Method for producing a hole

摘要

The method for producing a hole (7) in a layer system of turbine component using pulsed laser beam of a laser that has a pulse length, where the layer system has a metallic substrate (4) and an external ceramic layer, comprises guiding an energy beam over the surface of the component with short pulse length during ablation process in order to remove the material in the area of a plain of the hole to be produced, and with long pulse length in order to remove a metallic intermediate layer or the metallic substrate, where the short pulse has a power of adjustable kilowatt range. The method for producing a hole (7) in a layer system of turbine component using pulsed laser beam of a laser that has a pulse length, where the layer system has a metallic substrate (4) and an external ceramic layer, comprises guiding an energy beam over the surface of the component with short pulse length during ablation process in order to remove the material in the area of a plain of the hole to be produced, and with long pulse length in order to remove a metallic intermediate layer or the metallic substrate, where the short pulse has a power of adjustable kilowatt range. The long or short pulse length is used in the first ablation process as in the last ablation process. The pulse length during the first ablation process is 100 ns or 10 ms and the pulse length in the last ablation process is 10 ms or 100 ns. The external surface of the hole is produced with short pulse length and a lower area (10) of the hole is produced with long pulse length. An external edge area is produced with short pulse length and the internal area (12) of the hole is produced with long pulse length. The pulse length is changed from the external surface up to the depth of the hole. The long pulse has pulse duration of 0.4 ms, energy of 8 Joule and power of 20 kilowatt. The energy of the short pulse is in single milli-joule range. In the longer pulse, the cross-sectional surface of the removed area on the component corresponds to the cross-sectional surface of the hole. An output power of the laser is constant during using the long and short pulse so that the pulse length is not changed for the long or short pulse. The output power of the laser is 500 watt in the longer pulse. The metallic layer has a composition of the type of MCrAlX, where M is iron, cobalt or nickel and X is yttrium and/or rare earth elements.