| 摘要 |
PROBLEM TO BE SOLVED: To prevent inner cracks when an impeller formed of a fiber reinforced resin is manufactured by injection molding.SOLUTION: A method for manufacturing an impeller includes: an injection step of filling a cavity with a molten resin from a side of a gate into which a molten resin containing a reinforced fiber flows toward a side of an opposite gate opposite to the side of the gate; and a pressure holding step of applying a necessary pressure to the filled molten resin. In the injection step and the pressure holding step, directional cooling is performed in which such a temperature gradient is provided so that the temperature becomes lower from the side of the gate to the side of the opposite gate. According to the method for manufacturing the impeller, the temperature of the side of the opposite gate is low, and accordingly contraction accompanied with lowering of a temperature of the molten resin occurs on the side of the opposite gate. On the other hand, the temperature of the side of the gate is made high, and thereby the molten resin can be supplied from the side of the gate for the portion of the contraction on the side of the opposite gate and accordingly, inside tensile residual stress and cracks due to the contraction can be prevented.SELECTED DRAWING: Figure 1 |
