Induction heating tool for punch forming thermoplastic composites

Abstract

The invention relates to an induction heating tool for punch forming thermoplastic composites. A tool for punch forming a thermoplastic component may include a frame reinforced with a filler material. A filler material (e.g., cast ceramic) is configured to provide pressure resistance to the frame and thermally insulate the frame. A forming plate is coupled to the frame, and the plate has a front face defining a forming surface of the tool. In some embodiments, one or more induction heating elements are configured to heat a plate, where each of the one or more induction heating elements includes a conductor (e.g., a Litz wire) coupled to a susceptor material (e.g., # imgabs0 #), and the one or more induction heating elements are configured to be self-regulated with respect to temperature.

Description

Technical Field

[0001] The present disclosure relates to apparatus and methods for stamping thermoplastic composite materials using a heated tool. Background Art

[0002] Press tools used for thermoplastic part forming are heated for the forming process. This heating is provided by standard resistance heating methods, in which the entire tool is heated. Due to their typically large size and correspondingly large thermal mass, thermoplastic press tools take a long time to heat up to operating temperature. Therefore, they are often preheated before installation, for example in order to reduce downtime of a given press or other forming equipment. Due to the high cost of presses and the corresponding need to keep their utilization high, it is often desirable to reduce downtime. However, preheating press tools requires additional equipment and takes up valuable floor space in the manufacturing facility. In addition, installing preheating tools in a press may also pose safety and practicality issues. In addition, heated press tools also take a long time to cool down after use, which adds further safety and practicality issues. Summary of the invention

[0003] By rapidly heating a stamping and forming tool, such as by induction heating, potential advantages can be achieved by streamlining the process and increasing productivity. The present disclosure provides systems, apparatus, and methods related to a self-regulating induction heating system for heated stamping and forming tools.

[0004] In some examples, a tool for stamping and forming a thermoplastic part includes: a frame reinforced by a filler material configured to provide compression resistance and thermal insulation to the frame; a plate coupled to the frame, wherein the plate has a front face defining a forming surface of the tool; and one or more induction heating elements configured to heat the plate, wherein each of the one or more induction heating elements includes a conductor coupled to a susceptor material such that the one or more induction heating elements are configured to self-regulate with respect to temperature.

[0005] In some examples, a stamping and forming press includes: one or more stamping and forming tools mounted in the press, each of the stamping and forming tools including: a heated forming tool including: a structural frame having one or more cavities; a metal plate coupled to the structural frame, wherein the metal plate has a front face defining a forming surface of the forming tool; one or more induction heating elements configured to heat the metal plate, each of the one or more induction heating elements including a conductor coupled to a susceptor material; and a filler material disposed in one or more cavities of the structural frame, wherein the filler material is configured to resist compression and to insulate the structural frame.

[0006] In some examples, a method for stamping a thermoplastic part includes: installing a stamping tool in a stamping press without preheating the stamping tool, the stamping tool including one or more induction heating elements, the one or more induction heating elements being configured to heat a forming surface of the stamping tool, wherein each of the one or more induction heating elements includes a conductor coupled to a susceptor material; heating the forming surface of the stamping tool by applying power to the one or more induction heating elements so that the forming surface reaches and maintains an operating temperature determined at least in part by the Curie temperature of the susceptor material; and press-molding the thermoplastic part using the stamping tool.

[0007] The features, functions, and advantages can be achieved independently in various embodiments of the present disclosure or may be combined in yet other embodiments further details of which can be seen with reference to the following description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a schematic diagram of an illustrative stamping and forming press including one or more induction heating tools according to aspects of the present disclosure.

[0009] Figure 2 is a schematic cross-sectional side view of a portion of an illustrative stamping tool of the present disclosure.

[0010] Figure 3 is a schematic cross-sectional side view of a portion of another illustrative stamping tool of the present disclosure.

[0011] Figure 4 is a schematic top view of a portion of yet another illustrative stamping tool of the present disclosure.

[0012] Figure 5 is a block diagram describing the steps of an illustrative method for stamping a composite part according to aspects of the present disclosure.

[0013] Figure 6is a block diagram of an illustrative aircraft manufacturing and service method according to the present teachings.

[0014] Figure 7 is a block diagram of an illustrative aircraft in which illustrative embodiments may be implemented. DETAILED DESCRIPTION

[0015] Various aspects and examples of induction heating tools for stamping thermoplastic composite parts and related methods are described below and shown in the relevant drawings. Unless otherwise stated, the system or device and / or its various components according to the present teachings may include at least one of the structures, components, functions and / or variants described, shown and / or incorporated herein. In addition, unless specifically excluded, the process steps, structures, components, functions and / or variants described, shown and / or incorporated herein in conjunction with the present teachings may be included in other similar devices and methods, including being interchangeable between the disclosed embodiments. The following description of various examples is merely illustrative in nature and is in no way intended to limit the present disclosure, its application or use. In addition, the advantages provided by the examples and embodiments described below are illustrative in nature, and not all examples and embodiments provide the same advantages or the same degree of advantages.

[0016] Typically, in the figures, elements that may be included in a given example are shown with solid lines, while optional elements in a given example are shown with dotted lines. However, the elements shown with solid lines are not required for all examples of the present disclosure, and the elements shown with solid lines may be omitted from a particular example without departing from the scope of the present disclosure.

[0017] In general, the system of the present disclosure includes one or more heated forming tools, each of the tools having a structural frame defining one or more cavities. A metal sheet is coupled to the structural frame, defining a forming surface of the forming tool. One or more induction heating elements are configured to heat the metal sheet, and each of the induction heating elements includes a conductor and a susceptor material. For example, a copper conductor may be coated with a susceptor material, coaxial with a susceptor material, wrapped in a susceptor material, wrapped with a susceptor material, coupled to a susceptor material, and / or interwoven with a susceptor material. In some examples, one or more Litz wires are wrapped with 36 or 42 susceptor material (or other suitable chemical) and embedded in or placed adjacent to the metal forming plate to form a self-regulating heating element configured to heat only the forming plate. In some examples, the Litz wire wrapped with the smart susceptor wire can be further clad (wrapped, wrapped, etc.) with copper to prevent interaction with the metal tooling facing the structure. In order to provide compression resistance and to insulate the structural frame, a solid filler (e.g., cast ceramic) is provided in the cavity of the structural frame.

[0018] The forming or stamping press may utilize at least one of the heated forming tools. For example, the press may include a set of two heated forming tools in a complementary arrangement. The tool set is positioned in the press, and the press presses the two heated tools together to form and maintain complete consolidation of the thermoplastic part.

[0019] Standard processes for press-forming thermoplastic composites typically use large heated tools where the entire tool is heated (and preheated prior to installation). This approach requires a large amount of energy, poses potential safety issues when changing tools, and requires expanded factory space to preheat and stage the tools. The disclosed systems and methods address these issues by using self-regulating induction heaters to heat only the forming sheet portion of the tool while insulating and (in some cases) actively cooling the rest of the tool.

[0020] In some examples of the present disclosure, the Litz wire is wound with 36 smart sensor lines to create self-regulating heating elements. These heating elements can be mounted relative to the heating surface in a manner that provides appropriate heat to the tool surface. In general, proximity to the heating surface results in more efficient heating. Therefore, the heating element can be set against, in direct contact with, or close to the back side of the tool surface (e.g., the above-mentioned metal plate). In some examples, the heating element is partially or entirely set in a groove or channel on the back side of the tool surface. Setting the heating element in a groove or channel on the back side of the tool surface can facilitate isolating the heat energy generated by the heating element from the surface itself, thereby reducing the transfer of heat energy to the rest of the tool. Cast ceramics can be used to fill the back of the tool (e.g., egg crate), (1) to keep the induction heat isolated from the face of the tool, and (2) to resist deformation of the tool face during the stamping process. Water cooling channels can be included to further maintain the temperature of the egg crate reinforcement member of the tool that is positioned away from the tool surface.

[0021] The disclosed system takes advantage of the rapid heating and self-regulation of an induction heating circuit that includes a smart susceptor. Generally speaking, alternating current (AC) is passed through a conductor, generating a magnetic field. A susceptor material is positioned adjacent to the conductor.

[0022] Generally speaking, a susceptor is a material that converts electromagnetic energy into heat energy. Depending on the application, the susceptor may or may not be ferromagnetic. For example, in some cases, copper may be used as a susceptor material. However, so-called smart susceptors are ferromagnetic and therefore have a higher relative magnetic permeability. Smart susceptors are magnetically conductive until they reach a certain temperature (called the Curie temperature of the material), above which the material becomes non-magnetic. The susceptors of the present disclosure may include any suitable metal, alloy, or other material that is electrically conductive and has a Curie temperature within the range required for the operation of the forming tool. For example, the susceptor may include at least one of iron, cobalt, nickel, molybdenum, and / or chromium. For example, the susceptor material Kovar is a nickel-cobalt-iron alloy, while the susceptor material It is a nickel-iron alloy.

[0023] The susceptor material extends along the length of the conductor and heats due to the induction of the magnetic field caused by the AC current in the nearby conductor. However, the temperature of the susceptor does not rise above the Curie temperature (in fact, it tends to stabilize at a lower temperature). As the susceptor heats, the thermal profile of the susceptor gradually approaches the leveling / stabilization (levelling) temperature, at which the susceptor remains in thermal equilibrium. The leveling temperature is typically a few degrees lower than the Curie temperature of the susceptor (e.g., within 2°F, or within 10°F, or within 50°F, or within 100°F). If the susceptor begins to cool, its magnetic permeability increases and the heating process begins again. Therefore, the susceptor material can be selected to achieve the desired operating temperature without the need for complex temperature control. Because of these self-regulating characteristics, these susceptor materials are sometimes called "smart" susceptors.

[0024] Litz wire is a conductor designed to be effective for high frequency applications (such as induction) with reduced skin effect and reduced proximity effect. Litz wire consists of multiple fine strands twisted or braided together. Each strand has a small enough diameter to evenly distribute the current through the strands. Each strand is also insulated from the other strands to reduce proximity effect.

[0025] In some examples, the Litz wire of the present disclosure is shielded by further wrapping or encapsulating the smart susceptor-wrapped Litz wire with a highly conductive material (e.g., copper or aluminum foil, tubing, and / or wire) configured to inhibit direct inductive heating of the metal tool plate in which the heating element is embedded. U.S. patent application Ser. No. 18 / 307,478, filed Apr. 26, 2023, includes suitable examples of such shielded Litz wires and is incorporated herein by reference in its entirety.

[0026] Figure 11 is a schematic diagram of a manufacturing environment 10 for stamping thermoplastic composite materials (e.g., parts including carbon fibers) using one or more heated tools. For example, manufacturing environment 10 may include any suitable environment in which illustrative embodiments of the present disclosure may be implemented, such as to manufacture one or more parts of an aircraft.

[0027] Thus, the environment 10 includes a stamping press 12 configured to operate at least one thermoforming tool 14 to form a workpiece including a thermoplastic part 16 . Figure 1 An illustrative second forming tool 14A is depicted having the same components and optional components as tool 14. When press 12 includes both forming tools 14 and 14A, the heated forming tools can be arranged in a complementary manner to cooperate in forming a workpiece. Generally, forming of the workpiece can include holding the thermoplastic part in a fixture or picture frame 18 and covering one or both sides of part 16 in an elastic sheet 20 that is configured to provide uniform pressure to the workpiece during stamping.

[0028] The tool 14 (and 14A, when present) may include a structural frame 22 reinforced by a filler material 24 configured to insulate the frame 22 from heat (e.g., heat generated at the face of the tool). The structural frame 22 has one or more cavities 26 filled with a pressure resistant filler 24. In some examples, the structural frame 22 includes a plurality of spaced-apart (e.g., metal) frame members and may constitute an egg-crate frame. The filler material 24 may include any suitable material configured to have a lower thermal conductivity than the frame 22 and to provide pressure resistance within an expected operating pressure range (e.g., 500 to 750 pounds per square inch (psi)). For example, the filler 24 may include a cast material, such as a cast ceramic.

[0029] A plate 28 (e.g., a metal plate) is coupled to the frame 22, and the plate 28 has a front face 30 that defines a forming surface of the tool. The plate 28 may include any suitable material that is configured to be heated under working pressure and temperature and to press the workpiece into a desired configuration. For example, the plate may include a metal such as steel. In some examples, the plate 28 includes a nickel-iron alloy such as 36, which provides a low coefficient of thermal expansion, thereby reducing forces between the cooler substructure and the heated forming surface. Some or all of the cavity 26 can extend into the plate 28, and the filler material 24 disposed in the cavity can be configured to resist deformation of the metal plate during operation. The plate 28 can have a uniform or constant thickness throughout its extent (e.g., across the width and / or length of the plate). In some examples, the thickness of the plate 28 varies from location to location, i.e., has a variable thickness. In some examples, the plate 28 has a maximum thickness of approximately one inch. For example, the thickness of the plate 28 can be 0.50 inches to 0.75 inches. In some examples, the forming surface of the plate 28 is planar. In some examples, the forming surface has a non-planar contour and / or a three-dimensional profile - for example, see Figure 2 The mid-plate 200 has a curved profile 202 .

[0030] One or more induction heating elements 32 are configured to heat the plate 28. Each of the induction heating elements 32 includes a conductor 34 coupled to a susceptor material 36. The conductor 34 may include any suitable conductive material, such as copper. In some examples, the conductor 34 includes one or more Litz wires. The susceptor material 36 may include any suitable susceptor extending along the length of the conductor and may take any suitable form, such as a wire, a coating, a strand, a sheath, a container, etc. In some examples, the susceptor material 36 includes a nickel-iron alloy (e.g., For example 36) or an iron-nickel-cobalt alloy. In some examples, the susceptor is twisted with the conductor (e.g., braided, twisted, braided, etc.). In some examples, the susceptor is coated on the conductor and / or configured as a sheath of the conductor.

[0031] The heating element(s) 32 may be disposed in any suitable location configured to heat the plate 28 to an operating temperature (e.g., to heat the entire plate 28). In some examples, the one or more induction heating elements are coupled to a rear surface of the plate 28 (i.e., a surface of the plate facing away from the molding surface). For example, the heating element(s) 32 may be disposed on the rear surface of the plate, such as Figure 2 In the example shown in FIG. 2 , one or more heating elements 204 are disposed on the plate 200. In some examples, the heating element(s) 32 may be at least partially embedded in the plate, for example, the heating element(s) may be disposed in one or more channels or grooves, such as Figure 3 , where a plate 300 has a plurality of channels or grooves 302 on the back side of the plate, and one or more heating elements 304 are disposed in the grooves.

[0032] The heating element(s) 32 may be arranged on or adjacent to the plate 28 in any suitable manner. For example, a single heating element may extend across all or a portion of the plate. In some examples, one of the heating elements is arranged on the rear surface of the plate in a serpentine or sinusoidal pattern. See Figure 4 Heating elements 402 on mid-plate 400. For example, if more than one temperature is desired, different heating elements may be used in different portions or regions of the plate. In some examples, multiple heating elements may be mounted side by side to provide further heating and / or redundancy. In some cases, different numbers of heating elements may be powered to provide further control over heating.

[0033] In some examples, the press 12 also includes a cooling system 40 configured to cool the structural frame 22 of the tool 14. The induction heating element(s) are self-regulating and are configured and / or positioned to directly heat the plate 28 only. However, radiative and / or conductive heating of the structural frame 22 may occur. In order to reduce this undesirable heating, an insulating filler material 24 is used, and one or more cooling lines or channels may be configured to remove heat from the structural frame. For example, one or more cooling channels may be configured to convey a liquid coolant, such as water. A cooling circuit, such as an isolated cooling circuit, may be provided for the unheated portion of the tool. A coolant, such as water or a water-glycol mixture, circulates through cooling pipes, channels, and / or tubes extending through the filler 24 and / or adjacent structural frame 22. In an example using a tube, the tube may include any suitable thermally conductive material configured to transfer heat between the tool and the coolant, such as stainless steel or copper. The pipes and / or channels may be formed directly in the filler material and / or structural frame material. The coolant is pressurized and caused to flow by a cooling pump and is configured to absorb heat when passing through the tool. The heated coolant then flows to a heat exchanger (e.g., a radiator) where the heat is dissipated to another medium (e.g., ambient air). Whether or not they pass through fill material, the pipes, channels, and / or tubes of the coolant system can be designed to follow the contours of the structural frame to better control the cooling effect of these frame members. Dedicated portions of the cooling system (e.g., pumps and heat exchangers) can be positioned adjacent to the press so that one or more tools can be connected sequentially or simultaneously and cooled accordingly (e.g., using flexible coolant lines attached to fittings on the tool). In some examples, the pump and / or heat exchanger can be located on the tool so that the coolant system is self-sufficient.

[0034] Inductive heating of the susceptor is caused by passing an AC current through the conductors of the inductive heating element(s). To this end, the tool 14, press 12, and / or manufacturing environment 10 may include one or more power supplies 42 that are electrically coupled to the inductive heating elements to provide the AC current. A controller 44 may be included to control the operation of the system, such as by controlling when the power supply is turned on and off.

[0035] As described above, the stamping tool 14A may include any or all of the components described with respect to the tool 14. Thus, Figure 1 Depicted are structural frame 22A, fill material 24A, cavity 26A, plate 28A having front face 30A, induction heating element 32A, and cooling system 40A.

[0036] Figure 5 A flow chart is schematically provided that represents illustrative, non-exclusive steps of a method 500 for press-forming a thermoplastic composite part according to the present disclosure. Figure 5 In the embodiment, some steps are shown in the dashed boxes, indicating that these steps may be optional or may correspond to optional versions of the method according to the present disclosure. That is, not all methods according to the present disclosure need to include the steps shown in the solid boxes. Figure 5 The methods and steps shown in are not limiting, and other methods and steps are also within the scope of the present disclosure, including methods with more or less than the number of steps shown, as understood from the discussion herein. Aspects of the above-described apparatus and systems can be used for the method steps described below. Where appropriate, reference can be made to components and systems that can be used to perform each step. These references are for illustration only and are not intended to limit the possible ways to perform any particular step of the method.

[0037] Step 502 of method 500 includes installing a stamping tool in a stamping press. In some examples, this is done without first preheating the tool, in contrast to standard methods. The stamping tool can include any or all of the aspects described above with respect to tool 14. In some examples, the stamping tool includes a frame reinforced by a pressure-resistant filler material and a plate coupled to the frame, the pressure-resistant filler material being configured to thermally insulate the frame. The plate has a front face that defines a forming surface of the tool. One or more induction heating elements are configured to heat the plate, and each of the one or more induction heating elements includes a heat exchanger coupled to a susceptor material (e.g., a nickel-iron alloy, such as 36) of a conductor (e.g., Litz wire).

[0038] Step 504 of method 500 includes using a filler material having a lower thermal conductivity than the frame to resist undesired heating and compression of the tool. For example, a solid filler material can provide rigid reinforcement while also insulating the frame of the tool. Unlike conventional systems, method 500 involves heating only the forming plate of the tool (see step 506). In other words, the method includes avoiding actively heating the rest of the stamping tool (e.g., the frame).

[0039] The frame of the stamping tool can include a plurality of metal frame members that are coupled to the plate and define one or more cavities. For example, the frame can be an egg crate frame. The plate can include metal (e.g., steel), can have a uniform or varying thickness, and can be thin relative to the overall size of the tool, such as a maximum thickness of one inch. In some examples, the forming surface of the plate has a non-planar and / or three-dimensional contour.

[0040] The filler material is disposed in one or more cavities of the tool, resists compression to strengthen the tool and prevent plate deformation, and has a lower thermal conductivity than the frame to provide thermal insulation. In some examples, the filler material comprises a casting material (eg, ceramic).

[0041] In some examples, step 506 of method 500 includes preparing a composite material blank for a stamping press to perform a forming operation. For example, the blank can be preheated in an (e.g., infrared) oven or similar device to facilitate forming. The blank can be placed on, loaded into, and / or coupled to a frame that is configured to facilitate handling of the blank without damaging or unnecessarily contacting the composite material, referred to as a frame. In some cases, the blank is clamped to the frame.

[0042] Step 508 of method 500 includes heating (e.g., directly) a plate of a stamping tool by applying power to one or more induction heating elements so that a forming surface of the plate reaches and maintains an operating temperature determined at least in part by the Curie temperature of the susceptor material. In some examples, heating the plate to reach the operating temperature takes less than half an hour. In some examples, the operating temperature is a leveling temperature that is below the Curie temperature.

[0043] In some examples, the heating element(s) are configured to heat the board only directly. For example, one or more induction heating elements may be coupled to (e.g., at least partially embedded in) the back surface of the board. For example, the induction heating element(s) may be disposed in one or more channels or grooves on the back side of the board.

[0044] Step 510 of method 500 includes press-forming a thermoplastic component using a stamping tool. In some examples, the thermoplastic component includes a composite material (e.g., carbon fiber). As described in step 506, the thermoplastic component can be placed in a stamping press as a composite blank, such as on a drawing frame.

[0045] In some examples, press forming a thermoplastic part using a stamping tool includes pressing the thermoplastic material against an underlying surface (i.e., between two forming surfaces). In some examples, the underlying surface is a second tool having a complementary forming surface. In some examples, one tool may be referred to as a "male" tool and the other tool as a "female" tool.

[0046] In some examples, step 510 of method 500 includes actively cooling the frame using a liquid coolant system. Actively cooling the frame can include transferring or absorbing heat from the frame into a flowing coolant. The coolant system can include any suitable coolant (e.g., water) and can include one or more channels, tubes, or other pathways configured to flow the coolant around components of the frame to remove heat. In some examples, the liquid coolant system can be an integral part of the tool and / or press.

[0047] In some examples, step 512 of method 500 includes removing the stamping tool from the press. This step may include disconnecting the stamping tool from the power supply. Step 514 of method 500 includes installing a second stamping tool into the press to replace the first stamping tool.

[0048] Step 512 may also include removing the tool from the press without waiting for the tool to cool, and step 514 may include installing a second stamping tool in the stamping press without preheating the tool. The induction heating method of the present disclosure enables faster changeover times because relatively rapid heating can be performed with the tool in the press. Compared to conventional methods, the percentage of the heated mass of the tool is much smaller, so the heating and cooling times are shortened. In addition, since a large portion of the tool is not heated, it can be more easily and safely handled immediately or very quickly after the pressing operation is completed. Therefore, step 512 can be performed without waiting for the previously used tool to cool and / or without waiting for the replacement tool to heat up. In other words, compared to conventional systems, the previous tool can be removed hot and the replacement tool can be installed cold, for example, without increasing the overall changeover time.

[0049] Illustrative embodiments of the present disclosure may be used in Figure 6 Aircraft manufacturing and service method 600 is shown and Figure 7 The description will be made in the context of the aircraft 700 shown. Figure 6, an illustration of an aircraft manufacturing and service method is depicted in accordance with an illustrative embodiment.

[0050] During pre-production, aircraft manufacturing and service method 600 may include specification and design 602 of aircraft 700 and material procurement 604. During production, component and subassembly manufacturing 606 and system integration 608 of aircraft 700 occurs. Thereafter, aircraft 700 may go through certification and delivery 610 to be placed into service 612. While in service 612 with a customer, aircraft 700 is scheduled for routine maintenance and service 614, which may include modification, reconfiguration, refurbishment, or other maintenance and service.

[0051] Each of the processes of aircraft manufacturing and service method 600 can be performed or implemented by a system integrator, a third party, and / or an operator. In these examples, the operator may be a customer. For the purposes of this specification, a system integrator may include, but is not limited to, any number of aircraft manufacturers and major system subcontractors; a third party may include, but is not limited to, any number of suppliers, subcontractors, and vendors; and an operator may be an airline, a leasing company, a military entity, a service organization, etc.

[0052] Reference now Figure 7 , depicts a diagram of an aircraft in which an illustrative embodiment may be implemented. In this example, aircraft 700 is passing Figure 6 Aircraft manufacturing and service method 600 is produced and may include airframe 702 having plurality of systems 704 and interior 706. Examples of systems 704 include one or more of propulsion system 708, electrical system 710, hydraulic system 712, and environmental system 714. Any number of other systems may be included.

[0053] Apparatus and methods embodied herein may be used during at least one of the stages of aircraft manufacturing and service method 600. One or more illustrative embodiments may be used in Figure 6 The components and subassemblies are manufactured or used during at least one of manufacturing 606 , system integration 608 , placing into service 612 , or maintenance and service 614 .

[0054] A portion of fuselage 702 of aircraft 700 may be formed by method 500, and method 500 may be performed during component and subassembly manufacturing 606. During component and subassembly manufacturing 606, press 12 may be used to form the composite structure. In some illustrative examples, the composite structure formed using method 500 exists and is used during service 612. Method 500 may be performed during maintenance and service 614 to form a replacement part.

[0055] Illustrative, non-exclusive examples of inventive subject matter according to the present disclosure are described in the following enumerated paragraphs:

[0056] A1. A tool for stamping a thermoplastic part, the tool comprising:

[0057] a frame reinforced by a fill material configured to thermally insulate the frame;

[0058] a plate coupled to the frame, wherein the plate has a front face defining a molding surface for the tool; and

[0059] One or more induction heating elements are configured to heat the plate, wherein each of the one or more induction heating elements comprises a conductor coupled to a susceptor material.

[0060] A2. The tool of A1, wherein the frame comprises a plurality of metal frame members.

[0061] A3. A tool according to A1 or A2, wherein the thermal conductivity of the filler material is lower than that of the frame.

[0062] A4. The tool of any of paragraphs A1 to A3, wherein the filler material comprises a casting material.

[0063] A5. The tool of any of paragraphs A1 to A4, wherein the filler material comprises ceramic.

[0064] A6. The tool of any of paragraphs A1 to A5, wherein the filler material is configured to provide compression resistance.

[0065] A7. The tool of any of paragraphs A1 to A6, wherein the frame is an egg crate frame.

[0066] A8. The tool of any of paragraphs A1 to A7, wherein the plate comprises metal.

[0067] A9. The tool of any of paragraphs A1 to A7, wherein the plate comprises steel or a nickel-iron alloy (eg, invar 36).

[0068] A10. The tool of any of paragraphs A1 to A9, wherein the plate has a variable thickness.

[0069] A11. The tool of any of paragraphs A1 to A10, wherein the maximum thickness of the plate is 1 inch.

[0070] A12. The tool of any of paragraphs A1 to A11, wherein the molding surface has a non-planar profile.

[0071] A13. A tool according to any of paragraphs A1 to A12, wherein the conductor is a Litz wire.

[0072] A14. The tool of any of paragraphs A1 to A13, wherein the susceptor material is a nickel-iron alloy.

[0073] A15. The tool of any of paragraphs A1 to A14, wherein the susceptor is entangled with the conductor.

[0074] A16. The tool of any of paragraphs A1 to A15, wherein the susceptor is coated on the conductor.

[0075] A17. The tool of any of paragraphs A1 to A16, wherein the susceptor extends along the length of the conductor.

[0076] A18. The tool of any of paragraphs A1 to A17, wherein the one or more induction heating elements are coupled to a rear surface of the plate.

[0077] A19. The tool of any of paragraphs A1 to A18, wherein the one or more induction heating elements are at least partially embedded in the plate, such as disposed in a channel or groove.

[0078] A20. The tool of any of paragraphs A1 to A19, further comprising a cooling system configured to cool a frame of the tool.

[0079] A21. A tool according to A20, wherein the cooling system includes pipes, channels and / or tubes arranged at least partially adjacent to the frame of the tool.

[0080] A22. A tool according to A21, wherein one or more of the pipes, channels and / or tubes pass through the filler material.

[0081] A23. A tool according to A20, wherein the cooling system includes a stainless steel tube disposed adjacent to a frame of the tool, the tube being configured to contain a liquid coolant.

[0082] A24. The tool of A20, wherein the cooling system is configured to be coupled to a coolant pump and a heat exchanger, wherein the coolant pump is configured to pressurize the coolant and the heat exchanger is configured to remove heat from the coolant.

[0083] A25. The tool of A24, wherein the coolant pump and / or the heat exchanger are disposed on the tool.

[0084] A26. The tool of any of paragraphs A1 to A25, further comprising one or more power sources coupled to the one or more induction heating elements.

[0085] A27. The tool of any of paragraphs A1 to A26, wherein the one or more induction heating elements are configured to heat only the plate.

[0086] A28. The tool of any of paragraphs A1 to A27, wherein the one or more induction heating elements are self-regulating with respect to temperature.

[0087] A29. The tool of any of paragraphs A1 to A28, wherein the one or more induction heating elements are configured to heat only the plate, and wherein the tool includes no other heating elements.

[0088] A30. A stamping press comprising a tool as described in any of paragraphs A1 to A29.

[0089] A31. A stamping press according to A30, further comprising a second one of the tools according to any of paragraphs A1 to A29, wherein the plate of the second one of the tools has a complementary shape relative to the plate of the first one of the tools.

[0090] B1. A heating forming tool, the tool comprising:

[0091] a structural frame having one or more cavities;

[0092] a metal sheet coupled to the structural frame, wherein the metal sheet has a front face defining a forming surface of the forming tool;

[0093] one or more induction heating elements configured to heat the metal plate, each of the one or more induction heating elements comprising a conductor coupled to a susceptor material; and

[0094] A fill material is disposed in one or more cavities of the structural frame, wherein the fill material is configured to resist compression and to thermally insulate the structural frame.

[0095] B2. The thermoforming tool of B1, wherein the metal sheet comprises steel.

[0096] B3. A heated forming tool according to B1 or B2, wherein the one or more induction heating elements are configured to heat the entire metal sheet.

[0097] B4. The heated forming tool of any of paragraphs B1 to B3, wherein the one or more induction heating elements are coupled to the metal plate.

[0098] B5. A heated forming tool according to B4, wherein the one or more induction heating elements are coupled to the rear surface of the metal sheet.

[0099] B6. A heated forming tool according to B4, wherein the one or more induction heating elements are each at least partially disposed in a groove (e.g., a corresponding groove) in the rear surface of the metal plate.

[0100] B7. A heated forming tool according to B4, wherein the one or more induction heating elements are at least partially embedded in the metal sheet.

[0101] B8. The heated forming tool of any of paragraphs B1 to B7, wherein the conductor comprises Litz wire.

[0102] B9. A heated forming tool according to any of paragraphs B1 to B8, wherein the susceptor material comprises a nickel-iron alloy.

[0103] B10. The heating forming tool of any of paragraphs B1 to B9, further comprising a cooling system configured to cool the structural frame.

[0104] B11. A heated forming tool according to B10, wherein the cooling system comprises one or more cooling channels.

[0105] B12. A heated forming tool according to B11, wherein the one or more cooling channels are configured to convey a liquid coolant.

[0106] B13. A heated forming tool according to B12, wherein the liquid coolant comprises water.

[0107] B14. The thermoforming tool of any of paragraphs B1 to B13, wherein the forming surface has a three-dimensional topography.

[0108] B15. The thermoforming tool of any of paragraphs B1 to B14, wherein the structural frame comprises a plurality of spaced-apart frame members.

[0109] B16. The thermoforming tool of any of paragraphs B1 to B15, wherein the structural frame comprises an egg crate frame.

[0110] B17. The thermoforming tool of any of paragraphs B1 to B16, wherein the metal sheet has a uniform thickness.

[0111] B18. A thermoforming tool according to B17, wherein the uniform thickness is less than or equal to one inch.

[0112] B19. The thermoforming tool of any of paragraphs B1 to B18, wherein the maximum thickness of the metal sheet is 1 inch.

[0113] B20. The thermoforming tool of any of paragraphs B1 to B19, wherein the filler material is further configured to resist deformation of the metal sheet during operation.

[0114] B21. A thermoforming tool according to any of paragraphs B1 to B20, wherein the supporting filler is a solid material.

[0115] B22. A thermoforming tool according to any of paragraphs B1 to B21, wherein the support filler comprises a ceramic material.

[0116] B23. The thermoforming tool of any of paragraphs B1 to B22, wherein the support filler comprises a ceramic cast into the one or more cavities.

[0117] B24. A thermoforming tool according to any of paragraphs B1 to B23, wherein the support filler comprises a material having a lower thermal conductivity than the structural frame.

[0118] B25. The thermoforming tool of any of paragraphs B1 to B24, wherein each of the one or more cavities extends to a rear surface of the metal sheet.

[0119] B26. The heated forming tool of any of paragraphs B1 to B25, further comprising one or more power sources coupled to the one or more induction heating elements.

[0120] B27. The heated forming tool of any of paragraphs B1 to B26, further comprising an electronic controller configured to selectively control power to the one or more induction heating elements.

[0121] B28. A stamping press comprising at least one heated forming tool according to any of paragraphs B1 to B27.

[0122] B29. A stamping press according to B28, wherein the press comprises two heating forming tools arranged complementary to each other.

[0123] C1. A method for stamping a thermoplastic component, the method comprising:

[0124] installing a stamping tool in a stamping press, the stamping tool comprising a frame reinforced by a filler material configured to resist compression and thermally insulate the frame, a plate coupled to the frame, wherein the plate has a front face defining a forming surface of the tool, and one or more induction heating elements configured to heat the plate, wherein each of the one or more induction heating elements comprises a conductor coupled to a susceptor material;

[0125] heating a sheet of the stamping and forming tool by applying power to the one or more induction heating elements so that a forming surface of the sheet reaches and maintains an operating temperature determined at least in part by the Curie temperature of the susceptor material; and

[0126] Use stamping tools to press-form thermoplastic parts.

[0127] C2. The method according to C1 further includes actively cooling the frame.

[0128] C3. The method of C2, wherein actively cooling the frame comprises using a liquid coolant system.

[0129] C4. The method of any of paragraphs C1 to C3, wherein the thermoplastic component comprises a composite material.

[0130] C5. A method according to C4, wherein the composite material comprises carbon fibers.

[0131] C6. The method of any of paragraphs C1 to C5, wherein heating the plate to reach the operating temperature takes less than half an hour.

[0132] C7. A method according to any of paragraphs C1 to C6, wherein the frame includes a plurality of metal frame members.

[0133] C8. The method of any of paragraphs C1 to C7, wherein the frame defines one or more cavities and the fill material is disposed in the one or more cavities.

[0134] C9. A method according to any of paragraphs C1 to C8, wherein the thermal conductivity of the filler material is lower than that of the frame.

[0135] C10. The method of any of paragraphs C1 to C9, wherein the filler material comprises a casting material.

[0136] C11. A method according to any of paragraphs C1 to C10, wherein the filler material comprises ceramic.

[0137] C12. The method of any of paragraphs C1 to C11, wherein the frame is an egg crate frame.

[0138] C13. The method of any of paragraphs C1 to C12, wherein the plate comprises metal.

[0139] C14. The method of any of paragraphs C1 to C13, wherein the plate comprises steel.

[0140] C15. The method of any of paragraphs C1 to C13, wherein the plate comprises an iron-nickel alloy.

[0141] C16. The method of any of paragraphs C1 to C15, wherein the plate has a variable thickness.

[0142] C17. The method of any of paragraphs C1 to C16, wherein the maximum thickness of the plate is 1 inch.

[0143] C18. The method of any of paragraphs C1 to C17, wherein the molding surface has a non-planar profile.

[0144] C19. A method according to any of paragraphs C1 to C18, wherein the conductor is a Litz wire.

[0145] C20. A method according to any of paragraphs C1 to C19, wherein the susceptor material is a nickel-iron alloy or a nickel-iron-cobalt alloy.

[0146] C21. The method of any of paragraphs C1 to C20, wherein the one or more induction heating elements are coupled to the rear surface of the plate.

[0147] C22. The method of any of paragraphs C1 to C21, wherein the one or more induction heating elements are at least partially embedded in the plate.

[0148] C23. The method of any of paragraphs C1 to C22, wherein the one or more induction heating elements are configured to directly heat only the plate.

[0149] C24. The method of any of paragraphs C1 to C22, wherein compression molding the thermoplastic component using a stamping tool includes pressing the thermoplastic component against an underlying surface.

[0150] C25. A method according to C24, wherein the underlying surface includes a second one of the stamping tools.

[0151] C26. The method of any of paragraphs C1 to C25 further includes removing the stamping tool from the press.

[0152] C27. A method according to C26, wherein removing the tool includes disconnecting the one or more induction heating elements from an electrical power source.

[0153] C28. A method according to C26 or C27, wherein removing the tool from the press includes removing the tool from the press without waiting for the tool to cool.

[0154] C29. The method of any of paragraphs C1 to C28, wherein installing the stamping tool in the stamping press includes installing the tool without preheating the tool.

[0155] D0. A stamping press, comprising:

[0156] One or more stamping and forming tools mounted in a press, each of the stamping and forming tools comprising:

[0157] a structural frame having one or more cavities;

[0158] a metal sheet coupled to the structural frame, wherein the metal sheet has a front face defining a forming surface of the forming tool;

[0159] one or more induction heating elements configured to heat the metal plate, each of the one or more induction heating elements comprising a conductor coupled to a susceptor material; and

[0160] A fill material is disposed in one or more cavities of the structural frame, wherein the fill material is configured to resist compression and to thermally insulate the structural frame.

[0161] D1. A stamping press according to D0, wherein the metal plate comprises steel.

[0162] D2. A stamping press according to D0 or D1, wherein the one or more induction heating elements are coupled to the metal plate and are configured to directly heat only the metal plate.

[0163] D3. A stamping press according to D2, wherein the one or more induction heating elements are each at least partially disposed in a corresponding groove in the rear surface of the metal plate.

[0164] D4. A stamping press according to any one of D0 to D3, wherein the conductor comprises a Litz wire.

[0165] D5. The stamping press according to any one of D0 to D4 also includes a cooling system, which is configured to actively cool the structural frame.

[0166] D6. A stamping press according to any one of D0 to D5, wherein the one or more stamping tools include a first stamping tool and a relative second stamping tool, wherein the shape of the forming surface of the first stamping tool is complementary to the shape of the forming surface of the second stamping tool.

[0167] E0. A method for stamping a thermoplastic component, the method comprising:

[0168] installing a stamping and forming tool in a stamping and forming press without preheating the stamping and forming tool, the stamping and forming tool comprising one or more induction heating elements configured to heat a forming surface of the stamping and forming tool, wherein each of the one or more induction heating elements comprises a conductor coupled to a susceptor material;

[0169] heating a forming surface of the stamping and forming tool by applying power to the one or more induction heating elements so that the forming surface reaches and maintains an operating temperature determined at least in part by the Curie temperature of the susceptor material; and

[0170] Use stamping tools to press-form thermoplastic parts.

[0171] E1. A method according to E0, wherein the stamping tool further comprises a frame reinforced by a filler material, wherein the filler material is configured to resist compression and insulate the frame, and the method further comprises actively cooling the frame.

[0172] E2. The method of E0 or E1, wherein actively cooling the frame comprises absorbing heat from the frame into a flowing coolant.

[0173] E3. The method according to any one of E0 to E2 also includes avoiding actively heating the frame of the stamping tool.

[0174] E4. A method according to E3, wherein the conductor comprises a Litz wire.

[0175] As used herein, the terms "suitable for" and "configured to" mean that an element, component, or other subject matter is designed and / or intended to perform a given function. Therefore, the use of the terms "suitable for" and "configured to" should not be interpreted to mean that a given element, component, or other subject matter is merely "capable of" performing a given function, but rather that the element, component, and / or other subject matter is selected, created, implemented, used, programmed, and / or designed specifically for the purpose of performing that function. The following is also within the scope of the present disclosure: elements, components, and / or other narrated subject matter that are described as being suitable for performing a particular function may additionally or alternatively be described as being configured to perform that function, and vice versa. Similarly, a subject matter that is described as being configured to perform a particular function may additionally or alternatively be described as being operable to perform that function.

[0176] “Comprising,” “including,” and “having” (and variations thereof) are used interchangeably to mean including but not necessarily limited to, and are open-ended terms that are not intended to exclude other unrecited elements or method steps.

[0177] Terms such as "first," "second," and "third" are used to distinguish or identify individual members of a group, etc., and are not intended to indicate sequence or numerical limitations.

[0178] A "controller" or "electronic controller" includes processing logic programmed with instructions to perform control functions on a control element. For example, an electronic controller may be configured to receive an input signal, compare the input signal with a selected control value or set point value, and determine an output signal to a control element (e.g., a motor or actuator) to provide a corrective action based on the comparison. In another example, an electronic controller may be configured to interface between a host device (e.g., a desktop computer, a mainframe, etc.) and a peripheral device (e.g., a memory device, an input / output device, etc.) to control and / or monitor input and output signals to and from the peripheral device. "Processing logic" describes any suitable device or hardware that is configured to process data by performing one or more logical and / or arithmetic operations (e.g., executing coded instructions). For example, processing logic may include one or more processors (e.g., a central processing unit (CPU) and / or a graphics processing unit (GPU)), a microprocessor, a processing core cluster, an FPGA (field programmable gate array), an artificial intelligence (AI) accelerator, a digital signal processor (DSP), and / or any other suitable combination of logic hardware.

[0179] As used herein, the term "and / or" placed between a first entity and a second entity refers to one of (1) the first entity, (2) the second entity, and (3) the first entity and the second entity. Multiple items listed with "and / or" should be interpreted in the same manner, i.e., "one or more" of the entities so combined. In addition to the entities explicitly identified by the "and / or" clause, other entities may optionally be present, whether related or unrelated to those entities explicitly identified. Thus, as a non-limiting example, when used in conjunction with open language such as "including", a reference to "A and / or B" may refer to only A (optionally including entities other than B) in one example; to only B (optionally including entities other than A) in another example; and to both A and B (optionally including other entities) in yet another example. These entities may refer to elements, actions, structures, steps, operations, values, etc.

[0180] The steps of the various disclosed elements and methods of the equipment disclosed herein are not necessary according to all equipment and methods disclosed herein, and the present disclosure includes all novel and non-obvious combinations and sub-combinations of the various elements and steps disclosed herein. In addition, one or more of the various elements and steps disclosed herein can define an independent invention theme separated from the entirety of the disclosed equipment or method. Therefore, this invention theme does not need to be associated with the specific equipment and methods clearly disclosed herein, and this invention theme can find practicality in the equipment and / or methods not clearly disclosed herein.

Claims

1. A tool (14) for stamping a thermoplastic part (16), the tool (14) comprising: a frame (22) reinforced by a filler material (24) configured to provide compression resistance to the frame (22) and to thermally insulate the frame (22); a plate (28) coupled to the frame (22), wherein the plate (28) has a front face (30) defining a molding surface for the tool (14); and One or more induction heating elements (32) configured to heat the plate (28), wherein each of the one or more induction heating elements (32) includes a conductor (34) coupled to a susceptor material (36) such that the one or more induction heating elements (32) are configured to self-regulate with respect to temperature.

2. The tool (14) according to claim 1, wherein the thermal conductivity of the filler material (24) is lower than that of the frame (22).

3. The tool (14) of claim 1, wherein the filler material (24) comprises a cast ceramic.

4. The tool (14) of claim 1, wherein the frame (22) includes a plurality of metal frame members defining one or more cavities (26), and the filler material (24) is disposed in the one or more cavities (26).

5. The tool (14) of claim 1, wherein the one or more induction heating elements (32) are configured to heat only the plate (28), and wherein the tool (14) includes no other heating elements.

6. The tool (14) of claim 1, wherein the conductor (34) is a Litz wire.

7. The tool (14) of claim 1, wherein the susceptor material (36) is a nickel-iron alloy or an iron-nickel-cobalt alloy.

8. The tool (14) of claim 1, wherein the one or more induction heating elements (32) are coupled to a rear surface of the plate (28).

9. A stamping press (12), comprising: One or more stamping and forming tools (14) installed in the stamping and forming press (12), each of the stamping and forming tools (14) comprising: a structural frame (22) having one or more cavities (26); a metal plate (28) coupled to the structural frame (22), wherein the metal plate (28) has a front face (30) defining a forming surface for the forming tool (14); one or more induction heating elements (32) configured to heat the metal plate (28), each of the one or more induction heating elements (32) comprising a conductor (34) coupled to a susceptor material (36); and A filler material (24) is disposed in the one or more cavities (26) of the structural frame (22), wherein the filler material (24) is configured to resist compression and to thermally insulate the structural frame (22).

10. The stamp forming press (12) of claim 9, wherein the metal sheet (28) comprises steel.

11. The stamping press (12) of claim 9, wherein the one or more induction heating elements (32) are coupled to the metal plate (28) and are configured to directly heat only the metal plate (28).

12. The stamping press (12) according to claim 11, wherein: The one or more induction heating elements (32) are each at least partially disposed in a corresponding recess in the rear surface of the metal plate (28).

13. The stamping press (12) of claim 9, wherein the conductor (34) comprises a Litz wire.

14. The stamping press (12) of claim 9, further comprising a cooling system (40) configured to actively cool the structural frame (22).

15. The stamping press (12) according to claim 9, wherein: The one or more stamping and forming tools (14) include a first stamping and forming tool (14) and an opposite second stamping and forming tool (14), wherein the shape of the forming surface of the first stamping and forming tool (14) is complementary to the shape of the forming surface of the second stamping and forming tool (14).

16. A method (500) of stamping a thermoplastic component (16), the method (500) comprising: installing (502) a stamping tool (14) in a stamping press (12) without preheating the stamping tool (14), the stamping tool (14) comprising one or more induction heating elements (32) configured to heat a forming surface of the stamping tool (14), wherein each of the one or more induction heating elements (32) comprises a conductor (34) coupled to a susceptor material (36); heating (504) a forming surface of the stamping tool (14) by applying power to the one or more induction heating elements (32) such that the forming surface reaches and maintains an operating temperature determined at least in part by the Curie temperature of the susceptor material (36); and A thermoplastic part (16) is compression molded (508) using the stamping tool (14).

17. The method (500) of claim 16, wherein: The stamping tool (14) also includes a frame (22) reinforced by a filler material (24) configured to resist compression and thermally insulate the frame (22), and the method (500) also includes actively cooling (510) the frame (22).

18. The method (500) of claim 17, wherein actively cooling (510) the frame (22) comprises absorbing heat from the frame (22) into a flowing coolant.

19. The method (500) of claim 16, further comprising avoiding actively heating a frame (22) of the stamping tool (14).

20. The method (500) of claim 19, wherein the conductor (34) comprises a Litz wire.

Images