Method of teaching position

A method of teaching a position of a machining track in a machine comprising:

• a first arm turning in a first horizontal plane;
• a first motor for turning said first arm;
• a second arm provided to a front end of said first arm, said second arm turning in a second horizontal plane;
• a second motor for turning said second arm;
• a holding unit for holding a work piece, said holding unit provided to a front end of said second arm, said holding unit rotating about a vertical axis;
• a third motor for rotating said holding unit;
• and
• a control unit controlling said motors to turn and rotate said first arm, said second arm and said holding unit, said control unit moving the work piece to positions, which have been stored, so as to make a part of the work piece contact with a machining tool, said method comprising the steps of:
• driving said motors with detecting exciting currents, by said control unit, so as to move the work piece from a position short of an object position to the object position;
• making the work piece contact with the machining tool, which corresponds to the object position;
• turning off the exciting currents of said all motors if at least one of the exciting currents, which respectively run through said motors, is greater than a predetermined value;
• and
• storing a position of the work piece as the object position after counter forces, which work from the machining tool to said arms and said motors, and frictional forces, which are generated in said arms and said motors, are balanced after the exciting currents are turned off and the work piece is in contact with the machining tool.