A die crack is an open line in the die. When a coin is stamped metal flows into the crack thus causing a raised (relief) line on the coin.
Same with "cuds" where part of the die has broken off. PMD
usually removes metal or, sometimes shifts it around (so some could be raised but it has come from somewhere else on the coin, which will be incused [below the surface]).
The only PMD
that I could think of to give a raised surface would be where someone attacks it with a welder or gas torch and melts metal onto the surface. I haven't come across this but would not be surprised).