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EP-4741145-A2 - METHODS AND SYSTEMS FOR FORMING COMPOSITE PARTS

EP4741145A2EP 4741145 A2EP4741145 A2EP 4741145A2EP-4741145-A2

Abstract

A method for forming composite parts includes loading an uncured composite material into a middle cavity of a chamber between an upper membrane and a lower membrane, wherein a lower cavity is defined below the lower membrane, and wherein an upper cavity is defined above the upper membrane, wherein a forming tool is disposed within the upper cavity. A vacuum is applied to the upper cavity, the middle cavity, and the lower cavity to remove at least a portion of gas entrapped within the uncured composite material. The vacuum is released from the upper cavity and the lower cavity, and the chamber is heated to a forming temperature of the uncured composite material. Pressure is controlled in the upper cavity and the lower cavity to form the heated composite material, wherein a greater pressure is applied to the lower cavity than to the upper cavity such that a pressure differential between the lower cavity and the upper cavity causes the heated composite material to form around the forming tool. The chamber is heated to a curing temperature to cure the heated composite material. (Fig. 1)

Inventors

  • Philibert, Joseph H.

Assignees

  • The Boeing Company

Dates

Publication Date
20260513
Application Date
20240703

Claims (15)

  1. A method (100) for forming composite parts, the method comprising the steps of: loading an uncured composite material into a middle cavity of a chamber between an upper membrane and a lower membrane, wherein the upper membrane preferably is spaced from the uncured composite material, wherein a lower cavity is defined below the lower membrane, and wherein an upper cavity is defined above the upper membrane, wherein a forming tool is disposed within the upper cavity (102); applying a vacuum to the upper cavity, the middle cavity, and the lower cavity to remove at least a portion of gas entrapped within the uncured composite material (104); releasing the vacuum from the upper cavity and the lower cavity (106); heating the chamber to a forming temperature of the uncured composite material to yield a heated composite material (108); controlling pressure in the upper cavity and the lower cavity to form the heated composite material, wherein a greater pressure is applied to the lower cavity than to the upper cavity such that a pressure differential between the lower cavity and the upper cavity causes the heated composite material to form around the forming tool (110); and heating the chamber to a curing temperature to cure the heated composite material, thereby yielding a cured composite material (112); wherein, in the step of releasing the vacuum (106), the vacuum is released from the upper cavity before the vacuum is released from the lower cavity.
  2. The method of Claim 1, wherein, in the step (102) of loading the uncured composite material into the middle cavity, the uncured composite material comprises a fiber-reinforced resin and/or wherein, in the step (102) of loading the uncured composite material into the middle cavity, the uncured composite material comprises multiple plies of fiber-reinforced resin.
  3. The method of any of Claims 1 to 2, wherein the step of applying the vacuum to the upper cavity, the middle cavity, and the lower cavity (104) comprises applying the vacuum to the upper cavity and the lower cavity before applying the vacuum to the middle cavity.
  4. The method of any of Claims 1 to 3, wherein, in the step of heating the chamber to the forming temperature (108), the chamber is heated to the forming temperature before the vacuum is release from the upper cavity and/or wherein, in the step of heating the chamber (108) to the forming temperature, the chamber is heated to the forming temperature before the vacuum is release from the lower cavity.
  5. The method of any of Claims 1 to 4, wherein, in the step of controlling pressure in the upper cavity and the lower cavity to form the heated composite material (110), the pressure differential between the lower cavity and the upper cavity, combined with positioning of the heated composite material between the upper membrane and the lower membrane, results in an S-shaped deformation of the heated composite material as it is pressed upwards and conforms around the forming tool, and/or wherein, in the step of controlling pressure in the upper cavity and the lower cavity to form the heated composite material (110), the pressure differential between the lower cavity and the upper cavity is between about 1 psi and about 100 psi.
  6. The method of any of Claims 1 to 5, wherein, in the step of heating the chamber to a curing temperature to cure the heated composite material (112), the upper cavity and the lower cavity are pressurized to a curing pressure while the chamber is heated to the curing temperature, and/or wherein, in the step of heating the chamber to a curing temperature to cure the heated composite material (112), the curing temperature of the chamber is between about 100 °C and 250 °C.
  7. The method of any of Claims 1 to 6, wherein the vacuum is maintained in the middle cavity through the forming of the heated composite material.
  8. The method of any of Claims 1 to 7, wherein the vacuum is maintained in the middle cavity through the heating of the chamber to the curing temperature to cure the heated composite material.
  9. The method of any of Claims 1 to 8, further comprising a step of releasing the vacuum from the middle cavity after curing of the cured composite material (114).
  10. The method of any of Claims 1 to 9, further comprising a step of cooling the cured composite material (116).
  11. A system (2) for forming composite parts, the system comprising: a housing (4) defining a chamber (6), the housing including a loading access (8) into the chamber, and the housing preferably comprising an autoclave; an upper membrane (10) disposed within the chamber, an upper cavity (14) defined above the upper membrane; a lower membrane (12) disposed within the chamber under the upper membrane, wherein a middle cavity (16) is defined between the upper membrane and the lower membrane, and wherein a lower cavity (18) is defined below the lower membrane, wherein the loading access is in communication with the middle cavity; a first vacuum port (20) in communication with the upper cavity; a second vacuum port (22) in communication with the middle cavity; a third vacuum port (24) in communication with the lower cavity; a first pressure control valve (26) in communication with the upper cavity; a second pressure control valve (28) in communication with the lower cavity; and a forming tool (30) disposed within the upper cavity, wherein the system (2) is configured to, in a step of releasing the vacuum, release the vacuum from the upper cavity before the vacuum is released from the lower cavity.
  12. The system of Claim 11, wherein the upper membrane (10) and the lower membrane (12) are substantially impermeable to air.
  13. The system of Claim 11 or 12, further comprising a heater (32) operatively coupled to the housing to provide heat to the chamber.
  14. The system of any of Claims 11 to 13, further comprising a pressure sensor (34), (36), (38) associated with each of the upper cavity, the middle cavity, and the lower cavity, each pressure sensor configured to detect and relay real-time pressure data for its respective cavity, and/or further comprising a temperature sensor (40) associated with the chamber, configured to detect and relay real-time temperature data of the chamber.
  15. The system of any of Claims 11 to 14, further comprising a controller (42) configured to manage and adjust operational parameters of the system.

Description

FIELD The present application relates to the field of composite materials, specifically to methods and systems for forming and curing composite materials. BACKGROUND Composite materials, composed of two or more distinct materials, have found widespread applications in various industries such as aerospace, automotive, and construction. These materials combine the strengths of individual components, like high strength-to-weight ratio, corrosion resistance, and durability. However, manufacturing composite parts often involves complex processes that require careful control of multiple parameters like temperature, pressure, and curing time. Traditional methods often involve steps such as laying up layers of fiber-reinforced resin, vacuum bagging, and curing in an autoclave. These processes are time-consuming, labor-intensive, and present challenges with respect to ensure a consistent and defect free final product. Entrapped gases, for instance, can cause voids in the material. As a result, there is a continuing need for improved methods and systems that can produce high-quality composite parts more efficiently and consistently. Accordingly, those skilled in the art continue with research and development in the field of composite materials, aiming to develop methods and systems that can optimize the forming and curing processes, and result in composite parts with enhanced properties and performance. SUMMARY In one embodiment, there is a method for forming composite parts, the method comprising the steps of: loading an uncured composite material into a middle cavity of a chamber between an upper membrane and a lower membrane, wherein a lower cavity is defined below the lower membrane, and wherein an upper cavity is defined above the upper membrane, wherein a forming tool is disposed within the upper cavity; applying a vacuum to the upper cavity, the middle cavity, and the lower cavity to remove at least a portion of gas entrapped within the uncured composite material; releasing the vacuum from the upper cavity and the lower cavity; heating the chamber to a forming temperature of the uncured composite material to yield a heated composite material; controlling pressure in the upper cavity and the lower cavity to form the heated composite material, wherein a greater pressure is applied to the lower cavity than to the upper cavity such that a pressure differential between the lower cavity and the upper cavity causes the heated composite material to form around the forming tool; and heating the chamber to a curing temperature to cure the heated composite material, thereby yielding a cured composite material. In another embodiment, there is a system for forming composite parts, the system comprising: a housing defining a chamber, the housing including a loading access into the chamber; an upper membrane disposed within the chamber, an upper cavity defined above the upper membrane; a lower membrane disposed within the chamber under the upper membrane, wherein a middle cavity is defined between the upper membrane and the lower membrane, and wherein a lower cavity is defined below the lower membrane, wherein the loading access is in communication with the middle cavity; a first vacuum port in communication with the upper cavity; a second vacuum port in communication with the middle cavity; a third vacuum port in communication with the lower cavity; a first pressure control valve in communication with the upper cavity; a second pressure control valve in communication with the lower cavity; and a forming tool disposed within the upper cavity. In another embodiment, there is a method for forming composite parts, the method comprising: loading an uncured composite material comprising multiple plies of fiber-reinforced resin into a chamber between an upper membrane and a lower membrane; heating the chamber to a forming temperature of the uncured composite material to yield a heated composite material; forming the heated composite material by controlling pressure in the chamber to press the upper and lower membranes against the heated composite material; and heating the chamber to a curing temperature to cure the formed composite material, thereby yielding a cured composite material. Other embodiments of the disclosed methods and systems will become apparent from the following detailed description, the accompanying drawings and the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 illustrates a flowchart of an exemplary method of the present description for forming composite parts including loading an uncured composite material into a chamber, applying and releasing a vacuum, heating and pressurizing the material to form and cure it, and cooling the cured material. The pressure in the cavities and the vacuum in the middle cavity are manipulated at different stages to aid in the formation and curing of the material.Fig. 2 illustrates an exemplary system of the present description for forming composite parts, which include