a die in the form of a permanent mold, wherein the permanent mold establishes an outer contour of the helical cast body, wherein the die is made of a ceramic material or is coated with a ceramic material, the die comprising:

a supporting tool, which supports the die from outside the die, and

a mold core, which defines a continuous opening inside the helical cast body, wherein the mold core is made of a ceramic material or is coated with a ceramic material, and wherein the mold core is designed as a core puller, wherein the core puller includes two or more movable sub-bodies, wherein the two or more movable sub-bodies are movable with respect to one another and wherein at least two of the two or more movable sub-bodies form a portion of a surface of the core puller that abuts the helical cast body, wherein the core puller comprises at least two non-dissolvable sub-bodies, wherein the at the least two non-dissolvable sub-bodies form a portion of a surface of the core puller that abuts the helical cast body, and wherein only the at least two non-dissolvable sub-bodies make contact with a casting material or melt.