FP-300 Laser Cleaning Guide — Aircraft Surface Restoration — Aviation Laser Support | Aviation Laser

1. SYSTEM SPECIFICATIONS FeatherPulse FP-300 Core Parameters

• Wavelength: 1064 nm (Ytterbium-doped fiber)

• Average Power: 300W maximum

• Pulse Duration: 20-200 ns (adjustable)

• Repetition Rate: Up to 500 kHz

• Spot Size: 0.8 mm

• Beam Profile: TEM00 Gaussian (M2 ≈ 1.1-1.3)

• Scan Patterns: Petal, Raster, Circular, Spiral Critical Safety Thresholds

• Maximum Substrate Temperature: 120°C (monitor with IR sensor)

• Base Metal Loss Limit: <2% thickness

• Surface Roughness Target: Ra 0.8-1.6 μm

2. BASELINE STARTING PARAMETERS Your Specified Starting Point:

• Power: 75% (225W)

• Frequency: 45 Hz (45 kHz)

• Pulse Duration: 165 ns

• Scan Pattern: Petal form

• Application: White glossy enamel paint with primer Fluence Calculation Formula: Fluence (J/cm2) = Pulse Energy (J) / (0.785 × d2) where d = spot diameter in cm

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3. PAINT REMOVAL PARAMETERS BY TYPE 3.1 EPOXY/POLYURETHANE PRIMER Standard Military Spec: MIL-PRF-23377, MIL-PRF-85582 Parameter Range Optimal Notes Power 200-250W 225W 75% setting Pulse Width 80-100 ns 90 ns Shorter for thin layers Rep Rate 25-40 kHz 35 kHz Higher for uniform removal Spot Diameter 0.8 mm 0.8 mm Maintain focus Fluence 3-7 J/cm2 5 J/cm2 Threshold ~5 J/cm2 Scan Speed 18K-25K mm/s 20K mm/s Adjust for thickness Passes 1-2 2 Stop at dull-grey substrate Scan Pattern Petal/Raster Petal 30-50% overlap Visual Indicators:

• Yellow/green primer completely gone

• Substrate appears dull-grey (not shiny)

• No visible melting or pitting 3.2 ACRYLIC POLYURETHANE TOPCOAT Standard: MIL-PRF-85285 Parameter Range Optimal Notes Power 240-300W 270W 90% setting Pulse Width 90-120 ns 105 ns Longer for thicker coats Rep Rate 12-20 kHz 16 kHz Lower prevents overheating Spot Diameter 0.6±0.1 mm 0.6 mm Smaller for precision

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Aviation Laser Services © 2025 Parameter Range Optimal Notes Fluence 17-25 J/cm2 20 J/cm2 Damage threshold ~25 J/cm2 Scan Speed 15K-25K mm/s 18.5K mm/s Slower for complete removal Passes 2-4 3 Layer-by-layer approach Scan Pattern Raster Raster Systematic coverage 3.3 SPECIALTY COATING ADJUSTMENTS Two-Component Epoxy Paint

• Power Increase: +10-15% from baseline

• Pulse Duration: 150-180 ns

• Multiple Passes: 3-5 required

• Scan Speed: Reduce by 25% Polysiloxane Coatings

• Power: Maximum 280W

• Pulse Width: 100-120 ns

• Caution: Silicon residue may require secondary cleaning Fluoropolymer Coatings (Rain Erosion)

• Power: 250-280W

• Pulse Duration: 120-150 ns

• Scan Pattern: Circular for even removal

• Note: Extremely resistant, may need chemical pre-treatment

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4. PAINT COLOR-SPECIFIC ADJUSTMENTS 4.1 COLOR ABSORPTION CHARACTERISTICS Paint Color Absorption Rate Power Adjustment Pulse Duration Notes Black Very High (95%) -15% to -20% -10 ns Risk of overheating Dark Blue High (85%) -10% to -15% Standard Monitor temperature Dark Green High (80%) -10% Standard Good absorption Red Moderate (70%) Baseline Standard Standard settings Grey Moderate (65%) Baseline Standard Neutral response Yellow Low (45%) +10% +10 ns Requires more energy White Very Low (35%) +15% to +20% +15 ns Maximum reflection Metallic Variable (40-60%) +5% to +10% Standard Test first 4.2 DETAILED COLOR PARAMETERS WHITE PAINT (Your Starting Point) Parameter Initial Adjustment Final Power 225W (75%) +15% 260W (87%) Frequency 45 kHz No change 45 kHz Pulse Duration 165 ns +10 ns 175 ns Scan Speed Standard -15% 275 mm/s Passes 2 +1 3

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Aviation Laser Services © 2025 BLACK PAINT Parameter Initial Adjustment Final Power 225W (75%) -20% 180W (60%) Frequency 45 kHz +10 kHz 55 kHz Pulse Duration 165 ns -15 ns 150 ns Scan Speed Standard +20% 360 mm/s Passes 2 No change 2 BLUE GLOSS Parameter Initial Adjustment Final Power 225W (75%) -10% 200W (67%) Frequency 45 kHz No change 45 kHz Pulse Duration 165 ns -5 ns 160 ns Scan Speed Standard +10% 330 mm/s Passes 2 No change 2 RED PAINT Parameter Initial Adjustment Final Power 225W (75%) No change 225W (75%) Frequency 45 kHz No change 45 kHz Pulse Duration 165 ns No change 165 ns Scan Speed Standard No change 300 mm/s Passes 2 No change 2

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5. ALUMINUM SUBSTRATE SPECIFICATIONS 5.1 ALUMINUM 2024-T3 (BARE) Composition: Cu 4.2%, Mg 1.6%, Mn 0.8% Parameter Setting Critical Limits Max Fluence 24 J/cm2 Damage threshold Max Temperature 110°C Lower than Alclad Cleaning Threshold 2-4 J/cm2 For oxide removal Surface Finish Target Ra 1.0-1.2 μm Ideal for primer Max Power 250W Prevent melting 5.2 ALCLAD ALUMINUM Pure aluminum cladding over 2024 core Parameter Setting Critical Limits Max Fluence 20 J/cm2 Preserve cladding Max Temperature 120°C Standard limit Cladding Thickness 25-75 μm Do not penetrate Power Limit 240W Protect cladding Visual Stop Satin finish Not mirror polish 5.3 ALODINE COATED (CHROMATE CONVERSION) MIL-C-81706 / MIL-DTL-5541 Parameter Setting Critical Limits Max Fluence 15 J/cm2 Preserve coating Cleaning Mode Gentle Selective removal Power Range 150-200W Lower settings

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Aviation Laser Services © 2025 Parameter Setting Critical Limits Pulse Duration 60-80 ns Short pulses Color Change Gold to light gold Stop indicator 5.4 ANODIZED ALUMINUM Type II (MIL-A-8625) Parameter Range Optimal Pulse Width 60-90 ns 75 ns Rep Rate 30-40 kHz 35 kHz Spot Diameter 0.8mm 0.8 mm Fluence 1.5-3 J/cm2 2 J/cm2 Scan Speed 300-450 mm/s 375 mm/s Passes 1 Single pass only Power 200-240W 220W

6. CORROSION REMOVAL PARAMETERS 6.1 CORROSION TYPES - LASER EFFECTIVE PITTING CORROSION Effectiveness: EXCELLENT Parameter Light Pits (<0.003") Medium Pits (0.003-0.010") Deep Pits (>0.010") Power 180-200W 220-250W 260-280W Pulse Width 80-100 ns 100-120 ns 120-150 ns Rep Rate 30-40 kHz 25-35 kHz 20-30 kHz Fluence 2-4 J/cm2 4-6 J/cm2 6-8 J/cm2

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Aviation Laser Services © 2025 Parameter Light Pits (<0.003") Medium Pits (0.003-0.010") Deep Pits (>0.010") Scan Speed 200-300 mm/s 150-200 mm/s 100-150 mm/s Passes 2-3 3-4 4-6 Pattern Circular Petal Cross-hatch Process Notes:

• Start with low power "mapping" pass

• Increase power progressively

• Final pass at low power for surface finish

• Stop when satin aluminum visible SURFACE OXIDATION Effectiveness: EXCELLENT Severity Power Duration Speed Passes Light Bloom 150W 60 ns 25K mm/s 1 Moderate 180W 80 ns 20K mm/s 2 Heavy 220W 100 ns 18K mm/s 2-3 FILIFORM CORROSION Effectiveness: GOOD

• Challenge: Subsurface propagation

• Approach: Layer removal technique

• Power: 200-240W

• Multiple Angles: Rotate scan pattern 45°

• Passes: 3-5 minimum

• Verification: Eddy current after cleaning

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• Power Range: 180-220W

• Caution: May require mechanical blend

• Focus: Remove corrosion products only

• Post-Treatment: Immediate conversion coating 6.2 CORROSION TYPES - LASER INEFFECTIVE INTERGRANULAR CORROSION Effectiveness: POOR - DO NOT USE LASER Reasons:

• Penetrates along grain boundaries

• Not visible from surface

• Laser cannot reach internal structure

• Risk of masking deeper damage Required Action:

• Stop laser cleaning immediately

• Mark area for engineering evaluation

• Potential part replacement required

• NDI inspection mandatory EXFOLIATION CORROSION Effectiveness: POOR - LIMITED USE Limitations:

• Layer separation internal

• Surface cleaning inadequate

• Structural integrity compromised

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• Maximum 150W power

• Evaluation pass only

• Engineering approval required

• Consider alternative methods STRESS CORROSION CRACKING Effectiveness: NOT APPLICABLE

• Never attempt laser cleaning

• Requires specialized repair

• Engineering evaluation only

7. ADVANCED PARAMETER OPTIMIZATION 7.1 SCAN PATTERN SELECTION Pattern Best Use Overlap Speed Factor Petal Curved surfaces, initial removal 30-50% 1.0x Raster Flat panels, systematic coverage 20-30% 1.2x Circular Spot treatment, corrosion pits 40-60% 0.8x Spiral Fastener areas, small zones 50-70% 0.7x Cross-hatch Stubborn coatings, deep corrosion 60-80% 0.6x 7.2 MULTI-LAYER REMOVAL STRATEGY Layer 1: Topcoat

• Power: 90% (270W)

• Speed: Fast (25K mm/s)

• Objective: Bulk removal

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• Power: 75% (225W)

• Speed: Medium (20K mm/s)

• Objective: Controlled removal Layer 3: Surface Prep

• Power: 50% (150W)

• Speed: Slow (15K mm/s)

• Objective: Final cleaning 7.3 EDGE AND RIVET LINE TREATMENT Feature Power Reduction Speed Adjustment Special Notes Panel Edges -20% -30% Prevent burn-through Rivet Heads -15% -25% Circular pattern Lap Joints -25% -40% Risk of hidden corrosion Fastener Holes -30% -50% Minimum passes

8. QUALITY CONTROL CHECKPOINTS 8.1 PRE-CLEANING VERIFICATION

• Substrate thickness measurement

• Corrosion depth assessment

• Paint system identification

• Coupon test completed

• PPE and ventilation active 8.2 DURING CLEANING MONITORING

• Surface temperature <120°C

• No visible melting

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• Uniform removal pattern

• No base metal discoloration

• Fume extraction functioning 8.3 POST-CLEANING INSPECTION

• Surface roughness Ra 0.8-1.6 μm

• Water break-free test passed

• Thickness loss <2%

• No heat affected zones

• Ready for conversion coating

9. TROUBLESHOOTING GUIDE Problem Likely Cause Solution Incomplete removal Power too low Increase 10% increments Surface melting Excessive fluence Reduce power/increase speed Uneven cleaning Poor overlap Adjust scan pattern Substrate damage Over threshold Reduce to 80% power Slow removal rate Wrong wavelength absorption Adjust for paint color Oxidation after cleaning No protection Apply conversion coat <8hrs Rough surface Too many passes Reduce passes, optimize parameters Heat buildup Slow scanning Increase speed, add cooling

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10. SAFETY PROTOCOLS 10.1 MANDATORY PPE

• Laser safety goggles (OD 6+ at 1064nm)

• Respirator with HEPA/activated carbon

• Nitrile gloves

• Hearing protection

• Full coverage clothing 10.2 ENVIRONMENTAL CONTROLS

• Fume extraction: 99.95% HEPA filtration

• Activated carbon for VOCs

• Temperature monitoring: IR thermometer

• Restricted access zone

• Warning signage posted 10.3 WASTE MANAGEMENT

• Collect ablated material

• No hexavalent chromium detected in trials

• Dispose per local regulations

• Document waste stream

11. DOCUMENTATION REQUIREMENTS 11.1 RECORD KEEPING

• Aircraft tail number

• Panel/station identification

• Date and operator

• Parameters used

• Number of passes

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• Pre/post thickness

• Surface roughness

• Photos before/after 11.2 MAINTENANCE RELEASE

• Cleaning method: Laser (FP-300)

• Specification compliance: MIL-STD

• NDI verification completed

• Conversion coating applied

• Primer/topcoat schedule

12. QUICK REFERENCE CARDS CARD 1: WHITE PAINT ON 2024-T3 ALCLAD Power: 260W (87%) Frequency: 45 kHz Pulse: 175 ns Pattern: Petal Speed: 275 mm/s Passes: 3 Temp Limit: 120°C CARD 2: CORROSION REMOVAL Light Pits: 180W / 80ns / 300mm/s Medium Pits: 220W / 100ns / 200mm/s Heavy Pits: 260W / 120ns / 150mm/s Oxide: 180W / 80ns / 350mm/s STOP if intergranular detected

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- Temperature >120°C

- Visible melting

- Mirror finish appearing

- Smoke without extraction

- Substrate discoloration

- Cracks visible APPENDIX A: CONVERSION FACTORS Metric Imperial Conversion 1 mm/s 2.36 in/min × 2.36 1 J/cm2 0.1 MW/cm2 @ 100ns pulse 1 μm 39.4 μin × 39.4 °C °F (°C × 9/5) + 32 APPENDIX B: VALIDATED THRESHOLDS Based on MRO Testing & FAA Compliance:

• Primer removal threshold: 5.09 J/cm2

• Topcoat removal threshold: 17.7 J/cm2

• Aluminum damage threshold: 24.8 J/cm2

• Oxide film removal: 1.43-1.82 J/cm2

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