In the past decade, laser cleaning and paint removal have become a hot subject in a variety of industries.As industrial grade nanosecond pulsed lasers with an average power beyond 1kW have become available, the capability emerged to process most material and structures at commercially viable speeds. Such lasers typically feature pulse peak power beyond 100kW and typically beyond 1MW. The high peak power ensures interaction with nearly any material, leading to ablation, decomposition, or detachment based on the material properties and the beam size.
Such industrial lasers are based in either q-switching or power amplification of diode signals, offering pulses of high peak power. Each pulse is a packet of energy capable of evaporating a set volume of coating, detaching it from its substrate, or melting and restructuring its surface.
Several projects on laser paint and coating removal for commercial and defense aircraft have already been conducted with systems like the LADS I, LADS II, and the ARBSS being built and tested on aircraft and aircraft components. In 2017 a commercial laser paint removal system was commissioned by Singapore airlines, using advanced scanners by EWI and a large 8 axes robot by NTS.
The marine industry, however, offers a greater diversity of applications, with a potential annual market for commercial vessel paint removal standing at around $300 million, exceeding that of the aircraft industry which is estimated at $250 million globally. If other more localized processes such as selective rust and corrosion removal, shaft and propeller resurfacing, and others are added to the market, the estimate rises to $2.3 billion annually.
However, market accessibility is low as the sector suffers low commercial utilization.
For marine applications the coatings that are used are much thicker than aerospace coatings, often ~1 mm. Coating thickness variations are also much less controlled, and coating consistency is often changed during service. Deep substrate corrosion typically accompanies any degradation of the coating, and access to complicated structural geometries is nearly impossible. Moreover, the surface area of a commercial vessel is significant, and dockyard delays need to be minimized. Pulsed lasers, however, with power above 1kW can serve these large area, time-sensitive applications well.
In the second part of this series (Loaser Coating Removal by Different Laser Methods), we’ll explore the relationship between process speeds and efficacy in this specialized application space.
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