Manufacture of honeycomb sandwich

Claim 2

A continuous method of producing a honeycomb sandwich assembly comprising: layering a sheet of thermoplastic adhesive upon a honeycomb core; setting a layer of thermosetting laminae upon said adhesive sheet as to form an unbonded assembly consisting of said honeycomb core, said adhesive sheet and said laminae layer; locally evacuating the space about the unbonded assembly; heating the unbonded assembly in a pressurized oven to the laminate curing temperature while supporting said layer of laminae upon said thermoplastic sheet; maintaining laminate curing temperature and pressure levels until the laminate is substantially cured; increasing the temperature while decreasing the pressure level within the pressurized oven until the assembly reaches thermoplastic softening temperature and bonding pressure levels; compressing said softened thermoplastic layer as to form a bond between said honeycomb core and said laminate; decreasing the temperature below the thermoplastic softening level and post-curing the bonded assembly; and slowly cooling the bonded assembly to room temperature.

Claim 3

The method as recited in claim 1 wherein said thermosetting laminae layer is formed by stacking a plurality of plies of reinforced thermosetting lamina.

Claim 4

The method as recited in claim 1 wherein the laminate is cured at a temperature between 225° F. and 600° F.

Claim 5

The method as recited in claim 1 wherein the laminate is cured at a pressure of between 8 p.s.i. and 45 p.s.i.

Claim 6

The method as recited in claim 1 wherein the assembly is bonded at a temperature between 345° F. and 375° F.

Claim 7

The method as recited in claim 1 wherein the assembly is bonded at a pressure of about 5 p.s.i.

Claim 8

The method as recited in claim 1 wherein said step of post-curing the assembly includes the step of maintaining the assembly at a series of discrete post-curing temperature levels, each of said discrete temperatures being sustained for a predetermined interval before proceeding to the succeeding discrete level.

Claim 9

A continuous method of producing a honeycomb sandwich assembly comprising: layering a sheet of thermoplastic adhesive upon a honeycomb core; setting a layer of thermosetting laminae upon said adhesive sheet as to form an unbonded assembly consisting of said honeycomb core, said adhesive sheet and said laminae layer; locally evacuating the space about the assembly; heating the assembly in a pressurized oven to the laminate curing temperature while supporting said layer of laminae upon said thermoplastic sheet; maintaining laminate curing temperature and pressure levels until the laminate is substantially cured; increasing the temperature while decreasing the pressure level within the pressurized oven until the assembly reaches thermoplastic softening temperature and bonding pressure levels; compressing said softened thermoplastic layer as to form a bond between said honeycomb core and said laminate; decreasing the temperature below the thermoplastic softening temperature; removing the bonded assembly from the pressurized oven and relocating the bonded assembly in an unpressurized oven; post-curing the bonded assembly in the unpressurized oven; and slowly cooling the bonded assemblyto room temperature.

Claim 10

A continuous method of producing a honeycomb sandwich assembly comprising: layering a sheet of thermoplastic adhesive upon a honeycomb core; setting a layer of thermosetting laminae upon said adhesive sheet as to form an unbonded assembly consisting of said honeycomb core, said adhesive sheet and said laminae layer; locally evacuating the space about the assembly; heating the assembly in a pressurized oven to the laminate curing temperature while supporting said layer of laminae upon said thermoplastic sheet; maintaining laminate curing temperature and pressure levels until the laminate is substantially cured; increasing the temperature while decreasing the pressure level within the pressurized oven until the assembly reaches thermoplastic softening temperature and bonding pressure levels; compressing said softened thermoplastic layer as to form a bond between said honeycomb core and said laminate; decreasing the temperature below the thermoplastic softening temperature; removing the bonded assembly from the pressurized oven and relocating the bonded assembly in an unpressurized oven; post-curing the bonded assembly in the unpressurized oven; and slowly cooling the bonded assemblyto room temperature.

Claim 11

The method as recited in claim 8 wherein said thermosetting laminae layer is formed by stacking a plurality of plies of reinforced thermosetting lamina.

Claim 12

The method as recited in claim 8 wherein the laminate is cured at a temperature between 225° F. and 600° F.

Claim 13

The method as recited in claim 8 wherein the laminate is cured at a pressure of between 8 p.s.i. and 45 p.s.i.

Claim 14

The method as recited in claim 8 wherein the assembly is bonded at a temperature between 345° F. and 375° F.

Claim 15

The method as recited in claim 8 wherein the assembly is bonded at a pressure of about 5 p.s.i.

Claim 16

The method as recited in claim 8 wherein said step of post-curing the assembly includes the step of maintaining the assembly at a series of discrete post-curing temperature levels, each of said discrete temperatures being sustained for a predetermined interval before proceeding to the succeeding discrete level.