The energy density threshold evaluation for high-precision laser cleaning of the oxidized layer on 7075 aluminum alloy with 100 ns laser

Research Progress and Challenges in Laser-Controlled Cleaning of Aluminum Alloy Surfaces

“…The existing studies have shown that the removal effect of oxide films and paint layers from the aluminum alloy surface is gradually improved with increasing laser beam power. However, when the power rises to a certain extent, the oxide film and paint layer are removed, and the aluminum alloy substrate is ablated [ 12 , 50 , 51 , 52 , 53 , 54 , 62 ]. Shao et al [ 50 ] used a pulsed laser to clean the oxide film from a 7075 aluminum alloy surface, and the laser beam power was increased from 16 to 160 W. The experimental results displayed that the oxide film on the aluminum alloy surface was removed entirely when the laser beam power was 80 W. The oxide film only cracked when the power was lower than 80 W since there was not enough power.…”

“…However, when the power rises to a certain extent, the oxide film and paint layer are removed, and the aluminum alloy substrate is ablated [ 12 , 50 , 51 , 52 , 53 , 54 , 62 ]. Shao et al [ 50 ] used a pulsed laser to clean the oxide film from a 7075 aluminum alloy surface, and the laser beam power was increased from 16 to 160 W. The experimental results displayed that the oxide film on the aluminum alloy surface was removed entirely when the laser beam power was 80 W. The oxide film only cracked when the power was lower than 80 W since there was not enough power. The microcracks started to emerge on the surface when the laser beam strength topped 80 W. As the power rose, the fissures became deeper and deeper, seriously damaging the substrate ( Figure 2 ).…”

“…As the scanning speed rises to 1000 mm/s, the micro-cracks on the aluminum alloy surface vanish, the dense structure is formed, and the oxidized layer is removed. When the laser scanning speed reaches 3000 mm/s, the fish scale phenomena begin to appear on the surface [ 50 ]. Therefore, when the scanning speed is suitable, the oxide film will be removed without damaging the substrate.…”

“… Morphology of laser-cleaned 7075 aluminum alloy with different laser powers [ 50 ]. ( a ) 16 W; ( b ) 32 W; ( c ) 48 W; ( d ) 80 W; ( e ) 96 W; ( f ) 160 W. …”

“… Morphology of a laser-cleaned surface with different scanning velocities [ 50 ]. ( a ) 20 mm/s; ( b ) 200 mm/s; ( c ) 1000 mm/s; ( d ) 3000 mm/s; ( e ) 5000 mm/s; ( f ) 10,000 mm/s.…”