Method of shaping a carrier sheet of high hardness

A method for shaping a rigid carrier sheet, the method comprising the steps of:

• providing the rigid carrier sheet having a thickness of at least 6 mm;
• covering a front surface of the rigid carrier sheet with a removable vibration-absorbing protective layer;
• providing the surface of the protective layer remote from the rigid carrier sheet with a glass sheet;
• on the back surface of the rigid carrier sheet opposite the front surface thereof, forming a plurality of cavities according to a predetermined pattern, the step of forming comprising:
• forming the cavities by milling so that in each of the cavities a remaining thickness of the rigid carrier sheet along the front surface is at least 3 mm and at most 5 mm;
• during said milling, at least one physical property of the vibration of the rigid carrier sheet is continuously measured on the front surface of the rigid carrier sheet by means of at least one sensor;
• on the basis of at the least one physical property measured by the sensor, adjusting the operation of a milling tool so that the vibration properties of the rigid carrier sheet do not exceed predetermined threshold values;
• by applying a first scanning, taking a first 3D image of the surface roughness of the milled cavities;
• further reducing the surface roughness of the milled cavities by shot blasting, wherein during the shot blasting, the operation of a shot blasting tool is controlled using parameters determined on the basis of the first 3D image taken during the first scanning;
• by applying a second scanning, taking a second 3D image of the surface roughness of the cavities treated by the shot blasting;
• and
• by applying laser beam milling, further reducing the surface roughness of the shot blasted cavities, wherein the operation of a laser beam milling tool is controlled on the basis of the second 3D image taken by the second scanning after said shot blasting so that the surface roughness of the laser-beam-milled cavities falls in a submicron range.