Abstract: A method for producing a model mould core blank uses a ceramic blank fixed to a processing holder. During fixing, a lost core is manufactured from the ceramic blank based on a CNC manufacturing process 3D model, the processing holder being fastened in the running CNC machine. A model blank is produced by casting model material around the lost core while fixing persists. The model blank becomes part of another method for producing a model mould core, wherein an outer contour of a lost model is produced from and/or on the model blank on the basis of a second CNC manufacturing process 3D model, wherein fixing and processing holder fastening also occurs. Another method produces a precision casting mould, in which a ceramic mould is applied to the outer contour of the lost model, and a cast part having a hollow cavity structure is produced by the precision casting mould.