PURPOSE: To effectively remove casting flash obstructing the discharge of a core sand at each position of an aluminum casting.

CONSTITUTION: The aluminum casting 6 is held with an end effector 3 fitted to the tip part of an arm of a six axial articulated robot 2 and carried to near a spindle device 4 arranged at near the robot 2. The six axial articulated robot 2 pushes the aluminum casting 6 in the holding condition to a drill tool 5 rotated at high speed and fitted to a spindle device 4 and the casting flash is bored, crushed and removed. As the same way, the casting flash at each position of the aluminum casting 6 is removed. Thereafter, the six axial articulated robot 2 releases the held aluminum casting 6 to complete the pre-treatment process for removing the core.