Last week the material arrived. A few days ago, I sawed the aluminium sheets into correct pieces. Every piece is about 10mm larger in x and y.
As said before, the main problem will be the 0.2mm holes that should be created. Thus, I ordered 10 drills with 0.214mm diameter a few weeks ago with 1mm shafts. I used one to do some test cuts, i.e., drilling 3 holes each 3mm deep (15xD). And surprisingly, it just worked. The holes had been drilled by the mill without a problem.
Ok, so with the successful test cuts, I prepared the sacrifice plate.