Abstract: A laser cutting method is provided for laser cutting a workpiece made of a metallic material to form hole having a desired shape, in which many of a second set of laser cutting conditions are different from a set of first laser cutting conditions, in order to avoid a chipping phenomenon when switching laser cutting conditions. The first laser cutting conditions are used for cutting the workpiece up to a predetermined distance short of the end point of the cut. The second set of cutting conditions are used for cutting the workpiece between an end point of the cut along the circumference of the hole, and a point a predetermined distance short of the end point of the cut. The focus position in the second laser cutting conditions is the same as the focus position in the first laser cutting conditions. Moreover, other of the second cutting conditions are the same as corresponding ones of the first set of cutting conditions.

Abstract: A laser beam machine comprises an optical fiber cable for transmitting laser light, a beam output optical assembly for converging and emitting a laser beam and flexible protective conduits arranged along the X- and Y-axes accommodating the optical fiber cable as well as power and control cables for X-and Z-axis drive motors and an assist gas tube. While the beam output optical assembly can be moved along the X-, Y- and Z-axes, the flexible protective conduits do not bend in excess of the permissible bending radius of the optical fiber cable. The laser beam machine thus constructed provides improved reliability, safety and maintainability of the optical fiber cable as well as high laser beam converging performance and an enlarged machining area. In another embodiment a nozzle centering device is provided between an optical fiber cable and a nozzle housing holding a collimator lens and a condensor lens to align the optical axis of the optical fiber cable with the nozzle housing.

Abstract: In a laser beam machine comprising: a laser oscillator for generating a laser beam; a machining head for applying the laser beam, as a light spot, to a workpiece mounted on a machining table; and a control unit for controlling the movement of the machining table in an X-Y plane, the laser beam is kept inclined with respect to the workpiece in the machining direction, whereby, when the machining speed is increased, the sticking of dross to the workpiece is suppressed, and the machining speed can be increased accordingly.