Material surface modification using friction stir welding hybrid process

A method for removing detrimental surface features on a work piece during friction stir welding, said method comprising:

• 1) providing a friction stir welding (FSW) tool comprised of a shank, a shoulder with a desired surface profile, and an inner collar disposed around the shoulder near a working end;
• 2) creating a hybrid friction stir welding tool by providing a floating outer collar that is movably coupled to the inner collar by two rocker pins disposed through the inner collar and the floating outer collar along a common axis and on opposite sides of the FSW tool so that the floating outer collar pivots by rotating on the two rocker pins with respect to the inner collar of the friction stir welding tool while the friction stir welding tool and the floating outer collar rotate together such that the floating outer collar remains substantially parallel to a surface of a work piece while the friction stir welding tool and the inner collar may operate at an angle that is not perpendicular to the surface;
• 3) providing at least one cutting insert on the floating outer collar to enable the at least one cutting insert to make contact with a work piece during friction stir welding;
• and
• 4) removing surface features from a surface of the work piece as the floating outer collar rotates with the friction stir welding tool as they move along a surface of the work piece.