What Happens When You Use Laser Cleaning on Aircraft Skins?
✈Why Cleaning Aircraft Surfaces Matters
Aircraft exteriors—typically made of aluminum alloys—are constantly subjected to harsh conditions: low temperatures, high pressure, UV radiation, and fluctuating humidity. Over time, paint can crack, peel, or suffer mechanical damage. When aircraft undergo major maintenance, coatings must be completely removed to inspect the substrate for fatigue cracks, pits, and other surface flaws—critical for safety and aerodynamics.
Traditional Cleaning Methods & Their Drawbacks
Historically, paint stripping has relied on mechanical abrasion or chemical solvents. These methods are:
- Costly and labor-intensive
- Harmful to workers and the environment
- Potentially damaging to underlying metal
Enter laser cleaning, a non-contact, selective, and environmentally friendly alternative. It uses laser energy absorbed by the paint layer to vaporize or spall coatings—leaving the underlying metal intact. It’s precise, efficient, and lends itself well to automation.
In many cases, it has been shown to produce finer microstructures, smoother surfaces, and better adhesion for subsequent coatings compared to conventional techniques.
Key Findings from Recent Research
A Study on 2024‑T351 Aluminum in Vacuum (2023)
A research team investigated the effects of laser paint removal on 2024‑T351 aluminum alloy. After cleaning:
- Surface microhardness increased by approximately 10.6%
- Ultimate tensile strength showed about an 8.4% boost
- A more detailed breakdown found improvements of 9.7% (microhardness), 6.6% (UTS), and 13.2% (yield strength)
Microscopy (TEM/SEM) revealed dislocation proliferation and grain refinement in the surface layer—key drivers for enhanced mechanical properties. Notably, the laser cleaning did not significantly alter surface roughness under optimized conditions.
Study in Photonics (2023) on Boeing 737 Skins
In another investigation, multi-layer paint on actual Boeing 737 skin was cleanly stripped at a laser fluence of 5.09 J/cm² and a scan speed of 700 mm/s, without substrate damage. Post-cleaning:
- Nanoindentation hardness rose by 3.587% versus mechanically lapped samples
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Electron backscatter diffraction (EBSD) revealed plastic deformation and resulting strain hardening
The study concluded that the mechanisms at play—thermal breakdown, evaporation, and spallation—collectively remove paint while enhancing substrate integrity.
Summary: Advantages of Laser Paint Removal
| Benefit | Effect on Aluminum Alloy |
|---|---|
| Precise, non-destructive cleaning | Retains structural integrity, removes all layers |
| Microstructural refinement | Grain size reduction and dislocation increase |
| Improved mechanical properties | Gains in hardness, tensile, and yield strength |
| Environmentally friendlier | No toxic chemicals, reduced worker risk |
Final Takeaway
Laser cleaning is rapidly emerging as the optimal method for removing paint from aluminum alloy aircraft skins. It achieves complete paint removal, enhances mechanical performance through grain and dislocation engineering, and operates with minimal environmental drawbacks. With its ability to treat complex surfaces quickly and cleanly, laser cleaning is poised to revolutionize large-scale aircraft maintenance.
References
- Sun, Q., et al. (2023). Mechanical properties and microstructure characteristics of 2024‑T351 aluminum alloy specimen subjected to paint removal by laser cleaning. Vacuum, 211, 111927.
- Li, W., et al. (2023). Removal Mechanisms and Microstructure Characteristics of Laser Paint Stripping on Aircraft Skin Surface. Photonics, 10(1), 96.
- Zou, W., et al. (2021). Characteristics of the audible acoustic signal in the process of laser cleaning of paint on the metal surface. Optics and Laser Technology, 144, 107388.
- Lu, Y., et al. (2020). Ultraviolet laser cleaning and surface characterization of AH36 steel for rust removal. Journal of Laser Applications, 32, 032023.