Transcript Sealant Removal from A-10 Center Wing Fuel Tanks Using a

Sealant Removal from A-10 Center Wing
Fuel Tanks Using a Portable Hand-Held
Nd: YAG Laser System
Norman J. Olson
Pacific Northwest National Laboratory
Richland, Washington 99352
Mitchell Wool
General Lasertronics Corporation
San Jose, California 95112
2005 CTMA Symposium – Tacoma, WA
April 18-21, 2005
The Problem
> 300 A-10 Aircraft in Service
Center Wing Fuel Tank Cells
Have Fasteners Covered with
Sealant
(Primer Coating Elsewhere)
Sealant in Fuel Tanks Needs
to be Removed for NDE
and/or Repair
Sealant Removal from Center
Wing Tanks is Tedious and
Expensive
Need a Less-Expensive,
Faster Alternative
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The Problem
Current Technology is Hand
Scraping
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Difficult and Slow
Incomplete Cleaning is Highly
Likely
Damage to Substrate is Likely
Laser Coating Removal
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Offers Potential
Minimal Experience in
Confined Spaces
Many Unanswered Questions
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Demonstration Objectives
and Requirements
A portable Nd: YAG laser that can remove sealant more
economically than current methods,
A hand-held delivery system that is capable of removing all
sealant in the center wing section,
A hand-held delivery system that is easy and safe to use,
A system that has the potential to remove only sealant and
not primer (color recognition), and
A system that has reasonable reliability so that it will be
operational for long periods of time without maintenance.
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Target for Demonstration
A-10 SPO Sent Retired Center
Wing Fuel Tank Section to
General Lasertronics Corporation
Facilities in San Jose, CA
Demo Wing Section Had Eight
(8) Access Ports to Fuel Cells
There Were Approximately 600
Fasteners Covered with Sealant
in Each of the Eight (8) Fuel Cells
Access Ports Barely Large
Enough for Operator
Cell
Opening
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Attributes Needed to Meet Requirements
for A-10 Center Wing Tank
Portability and reliability – DP Nd: YAG laser
Compact hand-held end effector that can operate
in confined space – GLC SBIR design
Ability to see target area even if there are
obstacles in line of sight
Meet laser safety and environmental issues
TWO-dimensional automated beam scanning to
eliminate substrate damage potential and to
ensure complete and systematic coating removal
Color recognition – potential to selectively remove
sealant without disturbing other coatings
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200 and 500 Watt Demonstrations Using
GLC-Developed Systems
200 watt , 13 kHz, Nd: YAG
Lamp-Pumped, Q-Switched
System was Used for the Demo
Conducted 9/21/2004
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US Laser 406Q laser
500 watt, 10 kHz, Nd: YAG,
Diode-Pumped, Q-Switched
System was Used for the Demo
Conducted 12/9-10/2004
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Cutting Edge Optronics Laser:
Northrop-Grumman
Operator Uses Video Display if
Line-of-Sight Obstructions Exist
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GLC Confined Space Tool
for Laser Coating Removal
End Effector Consists of:
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Laser Aperture
Two-Dimensional Scanning
25 cfm Air Blow from Aperture
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Cooling
Clear Work Area
Video Camera
Optical Fiber Umbilical
Cell Waste Evacuation
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Separate 300 CFM Purge
Remove Ablated Debris
Remove Sealant Vapors
Maintain Good Visibility
Camera
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Demonstration Results
Sealant Removed from
Equivalent Fastener
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200 watt in ~ 1 Minute
500 watt in < ½ Minute
Estimate of Labor for Entire
Center Wing Fuel Tank

GLC Laser Tool Using the
500 watt System
One 8 Hour Shift
24 Equivalent
Fasteners
Conventional Scraping
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Has never been fully
completed
>> 800 work hours
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Demonstration Results
Color Recognition Potential
Demonstrated on
Automated System to
Remove Coatings from
Other Aircraft
Color Recognition
Previously Demonstrated
with a GLC Hand-Held
Delivery Tool
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Demonstration Objectives Met
A portable Nd: YAG laser can easily remove sealant more
economically than current scraping methods
A hand-held delivery system could be configured to remove
all sealant in the center wing section
With minimal operator training, a hand-held laser delivery
system is easy and safe to use
The system could be configured to remove only sealant and
not primer by implementing existing color-dependent
sensing technology and automated laser firing controls
The system has reasonable reliability so that it will be
operational for long periods of time without maintenance.
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Safety
Requirements
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Filtered (Clear) Glasses Worn by Operators
Work Area Secured the Same as a Welding Area
No Other Personal Protective Equipment Needed
Recommendations
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Two Operators in Work Area
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Improve Productivity by Maximizing Trigger Time
Keep Work Area Clear of Unauthorized Personnel
Could Enclose Work Area with Filtered Glass
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Recommendation for NCMS/
CTMA Project
Implement System at Hill AFB
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Build hand-held laser system for test, evaluation, and
subsequent installation
Develop laser system operating parameters to ensure
sealant removal without 2024-T3 Al substrate damage
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Systematic exposure over a range of laser conditions
Collect metallographic and SEM information and relate to
mechanical test data over statistically significant data sets
Develop end-effector attachments for easier access to all
fasteners within A-10
Project Funding ~ $1500K, including cost-sharing
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