US 12,070,892 B2
Constrained forming of contoured composite hat stringers
Steven Joseph Plummer, Seattle, WA (US); Kurtis Shuldberg Willden, Kent, WA (US); and Megan E. Bliss, Des Moines, WA (US)
Assigned to The Boeing Company, Chicago, IL (US)
Filed by The Boeing Company, Arlington, VA (US)
Filed on Apr. 25, 2023, as Appl. No. 18/306,432.
Application 18/306,432 is a division of application No. 17/447,593, filed on Sep. 14, 2021, abandoned.
Claims priority of provisional application 63/079,805, filed on Sep. 17, 2020.
Prior Publication US 2023/0256663 A1, Aug. 17, 2023
Int. Cl. B29C 70/56 (2006.01); B29C 51/00 (2006.01); B29C 51/08 (2006.01); B29C 51/20 (2006.01); B29C 51/28 (2006.01); B29C 70/28 (2006.01); B29C 70/46 (2006.01); B29L 31/00 (2006.01); B29L 31/30 (2006.01)
CPC B29C 51/28 (2013.01) [B29C 51/004 (2013.01); B29C 51/087 (2013.01); B29C 51/20 (2013.01); B29C 70/462 (2013.01); B29K 2821/00 (2013.01); B29K 2995/0082 (2013.01); B29L 2031/003 (2013.01); B29L 2031/3082 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method of forming a contoured composite hat stringer having a contoured hat section including sides and a cap, comprising:
placing a composite charge on a pair of dies mounted to a flexible bottom plate, the pair of dies forming a die cavity;
installing an inflatable bladder within the die cavity, the inflatable bladder resting on the flexible bottom plate;
inflating the inflatable bladder to completely fill the die cavity;
forcing the composite charge into the die cavity with a punch mounted to a flexible top plate, the punch in contact with a first side of the composite charge;
constraining the cap between the inflated bladder and the punch as the composite charge is being forced into the die cavity, the inflated bladder in contact with the cap from a second side of the composite charge; and
applying pressure to outer edges of the composite charge with a pair of inflatable flange pinch bladders, the pair of inflatable flange pinch bladders positioned between the outer edges of the composite charge and the flexible top plate and in contact with the first side of the composite charge, wherein the applying pressure includes allowing the outer edges of the composite charge to slip over the pair of dies during the forcing the composite charge into the die cavity.