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Portable Laser Coating Removal Systems (PLCRS) : 

Portable Laser Coating Removal Systems (PLCRS) Randall Straw AFRL/MLSC (CTC) (937) 255-5598 randall.straw@wpafb.af.mil 23 October 2002

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Overview Introduction AF Laser Strategy Baseline Processes & Potential Applications Project Objectives & Project Team Project Stakeholders & Demo Sites Accomplishments to Date Test Plan Preliminary Test Results Project Milestones Summary & Conclusions

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DEM/VAL Handheld Laser Technology for Paint Stripping (Nd:YAG, CO2, Diode) - Conventional Coatings - Specialty Coatings – RAM, Sealants, Adhesives - Glovebox Applications DEM/VAL Robotic Laser Technology for Coating Removal - Aircraft Wheels - Radomes - Outer Mold Line Aircraft (Long Term) DEM/VAL Laser Technology for Cleaning and Preparation - Precision Cleaning - Adhesive Bonding - Composite Preparation - Repair Processes (Field/Depot) AF Laser Strategy

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Background Methylene chloride and phenol are still used extensively for stripping components. Supplemental stripping is an expensive, time-consuming process that creates hazardous waste & emissions. Conventional coating systems covered in this project. Specialty coatings will be evaluated in a separate project.

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Representative strip rates and coating system (Baseline Process) Baseline Processes

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Potential Applications

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Potential Applications (Cont’d)

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Potential Applications (Cont’d)

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Potential Applications (Cont’d)

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To demonstrate, qualify and implement a portable, hand-held laser system for depainting of various weapon system components at both depot and field levels. Strip components, small areas of aircraft and ground vehicles, tanks, and helicopters. Qualify laser technologies Evaluation Factors: Strip rate Logistic footprint Ergonomics Power needs Operational /Technical Requirements Project Objectives

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Project Stakeholders & Demo Sites Stakeholders U.S. Air Force U.S. Marine Corps U.S. Army National Aeronautical and Space Administration (NASA) Northrop Grumman Boeing Aerospace Lockheed Martin Aircraft U.S. Navy (monitoring) Proposed Site Demo Locations WR-ALC, GA OC-ALC, OK OO-ALC, UT Kennedy Space Center, FL Barstow USMC, CA Edwards AFB, CA Corpus Christi Army Depot, TX Wright Patterson AFB, OH* *Initial Demonstration

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Project Team AFMC/LGP-EV (D. Meredith) Program Management Tri-Service Stakeholders UDRI Support Contractor Quantel Laserline SLCR SAIC ESTCP CleanLaser P2 IPT

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Accomplishments-to-Date Joint Test Protocol (JTP) Identifies stakeholder requirements necessary to dem/val technology Received endorsements from F-16, A-10, T-37,B-52, ICBM, Minuteman III, T-38, SOF SPO, Production Council at WR-ALC, Commodities Directorate (OO-ALC), TIESM (OC-ALC), LP (OC-ALC) Potential Alternative Report (PAR) Includes detailed information on 14 laser vendors Completed Feb 01 Site Surveys (Baseline Process Information) Cost Benefit Analysis (CBA) Laser Optimization & Strip Rate Evaluations Currently Laboratory Testing

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Laser Systems Highly Portable Low Cost Highly Maneuverable Suited for Small Area Stripping Adaptable for Glove box Design Highly Portable Low Cost Highly Maneuverable Suited for Small Area Stripping Adaptable for Glove box Design Highly Portable Low Cost Highly Maneuverable Suited for Larger Area Stripping Diode Nd:YAG TEA-CO2 Ave. Strip Rate Low-Medium Cost Suited for Large Area Stripping Nd:YAG

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Test Plan Materials to be tested 2024-T3 Al both bare and clad 7075-T6 Al both bare and clad Metallic (Al) honeycomb Fiberglass/Epoxy Graphite/Epoxy Steel 4130 Kevlar

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Coating Systems

Test Plan: 

Test Plan Strip Rate Substrate Temperature Measurements Embedded Thermocouples Adhesive Temperature Sensors Damage Assessments Warping & Denting Metal Erosion Resin erosion and fiber damage on composite materials Hardness Testing Rockwell Hardness & Micro-hardness

Test Plan (Cont’d): 

Test Plan (Cont’d) Mechanical Testing (Metals) Tensile Testing Fatigue Testing Smooth (=Standard Fatigue) Open Hole Center-crack Clad penetration Confirmation of Cladding Penetration Determination of Cladding Loss Surface profile/roughness

Test Plan (Cont’d): 

Test Plan (Cont’d) Damage Assessment to Honeycomb Materials Measure peel resistance of adhesive bond between face sheets and honeycomb core. Damage Assessment to Composite (Graphite Epoxy) Materials (on hold) Four Point Flexure Tension Testing Compression Testing Open Hole Fatigue Testing Note: All test panels will undergo 4 paint and de-paint cycles unless specified otherwise.

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Preliminary laser demonstrations at vendors sites showed that laser meet or exceed the goal of 0.06 ft2/min / baseline process strip rate. TEA-CO2 (250W): 0.014-0.068 ft2/min Nd:YAG (40W): 0.012 –0.056 ft2/min Diode : 0.039 – 0.15 ft2/min Nd:YAG (120W): 0.032 – 0.090 ft2/min More data being generated Strip Rates depend on coating thickness, coating type, and substrate. Preliminary Test Results

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Preliminary Effluent Testing Results (TEA-CO2 Laser) No detectable levels of hazardous vapors / volatile bi-products. Paint particulates primary concern (Chromated) Half-face mask used as extra precaution to avoid inhalation of chromated paint particulates. Hearing protection required. (94.9 dbA TWA based on an OSHA 5db exchange rate) Some Air Sampling not Completed to Date Air Sampling will be conducted on each laser Air sample results will be compared to Air Force Occupational Exposure Limits (OELs) Vacuum systems being integrated to the laser system to capture dust/fumes. Preliminary Test Results (Cont’d)

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Project Summary Moving forward in gathering test data Preliminary laser strip rates can compete with baseline operations High demand and interest (DoD and Industry) for supplemental stripping tools / handheld lasers Future is very promising Developing technical order, procurement specification, and addressing safety issues.

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Project Milestones Laser Optimization – Phase I Completed Strip Rate Evaluations (on-site) Completed Laboratory Testing Apr 02-Dec 03 Design Review & Optimization Phase II Aug 03 Final Design Review & Lab Test Results Dec 03 DoD Dem/Val Testing at Sites Jan 04-Jan 05 Procurement Specification & Tech Order May 05

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Conclusions “ Lasers are the Stripping Wave of the Future “

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Contact Information Randall Straw AFRL/MLSC (CTC) (937) 255-5598 randall.straw@wpafb.af.mil

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Preliminary Strip Rates (Vendor Sites) Preliminary Test Results - Strip Rates (on-site) Note: All data in ft2/min Lasers meet goal of 0.06 ft2/min / baseline process strip rate

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Preliminary Test Results TEA-CO2 Demo Strip Rates (Interim Data)