Sand core, sand mold and method for manufacturing a sand core

Abstract

A sand core for casting a screw rotor comprising a main body having two head surfaces and a profile surface having helical lobes extending between the two head surfaces, wherein the sand core (1) includes an integral piece (2) having an internal cavity (3), wherein the internal cavity (3) is at least partially bounded by the integral piece (2) by means of a rotationally symmetric surface formed by helical grooves (5) about a rotationally symmetric axis, wherein the helical grooves (5) have a profile for forming the helical lobes during casting of the screw rotor, wherein an outer surface of the integral piece (2) is provided with an opening or a plurality of openings (4) extending into the internal cavity (3), wherein the opening or each of the plurality of openings (4) is adjacent to the helical grooves (5).

Dependencies are inferred from the claim text.