Patent ID: 8562893

Claim:
A molding method for forming an impeller including a main body and a plurality of blades arranged at one surface of the main body to circumferentially adjoin one another, each of the blades being inclined at different inclination angles at radially outward and inward sides toward one side in a rotating direction of the impeller, the molding method comprising: a mold clamping process including a first mold for forming one side of the blades, a second mold firmly clamped with the first mold to face the first mold, and a core arranged at the first mold relative to the blades, the mold clamping process clamping the first mold to the second mold in a state where the core is arranged between the first mold and the second mold; an injecting process injecting resin in a cavity obtained by the mold clamping process; and a mold removing process including the steps of: releasing at least the first mold from the clamped state obtained by the mold clamping process to generate an opened portion in the first mold after the resin is hardened, rotating the core about a rotational axis toward the opened portion of the first mold, the rotational axis extending from the radially outward side to the radially inward side of the impeller, and separating the core from the resin-molded impeller, wherein the mold removing process includes a first movement phase for separating the resin-molded impeller in contact with the core from the first mold along a rotational axle of the impeller, and a second movement phase for rotating the core about the rotational axis in the middle of the first movement phase.