Patent Description:
Polymer composites are tough, light-weight materials created by combining two or more functional components, such as reinforcing fibers bound in polymer resin matrix. Fabrication of thermoset composite parts commonly requires the application of both pressure and heat to complete the curing and consolidation process. For example, different pressure and temperature profiles, i.e. variations as a function of time, may be used to process thermoset composite parts. Generally, curing of a thermoset composite part is carried out in a pressurized autoclave where a heat source, such as resistive heating elements, supplies heat to the thermoset composite before or while a consolidation pressure is applied to the thermoset composite part. Production rate is significantly impacted by the time required to bring the autoclave up temperature and to heat the thermoset composite part before applying the consolidation pressure in the overall cure cycle time. Accordingly, there is a need to reduce the cure cycle time of thermoset composite parts by providing more efficient methods for the processing of the thermoset composite parts.

<CIT> describes reducing a thermal cycle time for curing a thermoset composite part in an autoclave by placing a heating blanket in proximity to an area of the composite part that is slow to heat, and inductively heating the area of the composite part that is slow to heat using the heating blanket.

This summary is intended merely to introduce a simplified summary of some aspects of one or more implementations of the present disclosure. This summary is not an extensive overview, nor is it intended to identify key or critical elements of the present teachings, nor to delineate the scope of the disclosure. Rather, its purpose is merely to present one or more concepts in simplified form as a prelude to the detailed description below.

The foregoing and/or other aspects and utilities embodied in the present disclosure may be achieved by providing a method for curing a thermoset composite part, including placing a thermoset composite part within a heating assembly; using the heating assembly to heat the thermoset composite part to a predetermined temperature; placing the heating assembly within a pressurization vessel; using the pressurization vessel to apply a consolidation pressure to the thermoset composite part until cure of the thermoset composite is complete; removing the heating assembly from the pressurization vessel; and using the heating assembly to cool down the thermoset composite part.

The heating assembly may include a cure tool configured to receive the thermoset composite part.

The heating assembly may further include one or more heating blankets configured to cover at least a portion of the thermoset composite part disposed on the cure tool or a portion of the cure tool corresponding to the portion of the thermoset composite part disposed on the cure tool, wherein the one or more heating blankets are configured to heat at least the portion of the thermoset composite part to the predetermined temperature.

The cure tool may include a heating element and may be configured to heat at least a portion of the thermoset composite part disposed on the cure tool to the predetermined temperature.

The cure tool may include a thermally conductive tool surface, and the tool surface may include a first surface configured to contact at least the portion of the thermoset composite part and a second surface configured to contact at least a portion of the one or more heating blankets, such that, heat generated by the one or more heating blankets is transmitted through the tool surface to heat at least the portion of the thermoset composite part in contact with the tool surface to the predetermined temperature.

At least one of the one or more heating blankets may be an inductive heating blanket including a smart susceptor, and the smart susceptor may have a Curie temperature corresponding to the predetermined temperature.

The consolidation pressure is applied to the thermoset composite part after the predetermined temperature is reached.

The heating assembly may heat the thermoset composite part within the pressurization vessel.

The heating assembly may be the source for heating the thermoset composite part.

The heating assembly may be removed from the pressurization vessel before the thermoset composite part has cooled down, and the cooling down of the thermoset composite part may be completed outside of the pressurization vessel.

The heating assembly heats the thermoset composite part to the predetermined temperature before placing the heating assembly within the pressurization vessel.

The predetermined temperature may be one or more temperatures along a curing temperature profile for the thermoset composite part and the consolidation pressure may be one or more pressures applied along a curing pressure profile for the thermoset composite part.

The foregoing and/or other aspects and utilities embodied in the present disclosure may also be achieved by providing a method for curing a thermoset composite part, including placing a thermoset composite part within a heating assembly and heating the thermoset composite part according to a temperature profile for the thermoset composite part; placing the thermoset composite part within a pressurization vessel when the thermoset composite part reaches a predetermined temperature and applying a consolidation pressure to the thermoset composite part according to a pressure profile for the thermoset composite part; and removing the thermoset composite part from the pressurization vessel and cooling down the thermoset composite part.

The heating assembly may be the only heat source for the thermoset composite part.

The heating assembly may include one or more heating blankets configured to heat at least a portion of the thermoset composite part.

The heating of the thermoset composite starts outside of the pressurization vessel and the cool down of the thermoset composite part may be completed outside of the pressurization vessel.

Further areas of applicability will become apparent from the detailed description provided hereinafter.

The accompanying drawings, which are incorporated in, and constitute a part of this specification, illustrate implementations of the present teachings and, together with the description, serve to explain the principles of the disclosure. In the figures:.

It should be noted that some details of the figures have been simplified and are drawn to facilitate understanding of the present teachings rather than to maintain strict structural accuracy, detail, and scale.

Reference will now be made in detail to exemplary implementations of the present teachings, examples of which are illustrated in the accompanying drawings. Generally, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

A thermoset composite part is generally cured by subjecting it to a combination of heat and pressure according to a predetermined cure schedule specifying applied pressures, temperatures and durations for which the pressures and temperatures are maintained. These schedule temperatures and pressures are sometimes referred to as the curing temperate profile and the consolidation pressure profile.

With respect to fiber-reinforced thermoset polymer composite parts, curing generally refers to the application of heat and/or pressure to crosslink and consolidate the fibers of a fiber-reinforced thermoset polymer composite part. While thermoset resins can be partially cured (i.e. crosslinked) without the application of pressure, it often results in a poorly consolidated part. Accordingly, as used herein, the terms "cure" and "curing" include both the application of heat (to cure/crosslink) and the application of pressure (to consolidate) fiber-reinforced thermoset polymer composite parts, such as the thermoset composite parts of the present disclosure.

As described below, the inventors have developed a new system and method for curing thermoset composite parts requiring the application of both heat and pressure. While the following description of the system and methods are made in relation to a thermoset composite part, please note the present disclosure is not limited thereto. The system and method described below is applicable to other materials requiring the applications of heat and pressure to cure, such as to cure adhesives for structural bonding and to consolidate thermoplastic fiber-reinforced composites.

As illustrated in <FIG>, in one implementation of the present disclosure, a system <NUM> for curing a thermoset composite part <NUM> may include a heating assembly <NUM> and a pressurization vessel <NUM>. The heating assembly <NUM> may be configured to receive the thermoset composite part <NUM> and to heat the thermoset composite part <NUM> to a predetermined temperature, for example, the curing temperature, or according to the curing temperature profile required to cure the thermoset composite part <NUM>. The pressurization vessel <NUM> may be configured to apply a consolidation pressure or consolidation pressure profile to the thermoset composite part <NUM> when the heating assembly <NUM> is placed within the pressurization vessel <NUM>, for example, after the thermoset composite part <NUM> has reached a curing temperature or at a specific temperature of the curing temperature profile.

The thermoset composite part <NUM> may include laminated plies of fiber reinforced polymer resin, such as, carbon fiber epoxy or other thermosets that must be heated to a preselected temperature in order to effect curing. For example, as illustrated in <FIG>, the thermoset composite part <NUM> may include a sandwich panel of a honeycomb core <NUM> sandwiched between inner and outer face sheets <NUM> and <NUM>. In one implementation, the honeycomb core <NUM> is stable at the predetermined temperature. Each of inner and outer face sheets <NUM> and <NUM> may include multiple laminated plies (not shown) of a fiber reinforced thermosetting resin, such as carbon fiber epoxy. However, please note that while one type of thermoset composite part <NUM> is illustrated in <FIG>, the present disclosure is not limited thereto, and a wide range of other constructions and geometries are possible for the thermoset composite part <NUM>.

Consolidation is an important step in the curing process of a composite article. Generally, a consolidation pressure is applied during processing of a composite article to remove trapped air or volatiles produced by the cross-linking reaction of the thermoset resin. Consolidation process also helps to ensure intimate contact of the fibers and the resin within the final cured composite article.

Accordingly, in some implementations, the pressurization vessel <NUM> is configured to apply a predetermined pressure to the thermoset composite part <NUM>. For example, the pressurization vessel <NUM> may be configured to apply a consolidation pressure to a thermoset composite part <NUM> for a predetermined period. In one implementation, the predetermined period for the application of the consolidation pressure starts only after the thermoset composite part <NUM> is heated to a predetermined temperature, such as a curing temperature. In other implementations, the predetermined period for the application of the consolidation pressure starts before the thermoset composite part <NUM> is heated to a predetermined temperature. In some implementations, the pressure level may also be increased or decreased as a function of time and temperature according to the temperature and pressure profiles.

In one implementation, the consolidation pressure is <NUM> kPa or less (<NUM> psi or less), <NUM> kPa or less (<NUM> psi or less), or <NUM> kPa or less (<NUM> psi or less). In another implementation, the consolidation pressure is from about <NUM> kPa (<NUM> psi) to about <NUM> kPa (<NUM> psi). In one implementation, the consolidation pressure may be from about atmospheric pressure to about <NUM> kPa (<NUM> psi).

In some implementations, the heating assembly <NUM> is the only component configured to heat the thermoset composite part <NUM> to a predetermined temperature. Accordingly, in some implementations, the heating assembly is the source for heating the thermoset composite part. In other implementations, the pressurization vessel <NUM> is not configured to heat the thermoset composite part <NUM>. In other implementations, the pressurization vessel <NUM> does not include heating elements capable of heating the thermoset composite part <NUM> to a predetermined temperature, such as a curing temperature. In some implementations, the pressurization vessel <NUM> may be an autoclave with a heating capability, however, the pressurization vessel <NUM> is nonetheless not used to heat the thermoset composite part <NUM>.

In one implementation, the predetermined temperature or temperature profile may be from just above room temperature <NUM> (<NUM> °F) to about <NUM> (<NUM> °F). In other implementations, the predetermined temperature or temperature profile may be from just above room temperature <NUM> (<NUM> °F) to about <NUM> (<NUM> °F).

The pressurization vessel <NUM> may include a cure rack <NUM> to support the heating assembly <NUM>. In some implementations, the pressurization vessel <NUM> and/or the cure rack <NUM> may also include a power supply <NUM> to supply power to the heating assembly <NUM> within the pressurization vessel <NUM>.

In order to increase a processing rate of a number of thermoset composite parts <NUM>, in some implementations, the pressurization vessel <NUM> includes one or more pressurization chambers <NUM> (see pressurization chambers <NUM>-<NUM> in <FIG>).

The pressurization vessel <NUM> may also include airlocks (see airlocks <NUM>, <NUM>, <NUM> in <FIG>) between the one or more pressurization chambers <NUM> to facilitate the movements of various heating assemblies <NUM>, each supporting a thermoset composite part <NUM>, through the pressurization vessel <NUM>. For example, see this process as described below with respect to method <NUM>.

In one implementation, the heating assembly <NUM> includes a cure tool <NUM> and one or more heating blankets <NUM>. The heating assembly may be configured to move into the pressurization vessel <NUM>, and the pressurization vessel <NUM> may include a cure rack <NUM> to support the heating assembly <NUM> inside of the pressurization vessel <NUM>.

In some implementations, the system <NUM> includes a cart <NUM> (not illustrated) to transport the heating assembly <NUM> into and/or within the pressurization vessel <NUM>. For example the cart <NUM> may support the heating assembly <NUM> and provide an on-board power source to power the heating assembly <NUM>, for example, an alternating current power supply <NUM>. In other implementations, the cart <NUM> may be configured to connect to the power supply <NUM> of the pressurization vessel <NUM> to provide power to the heating assembly <NUM> when within the pressurization vessel <NUM>. In other implementations, the cart may provide an on-board source of vacuum to the heating assembly. The cart may be configured to move on rails or overhead tracts, and the pressurization vessel <NUM> may be configured to allow the movement of the cart <NUM> into and within the pressurization vessel <NUM>. In some implementations, the cart <NUM> may be self-propelled.

The cure tool <NUM> may be configured to receive and support the thermoset composite part <NUM> during a curing process. For example, the cure tool <NUM> may have a receiving face <NUM> with a shape that substantially matches the shape of the thermoset composite part <NUM>.

In some implementations, the cure tool <NUM> may be heated. For example, the cure tool <NUM> may include a heated tool surface <NUM>. The heated tool surface <NUM> may be disposed on the receiving face <NUM> and may cover at least a portion of the receiving face <NUM>. The heated tool surface <NUM> may be configured to contact at least a portion of the thermoset composite part <NUM> supported by the cure tool <NUM>.

The heated tool surface <NUM> may include a rigid layer of a suitable resin, such as epoxy or bis-maleimides (BMI), which encases an induction heating circuit <NUM>. The rigid layer of resin may form an upper surface of the heated tool surface <NUM> and may be configured to match a lower surface of the thermoset composite part <NUM> disposed on the cure tool <NUM>. In other implementations, other resins may be employed to fabricate the heated tool surface <NUM>, including, but not limited to, polybenzoxazine (BXA).

The induction heating circuit <NUM> may include a plurality of inductive coil circuits, and the heated tool surface <NUM> may be configured to heat at least a portion of the thermoset composite part <NUM> to a predetermined temperature, such as a curing temperature or temperature profile. While some implementations use inductive heating to heat the cure tool <NUM>, the present disclosure is not limited thereto and other heating methods may be used to heat the cure tool <NUM>, such as resistive heating, forced air, heated oil, etc..

In other implementations, the heated tool surface <NUM> is a thermally conductive tooling surface and is heated by a heating blanket <NUM> disposed in contact with the heated tool surface <NUM>. For example, a first surface of the heated tool surface <NUM> may be in contact with at least a portion of the thermoset composite part <NUM>, while another opposite second surface of the heated tool surface <NUM> may be in contact with at least a portion of the one or more heating blankets <NUM>. Accordingly, heat from the one or more heating blankets <NUM> may be transmitted through the heated tool surface <NUM> to heat at least a portion of the thermoset composite part <NUM>.

As illustrated in <FIG>, the thermoset composite part <NUM> may be disposed on the cure tool <NUM>, and at least a portion of the thermoset composite part <NUM> in contact with the heated tool surface <NUM> is heated by the heated tool surface <NUM> either directly or indirectly by the one or more heating blankets <NUM>.

The one or more heating blankets <NUM> may be used to heat at least a portion of the thermoset composite part <NUM> supported by the cure tool <NUM>. For example, as illustrated in <FIG>, the one or more heating blankets <NUM> may be disposed directly over a thermoset composite part <NUM> placed on an upper surface of the cure tool <NUM>, to contact and directly heat the thermoset composite part <NUM>. In other implementations, the one or more heating blankets <NUM> may be disposed to heat an exposed, outside, surface of the cure tool <NUM> to indirectly heat the thermoset composite part <NUM>.

As will be discussed below in more detail, the one or more heating blankets <NUM> generate heat through electrical induction, and the generated heat is transferred to the thermoset composite part <NUM> and/or the cure tool <NUM> primarily through conduction, although, depending upon the geometry of the thermoset composite part <NUM>, the cure tool <NUM>, and/or the placement of the one or more heating blankets <NUM>, the heat may also be transferred through convection and radiation. In one implementation, at least one of the one or more heating blankets <NUM> is an inductive heating blanket.

The one or more heating blankets <NUM> may be formed of a flexible material that allows them to substantially conform to the geometry of the thermoset composite part <NUM> or the cure tool <NUM>.

The one or more heating blankets <NUM> may employ any of various heating techniques to generate the heat necessary to heat the thermoset composite part to a predetermined temperature, such as a curing temperature or temperature profile. For example, the details of one suitable implementation of a heating blanket <NUM> are illustrated in <FIG>, wherein magnetic properties of magnetic materials are employed in combination with the application of high frequency alternating electrical power to generate heat. In this exemplary implementation, a heating blanket <NUM> comprises upper and lower face sheets <NUM> and <NUM> forming a housing <NUM> having an interior <NUM> that is filled with a thermally conductive matrix <NUM> (<FIG>). The upper and lower face sheets <NUM> and <NUM> are preferably formed of a flexible, resilient material possessing a relatively high thermal conductivity and a relatively low electrical conductivity. For example, the upper and lower face sheets <NUM> and <NUM> may include silicone, rubber, polyurethane or other suitable elastomers that provide dimensional stability to the housing <NUM> while maintaining sufficient flexibility to allow the heating blanket <NUM> to conform to at least a portion of the surface of the thermoset composite part <NUM> and/or at least a portion of the cure tool <NUM>, including surfaces that are irregular or contoured. In one implementation, the matrix <NUM> includes an elastomer that is cast around an inductive heating element <NUM>. In still other implementations, however, the heating blanket <NUM> may not be flexible and the housing <NUM> may be formed into a permanent, non-flexible shape that suits a particular application or thermoset composite part <NUM>.

As described above, an inductive heating element <NUM> may be embedded within the matrix <NUM>. The inductive heating element <NUM> may include an electrical conductor <NUM> and a surrounding susceptor sleeve <NUM> which are co-axially arranged. The electrical conductor <NUM> may comprise, for example and without limitation, a Litz wire over which a spiral type susceptor is sleeved. The susceptor sleeve <NUM> may extend substantially the entire length of the electrical conductor <NUM>. Axial spacing between the electrical conductor <NUM> and the susceptor sleeve <NUM> electrically insulates the susceptor sleeve <NUM> from the electrical conductor <NUM>. In the disclosed implementation, the inductive heating element <NUM> is arranged in a serpentine pattern with generally parallel legs <NUM>, however other patterns and layout arrangements are possible. While only a single inductive heating element <NUM> is shown in the exemplary implementation, other implementations may include multiple inductive heating elements <NUM>. The susceptor sleeve <NUM> is inductively heated by alternating electrical current flow through the electrical conductor <NUM>. The inductively heated susceptor sleeve <NUM> conducts heat to the matrix <NUM>, which in turn conducts heat through the housing <NUM> to the thermoset composite part <NUM> and/or the cure tool <NUM> (<FIG> and <FIG>), against which the heating blanket <NUM> is in contact.

The matrix <NUM> may include ferromagnetic or superparamagnetic particles (not shown) to aid in heating the matrix <NUM>. Where ferromagnetic particles are employed, the matrix <NUM> is heated by hysteretic heating of the ferromagnetic particles to a temperature that is substantially below the Curie temperature of the particles. Where superparamagnetic particles are incorporated into the matrix <NUM>, the heat that is conducted through the matrix <NUM> is generated by relaxation heating of the superparamagnetic particles in correspondence to a Curie temperature range related to the size or diameter of the superparamagnetic particles.

Referring particularly to <FIG>, suitable wiring <NUM> connects the heating element <NUM> to an alternating current power supply <NUM> that may be either a portable or fixed power supply. The power supply <NUM> is connected to a power source, such as for example and without limitation, a conventional <NUM>, <NUM> volt or <NUM> volt outlet (not shown). The power supply <NUM> supplies alternating current to the conductor <NUM>, preferably in the range from approximately <NUM>,<NUM> to approximately <NUM>,<NUM>, although higher frequencies are possible. One or more thermal sensors <NUM> may be located between the heating blanket <NUM> and the structure against which it has been placed for monitoring the temperature of the structure in order to facilitate regulation of the magnitude or frequency of the alternating current supplied to the conductor <NUM>. The power supply <NUM> can be regulated by a suitable controller <NUM> based on the temperatures monitored by the thermal sensors <NUM>.

As shown in <FIG>, the susceptor sleeve <NUM> is formed of a magnetic material having a Curie temperature. The susceptor sleeve <NUM> may be formed as a solid or unitary component in a cylindrical arrangement, preferably from a braided material in a sleeve configuration around the conductor <NUM> in order to enhance flexibility of the heating blanket <NUM>.

The flow of alternating current through the conductor <NUM> results in the generation of a magnetic field <NUM> surrounding the susceptor sleeve <NUM>. Eddy currents <NUM> are generated within the conductor <NUM> as a result of exposure thereof to the magnetic field <NUM>, and these eddy currents <NUM> cause the inductive heating of the susceptor sleeve <NUM>. Heat from the susceptor sleeve <NUM> is then conducted through the matrix material <NUM>, and the housing <NUM> to the thermoset composite part <NUM> and/or the cure tool <NUM> (<FIG> and <FIG>) or other structure. The magnetic material from which the susceptor sleeve <NUM> is formed preferably has a high magnetic permeability and a Curie temperature that corresponds to the desired temperature to which the thermoset composite part <NUM> is to be heated by the heating blanket <NUM>, i.e. the cure temperature of the thermoset composite part <NUM>. The susceptor sleeve <NUM> and the conductor <NUM> are preferably sized and configured such that at temperatures below the Curie temperature of the susceptor sleeve <NUM>, the magnetic field <NUM> is concentrated in the susceptor sleeve <NUM> due to its magnetic permeability.

Heating of the susceptor sleeve <NUM> continues during application of the alternating current until the magnetic material from which the susceptor sleeve <NUM> is formed of reaches the Curie temperature. Upon reaching the Curie temperature, the susceptor sleeve <NUM> becomes nonmagnetic, at which point the magnetic fields <NUM> are no longer concentrated in the susceptor sleeve <NUM>. The induced eddy currents <NUM> and associated resistive heating diminishes to a level sufficient to maintain the temperature of the susceptor sleeve <NUM> at the Curie temperature, consequently the thermoset composite part <NUM> and/or the cure tool <NUM> remains heated to the desired cure temperature for the duration of the cure cycle, at which point the alternating current is removed from the conductor <NUM>.

It should be noted here that <FIG> illustrate only one of several possible constructions of a heating blanket <NUM>. Other constructions are possible. For example, and without limitation, the susceptor sleeve <NUM> may comprise a spring shaped coil that is sleeved over a Litz wire (conductor <NUM>). Alternatively, the heating blanket <NUM> may comprise a woven design wherein one direction of the weave comprises a Litz wire <NUM>, and the other direction of the weave comprises a smart susceptor wire. Moreover, in other implementations, the smart susceptors <NUM> may be encased in a flattened solenoidal coil (not shown) formed of a Litz wire.

As illustrated in <FIG>, in some implementations, the thermoset composite part <NUM> may be disposed on the cure tool <NUM>, and one or more heating blankets <NUM> may be disposed directly over the thermoset composite part <NUM>, or in contact with portions of the cure tool <NUM> supporting the thermoset composite part <NUM>, such that, at least a portion of the thermoset composite part <NUM> in direct or indirect contact with the one or more heating blankets <NUM> is heated by the one or more heating blankets <NUM>.

The heating assembly <NUM> may include a vacuum bag assembly <NUM> (not illustrated). In some implementations, the vacuum bag assembly <NUM> may be installed over the one or more heating blankets <NUM>. For example, the vacuum bag assembly <NUM> may include a bagging film to cover at least one of the one or more heating blankets <NUM> which may be sealed to an upper surface of the cure tool <NUM> and/or the thermoset composite part <NUM> by means of sealant. In some implementations, a vacuum is drawn from the vacuum bag assembly <NUM> to apply a negative pressure and draw out volatiles and other gasses that may be generated as a result of the curing process of the thermoset composite part <NUM>. In other implementations, the vacuum bag assembly <NUM> is placed and sealed over at least one of the one or more heating blankets <NUM> to compact the thermoset composite part <NUM> against the cure tool <NUM> during the curing process. In other implementations, the vacuum bag assembly <NUM> may be installed directly over the thermoset composite part <NUM> and may not cover the one or more heating blankets <NUM>.

In some implementations, the cart <NUM> provides a vacuum source for the vacuum bag assembly <NUM>.

<FIG> illustrates a method of curing a thermoset composite part according to implementations of the present disclosure.

As illustrated in <FIG>, a method <NUM> for curing a thermoset composite part <NUM> may begin with placing the thermoset composite part <NUM> in the heating assembly <NUM> in operation <NUM>.

Operation <NUM> may include placing an uncured thermoset composite part <NUM> on the cure tool <NUM>. In some implementations, one or more blankets <NUM> may also be placed either directly over at least a portion of the thermoset composite part <NUM> or in contact with at least portions of the cure tool <NUM> supporting the thermoset composite part <NUM>. In some implementations, at least a portion of the thermoset composite part <NUM> is disposed over a heated tool surface <NUM> of the cure tool <NUM>.

In operation <NUM>, the heating assembly <NUM> is used to heat the thermoset composite part <NUM> to a predetermined temperature. In some implementations, the predetermined temperature is a curing temperature corresponding to the composition of the thermoset composite part <NUM>. In other implementations, the predetermined temperature corresponds to a temperature along the curing temperature profile for the thermoset composite part <NUM>.

In operation <NUM> a consolidation pressure is applied. In implementations that are in accordance with the appended claims, the heating assembly <NUM> is moved within a pressurization vessel <NUM> once the thermoset composite part <NUM> has reached the predetermined temperature and a consolidation pressure is applied by the pressurization vessel <NUM>. In other implementations that are not in accordance with the wording of claim <NUM>, the heating assembly <NUM> is moved within a pressurization vessel <NUM> before the thermoset composite part <NUM> has reached the predetermined temperature and is heated to the predetermined temperature by the heating assembly <NUM> within the pressurization vessel <NUM>. The consolidation pressure is then applied by the pressurization vessel <NUM> once the predetermined temperature is reached.

In some implementations, the heating of the thermoset composite part <NUM> by the heating assembly <NUM> occurs entirely outside of the pressurization vessel <NUM>. In other implementations, the heating of the thermoset composite part <NUM> by the heating assembly <NUM> occurs partly outside of the pressurization vessel <NUM>. For example, in some implementations, the thermoset composite part <NUM> is heated to the point where resin may flow easily (that is, at a decreased viscosity of the resin) before placing the heating assembly <NUM> within the pressurization vessel <NUM>.

In operation <NUM>, the thermoset composite part <NUM> is maintained at the predetermined temperature for a predetermined time by the heating assembly <NUM>. For example, in one implementation, the thermoset composite part <NUM> is maintained at the predetermined temperature for a period of time corresponding to the application of the consolidation pressure within the pressurization vessel <NUM>. In another implementation, the thermoset composite part <NUM> is maintained at the predetermined temperature for a period of time outside of the pressurization vessel <NUM>, during the application of the consolidation pressure within the pressurization vessel <NUM>, and after the application of the consolidation pressure.

In operation <NUM>, the thermoset composite part <NUM> is allowed cooled down on the heating assembly <NUM> and removed from the heating assembly <NUM>. For example, in one implementation, the heating assembly <NUM> gradually reduces the heat applied to the thermoset composite part <NUM> to reduce its temperature from the predetermined temperature. In some implementations, the temperature reduction occurs while the heating assembly is within the pressurization vessel <NUM>. Once the temperature of the thermoset composite part <NUM> has reduced sufficiently, the heating assembly <NUM> may be removed from the pressurization vessel <NUM> to allow the thermoset composite part <NUM> to further fully cool down. In other implementation, the heating assembly <NUM> may be removed from the pressurization vessel <NUM> while the thermoset composite part <NUM> is still at or near the predetermined temperature and allowed to cool down outside of the pressurization vessel <NUM>. For example, in some implementations, the thermoset composite part <NUM> is stable at or near the predetermined temperature. Accordingly, the thermoset composite part <NUM> may be removed from the pressurization vessel <NUM> while at an elevated temperature and allowed to cool down outside of the pressurization vessel <NUM>.

<FIG> and <FIG> illustrate a method of curing a thermoset composite part according to implementations of the present disclosure. As illustrated in <FIG>, a multichamber pressurization vessel <NUM> may be used to allow higher processing rates for the curing of thermoset composite parts <NUM>.

The method <NUM> may begin by placing a first thermoset composite part <NUM> in a first heating assembly <NUM> in operation <NUM> (see <FIG>).

In operation <NUM>, the first thermoset composite part <NUM> is heated to a predetermined temperature by the first heating assembly <NUM> and placed within a first pressurization chamber <NUM> of the pressurization vessel <NUM> (see <FIG>). In one implementation that is in accordance with the appended claims, the first heating assembly <NUM> heats the first thermoset composite part <NUM> to the predetermined temperature before it is moved within the first pressurization chamber <NUM>. In another implementation that is not in accordance with the wording of claim <NUM>, the first heating assembly <NUM> heats the first thermoset composite part <NUM> to the predetermined temperature after it is moved within the first pressurization chamber <NUM>.

In operation <NUM>, a consolidation pressure is applied to the first thermoset composite part <NUM> within the first pressurization chamber <NUM>. Concurrently, a second thermoset composite part <NUM> is placed in a second heating assembly <NUM> and heated outside of the pressurization vessel <NUM> (see <FIG>).

In operation <NUM>, the first thermoset composite part <NUM> is moved to the second pressurization chamber <NUM>, and the second thermoset composite part <NUM> is moved within the first pressurization chamber <NUM> using airlocks <NUM>-<NUM> (see <FIG>).

In one implementation that is in accordance with the appended claims, the second heating assembly <NUM> heats the second thermoset composite part <NUM> to the predetermined temperature before it is moved within the first pressurization chamber <NUM>. In another implementation that is not in accordance with the wording of claim <NUM>, the second heating assembly <NUM> heats the second thermoset composite part <NUM> to the predetermined temperature after it is moved within the first pressurization chamber <NUM>.

In operation <NUM>, a consolidation pressure is applied to the second thermoset composite part <NUM> within the first pressurization chamber <NUM>. Concurrently, the first thermoset composite part <NUM> is cooled down by the first heating assembly <NUM> within the second pressurization chamber <NUM>.

In some implementations, a pressurization pressure is applied to the first and second thermoset composite parts <NUM> and <NUM> by at least one of the first pressurization chamber <NUM> and the second pressurization chamber <NUM> for a predetermined period of time. In other implementations, the pressurization pressure is applied by one of the first pressurization chamber <NUM> and the second pressurization chamber <NUM> for a predetermined period of time.

In operation <NUM>, the first thermoset composite part is removed from the second pressurization chamber <NUM> of pressurization vessel <NUM> and allowed to cool down (See <FIG>). For example, in some implementations, when the first thermoset composite part <NUM> cools down sufficiently it is removed from the second pressure chamber <NUM> and allowed to cool down completely outside of the pressurization vessel <NUM>. Concurrently, the second thermoset composite part <NUM> is moved to the second pressurization chamber <NUM> to allow a subsequent heated thermoset composite part to enter the pressurization vessel <NUM> (See <FIG>). In some implementations, the use of airlocks <NUM>-<NUM> allows the movement of thermoset composite part within the pressurization vessel <NUM> without the need to cycle the pressure up and down. That is, in some implementations, a pressure within the pressurization vessel <NUM> is maintained at the consolidation pressure or along a curing pressure profile during the movement of the first and second thermoset composite parts within the pressurization vessel <NUM>, as well as, during the introduction of any subsequent heated thermoset composite parts into the pressurization vessel <NUM>.

Accordingly, in some implementations, by using a heating assembly <NUM> to heat and cool down a thermoset composite part <NUM> outside of the pressurization vessel <NUM>, a curing cycle time for the thermoset composite part <NUM> can be optimized and a time spent within the pressurization vessel <NUM> can be minimized.

Implementations of the disclosure may find use in a variety of potential applications, particularly in the transportation industry, including for example, aerospace, marine, automotive applications, and other application where thermal curing of thermoset composite parts is carried out. Thus, referring now to <FIG> and <FIG>, implementations of the disclosure may be used in the context of an aircraft manufacturing and service method <NUM> as shown in <FIG> and an aircraft <NUM> as shown in <FIG>. During pre-production, exemplary method <NUM> may include specification and design <NUM> of the aircraft <NUM> and material procurement <NUM>. During production, component and subassembly manufacturing <NUM> and system integration <NUM> of the aircraft <NUM> takes place. Thereafter, the aircraft <NUM> may go through certification and delivery <NUM> in order to be placed in service <NUM>. While in service by a customer, the aircraft <NUM> is scheduled for routine maintenance and service <NUM>, which may also include modification, reconfiguration, refurbishment, and so on.

As shown in <FIG>, the aircraft <NUM> produced by exemplary method <NUM> may include an airframe <NUM> with a plurality of systems <NUM> and an interior <NUM>. Examples of high-level systems <NUM> include one or more of a propulsion system <NUM>, an electrical system <NUM>, a hydraulic system <NUM>, and an environmental system <NUM>. Any number of other systems may be included. Although an aerospace example is shown, the principles of the disclosure may be applied to other industries, such as the marine and automotive industries.

Systems and methods embodied herein may be employed during any one or more of the stages of the production and service method <NUM>. For example, components or subassemblies corresponding to production process <NUM> may be fabricated or manufactured in a manner similar to components or subassemblies produced while the aircraft <NUM> is in service. Also, one or more apparatus embodiments, method embodiments, or a combination thereof may be utilized during the production stages <NUM> and the <NUM>, for example, by substantially expediting assembly of or reducing the cost of an aircraft <NUM>. Similarly, one or more of apparatus embodiments, method embodiments, or a combination thereof may be utilized while the aircraft <NUM> is in service, for example and without limitation, to maintenance and service <NUM>.

Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the present teachings are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. Moreover, all ranges disclosed herein are to be understood to encompass any and all sub-ranges subsumed therein. For example, a range of "less than <NUM>" can include any and all sub-ranges between (and including) the minimum value of zero and the maximum value of <NUM>, that is, any and all sub-ranges having a minimum value of equal to or greater than zero and a maximum value of equal to or less than <NUM>, e.g., <NUM> to <NUM>. In certain cases, the numerical values as stated for the parameter can take on negative values. In this case, the example value of range stated as "less than <NUM>" can assume negative values, e.g. - <NUM>, -<NUM>, -<NUM>, -<NUM>, -<NUM>, -<NUM>, etc..

While the present teachings have been illustrated with respect to one or more implementations, alterations and/or modifications can be made to the illustrated examples without departing from the scope of the appended claims. For example, it will be appreciated that while the process is described as a series of acts or events, the present teachings are not limited by the ordering of such acts or events. Some acts may occur in different orders and/or concurrently with other acts or events apart from those described herein. Also, not all process stages may be required to implement a methodology in accordance with one or more aspects or implementations of the present teachings. It will be appreciated that structural components and/or processing stages can be added or existing structural components and/or processing stages can be removed or modified. Further, one or more of the acts depicted herein may be carried out in one or more separate acts and/or phases. Furthermore, to the extent that the terms "including," "includes," "having," "has," "with," or variants thereof are used in either the detailed description and the claims, such terms are intended to be inclusive in a manner similar to the term "comprising. " The term "at least one of" is used to mean one or more of the listed items can be selected. As used herein, the term "one or more of" with respect to a listing of items such as, for example, A and B, means A alone, B alone, or A and B. Further, in the discussion and claims herein, the term "on" used with respect to two materials, one "on" the other, means at least some contact between the materials, while "over" means the materials are in proximity, but possibly with one or more additional intervening materials such that contact is possible but not required. Neither "on" nor "over" implies any directionality as used herein. The term "conformal" describes a coating material in which angles of the underlying material are preserved by the conformal material. The term "about" indicates that the value listed may be somewhat altered, as long as the alteration does not result in nonconformance of the process or structure to the illustrated implementation. Finally, "exemplary" indicates the description is used as an example, rather than implying that it is an ideal. Other implementations of the present teachings will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure herein.

Terms of relative position as used in this application are defined based on a plane parallel to the conventional plane or working surface of a workpiece, regardless of the orientation of the workpiece. The term "horizontal" or "lateral" as used in this application is defined as a plane parallel to the conventional plane or working surface of a workpiece, regardless of the orientation of the workpiece. The term "vertical" refers to a direction perpendicular to the horizontal. Terms such as "on," "side" (as in "sidewall"), "higher," "lower," "over," "top," and "under" are defined with respect to the conventional plane or working surface being on the top surface of the workpiece, regardless of the orientation of the workpiece.

Claim 1:
A method (<NUM>, <NUM>, <NUM>) for curing a thermoset composite part (<NUM>), comprising:
placing a thermoset composite part (<NUM>) within a heating assembly (<NUM>);
using the heating assembly (<NUM>) to heat the thermoset composite part (<NUM>) to a predetermined temperature;
placing the heating assembly (<NUM>) within a pressurization vessel (<NUM>);
using the pressurization vessel (<NUM>) to apply a consolidation pressure to the thermoset composite part (<NUM>);
removing the heating assembly (<NUM>) from the pressurization vessel (<NUM>); and
using the heating assembly (<NUM>) to cool down the thermoset composite part (<NUM>);
wherein the heating assembly (<NUM>) heats the thermoset composite part (<NUM>) to the predetermined temperature before the heating assembly (<NUM>) is placed within the pressurization vessel (<NUM>).