Patent ID: 7665650

Claim:
A method of controlling a friction stir joining apparatus including a rotor having a tip portion; a rotation motor that rotates said rotor about a rotation axis; a straight movement motor that moves said rotor along said rotation axis, said tip portion of a rotating rotor being pressed against an object to be joined so that said object is softened and stirred by a frictional heat at a contact between said tip portion and said object, comprising: a rotation control step that variably controls a rotational speed of said rotor using a rotation control unit; and a straight movement control step that controls a straight movement of said rotor so as to control a pressure applied by said rotor to said object using a straight movement control unit, wherein a target value of at least either of said rotational speed or a moving speed of said rotor along said rotation axis is controlled by the rotation control unit or straight movement control unit to change before joining occurs during a joining operation in which said tip portion of said rotor is being disposed to be pressed by the straight movement against said object.