Relationship between temperature at cut front edge and kerf quality in fiber laser cutting of Al-Cu aluminum alloy

The characteristics of the temperature at cut front edge (T-ce) during fiber laser cutting of AA2219 aluminum alloy were studied. A temperature monitoring system employing an infrared laser thermometer was established to record the time-domain T-ce. A series of experiments was carried out to explore the relationship between the T-ce and kerf quality. There was an optimal T-ce range of 1800-1950 degrees C for accepted kerf. By calculating the forces acting on molten pool, the existence of the optimal T-ce range was demonstrated, and the effect of the T-ce on kerf quality was discussed. The kerf quality was mostly dependent on the angle of the resultant to the downward (theta). Only when the theta was around the minimum of 38 that is corresponding to optimal T-ce range, the kerf was accepted because the liquid metal was pushed away smoothly, although the resultant value was small. When increasing or decreasing the T-ce outside the optimal range, the kerf was bad because the increased theta intended to push the liquid metal backward to attach on the kerf rather than push them away. (C) 2016 Elsevier Ltd. All rights reserved.