http://newpotatoboxes.co.uk/onion-boxes/ Fine Blanking is a specialized form of Blanking where there is no fracture zone when shearing. This is achieved by compressing the whole part and then an upper and lower punch extract the blank. This allows the process to hold very tight tolerances, and perhaps eliminate secondary operations.
excellent dimensional control, accuracy, and repeatability through a production run;
excellent part flatness is retained;
straight, superior finished edges to other metal stamping processes;
smaller holes possible relative to thickness of material;
little need to machine details;
multiple features can be added simultaneously in 1 operation;
more economical for large production runs than traditional operations when additional machining cost and time are factored in (1000–20000 parts minimum, depending on secondary machining operations)