United Technologies Corporation

Sikorsky Aircraft Corporation

Alex C Dublinski

Thomas Arthur Carstensen

Philip J Ramey

Geoffrey C Davis

Joseph Goldberg

David A Evans

Michael A Kornitzky

Sharp, Jr, William

William Sharp, Jr

A method of fabricating a low total density, stabilized ramped honeycomb core for high pressure co-cure molding of a lightweight honeycomb core composite article includes forming the honeycomb core by net shaping stabilized honeycomb core material into a ramped honeycomb core. The ramped honeycomb core is prepared for lay-up and co-cure by applying a layer of low areal weight film adhesive to the upper and lower surfaces and to each ramped surface of the ramped honeycomb core. The honeycomb core material is stabilized for the net shaping operation by applying a layer of low areal weight film adhesive to the upper and lower surfaces of the honeycomb core material in a predetermined picture frame format.

Method of fabricating a low total density, stabilized ramped honeycomb

A method for high pressure co-cure molding of lightweight honeycomb core composite articles having ramped surfaces utilizing low total density, stabilized ramped honeycomb cores. The low total density, stabilized ramped honeycomb core is formed by net shaping stabilized honeycomb core material into a ramped honeycomb core, which is prepped for lay-up and co-cure by applying a layer of low areal weight film adhesive to the upper, lower and ramped surfaces thereof. The honeycomb core material is stabilized for the net shaping operation by a layer of the low areal weight film adhesive applied to the upper and lower surfaces of the material in a predetermined picture frame format. Composite prepregs and the ramped honeycomb core are layed-up in a semi-rigid molding assembly including a rigid base member and a complementary semi-rigid mold member having at least one internal rigid reinforcement insert, which is vacuum bagged and disposed in an autoclave. The vacuum bag is evacuated, and the layed-up molding assembly is subjected to a two stage pressure, temperature cycle for high pressure co-cure. The autoclave is pressurized to a dwell pressure, and the temperature is then raised from ambient to a dwell temperature whereupon the autoclave is stabilized for a dwell period. Next, the autoclave pressure is increased to a high pressure, and the temperature is raised to a co-cure temperature whereupon the autoclave is stabilized for a co-cure period to effect curing of the lay-up. After curing is complete, the autoclave is cooled, and then depressurized for removal of the composite molding apparatus.

Method for high pressure co-cure molding of lightweight honeycomb core

A composite molding apparatus for high pressure co-cure molding of lightweight honeycomb core composite articles having ramped surfaces utilizing low total density, stabilized ramped honeycomb cores. The composite molding apparatus is a semi-rigid molding assembly that includes a rigid base member and a complementary semi-rigid mold member that is formed from a combination of layers of fiber-reinforced elastomeric material and unreinforced elastomeric material. The semi-rigid mold member further includes internal rigid reinforcement inserts formed from a structurally rigid material and having a configuration that matches the configuration of the ramped surfaces of the honeycomb composite article. The rigid reinforcement inserts are interleaved between the layers of fiber-reinforced elastomeric material and/or unreinforced elastomeric material forming the semi-rigid mold member. The rigid reinforcement inserts of the semi-rigid mold member provide symmetric pressure distribution over the ramped surfaces of the honeycomb core and the overlayed composite prepregs during the high pressure co-cure process.

Composite molding apparatus for high pressure co-cure molding of

A method of making a flexible composite tool particularly adapted for composite molding and the composite tool made by this method. The method includes dissolving a B-staged fluoroelastomer in a suitable solvent such as methyl ethyl ketone or toluene to form a fluoroelastomer solution. A fabric is then coated with the fluoroelastomer solution. The solvent is evaporated and the impregnated fabric is sandwiched between unreinforced sheets to form a reinforced tooling material. The reinforced tooling material is laid up with alternating layers of unreinforced fluoroelastomer and then cured to form a composite tool which is stable through multiple thermal cycles. In addition, an elastomer tool can be provided with detail cavities shaped to accept separately formed detail structures, with each cavity including extra reinforcement in order to locate the details to close tolerances without extensive hand positioning or use of adhesives. The tool is useful in molding composites and is reusable. The life of the tool is further prolonged by a described method of repairing damaged portions of the tool.

Method for forming complex composite articles

Tool for forming complex composite articles

Growing community of inventors

Northford, CT, United States of America

Alex C Dublinski