Patent EP-2236239-A1 (EP)
Inventor: SCHUR STEFAN
IPC: B23K26/38
Filed: 2010-03-24
Abstract: The covering device (2) for a workpiece (4) such as a blade of an aircraft engine to be processed by a laser, where the workpiece has a cavity (10) accessible from outside over an opening (12) and a wall to be processed with the laser in a first area, comprises a holding device (20), with which the covering device is fixable to the workpiece and is again removable from the workpiece without any tools. The wall has a front side turned towards the laser during processing, and a rear side turned away from the laser during processing. The covering device has a first insert (22). The covering device (2) for a workpiece (4) such as a blade of an aircraft engine to be processed by a laser, where the workpiece has a cavity (10) accessible from outside over an opening (12) and a wall to be processed with the laser in a first area, comprises a holding device (20), with which the covering device is fixable to the workpiece and is again removable from the workpiece without any tools. The wall has a front side turned towards the laser during processing, and a rear side turned away from the laser during processing. The covering device has a first insert (22) and/or a second insert (24), which are insertable into the cavity through the opening of the workpiece and is clampingly fixable against the rear side of the wall using a first holding unit of the holding device. During processing, the covering device is adjacently fixed to a height of the first area at the rear side of the wall in a flat manner. The covering device comprises a laser-absorbing plastic such as nitrile butadiene rubber and/or a laser-reflecting plastic such as polyoxymethylene, and is formed complementary to the rear side of the respective wall of the workpiece. The first insert and/or the second insert have a laser-reflecting material at its front end in an insertion direction. The first holding unit of the holding device is formed by allowance of the first insert related to the cavity of the workpiece, so that the first insert automatically clamps against the rear side of the wall of the workpiece during insertion into the cavity of the workpiece. The first holding device is formed by the second insert and a connector, where the second insert is formed with respect to the cavity in an undersized manner and has a longitudinally extending opening in the insertion direction. The connector is insertable into the longitudinally extending opening. The system formed from the second insert and the connector inserted into the second insert has an allowance with respect to the cavity. The second insert is clamped against the rear side of the wall of the workpiece. The covering device includes a covering mask with a second holding unit of the holding device, which is formed by a multiply bent edge of the covering mask, so that the edge, when the covering mask is fixed at the rear side of the wall of the workpiece, engages the wall and lies on the front side of the wall in an area-wise manner. The covering mask has an aperture in the area of the opening for the cavity, where the first insert and/or second insert are insertable into the cavity of the workpiece through the aperture. The connector has a stop, which lies on the covering mask and fixes the covering mask additionally to the second holding unit on the rear side of the wall when it is inserted into the second insert. The covering device has an area with a reduced material thickness or an area with a continuous recess, so that a further wall arranged behind the covering device is processible with the laser by the covering device.