PLASTIC FORMING METHOD OF CENTRIFUGAL IMPELLER AND PLASTIC PUTTING PIECE USED IN THE SAME METHOD

摘要

PURPOSE:To prevent the curve of a core by setting a small plastic putting piece at deformable place of the core and inserting it into a metallic mold. CONSTITUTION:At the forming of the injection, the fused resin enters into a cavity 6a of the main plate side of an impeller 10 through a pin gate 8, and flows into a shroud side cavity 5a through a cavity 7 of a vane fitting part so as to be charged. The fused resin is charged earlier than the main plate side, though the core 3 tends to deform at the recessed part of the vane, the curve of the core 3 is restricted because the putting piece 20d is bonded to this place so that an upper projection 22d is placed in the deformation direction. The putting piece 20d is formed with the material to be weld so as to be finally integral, the putting piece 20d can be formed integrally with the impeller.