FP-300 LASER CLEANING GUIDE
Aircraft Paint & Corrosion Removal Technical Manual
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
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
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
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
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
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
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
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
GALVANIC CORROSION
Effectiveness: MODERATE
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
If Attempted:
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
Layer 2: Primer
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
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
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
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
CARD 3: EMERGENCY STOP CONDITIONS
- 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
Optimal cleaning window: 5-20 J/cm²
Document Version: 1.0Based on FeatherPulse FP-300 SystemAviation Laser Services © 2025Compliant with FAA AC 43-4B