Laser processing of thin copper and aluminium thin sheets with green (532nm) and infrared (1064nm) pulsed laser beam sources

Abstract

In this study processing of thin copper C101 (Cu C101) and aluminium 3003 (Al 3003) were investigated, using both infrared (IR), at 1064nm wavelength, and green, at 532nm wavelength, pulsed laser beam sources. The power density (peak power divided by the area of the minimum focused laser beam width) thresholds for keyhole initiation, when processing with the 1064nm laser source, were identified as 59kW/mm2 and 21kW/mm2 for 1mm thickness Cu C101 and Al 3003 coupons respectively. Melt depths up to 400µm were achieved in Cu C101 by tailoring the pulse energy. Melt depths up to 650µm were achieved in the case of Al 3003, with the power density of the laser pulse having a significant effect on the resultant melt depth. Conduction limited melting and welding was carried out in the case of the green wavelength, due to the limited output power of the 532nm pulsed laser sources available. The increased absorptivity of Cu C101 at 532nm introduced improved stability in the process, compared to the results achieved with the 1064nm wavelength laser beam. However, the same behaviour was not observed in the case of Al 3003.In this study processing of thin copper C101 (Cu C101) and aluminium 3003 (Al 3003) were investigated, using both infrared (IR), at 1064nm wavelength, and green, at 532nm wavelength, pulsed laser beam sources. The power density (peak power divided by the area of the minimum focused laser beam width) thresholds for keyhole initiation, when processing with the 1064nm laser source, were identified as 59kW/mm2 and 21kW/mm2 for 1mm thickness Cu C101 and Al 3003 coupons respectively. Melt depths up to 400µm were achieved in Cu C101 by tailoring the pulse energy. Melt depths up to 650µm were achieved in the case of Al 3003, with the power density of the laser pulse having a significant effect on the resultant melt depth. Conduction limited melting and welding was carried out in the case of the green wavelength, due to the limited output power of the 532nm pulsed laser sources available. The increased absorptivity of Cu C101 at 532nm introduced improved stability in the process, compared to the results achieved w...