Nanosecond-Pulsed-Laser Paint Stripping of HT250 Gray Cast Iron

A nanosecond-pulsed-laser paint stripping experiment is performed to reveal the influences of laser parameters on the surface morphology of laser paint stripping. The surface morphology and oxygen content arc observed; the three-dimensional morphology and surface roughness arc evaluated; the residual-paint-layer area is measured to characterize the cleaning rate. The results show that the roughness of the paint-stripped surface increases with the increasing laser power. With a decrease in the cleaning speed, the roughness first decreases and subsequently increases. Coking occurs with an increase in the pulse frequency. The paint removal mechanism changes from the vibration and ablation effects to the ablation effect with a decrease in the cleaning speed; this results in a decrease followed by an increase in the cleaning rate. Under the experimental condition of 50 W laser power, 90 kHz pulse frequency, and 7000 mm/s cleaning speed, the best laser cleaning is achieved, and the paint stripping rate is 99.1%.