In a preferred embodiment, a composite panel with a smooth outer surface, ready for painting with or without addition of primer, may be created by constructing a panel layup assembly upon a mold, the panel layup assembly including a composite panel having a core and a resin formulation, and a release film between the mold and the composite panel, where a smooth release surface of the release film is in contact with the composite panel upon construction; initiating curing of the composite panel at a first temperature within a lowermost ten percent of a curing temperature range of the resin formulation; continuing curing of the composite panel at a second temperature above the lowermost ten percent of the curing temperature range; and completing curing of the composite panel at a third temperature below the second temperature.

In a preferred embodiment, a composite panel with a smooth outer surface, ready for painting with or without addition of primer, may be created by constructing a panel layup assembly upon a mold, the panel layup assembly including a composite panel having a core and a resin formulation, and a release film between the mold and the composite panel, where a smooth release surface of the release film is in contact with the composite panel upon construction; initiating curing of the composite panel at a first temperature within a lowermost ten percent of a curing temperature range of the resin formulation; continuing curing of the composite panel at a second temperature above the lowermost ten percent of the curing temperature range; and completing curing of the composite panel at a third temperature below the second temperature.

Welded headgear sections can be produced by using a weld tool having pins protruding from a weld region contact surface to deliver high-frequency electromagnetic energy to a weld region defined by overlapping top and bottom headgear straps. The pins fully penetrate the top strap and at least partially penetrate the bottom strap. The pins concentrate the electromagnetic energy to achieve a weld joint of acceptable weld strength and aesthetic appeal.

Disclosed herein is a molded laminated structure having negative draft angles and methods of manufacturing a molded laminated structure having negative draft angles. A preliminary structure having a first outer layer and a second outer layer is molded with a bend that divides the preliminary structure into two sections with an angle between the two sections of less than 180-degrees. Portions that extends from the sections are at positive draft angles. A groove is formed in the preliminary structure at the bend but not formed in a constant cross-section of the second outer layer. The preliminary structure is folding along the bend to at least partially close the groove and form a molded laminated structure with portions that extend at a negative draft configuration while retaining the second outer layer continuous throughout the molded laminated structure.

A method for assembling two parts, referred to as first and second parts, the first part being produced from composite material with fibrous reinforcement embedded in a thermosetting or thermoplastic matrix, the method comprising the steps of: obtaining the first part comprising, on all or part of an outer surface, a first amorphous thermoplastic film; positioning the first part and the second part such that the first amorphous thermoplastic film is placed opposite the second part; introducing a thermosetting resin between the first amorphous thermoplastic film and the second part; at least partially polymerising the thermosetting resin. When the two parts comprise an amorphous thermoplastic film, the parts are positioned such that the respective amorphous thermoplastic films are placed opposite each other, and the thermosetting resin is introduced between the amorphous thermoplastic films.

A structural member including a lightweight core, one or more skins, and a crosslinking nanolayer interposed therebetween that results in significant mechanical strength in the structure. The core is a polymer of reduced density by way of included voids, such as an open or closed cell foam, honeycomb, or corrugated structure. The core polymer has a lower density and may have a higher softening or melting temperature than the polymer skin materials. The core may be discontinuous at the interface with the skin such that only a small percentage of the core surface is actually in contact with the skin compared to the overall area of the interface. The skin may be a thermoplastic layer that attaches to the core material. The skin may be a composite material including non-thermoplastic reinforcements. The crosslinking nanolayer is covalently bonded to the surface of the core material and provides molecular compatibility with the skin material.

In a preferred embodiment, a composite panel with a smooth outer surface, ready for painting with or without addition of primer, may be created by constructing a panel layup assembly upon a mold, the panel layup assembly including a composite panel having a core and a resin formulation, and a release film between the mold and the composite panel, where a smooth release surface of the release film is in contact with the composite panel upon construction; initiating curing of the composite panel at a first temperature within a lowermost ten percent of a curing temperature range of the resin formulation; continuing curing of the composite panel at a second temperature above the lowermost ten percent of the curing temperature range; and completing curing of the composite panel at a third temperature below the second temperature.

Disclosed herein is a molded laminated structure having negative draft angles and methods of manufacturing a molded laminated structure having negative draft angles. A preliminary structure having a first outer layer and a second outer layer is molded with a bend that divides the preliminary structure into two sections with an angle between the two sections of less than 180-degrees. Portions that extends from the sections are at positive draft angles. A groove is formed in the preliminary structure at the bend but not formed in a constant cross-section of the second outer layer. The preliminary structure is folding along the bend to at least partially close the groove and form a molded laminated structure with portions that extend at a negative draft configuration while retaining the second outer layer continuous throughout the molded laminated structure.

A structural member including a lightweight core, one or more skins, and a crosslinking nanolayer interposed therebetween that results in significant mechanical strength in the structure. The core is a polymer of reduced density by way of included voids, such as an open or closed cell foam, honeycomb, or corrugated structure. The core polymer has a lower density and may have a higher softening or melting temperature than the polymer skin materials. The core may be discontinuous at the interface with the skin such that only a small percentage of the core surface is actually in contact with the skin compared to the overall area of the interface. The skin may be a thermoplastic layer that attaches to the core material. The skin may be a composite material including non-thermoplastic reinforcements. The crosslinking nanolayer is covalently bonded to the surface of the core material and provides molecular compatibility with the skin material.

Disclosed herein is a molded laminated structure having negative draft angles and methods of manufacturing a molded laminated structure having negative draft angles. A preliminary structure having a first outer layer and a second outer layer is molded with a bend that divides the preliminary structure into two sections with an angle between the two sections of less than 180-degrees. Portions that extends from the sections are at positive draft angles. A groove is formed in the preliminary structure at the bend but not formed in a constant cross-section of the second outer layer. The preliminary structure is folding along the bend to at least partially close the groove and form a molded laminated structure with portions that extend at a negative draft configuration while retaining the second outer layer continuous throughout the molded laminated structure.