Appendix D
Evaluation Matrix Features and Factors Ranking Criteria

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The ranking of the features and factors of the scanner systems listed below used the general criteria for assigning numbers from 1 to 5;
Rank Explanation
1 Not applicable for aircraft applications
2 Limited for aircraft applications
3 Adequate but could be improved for aircraft applications
4 Good, generally applicable for aircraft applications
5 Ideal, meets all requirements for aircraft applications
Specific features and factors in the Evaluation Matrix Table were ranked with the following criteria:
Feature Rank Explanation
DESIGN
Basic Design General functionality for easy scan coverage of area of interest
1 Not applicable for aircraft applications
2 Limited for aircraft applications
3 Adequate but could be improved for aircraft applications
4 Good, generally applicable for aircraft applications
5 Ideal, meets all requirements for aircraft applications
Mount Type Implementation. relocation ease. stability
1 Not stable, fails often during scan
2 Fails occasionally during scan
3 Adequate but could be improved for aircraft applications
4 Good, generally applicable for aircraft applications
5 Ideal, meets all requirements for aircraft applications
Sensor Holder, Gimbals Design Ability to accommodate various sensor sizes and maintain sensor perpendicularity
1Not applicable for aircraft applications
2 Limited for aircraft applications
3 Adequate but could be improved for aircraft applications
4 Good, generally applicable for aircraft applications
5 Ideal, meets all requirements for aircraft applications
Couplant Feed Ultrasonic pulse-echo or resonance testing only
1 Not applicable for aircraft applications
2 Limited, couplant sprayed or wiped on
3 Adequate but could be improved by better design
4 Good, automatic feed with few problems
5 Ideal, automatic feed with no problems
Scanner Working Distance Hight Distance needed to scan between vertical obstruction and aircraft
1 Greater than 48 inches
2 Between 24 and 48 inches
3 Between 12 and 24 inches
4 Between 6 and 12 inches
5 Less than 6 inches
X-Y Axis Resolution
1 Greater than 0 50 inch
2 Between 0 35 to 0 50 inch
3 Between 0.20 to 0 35 inch
4 Between 0 05 to 0 20 inch
5 Between 0 01 to 0 05 inch
PORTABILITY
Scanner Weight
1 Over 30 pounds
2 Between 15 to 30 pounds
3 Between 5 to 15 pounds
4 Between 1 to 5 pounds
5 kinder 1 pound
Ruggedness General use of scanner without failure of machanical components
1 Not applicable for aircraft applications
2 Limited for aircraft applications
3 Adequate but could be improved for aircraft applications
4 Good, generally applicable for aircraft applications
5 Ideal, meets all requirements for aircraft applications
Deployment Ease Time from off the shelf to start of scan or relocation
1 Greater than 1 hour
2 Between 30 to 60 minutes
3 Between 15 to 30 minutes, 5 minutes relocation
4 Between 10 to 15 minutes, 2 minutes relocation
5 Under 10 minutes, 1 minute relocation
Computer Hardware Portability of total system. scanner. computer. motor controller etc.
1 System components greater than 100 pounds
2 System components greater than 50 pounds
3 System components between 25 and 50 pounds
4 System components between 10 and 25 pounds
5 System components less than 10 pounds
Motor Controller Physical size and weight considerations
1 Not applicable for aircraft applications
2 Limited for aircraft applications
3 Adequate but could be improved for aircraft applications
4 Good, generally applicable for aircraft applications
5 Ideal, meets all requirements for aircraft applications
ARTICULATION
Complex Shapes Scanner is usable on curvatures and irregular shapes
1 Scanner can only be used on flat surfaces
2 Scanner can only be used on curvatures greater than 10 feet radius
3 Scanner can only be used on curvatures greater than 5 feet radius
4 Scanner can be used on compound curvatures greater than 1 foot radius
5 Scanner can be used on all aircraft structures
Surface Conditions Surface roughness. obstructions, raised rivets. raised lap joints
1 Scanner operates on smooth surfaces only
2 Scanner cannot operate over lap joints
3 Scanner can operate over or around lap joints but not raised rivets
4 Scanner can operate over or around raised rivets
5 Scanner can accommodate all conditions
PERFORMANCE
Speed of coverage Time to scan 2 square foot area on fuselage
1 Greater than one hour
2 Between 30 to 60 minutes
3 Between 15 to 30 minutes
4 Between 5 to 15 minutes
5 Less than 5 minutes
Accuracy Scanner sensor location with respect to increment spot size (0.1 inch)
1 Over 5 spot sizes (greater than 0.5 inch)
2 5 spot sizes (0.5 inch)
3 2 spot sizes (0.2 inch)
4 1 spot size (0.1 inch)
5 Less than one spot size (< 0.1 inch)
Problems Factors that limit use of the scanner for some applications
1 Numerous and serious for aircraft applications :
2 Serious but can be remedied for aircraft applications
3 Annoying but can be improved for aircraft applications
4 Minor
5 None
USABILITY
Ease of Scan for Examiner Operator effort to scan an area greater than 1 square foot
1 Effort not tolerable for aircraft applications
2 Effort is tiring, tedious, but tolerable
3 Effort requires continuous operator attention, labor intensive
4 Effort requires occasional operator attention, not labor intensive
5 Effort is not required
Vertical Obstruction Clearance Needed Clearance needed to operate the scanner with the examiner conducting the scanner.
1 Greater than 48 inches
2 Between 24 to 48 inches
3 Between 12 to 24 inches
4 Between 6 to 12 inches
5 Less than 6 inches
SOFTWARE
Ease of Use for Examiner Experience and intuitive operation of software execution of commands
1 Difficult to execute, need to remember steps, commands etc.
2 Steps are not clear and confusing
3 Adequate but need to remember some commands
4 Good, generally needs 1 day of training
5 Very intuitive, self explanatory steps to follow
Ease of Setup Input Parameters Examiner ease to define scan area. scan limits. scan increments file names etc.
1 Difficult, need to run different programs etc.
2 Separate programs for scanner and image construction
3 All input parameters must be typed in from key board
4 Good, default values easy to change at graphical user interface
5 Ideal, macros, values easy to change as desired
Data Acquisition Characteristics Fast. high resolution data acquisition capabilities
1 Not applicable for aircraft applications
2 Less than 8 bit resolution
3 8 bit resolution, 286 PC or equivalent CPU
4 8 bit resolution, 386 PC or equivalent CPU
5 16 bit resolution, 486 PC or equivalent CPU
Image Display Large screen. 16 color palette or better. proportional XY image
1 Monochrome screen
2 8 color palette, image XY not proportional, 10 inch or less screen
3 8 color palette, image XY proportional but small, 10 inch or less screen
4 16 color palette, image XY proportional, large screen
5 256 color palette, image XY proportional and large, 15 inch screen
Imaging and Data Processing Advanced image processing features was not rated. the system real-time C-scan imaging capabilities were ranked
1 No real-time C-scan image
4 Real-time image but post processing necessary for final image
5 Real-time image for immediate interpretation of results
Hard Copy Capability Ability to provide immediate hard color copy of results
1 No hard copy capability
4 Hard copy only after data and image processing
5 Immediate hard copy capability
Operator Training for Experience Level Training for ASNT Level recommended by vendor when system is procured
1 Greater than two weeks for experienced Level II
2 2 weeks for Level II, or Level III
3 3 to 5 days for Level II or Level III
4 2 to 3 days for Level II or Level III
5 1 to 2 days for Level II or Level III
NDI Mode Support Modes supported can be eddy current. ultrasonic pulse-echo. and resonance bond testing
3 Only one mode supported
4 Two modes supported
5 Three Modes supported
COST
Cost Hardware & Software
1 Over $200,000
2 Between $100,000 and $200,000
3 Between $50,000 and $100,000
4 Between $25,000 and $50,000
5 Less than $25,000
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© Copyright 1. Nov 1997 Rolf Diederichs, rd@ndt.net