To provide a core sand removing method capable of completely removing the core sand while easily coping with even when the diameter of the hollow part of a work having a recessed part is small and reducing the initial cost and running cost of the removal device.
In this the core sand removing method, the core sand stuck to the inner peripheral surface of the hollow part 1 penetrated in a work W is removed by projecting a projection material P. At the time of removing, an injecting nozzle 20 which can inject the projection material P into the hollow part 1 is arranged at the one end side of the hollow part 1, and a hard bar-like member 21 provided with a changing surface 22 for changing the advancing direction of the projection material P at the tip end is entered from the other end side of the hollow part 1. Then, the projection material from the injecting nozzle 20 is abutted on the changing surface 22 of the hard bar-like member 21 and directed to the inner peripheral surface side of the hollow part 1, then the core sand is removed.
SAKAI SHIGEKAZU
HIRAGA MIKITOSHI
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