Process and tools for manufacturing composite ring frames
View Patent ↗The present invention relates to a process for manufacturing composite ring frames for aeronautical fuselages by means of the application of the RTM technology to two preforms with C- and L-shaped sections manufactured using two tools ( 21, 55 ) in the following steps: providing the material; hot-forming planar rectangular laminates ( 41 ); hot-forming laminates of right angle section ( 51 ) on one part of right angle section of the first tool ( 21 ), placing an elastic membrane ( 55 ) and applying a temperature and vacuum cycle; hot-forming the preforms into a C shape ( 11 ) and L shape ( 13 ) on a second curved tool ( 55 ) by deforming said laminates of right angle section ( 51 ) thereon, and applying a temperature and vacuum cycle. The invention also relates to said tools ( 21, 55 ).
1. A process for manufacturing composite ring frames for aeronautical fuselages by application of RTM technology to two preforms with C- and L-shaped sections, wherein said preforms are manufactured using a first tool and a second tool in the following steps:
a) providing the fabric for the preforms in pieces of material cut according to preset patterns;
b) hot-forming planar rectangular laminates by placing overlapping layers of pieces of material on a first tool in predetermined positions and number and applying pressure and temperature so that the overlapped pieces of material adhere to one another in local areas, and cutting the laminate into parts;
c) hot-forming laminates of right angle section from segments of said planar laminates of predetermined dimensions, obtained by cutting, on a part of a right angle section of the first tool, arranging on its top side a part intended for a flange of the preforms with a C- or L-shaped section, holding its longitudinal edge on the first tool and allowing the rest to be free, placing an elastic membrane on the first tool and applying a temperature and vacuum cycle;
d) hot-forming the preforms into a C shape and an L shape on a second curved tool by deforming said laminates of right angle section thereon, said deformation including in the case of C-shaped preforms the bending of a second flange, and applying a temperature and vacuum cycle.
2. A process for manufacturing composite ring frames for aeronautical fuselages according to claim 1 , wherein the preset patterns for the pieces of material include rectangular patterns at +/−45° and unidirectional tape reinforcement for a flange.