Abstract: The invention relates to a method for repairing flow channel segments of a turbomachine. The method comprises providing a monocrystalline or directionally solidified flow channel segment whose length and width extend along the flow channel, each being greater than the thickness thereof, and whose width and length delimit a surface which constitutes a bounding surface of a flow channel and has damage, cleaning the bounding surface to remove impurities, remelting at least a part of the bounding surface in a surface region so that melted material solidifies epitaxially in an inner region facing toward the unmelted material and forms a structural region in which the monocrystalline or directionally solidified structure is preserved, and that melted material solidifies in a polycrystalline fashion in an outer region which faces toward the flow channel and forms an edge region, and removing the edge region.

Abstract: The invention relates to a laser machining head (1) with an integrated sensor device for monitoring the focus position, wherein laser machining head (1) has a focusing lens (4) and a downstream protective glass (5) in order to focus a machining beam (9) that strikes focusing lens (4) as a parallel beam into a resultant focal point (11) of focusing lens (4) with downstream protective glass (5), in which focal point a workpiece (12) is arranged. A beam splitter (3), arranged upstream of focusing lens (4) in the beam path, is transmissive for a first portion of a laser beam (8) coupled into laser machining head (1), the machining beam (9), and is reflective for a second portion, a measurement beam (10).

Abstract: The invention relates to a laser machining head (1) with an integrated sensor device for monitoring the focus position, wherein laser machining head (1) has a focusing lens (4) and a downstream protective glass (5) in order to focus a machining beam (9) that strikes focusing lens (4) as a parallel beam into a resultant focal point (11) of focusing lens (4) with downstream protective glass (5), in which focal point a workpiece (12) is arranged. A beam splitter (3), arranged upstream of focusing lens (4) in the beam path, is transmissive for a first portion of a laser beam (8) coupled into laser machining head (1), the machining beam (9), and is reflective for a second portion, a measurement beam (10).