0.75 39/31 42/43 23/28 -- --

4 N/A -- -- -- -- --

5 0.25 83/46 56/50 59/67 85/36 54/26

6 0.25 57/37 35/20 49/49 100/52 100/32

7 0.5 83/30 45/20 49/24 -- --

8 0.65 40/-- -- -- -- --

Phased Array / Conventional Single Element

Ultrasonic Mode

Detection sensitivity and coverage

validation—

Inspection Coverage and Sensitivity Comparison

with Single Element Probe


• POD Specimen 1

• Design addresses normal

incidence across Bore ID

and Conical.

• Design also addresses

oblique incidence across

Conical.

POD specimen 1

Fixture

• 2nd POD Specimen

• Design addresses oblique

incidence across Bore ID.

POD specimen 2

1. Machined targets in representative specimen—POD analysis

Inspection Sensitivity Verification


1. Machined targets in representative specimen—POD analysis


POD of TESI UT 45 Shear Inspection on Conical Surface for 0.25 Inch Depth FBHs

Combination of T1, A, P3; T4,A,P2; T5,B,P3; T8,B,P2, 05/11/2006

0

5

10

15

20

25

30

35

40

0 10 20 30 40 50 60 70 80 90

Decision Threshold (%)

Fla

w,

Dia

m o

f F

BH

(M

ils

)

a50/50

a90/50

a90/95

Thresholds (% full scale)

Fla

w d

iam

ete

r (m

m)

a50/50

a90/50

a90/95


• Detection Sensitivity—Ultrasonic inspections verified with POD

analysis – POD for specific reflectivity and sphere diameter can be correlated with actual

embedded defect behavior


Sphere Diameter (mm)

Am

plit

ude


Summary

• Reliability and repeatability—Use automation – Software application used to automatically generate robot motion commands

– All probe calibration, positioning and performance checks automated

– Demonstrated with minimal long term performance variability


specific – System modular architecture allows for flexibility in incorporating part specific

inspection requirements

– Account for part-to-part dimensional variability for probe positioning and defect

location

• Inspection repeatability—verify probe performance – Verify probe positional accuracy each time it is used—demonstrated accuracy

repeatability with long term results

• Detection sensitivity and coverage validation— – Distinguished between coverage and sensitivity testing

– Verify coverage with geometrically correct specimens


automated dimensioning and ultrasonic inspection capability for … · 2011. 3. 1. · cleared for...

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