Mold for the processing of liquid metallic material

The invention relates to a mold for the processing of liquid metallic material, which has a wall, at least one sensor element for detecting the temperature and / or strain is disposed at least a portion of the mold in the. In order to allow the installation of an efficient monitoring element for the mold in a cost effective manner, the invention provides that the sensor element (2) comprises at least one light waveguide (1) of the mold is arranged in a groove (3) in the wall, wherein the optical waveguide (2) in the groove base (4) of the groove (3) is applied and wherein the from the optical waveguide (2) is not filled space of the groove (3) at least substantially, preferably completely, closed by a filler piece (5).