Abstract: Disclosed is a valve having a housing with a valve seat for a two-piece flap which is rotatably mounted on a drive shaft. An annular piston seal and an adjacent cover disk are disposed between the first part and the second part of the two-piece flap so as to revolve therearound. The diameter of the cover disk is smaller than the diameter of the annular piston seal which is embodied as a metal ring that is provided with a gap. The invention also relates to the use of the valve as a gas recirculation valve.

Abstract: In a method for laser drilling holes in a substrate, a laser beam is provided having a be spot diameter which is smaller than a diameter of a hole to be drilled. The laser beam is aligned to a new hole to be drilled, and a beam axis directed in a jump direction predefined by a starting position to a center of the hole to be drilled. The beam axis is directed in a defined radial traversing movement away from the center and onto a defined circular path. The angular direction of the traversing movement is defined as a function of the jump direction such that any change in direction of the beam axis at the center does not exceed a predefined maximum angle or else the direction is maintained.

Abstract: When holes are being drilled in an electric circuit substrate, a laser beam is moved on concentric circular tracks in the region of the hole to be drilled. The transition from one circular track to the next takes place in each case on an arc that departs approximately tangentially from the circular track last traversed and nestles approximately tangentially against the circular track newly to be described in such a way that in each case the starting point of a new circular track is offset by a prescribed angle from the starting point of the preceding circular track.

Abstract: To calibrate the optical system of a laser machine having a laser source, a deflecting unit and an imaging unit, firstly a first sample plate is arranged in the focal plane of the imaging unit, with prescribed grid points being marked by the laser beam. After that, the marked points are measured by means of a camera, and their position values are compared with the prescribed position values of the target points, in order to derive first correction values from this and store them. After that, a second sample plate is arranged in a second calibrating plane, at a distance from the focal plane, and is targeted by the laser beam and provided with markings. The second sample plate is measured by the camera, and the measured positions of the markings are compared with the positions of the target points, in order to derive second correction values and store them.

Abstract: When holes are being drilled in an electric circuit substrate, a laser beam is moved on concentric circular tracks in the region of the hole to be drilled. The transition from one circular track to the next takes place in each case on an arc that departs approximately tangentially from the circular track last traversed and nestles approximately tangentially against the circular track newly to be described in such a way that in each case the starting point of a new circular track is offset by a prescribed angle from the starting point of the preceding circular track.

Abstract: To calibrate the optical system of a laser machine having a laser source, a deflecting unit and an imaging unit, firstly a first sample plate is arranged in the focal plane of the imaging unit, with prescribed grid points being marked by the laser beam. After that, the marked points are measured by means of a camera, and their position values are compared with the prescribed position values of the target points, in order to derive first correction values from this and store them. After that, a second sample plate is arranged in a second calibrating plane, at a distance from the focal plane, and is targeted by the laser beam and provided with markings. The second sample plate is measured by the camera, and the measured positions of the markings are compared with the positions of the target points, in order to derive second correction values and store them.