Production method for impeller

A production method for an impeller which includes a disk which has a disk shape about an axis, a plurality of blades which are formed on a surface facing a first side in an axial direction of the disk with gaps therebetween in a circumferential direction about the axis, and a cover which covers the plurality of blades from the first side in the axial direction and in which a flow path is formed between the disk, the cover, and the blades, the production method comprising:

• forming an impeller molding body in which a reinforcement portion which reinforces an end portion of the impeller in which an inlet and an outlet of the flow path are formed and the impeller are integrated with each other, by an additive manufacturing method using a metal powder;
• removing metal powder remaining in the flow path;
• and
• removing the reinforcement portion from the impeller molding body,
• wherein when forming the impeller molding body, the impeller molding body is formed such that inner peripheral surfaces of the inlet and the outlet of the flow path are inclined with respect to a vertical direction and a horizontal direction,
• the reinforcement portion closes the flow path in the end portion and at an outside of the impeller so as to connect the disk and the cover to each other,
• the reinforcement portion includes a communication hole which allows the flow path to communicate with the outside, and
• when removing the metal powder, air is injected into the impeller molding body to remove the metal powder remaining in the flow path to the outside through the communication hole.