A core structure for a providing a cooling passage in a gas turbine engine includes a core body that has a first cooling passage core. The first cooling passage core has a first width in a chord-wise direction near a first wall. A second width in the chord-wise direction near a second wall. A third width in the chord-wise direction between the first and second walls. The third width being smaller than the first and second widths to form an hourglass shape.

A deburring method for a casting sand core 40 for removing burrs from a deburring target part 41 in the casting sand core 40 including the deburring target part 41, the deburring target part 41 being at least one of an opening and a cut-out part. The deburring method includes: inserting a bag 13 into the deburring target part 41 of the casting sand core 40; and inflating the bag 13 inserted into the deburring target part 41, and thereby pressing and breaking off burrs 42 formed on a peripheral surface of the deburring target part 41 by the inflated bag 13.

A core molding method capable of satisfactorily exhausting a gaseous body such as gas or water vapor that is generated inside an outer shell layer when a raw material is cured is provided. A core molding method according to one aspect of the present disclosure is a molding method of a core formed of a raw material including a binder and sand, and includes: filling a cavity of a molding die with the raw material; curing the raw material to form an outer shell layer; inserting a tip end part of an exhaust pipe having an internal pin inserted therein and an exhaust hole closed by the internal pin into a part surrounded by the outer shell layer through an opening provided in the molding die; and moving the internal pin and opening the exhaust hole.

A sand core making machine is provided that includes at least one transfer tool by means of which the material for making the core is transferred when said transfer tool is moved to an operating position. The machine also includes a curing tool by means of which the material previously transferred by the transfer tool is hardened and which is arranged in an operating position over the material to perform the hardening once the transfer tool has moved out of its operating position. The machine includes at least one articulated arm for moving the transfer tool and the curing tool to the respective operating position.

A sand core making machine is provided that includes at least one transfer tool by means of which the material for making the core is transferred when said transfer tool is moved to an operating position. The machine also includes a curing tool by means of which the material previously transferred by the transfer tool is hardened and which is arranged in an operating position over the material to perform the hardening once the transfer tool has moved out of its operating position. The machine includes at least one articulated arm for moving the transfer tool and the curing tool to the respective operating position.

A core molding method for molding a core having a twisted shape by use of a core mold includes a curing step and a mold extracting step. In the curing step, after the core mold is disposed along a vertical direction within a frame whose top is open, a self-hardening sand formed of a kneaded mixture of a sand, a resin and a curing agent is charged into the frame from the top of the frame, and then cured. In the mold extracting step, the core mold is extracted in the vertical direction from the core formed of the cured self-hardening sand while rotating the core mold and the frame relatively to each other around an axis of the core mold.

A core molding method for molding a core having a twisted shape by use of a core mold includes a curing step and a mold extracting step. In the curing step, after the core mold is disposed along a vertical direction within a frame whose top is open, a self-hardening sand formed of a kneaded mixture of a sand, a resin and a curing agent is charged into the frame from the top of the frame, and then cured. In the mold extracting step, the core mold is extracted in the vertical direction from the core formed of the cured self-hardening sand while rotating the core mold and the frame relatively to each other around an axis of the core mold.

A mold for producing a ceramic core by injecting a ceramic composition, the mold having a body in which a casting core cavity is formed, the cavity having a primary cavity and a secondary cavity connected by a plurality of segments, the mold being characterized in that it includes a primary arm configured in such a way as to allow an injection of ceramic composition into the primary cavity, and a secondary arm configured in such a way as to allow an injection of ceramic composition into the secondary cavity, and in that the ratio of the volume of the primary cavity to the volume of the secondary cavity is equal, plus or minus 15%, to the ratio of the volume of the primary arm to the volume of the secondary arm.

A mold for producing a ceramic core by injecting a ceramic composition, the mold having a body in which a casting core cavity is formed, the cavity having a primary cavity and a secondary cavity connected by a plurality of segments, the mold being characterized in that it includes a primary arm configured in such a way as to allow an injection of ceramic composition into the primary cavity, and a secondary arm configured in such a way as to allow an injection of ceramic composition into the secondary cavity, and in that the ratio of the volume of the primary cavity to the volume of the secondary cavity is equal, plus or minus 15%, to the ratio of the volume of the primary arm to the volume of the secondary arm.

A mould assembly for producing a casting core for a cooling jacket of an electric motor has an external mould and an internal mould enclosed by the external mould. The external mould forms an outer wall and the internal mould an inner wall of the core moulding cavity fillable with a core material and having a cylindrical shape. The internal mould has two first mould shells and two second mould shells. The two first mould shells and the two second mould shells jointly form the inner wall of the core moulding cavity. The second mould shells are arranged between the first mould shells. A first demoulding mechanism is arranged between the first mould shells and enables movement of the first mould shells toward one another. A second demoulding mechanism is arranged between the second mould shells and enables movement of the second mould shells toward one another.