A process for the production of a thin walled metal detail (4) with an undercut (2), whereas a mold (1) is equipped with a first mold half (10) and a second mold half (20), characterized in that the first mold half (10) is equipped with a core (10a) and moveable core (11) the latter giving shape to said undercut (2) wherein, a) the mold (1) in the closed position is filled with metal melt allowed to set after which, b) the mold is (1) opened by withdrawing the second mold half (20) at which, c) the moveable core (11) is pushed out in unison with at least one ejector pin hereby ejecting the metal detail (4) from the mold (1) whereupon, d) the metal detail (4) is removed from the moveable (11) core.