Patent ID: 7234626
Filing Date: 2007-06-26
Classification: B23K

Abstract:
1. A method for creating a friction stir weld free of an exit hole thereby joining a first workpiece, having a first thickness, and a second workpiece, having a second thickness, without using a conventional shouldered retractable pin tool and reducing the amount of overheating, comprising the steps of: plunging a portion of a rotating non-consumable shoulderless variable penetration friction stir welding tool into a joint to be welded wherein the tool comprises a substantially cylindrical body portion, a head portion, and a tip section, each integral to the tool, the body portion having a longitudinal axis about which it is rotable, a diameter, a sidewall substantially parallel to the longitudinal axis, a proximal end, and a distal end, the head portion located at the distal end of the body portion having a base with a diameter substantially equal to the diameter of the body portion forming a smooth transition between the body portion and the head portion, a face that converges to the tip section having a diameter and a center wherein the center is located substantially on the longitudinal axis, a height from the distal-most portion of the tip section to the base along the longitudinal axis; traversing the joint with the rotating tool ensuring that no portion of the tool, away from the entry penetration of the tool into the workpieces, comes in contact with the top surface of either workpiece; and gradually retracting the portion of the rotating tool from the workpieces while traversing the joint so that the tool exits the workpieces at a predetermined exit point leaving a friction stir weld free of an exit hole.