a curved - wing balloon is provided herein . a medical device embodying the invention may include an expandable balloon and an inner shaft positioned within the expandable balloon wherein the expandable balloon may be coupled to an inflation lumen , expandable from a first position to a second position , and having non - parallel sides when initially formed . a method employing the present invention may include placing an expandable medical balloon between a first forming blade and a second forming blade of a cam - former jaw system , moving the first forming blade from a first open position to a second closed position and moving the second forming blade from a first open position to a second closed position , the first forming blade having a first forming member , the second forming blade having a second forming member , the first forming member and the second forming member being in contact with the expandable balloon when in the second closed position , a mating surface of the first forming member being non - parallel to a mating surface of the second forming member when in contact with the balloon .