Method for producing a lost casting core

A method for producing a lost casting core (G), which has a side surface (S1, S2), in a core box (1) that is composed of at least two core box parts (2, 3), between which parts a parting plane (T) runs when the core box (1) is closed, wherein the core box delimits a mold cavity (8) that determines a shape of the casting core (G) to be produced, an inner surface (14, 15) that reproduces the side surface (S1, S2) of the casting core (G) is provided in the core box, and the parting plane (T) of the core box (1) runs through the inner surface, the method comprising:

• (a) producing a casting core insert (E) in one piece from a casting core molding material (F), which is mixed together from a basic molding material and a binder, and optionally, one or more additives, wherein the casting core insert (E) corresponds to a section of the casting core (G) to be produced, and wherein the casting core insert (E) carries at least one side surface section (SF1, SF2), which is equal to a corresponding section of the side surface of the casting core (G) to be produced;
• (b) positioning the casting core insert (E) in the mold cavity (8) of the core box (1) in a position in which the at least one side surface section (SF1, SF2) of the casting core insert (E) occupies a place where the corresponding section of the side surface (S1, S2) of the casting core (G) is located in a finished, produced casting core (G), wherein the parting plane (T) of the core box (1) runs through intersects the at least one side surface section (SF1, SF2) of the casting core insert (E) positioned in the core box (1);
• (c) introducing a casting core molding material (F), which is mixed together from a basic molding material and a binder, and optionally, one or more additives, into the mold cavity (8) of the core box (1), so as to produce the remaining a remainder of the casting core (G), wherein the casting core molding material (F) that penetrates into the mold cavity (8) comes into contact with the casting core insert (E) that sits in the mold cavity (8);
• and
• (d) solidifying the casting core molding material (F) that was introduced into the mold cavity (8), thereby forming a shape-fit and/or material-fit connection between the casting core molding material (F) that was introduced into the mold cavity (8) and the casting core insert (E).