Resin infusion method

• US 5,885,513 A
• Filed: 03/31/1997
• Issued: 03/23/1999
• Est. Priority Date: 03/31/1997
• Status: Expired due to Term

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Northrop Grumman Corporation
• Inventors: Louderback, Michael J., Friedrich, Robert W.
• Primary Examiner(s): Silbaugh, Jan H.
• Assistant Examiner(s): Staicovici, Stefan
• Application Number:
  US08/823,065
• Time in Patent Office: 722 Days
• Field of Search: 264/459, 264/478, 264/496, 264/510, 264/327, 264/257, 264/273, 264/279, 264/279.1, 425/174, 425/129.1
• US Class Current: 264/459
• CPC Class Codes: B29C 2035/0827 using UV radiation
• CPC Class Codes: B29C 35/0266 Local curing for repairing B29C73/34
• CPC Class Codes: B29C 35/0805 using electromagnetic radiation
• CPC Class Codes: B29C 70/443 and impregnating by vacuum or injection

Abstract

Method and apparatus of making a reinforced composite structure wherein a reusable mold closure is mated to a mold to close off a mold cavity in which a reinforcement is positioned. The mold closure or mold includes a plurality of collapsible resin supply ports through which resin is pumped into the mold cavity from a source of resin to infuse or impregnate the reinforcement with resin. After the resin is introduced into the mold cavity, the resin residing in the resin supply ports is selectively cured to form respective cured resin plugs on which the resin supply ports collapse to seal them in air-tight manner. The resin residing in the mold and infused in the reinforcement is not cured at that time. Instead, after the cured resin plugs are formed at the resin supply ports, the assembly of mold and mold closure with the resin infused reinforcement therein can be moved to a curing station, such as a curing oven, where the resin infused in the reinforcement is cured under vacuum in the mold in a separate readily controlled curing operation.

Claims

1. A method of making a reinforced composite structure, comprising:

a) introducing resin to resin supply port means communicated to a mold to infuse a reinforcement in the mold with the resin,

b) selectively curing the resin at said resin supply port means to form cured resin plugs with which said port means cooperate to provide an air-tight seal thereat, including avoiding curing of the resin infused in said reinforcement in said mold,

c) disconnecting the resin supply port means from communication with the resin source, and

d) then curing the resin infused in said reinforcement in said mold to form a reinforced composite structure in said mold.

2. The method of claim 1 wherein an ultraviolet and/or heat curable resin is introduced into the mold cavity and is selectively cured in step b) at said resin supply port means by exposure to ultraviolet radiation and/or heat at said ports.

3. The method of claim 2 wherein the resin is selectively cured at said resin supply port means in step b) with in said mold under vacuum such that said resin supply port means are collapsed onto the cured resin plugs to seal thereon to effect said air-tight seal.

4. The method of claim 2 wherein curing of the resin infused in said reinforcement in said mold is avoided in step b) by applying ultraviolet radiation and/or heat only to resin in said resin supply port means.

5. The method of claim 1 including disconnecting the resin supply port means from the resin source by disconnecting a resin supply tube disposed between the resin source and resin supply conduits in communication with said mold.

6. The method of claim 1 including after step c) and prior to step d), moving the mold with the resin infused reinforcement therein to a curing station where the resin infused in the reinforcment is cured under vacuum in said mold.

7. The method of claim 6 wherein the resin infused in said reinforcement is cured at the curing station by ultraviolet radiation directed through a mold closure member at one side of said mold and by heating an opposite side of said mold.

8. A method of making a reinforced composite structure, comprising:

a) positioning a reinforcement in a mold cavity of a mold,

b) disposing a reusable mold closure to close off said mold cavity with said reinforcement therein, said mold closure having a plurality of collapsible resin supply ports for introducing resin in said mold cavity,

c) communicating said mold cavity to a source of resin via said resin supply ports,

d) introducing resin through the resin supply ports and into the mold cavity to infuse said reinforcement with the resin,

e) selectively curing the resin at said resin supply ports to form cured resin plugs on which the resin supply ports collapse to provide an air-tight seal thereat, including avoiding curing of the resin infused in said reinforcement in said mold, and

f) then curing the resin infused in said reinforcement in said mold to form a reinforced composite structure in said mold.

9. The method of claim 8 wherein an ultraviolet and/or heat curable resin is introduced into the mold cavity and is selectively cured in step e) at said resin supply ports by exposure to ultraviolet radiation and/or heat at said ports.

10. The method of claim 9 wherein curing of the resin infused in said reinforcement in said mold is avoided in step e) by applying ultraviolet radiation and/or heat only to resin in said resin supply ports.

11. The method of claim 8 including after step e) and prior to step f), moving the mold and mold closure with the resin infused reinforcement therein to a curing station where the resin infused in the reinforcment is cured under vacuum in said mold.

12. The method of claim 11 wherein the resin infused in said reinforcement is cured at the curing station by ultraviolet radiation directed through said mold closure at one side of said mold and by heating an opposite side of said mold.

13. The method of claim 8 including communicating each of said resin supply ports to a respective one of resin supply conduits communicated to said resin source.

14. The method of claim 13 including in step e) avoiding curing of the resin in said resin supply conduits.

15. The method of claim 14 wherein uncured resin residing upstream of said plugs in said resin supply conduits is removed after said cured resin plugs are formed at said ports.

16. The method of claim 15 wherein the uncured resin residing in said resin supply conduits is removed by venting said resin supply conduits to ambient proximate said plugs and drawing a vacuum in said resin supply conduits.

17. The method of claim 16 wherein said resin supply conduits are disconnected from a resin supply tube after said resin is removed therefrom.