Molding tool, method of manufacturing molding tool and method of producing composite part in said tool

Abstract

A molding tool for producing a composite part using induction heating. The moulding tool comprises: a mould (10) having a contact surface adapted to be in contact with a material to be transformed into a composite part and an outer surface; at least one coil (21-23) or at least one wire (211-213) of a coil (21-23) arranged on an outer surface of the mould (10); and at least one clamping means (40). The clamping means has a first end (41), a second end (42) and an intermediate section (43) extending between the first end (41) and the second end (42). At least one of the first end portion (41) and the second end portion (42) is attached to an outer surface of the mold (10) using welding, brazing or soft brazing in order to at least partially secure the at least one coil (21-23) to the outer surface of the mold (10). The intermediate section (43) at least partially encloses the at least one wire (211-213) or coil (21-23) to hold the at least one wire (211-213) or coil (21-23) in position on the outer surface of the mold (10).

Description

Technical Field

[0001] The present invention relates to a moulding tool for producing a composite part using induction heating, a method of manufacturing a moulding tool and a method of producing a composite part using the tool. Background Art

[0002] Over the past few years, there has been an increasing interest in the use of lightweight materials in, for example, the automotive and aerospace industries, where a major goal is to reduce carbon emissions during transportation. For example, it has become increasingly common for vehicle or aircraft components to be made of fiber composite materials.

[0003] When producing fiber composite parts, such as car doors or aircraft components, it is important to have controlled heating and to ensure uniform heat distribution throughout the relevant area of ​​the part. There are several examples of molding tools for composite material manufacturing in the prior art, all of which have different disadvantages. For example, these molding tools are subject to a large thermal mass to be heated and cooled, which means long cycle times and high energy consumption. Another common problem is uneven heating, which has a negative impact on part performance and yield. Large physical space requirements and high capital expenditure investments as well as limitations in terms of size or temperature are other common challenges for existing solutions.

[0004] Common heat sources are ovens, heating autoclaves, heating cartridges, resistance wires, infrared lamps, all of which have their advantages and disadvantages. For some energy sources, such as thermal oil and high-pressure steam technology, environmental aspects are another important topic.

[0005] Examples of composite material production processes that typically use such heat sources and suffer from the above disadvantages are resin transfer molding and compression molding, which are typically used inside some type of press to hold the two mold halves together. Other examples are vacuum infusion, vacuum bagging, and autoclave processing, where one of the mold halves is typically replaced by a flexible membrane or bag, or where the mold halves are pushed together by a pressure differential between the inside and outside of the mold.

[0006] Therefore, there is a need for improved molding tools for manufacturing composite parts, which allow short cycle times, energy saving and result in high quality and output to enable cost-effective mass production. In addition, the molding tools also need to be strong, cost-effective and easy to manufacture, and have a long service life. Summary of the invention

[0007] The object of the present invention is to solve or at least alleviate the problems associated with the prior art. This object is achieved by means of the technology set out in the attached independent claims; preferred embodiments are defined in the associated dependent claims.

[0008] According to a first aspect, a molding tool for producing a composite part using induction heating is provided. The molding tool comprises: a mold having a contact surface and an outer surface, the contact surface being suitable for contacting a material to be transformed into a composite part; at least one coil or at least one wire of a coil, the at least one coil or at least one wire of a coil being arranged on the outer surface of the mold; and at least one clamping device having a first end, a second end, and an intermediate section extending between the first end and the second end, wherein at least one of the first end and the second end is attached to the outer surface of the mold using welding, brazing, or soldering so as to at least partially fix the at least one coil to the outer surface of the mold; wherein the intermediate section at least partially encloses at least one wire or coil to hold the at least one wire or coil in place on the outer surface of the mold; and wherein at least one wire or coil is electrically insulated from the mold and operatively connected to at least one processing device.

[0009] According to a second aspect, a method for manufacturing a molding tool according to the above is provided. The method comprises: providing a mold having a contact surface and an outer surface, the contact surface being suitable for contacting the material to be transformed into a composite part; providing at least one coil or at least one wire of the coil, and arranging at least one coil or at least one wire of the coil on the outer surface of the mold; providing at least one clamping device, the at least one clamping device having a first end, a second end, and an intermediate section extending between the first end and the second end; using welding, brazing or soldering to attach at least one of the first end and the second end of the at least one clamping device to the outer surface of the mold so as to at least partially fix the at least one coil to the outer surface of the mold; thereby, the intermediate section at least partially encloses at least one wire or at least one coil to keep the at least one wire or coil in place on the outer surface of the mold; and wherein the at least one wire or coil is electrically insulated from the mold and operatively connected to at least one processing device.

[0010] According to a third aspect, a method for producing a composite part is provided. The method comprises providing a molding tool according to the above with at least one clamping device; placing fibers and plastic material on contact surfaces of the mold; closing the mold; applying a consolidation pressure on the material to be processed; and inductively heating the mold containing the material according to a predetermined time-temperature curve to consolidate and / or cure the material to produce the composite part.

[0011] According to a fourth aspect, another method of producing a composite part is provided. The method comprises providing a molding tool according to the above with at least one clamping device; placing a fiber material to be processed on a contact surface of the mold; closing the mold; applying vacuum pressure and infusing the fiber material with a plastic material, the plastic material thereby forming part of the material to be processed; and inductively heating the mold containing the fiber and plastic material according to a predetermined time-temperature curve to produce the composite part.

[0012] In general, the advantages of using clamping devices compared to gluing the coil to the outer surface of the mold are that the manufacturing process of the induction heated molding tool can be accelerated and automated, and that temperatures can be reached where gluing does not work, for example, for thermoplastic composites with PA, PC or PET matrices or high-end matrices such as PEEK, PEI and PPS widely used in the aerospace industry. In other words, the clamping device should withstand high temperature applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] By way of example, embodiments of the present invention will now be described with reference to the accompanying drawings, in which:

[0014] Figure 1a is a cross-sectional view of a molding tool and material according to an embodiment,

[0015] Figure 1b is a cross-sectional view of a coil assembly attached to a mold of a molding tool according to an embodiment,

[0016] Figure 2 is a schematic block diagram of a molding tool associated with a processing device according to an embodiment,

[0017] Figure 3 is a schematic diagram of a coil assembly attached to a mold according to an embodiment,

[0018] Figure 4 is a perspective view of two wires clamped to at least one coil of a die according to an embodiment,

[0019] Figure 5 is a cross-sectional view of a clamping device attached to a mold according to an embodiment,

[0020] Figures 6 to 22 are different cross-sectional views of at least one wire of a coil clamped to a die by a clamping device,

[0021] Fig.23 is a schematic block diagram showing a method for producing a composite part according to an embodiment,

[0022] Fig.24is a schematic block diagram showing a method for producing a composite part according to another embodiment,

[0023] Fig.25 is a schematic diagram of a portion of a method of producing a composite part in a molding tool according to an embodiment, and

[0024] Fig.26 is a schematic block diagram illustrating a method of manufacturing a molding tool. DETAILED DESCRIPTION

[0025] Molding tools are often used to produce composite parts of different shapes. Typical parts to be produced are motor vehicle parts, sports equipment, drone or aircraft parts and wind energy components, such as, for example, body panels and structural parts, such as car doors, aircraft wings and windmill wings. Tools suitable within the scope of the inventive concept disclosed herein are shell tools and solid tools with single or multiple cavities. The inventive concept is mainly directed to induction heated tools for manufacturing composite articles.

[0026] Embodiments of the present invention will now be described with reference to the accompanying drawings. However, the present invention may be implemented in a variety of different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be exhaustive and complete and will fully convey the scope of the present invention to those skilled in the art. The terms used in the detailed description of the specific embodiments illustrated in the accompanying drawings are not intended to limit the present invention. In the accompanying drawings, the same reference numerals refer to the same elements.

[0027] Before turning to a detailed description of the molding tool and the novel and inventive method of attaching the coil to the mold 10, reference will be made to Figure 1a to Figure 1b Briefly describe the molding tool in relation to the material.

[0028] like Figure 1a and Figure 1b As shown in FIG. 1 , as can be seen from the cross-sectional view, the mold 10 has a body that includes a contact surface 11 and an outer surface 12. The mold body can be divided into several layers, which allows heat to be transferred from the outer surface 12 to the contact surface 11. The contact surface 11 is an inner area of ​​the mold 10 that is configured to face the material 110 that is to be transformed into the composite part A (e.g., during the molding process). Fig.25). The mold 10 can also be considered as a body having a cavity, which is sized and shaped to the desired shape of the part A to be produced. The contact surface 11 of the mold 10 is configured to receive a material 110. For example, the part A to be produced in the mold 10 of the molding tool is a car door, or any other composite part. The mold 10 can contain more than one cavity, and thus the mold 10 can produce several parts in a single production cycle, which parts are still referred to as the material 110 to be transformed into the composite part A.

[0029] Hereinafter, the contact surface 11 will be referred to as the front side of the mold, and the outer surface 12 will be referred to as the back side of the mold 10. The coil assembly 20 will be attached to the back side 12 of the mold, which will be further described later. The heating of the molding tool is caused by the coil assembly 20 arranged on the back side 12 of the mold 10.

[0030] Figure 1b An embodiment of a coil assembly 20 is shown attached to a mold 10 of a molding tool. Figure 1b The attachment of the coil assembly 20 is illustrated by dashed lines in FIG. 1 , which coil assembly 20 may include, for example, a combination of a main coil and a peripheral coil. The coil is attached to the back side 12 of the mold via a clamping device. Preferably, at least one part / end of the clamping device is attached to the back side of the mold. For example, the clamping device can be attached by welding, brazing or soldering. Alternatively, the clamping device can be regarded as a fixing element to which at least one coil can be clamped or clamped, for example see Fig.10 , Fig.11 and Fig. 22 .about Figures 5 to 22 Details regarding the clamping device are shown and described.

[0031] Typically, the mould 10 is at least partially made of a material selected from the group consisting of carbon fibre composites or metals. The material is preferably a material having a significant electrical conductivity, for example greater than 1 Siemens / metre, so as to be able to be heated by induction.

[0032] If the mold 10 is made of a carbon fiber composite material, the mold 10 can be a carbon fiber reinforced plastic (CFRP). Fiber reinforcement can also be a mixture of carbon and another type of technical fiber, such as glass fiber, basalt fiber, etc. The fiber can be continuous or chopped, unidirectional layer or multiaxial laminate or randomly oriented fiber. In a preferred embodiment, the fiber is woven. Different types of fibers and laminates have their specific advantages, such as stiffness, coefficient of thermal expansion (CTE), electrical properties and thermal properties, and preferably use carbon fibers with high thermal conductivity, such as pitch carbon fibers or high thermal conductivity polyacrylonitrile carbon fibers, to simplify uniform temperature generation. Similar selections are also applicable to matrix materials, where easy processing and low temperature processing as well as high temperature resistance and high glass transition temperature are advantageous. Low CTE and long durability or service life are also important characteristics. Examples of matrixes can be epoxy resins, bismaleimides, polyimides, benzoxazine, phenolic substances and also silicone resins, as well as thermoplastics or semi-crystalline materials, such as polycarbonate (PC), polyphenylene sulfide (PPS), polyetheretherketone (PEEK), etc.

[0033] If the mold 10 is at least partially made of metal, it can generally be steel, aluminum or an alloy such as invar. Nickel steel or coated steel are also common, but any metal is possible and may be beneficial, depending on the specific application. The purpose of using metal or carbon fiber composite materials is that the molding tool, and more importantly, the mold 10 of the molding tool should be able to be inductively heated. Basically, the molding tool is a susceptor, which means that it has the ability to absorb electromagnetic energy and convert electromagnetic energy into heat. In this case, the molding tool is inductively heated via the coil assembly 20. During the molding process, the material 110 to be processed, which is usually a mixture of fiber and polymer material, is configured to be heated by the molding tool of induction heating. The material 110 to be processed can also be a fiber material, which is later infused with resin during the molding process. In short, the resin or plastic material to be infused during the molding process is regarded as a part of the material 110 to be processed.

[0034] In some cases, the mold 10 and the material to be processed 110 can be of similar materials and can also absorb heat directly from induction. The material to be processed 110 will be discussed in more detail below. The mold 10 can be single-sided to reduce costs and provide a simpler molding tool when the requirements of one of the sides of the part are lower than the requirements of the other side. Depending on the process and requirements, the mold 10 can alternatively be double-sided, as two independent molding tools, tool halves, or as one molding tool, wherein at least one coil is connected together, although mechanically it may be two separate molds 10.

[0035] The material 110 to be processed in the mold 10 will be heated mainly due to the contact of the material 110 with the contact surface 11, but if the material 110 contains carbon fibers, it is also possible to absorb a certain amount of energy directly from the induction heating. The material 110 is typically a composite material based on a mixture of fiber materials and polymer materials. As a non-limiting example, the material can include multiple fiber layers embedded in a thermosetting or thermoplastic matrix, such as 10 layers of glass or carbon fibers. The material can be made of a woven mesh of fibers, or, for example, made of ordered or randomly oriented short-cut fibers. Optionally, the mesh is non-woven. The matrix can be, for example, epoxy resin, polyester (PET), polypropylene (PP), polyamide (PA), polycarbonate (PC), or the matrix can be a high-end amorphous or semi-crystalline thermoplastic material, such as polyphenylene sulfide (PPS), polyetherimide (PEI) or polyetheretherketone (PEEK), etc. The fiber can also be any other technical textile, such as flax fiber, aramid, ultra-high molecular weight polyethylene, etc. As a non-limiting example, glass fibers can be used as reinforcement in a polycarbonate-based matrix. Composite materials can also be constructed from mixed fiber reinforcements, such as glass fibers and carbon fibers. Typical processing temperatures range from slightly above room temperature to about 450 degrees Celsius, but may be even higher depending on the matrix material.

[0036] Part A is produced in the molding tool by heating the material 110 to be processed under pressure. In other words, part A is being produced when the material 110 is heated by the induction heated molding tool, either because the matrix material is already present at the beginning of the process or because the matrix material is added during the process using an infusion process. Preferably, the material 110 is processed under vacuum pressure to reduce the risk of voids, pinholes or insufficient wetting.

[0037] Figure 2 A molding tool 1 is shown, which includes a mold 10, a coil assembly 20 and a clamping device 40. The coil assembly 20 may include one or more coils 21, 22, 23. Figure 2 2 and 3. The coil assembly 20 is shown as a first coil 21, and possibly a second coil 22 and a third coil. The coil assembly 20 may include three coils, four coils, five coils, or any other reasonable number of coils.

[0038] Just as the mold 10 can have any suitable size and shape for the application, the coils 21, 22 can have any shape, size or configuration. An example of a coil configuration is a layout that produces a transverse flux or a longitudinal flux or a combination of transverse and longitudinal fluxes to produce a local or global circulating current in the mold 10. In a preferred embodiment, the coil assembly 20 includes more than one coil 21, 22, 23 covering part or all of the back side of the mold 10, wherein the current in each coil can be individually controlled to always achieve the desired mold 10 temperature in each position. This is Figure 3 . If the entire mold 10 is not heated, it is preferred to have at least one coil covering the main area of ​​the mold and at least one coil covering the periphery of the heated area in order to be able to compensate for heat losses due to thermal conduction. Each coil may be made of one or more parallel wires (not shown) to ensure thermal management.

[0039] The clamping means 40 is configured to at least partially secure at least one coil 21, 22 to the mold 10. Figures 5 to 22 The clamping means 40 is described in more detail.

[0040] In one embodiment, the molding tool 1 is arranged with one or more main coils, which are arranged on the back side 12 of the mold 10 using a clamping device 40. The main coils are electrically insulated from the mold 10 and are configured to inductively heat the mold 10 when current flows through the main coils. Preferably, the main coils are made of Litz wire, due to its flexibility and low losses at high frequencies. Depending on the size and application, there may be one or several wires in parallel to ensure good efficiency of the system.

[0041] For example, the molding tool 1 may include some cooling means to cool the temperature of the mold 10 after a processing cycle. Cooling may be performed from the outer surface 12 by delivering a cooling medium in the form of a gas and / or liquid using, for example, forced air and / or water or using cooling channels inside or adjacent to the mold 10.

[0042] In order to further improve the induction heating of the molding tool 1, soft magnetic elements and conductive elements (not shown) can be placed at predetermined areas along the coil assembly 20. Soft magnetic elements are generally made of magnetic materials with low hysteresis losses. Soft magnetic elements are produced in a way to avoid induced currents in the material. Typical examples of soft magnetic materials are soft magnetic composites, sometimes also referred to as powder cores or soft ferrites. The relative magnetic permeability should be much greater than 1, typically 10 to 10,000. Conductive elements are generally made of highly conductive materials such as copper or aluminum, and are intended to induce current without generating a large amount of losses. Soft magnetic and conductive elements are used to achieve the desired heating pattern, concentrate the magnetic flux density, improve the efficiency of the induction heating system, reduce stray magnetic fields and shield high-frequency electromagnetic fields to prevent unwanted areas or materials from being heated by induction.

[0043] Back to Figure 2 , at least one processing device 30 is provided, which is operatively connected to the coil assembly 20. The processing device 30 controls and excites the operation of the coil assembly 20, and thereby also controls the induction heating process, which heats the molding tool 1 and results in the production of the composite part A. The coils of the coil assembly 20 can be connected to the same processing device or different processing devices. The processing device 30 is configured to generate a high-frequency current in the coil assembly 20. Preferably, the processing device 30 is a frequency converter or includes a frequency converter. At least one processing device 30 is configured to generate an alternating voltage and current to the coil so as to inductively heat the mold 10 of the molding tool 1 so that the part A can be produced. In some embodiments, one processing device 30 can control multiple coils alone. In other embodiments, multiple processing devices 30 can be used to control the heating of the molding tool 1.

[0044] Preferably, the processing device 30 includes a certain intelligence in some type of microcontroller or central processing unit, memory, etc., and at least one type of interface (not shown) for operating the system, which is used as a human-machine interface in the form of a graphical display, buttons, knobs or the like, or as a communication interface controlled from a monitoring system, such as a PC or PLC.

[0045] Now go to Figures 4 to 22 , a clamping device 40 for clamping the coils 21, 22, 23 / wires 211, 212, 213 to the mold 10 is described. The principle of clamping the coils 21 to 23 to the outer surface 12 of the mold 10 can be applied to all types of coils, for coils consisting of one or more wires 211, 212, 213, which are clamped individually or together. Each clamping device 40 can be mounted on the mold to clamp one or several wires 211, 212 of a coil 21, one or several turns 211, 212 of the same coil 21, or several coils 21, 22 together, or to clamp a combination thereof.

[0046] Figure 4 Schematically illustrated is a part of a molding tool having two wires 211, 212 arranged in parallel of at least one coil, which are held together along the longitudinal axis of the wire by a plurality of clamping means 40. The number of clamping means 40 may vary depending on several factors, such as the length of the coil, the pattern of the coil and the size of the clamping means 40. Merely by way of example, the clamping means 40 are arranged 50 mm apart from each other.

[0047] exist Figure 4 In the embodiment, each clamping device 40 has a first end 41 and a second end 42, and the first end 41 and the second end 42 are respectively attached to the back side 12 of the mold 10, thereby clamping the wires 211, 212 of at least one coil to the mold 10. The first end 41 and the second end 42 can also be referred to as the first side section and the second side section. Optionally, only one of the first end 41 and the second end 42 is attached to the back side of the mold.

[0048] The middle section 43 of the clamping device 40 is high enough relative to the coils / wires 211, 212 and the side sections 41, 42 to fit the coils and at least one insulating element and hold the coils and at least one insulating element tightly in place relative to the outer surface 12 of the mold 10. The middle section 43 can be rigid or flexible, as long as the middle section 43 holds the coils in place during the manufacture of the composite part A. The height of the middle section 43 creates a gap or space between the central portion of the clamping device 40 and the outer surface 12 of the mold 10. In other words, the distance between the middle section 43 and the back side 12 of the mold 10 defines a space in which one or more wires of one or more coils, electrical insulation materials, thermal insulation materials, cooling channels, etc. can be arranged and clamped. The middle section 43 is preferably made of a material whose thickness is less than twice its skin depth at the operating frequency of the current configured to flow through the coil to prevent or at least reduce self-heating of the clamping device by the induction coil.

[0049] The first end 41, the second end 42 and the middle section 43 can be formed as an integral body or separately from each other. At least part of the clamping device 40 is made of a metal having a relative magnetic permeability of less than 100. The clamping device 40 is preferably made of stainless steel, titanium or copper. The clamping device is preferably attached to the mold 10 by welding, such as spot welding, MIG (metal inert gas) welding, MAG (metal active gas) welding, TIG (tungsten inert gas) welding, ultrasonic welding. Alternatively, the clamping device 40 can be attached to the mold 10 by soldering or brazing. The mold is defined as a molding tool that includes an insert, fastener or other device mounted to the molding tool, and the clamping device can be attached to the molding tool by welding, brazing or soldering. More specifically, the above-mentioned mounted or combined attachment is regarded as part of the outer surface 12 of the mold 10. As an example, if the mold is made of a carbon fiber composite, a metal part may be attached to the mold using, for example, gluing, during or after the composite is made; the clamp may be attached to the metal part using the methods described above. As another example, if the molding tool is made of a carbon fiber thermoplastic, a clamping device 40 made partially or entirely of a polymer material may be welded to the back side 12 of the mold 10 using, for example, ultrasonic welding or induction welding.

[0050] Go to Figure 5 , a clamping device 40 is shown from a cross-sectional view. A first side section 41 of the clamping device 40 and a second side section 42 of the clamping device 40 are each attached to the back side 12 of the mold 10 on opposite sides relative to a middle section 43 extending between the two side sections 41, 42. Figure 5 In the embodiment, the middle section 43 has an inverted U-shape and a substantially square cross-section. Alternatively, as illustrated in other figures, the middle section 43 may have a more rounded shape, such as an arc shape or the like.

[0051] The first side section 41 of the clamping device 40 has an attachment surface 41a facing the outer surface 12 of the mold 10. A welding interface 44 is provided between the first attachment surface 41a and the outer surface 12. Similarly, the second side section 42 has a corresponding attachment surface 42a facing the outer surface 12 of the mold 10, and a welding interface 45 is provided between the attachment surface 42a and the outer surface 12, or a welding interface 48 is provided between the attachment surface 42a and a part of the first side section 41. At the corresponding welding interfaces 44, 45, the clamping device 40 is welded to the back side 12 of the mold 10. Optionally, as Figure 8As shown in FIG. 1 , the attachment surfaces 41a, 42a are welded to a weldable element, such as a metal strip, which in turn is adhered to the back side 12 of the mold 10, as defined above, as part of the mold 10. For example, the metal strip is bonded to the back side 12. The clamping device 40 can be attached to the outer surface 12 of the mold 10 by any of welding, brazing or soldering.

[0052] Furthermore, the first side section 41 and the second side section 42 have respective upper surfaces 41b, 42b facing away from the back side 12 of the mold 10. The upper surfaces 41b, 42b can be subjected to a welding tool, such as a spot welder, a welding electrode or an ultrasonic tool, or other heat generators, such as a soldering iron or an open flame. When the clamping device 40 is to be attached to the back side 12, it may also be subjected to a pressing force during the attachment process.

[0053] The above article about Figure 5 The disclosed features, namely the side sections 41, 42, the middle section 43 and the attachment surfaces 41a, 42a are Figures 6 to 22 The common features of the embodiments shown in .

[0054] Figure 6 Share About Figure 5 The features described above and show the coil wire 211 clamped between the clamping device 40 and the back side 12 of the mold 10. The coil wire 211 is surrounded by the electrically insulating material 60, which is disposed all along the periphery of the wire 211 and the outer surface 12 of the mold 10. As can be seen, the middle section 43 also at least partially encloses the electrically insulating material 60. In addition, the electrically insulating material 60 is not limited to contacting the internal parts of the middle section 43.

[0055] Reference Figure 7 , the two wires 211, 212 of at least one coil are arranged in a space defined by the distance between the middle section 43 and the back side 12 of the die 10. A thermal insulation material 70 is provided between the wires 211, 212 and the back side 12 of the die 10. The main advantage of using such a material is that the die can be heated to a temperature higher than the wire can withstand, but the die can also save energy that would otherwise be spent on heating the wire by conduction.

[0056] As previously mentioned, the first side section 41 and the second side section 42 of the clamping device 40 can be welded to a weldable element, such as a metal strip 51, 52, which in turn is adhered to the back side 12 of the mold 10 and is considered to be part of the back side 12 of the mold 10. In one embodiment, the metal strips 51, 52 are bonded to the back side 12 of the mold 10. The weldable surface of each metal strip 51, 52 faces the corresponding attachment surface 41a, 42a of the clamping device 40. A weld interface 44, 45 is provided between the attachment surface 41a, 42a and the weldable surface of the metal strips 51, 52. This is in Figure 8 It is shown in Figure 8 In all other senses it is reflected in Figure 6 In the disclosed embodiments.

[0057] Fig. 9 Share About Figure 6 However, in Fig. 9 In the embodiment, the middle section 43 has a more curved or rounded shape and abuts against the electrically insulating material 60 along most of the periphery of the electrically insulating material 60 covering the wire 211 of the coil. As with all embodiments disclosed herein, the electrically insulating material 60 covers the wire 211 at least in this area along the longitudinal extension of the wire 211. In the area between the wire 211 of the coil and the electrically insulating material 60 surrounding it and the outer surface 12 of the mold 10, a thermal insulating material 70 is provided. Fig. 9 In the embodiment, the thermal insulation material 70 is preferably an air gap.

[0058] Go to Fig.10 , the two wires 211, 212 of at least one coil are arranged on the back side 12 of the mold 10. The first side section 41 and the second side section 42 of the clamping device 40 are shown as an inverted T-shape. In this embodiment, the middle section 43 of the clamping device 40 is pressed, riveted or bolted to the first side section 41 and the second side section 42 at the press / bolt interface 46, 47, and the first side section 41 and the second side section 42 are welded to the back side 12 of the mold 10 at their respective attachment surfaces 41a, 42a, thereby forming a welded interface 44, 45. Alternatively, the first side section 41 and the second side section 42 are soldered or brazed to the back side 12 of the mold. The clamping device 40 can also be composed of several welded sections, wherein the middle section 43 is welded to the first side section 41 and / or the second side section 42.

[0059] exist Fig.11In the embodiment of the present invention, the middle section 43 of the clamping device 40 is claw-shaped and is suitable for receiving two wires 211, 212 of at least one coil. As for all embodiments disclosed herein, the clamping device 40 can clamp a single wire or more than two wires. In this particular embodiment, the clamping device 40 can form a space that acts as a thermal barrier between the wires 211, 212 and the back side 12 of the mold 10. Preferably, the clamping device 40 is quite flexible so that the wires 211, 212 can be clamped in the direction toward the back side 12 of the mold 10, thereby forming a firm attachment.

[0060] like Fig.12 and Fig.13 As illustrated in , each wire may be associated with a cooling channel 80, 81, 82. The cooling channel is incorporated in or arranged in close proximity to the corresponding wire 211, 212, 213 of at least one turn of at least one coil. The purpose of the cooling channel is primarily for gas or liquid cooling, thereby preventing overheating of the coil, heat generated by losses in the wires 211 to 213 themselves or heat caused by thermal conduction from the hot mold 10. The intermediate section 43 at least partially encloses the cooling channel similarly to its enclosed coils as well as the electrical insulation elements 60, 61, 62 and the thermal insulation element 70. In Fig.12 In the embodiment, the coil / wire includes a cooling channel 80. In other words, the cooling channel 80 is incorporated into the wire 211 of the coil. The wire 211 is surrounded by an electrically insulating element 60, and a thermally insulating element 70 is provided between the electrically insulating element 60 and the back side 12 of the mold 10. Fig.13 In the embodiment, three wires 211, 212, 213 of at least one coil are provided. Each of the wires 211, 212, 213 is enclosed by a corresponding electrical insulating element 60, 61, 62. Instead of the cooling channels 80, 81, 82 being incorporated in the coil, the cooling channels 80, 81, 82 are arranged in close proximity to the coil / wire. The cooling channels 80, 81, 82 are surrounded by a material that prevents leakage of the cooling medium. The material may be the same as the material of one of the electrical insulating elements 60, 61, 62, which is associated with the corresponding wire 211, 212, 213.

[0061] exist Fig.14 , in which a soft magnetic element and / or an electrically conductive element 90 is arranged between the wires 211, 212 of at least one coil and the intermediate section 43 of the clamping device 40. The intermediate section 43 at least partially encloses the soft magnetic element and / or the at least one electrically conductive element 90, just as the intermediate section 43 encloses the wires 211, 212 and the electrically insulating elements 60, 61 around the wires 211, 212.

[0062] Go to Fig.15 , the support 95 is welded to the back side 12 of the mold 10. The support 95 is shaped so that the wire 211 fits in the recessed portion of the support 95. In other words, the support 95 fixes the coil wire 211 in place above the surface of the mold. However, the shape of the support 95 can have a variety of different shapes and is not limited to having a recessed portion / groove or the like. The support 95 can be regarded as a bridge that establishes a physical distance, and thereby separates the back side 12 of the mold 10 from the coil. The purpose of the support 95 is to achieve thermal insulation between the coil and the mold 10. For example, the support 95 can be made of the same material as the clamping device 40 and attached in the same way.

[0063] Fig.16 The embodiment shown in Fig.14 The implementation methods of Fig.16 In the embodiment of the present invention, the soft magnetic element 90 is cast, for example, around the middle section 43 of the clamping device 40. The conductive element can be a copper tube clamped around the clamping device. In addition, the entire clamping device 40 can be a conductive element, the purpose of which is to locally reduce the power. This will require the clamping device to be thicker than twice the skin depth. The wire 211 of the coil is clamped between the back side 12 of the mold and the soft magnetic element 90.

[0064] Go to Fig.17 , the first side section 41 of the clamping device 40 is attached to the back side 12 of the mold 10 by any of the above-mentioned means, i.e., by welding, brazing or soldering. As mentioned previously, the same reference numerals refer to the same elements. The second side section 42 of the clamping device 40 is attached to a mold surface that is orthogonal to the surface to which the first side section 41 is attached. The clamping device 40 described herein can be attached to essentially any geometric surface and can adapt to different mold geometries. Fig.17 In the embodiment, the wire 211 of the coil is located between the clamping device 40 and the back side 12 of the mold 10. The middle section 43 has a generally pointed shape in this configuration. In another embodiment (not shown), the middle section 43 can have a smoothly bent shape that conforms to the shape of the wire / coil to be clamped.

[0065] In some cases, such as from Figures 18 to 22 It will be clear that only one of the side segments, such as the first side segment 41, is attached to the mold 10. In these cases, the other of the side segments, such as the second side segment 42, is formed as a free end, or is in turn attached to another part of the clamping device, such as the first side segment 41, by any of welding, brazing or soldering.

[0066] Reference Fig.18, the first side section 41 of the clamping device is attached to the outer surface 12 of the mold 10 at a welding interface 44. The second side section 42 is at least partially wound around the wire 211 of the coil and is attached to the first side section 41 at another welding interface 48. The upper surface 42b of the second side section 42 can also face the upper surface 41b of the first side section 41. The attachment surface 42a of the second side section 42 can also face the upper surface 41b of the first side section 41. In any case, the clamping device surrounds the wire / coil and is welded to itself and the mold.

[0067] exist Fig.19 and Fig. 20 In the embodiment, the first side section 41 of the clamping device is attached to the back side 12 of the mold 10 at the welding interface 44. The second side section 42 is loose and clamps around the wire 211 of the coil to hold the wire 211 in place on the back side 12 of the mold. Fig.19 In the embodiment, the middle section 43 of the clamping device is substantially flat / square, while in Fig. 20 In the embodiment of the present invention, the middle section 43 of the clamping device is arc-shaped.

[0068] Go to Fig.21 , the first side section 41 of the clamping device is attached to the outer surface 12 of the mold, and the second side section 42 clamps the middle section 43 of the clamping device. For example, the first end 41 and the second end 42 are made of rounded studs with one or several barbs, and the middle section 43 is made of a thin metal sheet of a material, the thickness of which is preferably less than 2 times the skin depth of the material at the operating frequency, and the metal sheet contains deformable holes or slots that can be forced through the barbs of the studs to lock the wire 211 in place.

[0069] exist Fig. 22 In the embodiment of the present invention, a first side section 41 of the clamping device is attached to the rear side 12 of the mold, and the wires 211, 212 of at least one coil are clamped around the clamping device. This can be explained as follows. Two Litz wires 211, 212 are provided, through which the covering members thereof pass to make a hole (not shown) between the wires 211, 212. The second side section 42 of the clamping device is threaded through the hole. The wires 211, 212 are held in place by means of a spherical element protruding outwardly from the middle section 43 of the clamping device. In this way, the coil is held in place on the back side of the mold.

[0070] It should be understood that the above-mentioned wires 211, 212, 213 can be surrounded by electrical insulation elements. From the perspective of safety, assurance, EMC (electromagnetic compatibility) and functionality, it is beneficial that the mold 10 and the coils 21 to 23 are electrically insulated from each other, which means that during the entire service life of the molding tool 1, the electrical insulation elements can generally withstand thousands of volts. Certain types of wires, such as magnet wires or enamel wires, include Litz wires due to the enamel coating, which already have an insulating layer, thereby providing sufficient electrical insulation in some cases, but not providing sufficient electrical insulation in other cases. In the case of Litz wires, silk, nylon, polyimide, aramid or similar materials are usually used for winding to keep the strands together and further improve electrical insulation. Like cables, wires can also have one or more solid polymer layers to further improve electrical insulation and thermal insulation performance, and achieve, for example, resistance to cooling fluids or form leak-proof channels for cooling wires, or for other reasons suitable for application. The same reasoning also applies to the case where the wire is a solid or hollow conductor, such as a copper tube. The electrical and thermal insulation elements may also be loosely attached to the wires, partially or completely surrounding the wires, for example being bonded or clamped in place. Figures 4 to 22 The choice of insulation type is illustrated schematically.

[0071] exist Fig.23 A method for producing a composite article or part A using a molding tool 1 is shown in FIG. Fig.23 In the method described, the material to be processed placed in the mold is a mixture of fibers and plastic material. Fig.24 Another method is shown in , in which the material placed in the mould is a fibre material which is impregnated with a plastic material during the moulding process, so that the plastic material then forms part of the material 110 to be processed. Fig.25 Schematic diagrams of the various parts of these methods are provided.

[0072] exist Figure 23 to Figure 25In the method illustrated in , the material 110 to be processed may include technical fibers such as carbon, glass, aramid, ultra-high molecular weight polyethylene, flax or basalt fibers, or a mixture of fibers and plastic materials. The material 110 may be a prepreg, a sheet molding compound / block molding compound (SMC / BMC), a hybrid yarn, an intermediate material or a separate fiber and plastic, wherein the plastic may be in the form of a sheet or powder, for example. The plastic component may be a thermoplastic or a thermosetting plastic, and the fiber component may be a fiber bundle, a multiaxial material, a braid or a randomly oriented fiber. The stacking, number of layers, orientation, size and shape of the material 110 may vary greatly according to the processes and applications well known in the art. The material 110 may be placed in the mold in sequence, for example layer by layer, or may be preformed before being placed in the mold. In addition to fibers, the material 110 may also contain core materials / spacer materials / sandwich materials that are common in many composite parts, such as foam cores, honeycomb structures, etc., or the material 110 may contain metal inserts that are typically used for assembly purposes in the final application of the part A. The material 110 can even be transformed into a multi-material part A comprising a fiber composite material and a metal.

[0073] Fig.23 The method shown in comprises the step of providing 305 a molding tool 1 having a mold 10 configured to be inductively heated by a coil assembly 20 attached to the mold 10 by a clamping device 40 according to the teachings herein. Optionally, a release agent is added to the molding tool 1 at this stage to facilitate separation of the produced part A from the mold 10. The method further comprises placing 310 a material 110 to be processed on a contact surface 11 of the mold 10. Preferably, the material 110 is a fiber and plastic material in the form of a preform having a similar shape to the contact surface 11, which is easy to put into the mold.

[0074] In this case, with the plastic already in the mold, i.e. as matrix material combined in the fiber material placed in the mold, the method further comprises closing 312 the mold 10 and applying 315 a consolidation pressure on the material to be processed 110. The mold 10 can be closed, for example, by another molding tool 1 half or by a flexible membrane or bag.

[0075] Prior to applying 315 consolidation pressure on the material to be processed 110, the method may further comprise the step of applying 314 a vacuum or near-vacuum pressure on the material 110. Certain processes benefit from reduced pressure on the material, i.e. vacuum pressure, to remove entrained air and thereby enhance wettability of the matrix on the fibers during the manufacturing process and thereby reduce the risk of dry spots or voids in the produced part A.

[0076] For example, the consolidation pressure may be applied by arranging a vacuum bagging unit on top of the material 110 and performing vacuum bagging. The consolidation pressure may also be applied by a press, an autoclave, or simply by atmospheric pressure if a near-vacuum pressure exists inside the mold. In the latter case, the step of applying 315 the consolidation pressure on the material 110 typically means pulling a vacuum in the molding tool 1. In some cases, the vacuum pressure is the same as the consolidation pressure.

[0077] about Fig.23 The described method also includes inductively heating 320 the mold 10 containing the material 110. The heating can be performed according to a predetermined time-temperature curve to consolidate and / or cure the material 110 to produce a composite part A. The mold 10 is heated by a coil assembly 20, which is operatively connected to a processing device 30 as previously discussed. The molding tool 1 or its mold 10 can be heated before, during and / or after the step of applying pressure 315. In addition, the pressure does not have to remain constant throughout the process device, but can be increased, for example, when the material 110 becomes warmer, to improve part quality.

[0078] The mold 10 and the material to be processed 110 are kept in place in the molding tool 1 during a predetermined period of time, usually to ensure sufficient temperature throughout the material and proper consolidation / wetting of the fiber composite material. In the case of thermosetting plastics, the resin or plastic material should be fully cured before demoulding; while in the case of thermoplastics, the part becomes solid after cooling. Therefore, in the end, a cured or consolidated material 110 is provided and a composite part A is formed. This is Fig.25 There are several applicable processes for this method, such as those commonly referred to as compression molding, stamping, autoclave processing, non-autoclave processing, vacuum bagging, etc.

[0079] Now go to Fig.24 , the case where no matrix material is placed in the mold, that is, the case where the material 110 initially only includes fibers, possibly in combination with core materials / spacer materials / sandwich materials or metal inserts as described above. The method includes the step of placing the fiber material 110 in the mold after providing 305 the molding tool 1. Afterwards, the mold is closed 312, usually using another mold half, a flexible film or a bag-like piece. As in the above case, the closed mold can include a plurality of mold halves, bags or films or a combination of a plurality of mold halves, bags or films, which together provide a sealed or semi-sealed mold assembly. In this case, the material 110 placed on the contact surface 11 of the mold 10 can also be referred to as a stack or preform of fiber material.

[0080] and Fig.24The associated method further comprises the step of applying 314 a reduced pressure, preferably a vacuum or a pressure close to a vacuum, on the material 110. The evacuation of the gas may be carried out in a single or multiple openings and may be performed only at this step or during the entire production process.

[0081] The method further comprises the step of infusing 316 the material 110 in the mould 10 with a matrix material, preferably any type of low viscosity resin. In this case, the resin may also be referred to as plastic material. This may be done using so-called vacuum infusion, where the driving force is the pressure difference between the vacuum pressure in the mould and the ambient pressure. Higher pressures up to several hundred bars may also be used for infusion, commonly referred to as resin transfer moulding RTM, high pressure resin transfer moulding HPRTM, vacuum assisted resin transfer moulding VARTM, etc. As with the above with respect to Fig.23 Similar to what has been discussed, the method further includes inductively heating 320 the mold 10 containing the material 110 .

[0082] In both methods described above for producing composite part A, the steps of heating 320 and applying pressure or infusing the resin, i.e., plastic material, into the material 110 in the mold 10 may occur simultaneously. Heating may be performed according to a predetermined time-temperature profile to produce the composite part A. The mold 10 is heated by the coil assembly 20, which is in operative communication with the processing device 30 as previously discussed. Fig.24 In the case of the method described, the molding tool 1 or its mold 10 can be heated before, during and / or after the step of pouring the matrix material.

[0083] The warm tool is usually beneficial in reducing the viscosity of the resin, but will also usually initiate a chemical reaction to cure the resin, so different aspects are applied depending on the application and choice of materials. In the preferred case, proper wet-out of the fibers with resin is obtained, with no dry spots or voids. In this method, the typical matrix is ​​a thermoset resin, and the matrix needs to be cured. New plastics are constantly being developed, and this method can also be used for hybrid thermoset / thermoplastic matrices as well as low viscosity thermoplastics.

[0084] All methods described herein may also include actively or passively cooling at least a portion of the molding tool 1 and / or the produced part A formed therein 325. Finally, the method also includes demolding the part A from the molding tool 1 330. In certain applications, the part A may be demolded at the processing temperature, which is beneficial from a cycle time perspective. Conversely, a reduced demolding temperature is generally beneficial from a part quality perspective.

[0085] exist Fig.25 The figure shows the above Fig.23 and Fig.24Part of the method described. The material to be processed 110, i.e. a mixture of fiber material and polymer material, or a fiber material to be injected with resin or plastic material during the above-mentioned molding process, is arranged 310 in a molding tool 1. The fiber material can be, for example, a carbon fiber or a flax fiber material. Preferably, the mixture is in the shape of a preform, or in the shape of a mesh. Alternatively, the molding tool 1 is arranged in a streamlined system, in which a mesh of material is gradually fed into the molding tool 1. Before heating, the material 110 is shown in dotted lines. The material may extend beyond the heating area of ​​the molding tool 1, or be located inside the heating area, depending on the application. When the molding tool 1 is inductively heated 320 by a coil assembly driven by a processing device, the mixture of fiber and polymer material, i.e. the material to be processed 110, is consolidated or cured to form a part A having a shape corresponding to the shape of the molding tool 1. After curing or consolidation, the material to be processed is shown as a solid line. Once the process temperature profile has been completed, the molding tool is cooled 325 and part A is removed or demolded from the molding tool 330. The shape of part A corresponds to the contact surface of the mold.

[0086] Now refer to Fig.26 A method of manufacturing the molding tool 1 is described.

[0087] In a first step, a mold 10 is provided 405, the mold 10 being configured to be inductively heated. The mold 10 has a contact surface 11 and an outer surface 12 or back side. In a next step, at least one coil 21, 22, 23 is provided 410 and arranged 415 on the back side 12 of the mold 10. The coils 21, 22, 23 may be arranged in a desired pattern on the outer surface 12 of the mold 10 so that a preferred heating pattern can be achieved. The magnetic field generated by the current is configured to induce a current in at least one portion or portions of the mold 10 to be heated.

[0088] The mold 10 is configured to be heated by an alternating current of an operating frequency flowing through at least one coil 21 , 22 , 23 , and the magnetic field generated by the alternating current is configured to induce a current in at least a portion of the mold 10 to be heated.

[0089] As mentioned previously, the molding tool 1 comprises a mold 10, a coil assembly 20 and a clamping device 40. For example, the coil assembly 20 comprises one single coil. The coil assembly 20 may also comprise several coils.

[0090] At least one coil 21 , 22 , 23 is electrically insulated from the mold 10 and is in operative communication with at least one processing device 30 .

[0091] In a preferred embodiment, the wire 211, 212 of at least one coil 21, 22 comprises a Litz wire, i.e., a wire consisting of a plurality of fine strands, which are individually electrically insulated and twisted to reduce high-frequency losses caused by skin effect and proximity effect. In addition, the method may further include the step of arranging at least one soft magnetic element and / or conductive element 90 at a predetermined area along at least one coil 21, 22, 23.

[0092] Additionally, the method of manufacturing the molding tool 1 comprises providing 420 at least one clamping device 40, the at least one clamping device 40 being as described above with respect to Figures 4 to 15 The described means has a first end 41, a second end 42 and an intermediate section 43 extending between the first end 41 and the second end 42. Next, the method comprises attaching 425 at least the first end 41 of the at least one clamping device 40 to the outer surface 12 of the mold 10 by welding, brazing or soldering so as to at least partially fix the at least one coil 21, 22, 23 to the outer surface 12 of the mold.

[0093] In one embodiment, a molding tool for producing composite parts using induction heating is provided. The molding tool 1 includes a mold 10 having a contact surface 11 and an outer surface 12 or back side, the contact surface 11 being suitable for contacting a material 110 to be transformed into a composite part A. The mold 10 is configured to be inductively heated by at least one coil 21, 22, 23, the at least one coil 21, 22, 23 being attached to the back side 12 of the mold 10 using a clamping device 40, the clamping device 40 being fastened to the mold 10, preferably fastened to the mold 10 by welding. Optionally, the clamping device 40 is indirectly welded to the mold 10 by welding to a weldable material, which in turn is attached to the back side 12 of the mold. For example, in the case of a composite mold, bonded metal strips 51, 52 can be used as the weldable material (see Figure 7 The clamping device 40, more specifically the middle section 43 of the clamping device 40, can also be screwed, bolted, riveted or pressed to a separate part fused to the mold surface 12, such as, for example, Fig. 9 41, 42 in the T-shaped side sections 41, 42 in the mold 10. In addition, the clamping device 40 can be in the shape of a clamp that clamps the coils 21, 22, 23 from below, that is, the coils are clamped to the clamping devices 40 that are already in place on the outer surface 12 of the mold 10, rather than first arranging the coils and then clamping them. Another option for clamping is to attach multiple clamping devices 40 to the back side 12 of the mold 10 using welding, brazing or soldering, and pass at least one coil 21, 22, 23 through each clamping device.

[0094] The coils 21, 22, 23 are powered by an alternating current of at least one frequency flowing through at least one coil 21, 22, 23, which alternating current may vary over time. The magnetic field generated by the current is configured to induce a current in at least a portion of the mold 10 to be heated. Preferably, at least one coil 21, 22, 23 comprises Litz wires, which are electrically insulated from the mold 10 and are in operative communication with at least one processing device 30. The portion of the wire 211, 212 of the coil 21, 22 covered by the clamping device 40, such as the above-mentioned middle section 43, is less than twice the skin depth of the clamping device material at the operating frequency. The skin depth depends on the resistivity, the magnetic permeability, the operating frequency, and can be described as the depth below the surface of the conductor when the current density has dropped to a certain extent.

Claims

1. A moulding tool (1) for producing a composite part (A) using induction heating, the moulding tool (1) comprising: A mold (10) having a contact surface (11) and an outer surface (12), wherein the contact surface (11) is suitable for contacting a material (110) to be transformed into a composite part (A); at least one coil (21-23) or at least one wire (211-213) of a coil (21-23), the at least one coil (21-23) or the at least one wire (211-213) of the coil (21-23) being arranged on the outer surface (12) of the mold (10); and at least one clamping device (40), the at least one clamping device (40) having a first end (1), a second end (42), and an intermediate section (43) extending between the first end (41) and the second end (42), wherein at least one of the first end (41) and the second end (42) is attached to the outer surface (12) of the mold (10) using welding, brazing or soldering to at least partially fix the at least one coil (21-23) to the outer surface (12) of the mold (10); wherein the intermediate section (43) at least partially encloses the at least one wire (211-213) or coil (21-23) to hold the at least one wire (211-213) or coil (21-23) in place on the outer surface (12) of the mold (10); and Wherein, the at least one wire (211-213) or coil (21-23) is electrically insulated from the mold (10) and is operatively connected to at least one processing device (30).

2. The molding tool according to claim 1, wherein Each of the first end (41) and the second end (42) of the at least one clamping device (40) has a corresponding attachment surface (41a, 42a) facing the outer surface (12) of the mold (10), wherein a welding interface (44, 45, 48) is provided between the corresponding attachment surface (41a, 42a) and the outer surface (12) of the mold (10) and / or between the corresponding attachment surface (41a, 42a) and a part of the clamping device (40).

3. The molding tool according to claim 1 or 2, further comprising an electrically insulating material (60-62) arranged at least between the at least one wire (211-213) or coil (21-23) and the outer surface (12) of the mold (10), wherein The intermediate section (43) also at least partially encloses the electrically insulating material (60, 61, 62).

4. The molding tool according to any one of the preceding claims, further comprising a thermal insulation material (70) arranged between the at least one wire (211-213) or coil (21-23) and the outer surface (12) of the mold (10), wherein The intermediate section (43) also at least partially encloses the thermal insulation material (70); preferably, the thermal insulation material (70) is air.

5. The molding tool according to any one of the preceding claims, further comprising at least one cooling channel (80-82), the at least one cooling channel (80-82) being incorporated in or arranged in close proximity to the at least one wire (211-213) or coil (21-23), wherein The intermediate section (43) also at least partially encloses the at least one cooling channel (80-82).

6. The molding tool according to any one of the preceding claims, further comprising at least one soft magnetic element and / or at least one conductive element (90) at least partially arranged between the at least one wire (211-213) or coil (21-23) and the intermediate section (43), wherein The intermediate section (43) at least partially encloses the at least one soft magnetic element and / or the at least one electrically conductive element (90).

7. A moulding tool according to any one of the preceding claims, wherein The first end portion (41), the second end portion (42) and the middle section (43) are formed as an integral body or are formed separately from each other.

8. A moulding tool according to any one of the preceding claims, wherein The at least one coil (21-23) comprises Litz wire.

9. A moulding tool according to any one of the preceding claims, wherein: The mold (10) is heated by an alternating current of a certain operating frequency flowing through the at least one coil (21-23), wherein the magnetic field generated by the current is configured to induce a current in at least a portion of the mold (10) to be heated.

10. The molding tool according to claim 9, wherein The intermediate section (43) is made of a material having a thickness less than twice its skin depth at the operating frequency.

11. A moulding tool according to any one of the preceding claims, wherein The middle section (43) is made of metal, wherein the metal has a relative magnetic permeability of less than 100.

12. A method of manufacturing a moulding tool according to any one of claims 1 to 11, the method comprising: Providing (405) a mold (10), the mold (10) having a contact surface (11) and an outer surface (12), the contact surface (11) being suitable for contacting a material (110) to be transformed into a composite part (A); Providing (410) at least one coil (21-23) or at least one wire (211-213) of the coil (21-23), and arranging (415) the at least one coil (21-23) or the at least one wire (211-213) of the coil (21-23) on the outer surface (12) of the mold (10); providing (420) at least one clamping device (40), the at least one clamping device (40) having a first end (41), a second end (42), and an intermediate section (43) extending between the first end (41) and the second end (42); attaching (425) at least one of the first end (41) and the second end (42) of the at least one clamping device (40) to the outer surface (12) of the mold (10) using welding, brazing or soldering so as to at least partially secure the at least one coil (21, 22) to the outer surface (12) of the mold (10); Thereby, the intermediate section (43) at least partially encloses the at least one wire (211-213) or the at least one coil (21-23) to hold the at least one wire (211-213) or the coil (21-23) in place on the outer surface (12) of the mold (10); and Wherein, the at least one wire (211-213) or coil (21-23) is electrically insulated from the mold (10) and is operatively connected to at least one processing device (30).

13. A method of producing a composite part, the method comprising: Providing (305) a molding tool (1) having at least one clamping means (40) according to any one of claims 1 to 11; placing (310) fibers and plastic material (110) on the contact surface (11) of the mold (10); Closing the mold (10) (312); applying (315) a consolidation pressure on the material (110) to be processed; and The mold (10) containing the material (110) is inductively heated (320) according to a predetermined time-temperature curve to consolidate and / or cure the material (110) to produce the composite part (A).

14. The method according to claim 13, wherein: Prior to applying (315) consolidation pressure on the material (110) to be processed, the method further comprises the step of applying (314) vacuum pressure on the material (110).

15. The method according to claim 13 or 14, wherein: The method further comprises: Cooling (325) at least a portion of the molding tool (1) and / or the produced part (A); and The part (A) is demoulded (330) from the molding tool (1).

16. A method of producing a composite part, the method comprising: Providing (305) a molding tool (1) having at least one clamping means (40) according to any one of claims 1 to 11; placing (310) a fiber material (110) to be processed on the contact surface (11) of the mold (10); Closing the mold (10) (312); applying (314) vacuum pressure, and infusing (316) the fibrous material with a plastic material, the plastic material thereby forming part of the material (110) to be processed; and The mould (10) comprising the fibres and the plastic material (110) is inductively heated (320) according to a predetermined time-temperature profile to produce a composite part (A).

17. The method according to claim 16, wherein: The method further comprises: Cooling (325) at least a portion of the molding tool (1) and / or the produced part (A); and The part (A) is demoulded (330) from the molding tool (1).

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