Drilling with fiber lasers

Abstract

For drilling holes such as cooling holes in tool forms or turbine blades with diameters from 100 µm up to 1.5 mm flash lamp pumped laser sources e.g. slab lasers are commonly used. These laser sources have peak powers of several kW at pulse durations from microseconds up to milliseconds with a high beam quality. Due to the beam quality, small spot sizes and intensities greater than 106 W/cm2 are achieved. The mean power of these laser sources is in the range of some mW up to several hundred W rather small.So far fiber lasers are not used for laser drilling due to small peak powers and intensities. Meanwhile, fiber lasers with a scalable output power of 1 W up to 50 kW in multimode or up to 10 kW in single-mode with a beam quality of M² < 6 in the multimode and M² < 1.1 in single-mode are offered in cw. Furthermore fiber lasers with a beam quality of M² < 6 are offered with a maximum peak power of 6 kW in a pulsed operation mode. With these fiber lasers drilling seems to be possible. Thus laser drilling with fiber lasers is investigated and compared to flash lamp pumped Nd:YAG lasers.For drilling holes such as cooling holes in tool forms or turbine blades with diameters from 100 µm up to 1.5 mm flash lamp pumped laser sources e.g. slab lasers are commonly used. These laser sources have peak powers of several kW at pulse durations from microseconds up to milliseconds with a high beam quality. Due to the beam quality, small spot sizes and intensities greater than 106 W/cm2 are achieved. The mean power of these laser sources is in the range of some mW up to several hundred W rather small.So far fiber lasers are not used for laser drilling due to small peak powers and intensities. Meanwhile, fiber lasers with a scalable output power of 1 W up to 50 kW in multimode or up to 10 kW in single-mode with a beam quality of M² < 6 in the multimode and M² < 1.1 in single-mode are offered in cw. Furthermore fiber lasers with a beam quality of M² < 6 are offered with a maximum peak power of 6 kW in a pulsed operation mode. With these fiber lasers drilling seems to be possible. Thus laser drilling wi...