TRANSMISSION WELDING PROCESS, TRANSMISSION WELDING DEVICE AND TRANSMISSION WELDING ARRANGEMENT

Description

[0001] The invention relates to a transmission welding process for welding a first workpiece part, at least partially made of thermoplastic material, to at least one second workpiece part at a weld point. The invention further relates to various alternative uses of such a transmission welding process, in particular in the manufacture of an aircraft.

[0002] In practice, bolts and rivets are predominantly used in appropriately machined holes when creating connections in aircraft structural components, such as the fuselage of an aircraft or the like.

[0003] Embodiments of the invention focus on joining techniques and structures that can be produced with them, which can be manufactured with less effort than the joining techniques or structures used so far, have a lower weight and yet should provide at least comparable or improved reliability.

[0004] Due to their low weight and good adaptability to load conditions, there are increasing efforts to use fiber-reinforced composite materials, especially those with a thermoplastic matrix, in vehicle and aircraft construction. It is already a known method to join a workpiece consisting of a first workpiece made of thermoplastic fiber-reinforced composite material and a second workpiece made of thermoplastic fiber-reinforced composite material by welding.

[0005] The reference [1] Potente, H. et al., 1993, "Comparative investigation into the welding of glass-fibre reinforced PES"; Journal of Thermoplastic Composite Materials, Vol. 6, No 2, pp 147-159 describes a joining of workpiece parts made of thermoplastic fiber composite material by means of infrared welding, whereby the joining surfaces are irradiated with infrared light by infrared lamps in order to then be pressed together.

[0006] From the literature reference [2] DE 10 2009 043 376 A1, the joining of workpiece parts formed at least partially from thermoplastic material by means of laser welding is known.

[0007] From the reference [3] WO 2019 / 053086 A1, the joining of workpiece parts made of thermoplastic material by means of conduction welding is known.

[0008] US 2009 / 0056865A1 discloses a method for bonding a metal workpiece to a plastic workpiece.

[0009] US 3 477 194 A discloses a method for manufacturing packaging.

[0010] EP 0 958 128 B1 and DE 694 14 951 T2 disclose a method for welding plastics using infrared radiation.

[0011] The invention is based on the objective of enabling the welding of workpiece parts formed at least partially from thermoplastic material in a more universal way and with a smaller equipment and process setup.

[0012] To solve this problem, the invention provides a transmission welding process according to claim 1.

[0013] Advantageous embodiments are the subject of the dependent claims.

[0014] The invention provides a transmission welding process for welding a first workpiece part, at least partially made of thermoplastic material, to at least a second workpiece part at a welding point, comprising: guiding polychromatic, incoherent infrared light radiation through the first workpiece part to the welding point; a) Clamping the first workpiece part and the second workpiece part by means of at least one clamping element which is at least partially transparent to infrared light radiation, and b) guiding the infrared light radiation through the clamping element to the first workpiece part, wherein at least one area of ​​the first workpiece part or the entire first workpiece part is made of a thermoplastic fiber composite material and that the infrared light radiation is directed through the fiber composite material to the welding point.

[0015] Preferably, in the transmission welding process, at least the first workpiece part and the second workpiece part are welded together at a joint area to form one workpiece.

[0016] At least one area of ​​the first workpiece part or the entire first workpiece part is made of a thermoplastic fiber composite material and the infrared light radiation is directed through the fiber composite material to the welding point.

[0017] Preferably, the transmission welding process includes the step of generating polychromatic, incoherent infrared light radiation using an infrared lamp.

[0018] Preferably, the transmission welding process comprises the step of generating infrared light radiation in a wavelength range of 1.0 to 3.0 µm, preferably from 1.2 to 3.0 µm.

[0019] Preferably, the transmission welding process includes the step: generating the infrared light radiation as IR-B radiation according to DIN5031.

[0020] Preferably, the transmission welding process comprises the step of moving the infrared light radiation over the first workpiece part in order to continuously weld the workpiece parts along a welding area.

[0021] Preferably, the transmission welding process comprises the step of moving an infrared light source generating infrared light radiation over the first workpiece part in order to continuously weld the workpiece parts along a welding area.

[0022] It is preferred that step a) includes: a1) pressing the clamping element onto the first workpiece part.

[0023] It is preferred that step a) includes: a2) using a clamping element made of a material selected from the group of materials which includes a material transparent to infrared light radiation, a flexible material, a rigid material, glass, transparent plastic, polyimide, vacuum packing film and silicone and combinations of these materials.

[0024] It is preferred that step a) includes: a3) using a pressure plate or clamping jaw as a clamping element.

[0025] It is preferred that step a) comprises: a4) using a clamping element with at least one fluid medium cavity filled or fillable with a fluid medium.

[0026] It is preferred that step a) includes: a5) using a flexible clamping element and controlling the contact pressure of the flexible clamping element by means of a pressure fluid.

[0027] It is preferred that step a) includes: a6) moving the clamping element (26) over the first workpiece part (12).

[0028] It is preferred that step a) includes: a7) Using a clamping element rotatable about an axis of rotation (26).

[0029] It is preferred that step a) includes: a8) using a roller, cylinder or spherical clamping element or a rolling element (26).

[0030] It is preferred that step a) includes: a9) rolling the clamping element (26) over the first workpiece part (12).

[0031] It is preferred that step a) includes: a10) generating the infrared light radiation (32) inside the clamping element (26) designed as a rolling body.

[0032] It is preferred that step a) includes: a11) jointly moving an infrared light source and the clamping element (26) over the first workpiece part.

[0033] It is preferred that step a) includes: a12) using a clamping element having several rigid segments which are preferably flexibly linked to one another to represent the topology of the first workpiece part.

[0034] Preferably, the transmission welding process comprises the step: c) setting a temperature of the clamping element before, during and / or after step b) in order to influence the temperature of at least one area of ​​the workpiece.

[0035] Preferably, at least one of steps a) or c), in particular at least one of steps a1)-a12), more particularly a4), a5), in particular in combination with step c), comprises the step: using a clamping element with at least one channel and guiding a tempered fluid medium through the at least one channel.

[0036] Preferably, at least one of steps a) or c), in particular at least one of steps a1)-a12), more particularly a4), a5), in particular in combination with step c), comprises the step: passing a fluid medium transparent or transmissive to infrared light radiation through the clamping element.

[0037] Preferably, at least one of the steps a) or c), in particular at least one of the steps a1)-a12), more particularly a4), a5), in particular in combination with step c), comprises the step: preheating the clamping element and the workpiece to reduce the heating time for welding.

[0038] Preferably, at least one of steps a) or c), in particular at least one of steps a1)-a12), more particularly a4), a5), in particular in combination with step c), comprises the step: reheating or cooling of the clamping element and of the workpiece to improve the workpiece quality or the crystallization rate.

[0039] Preferably, at least one of the steps a) or c), in particular at least one of the steps a1)-a12), more particularly a4), a5), in particular in combination with step c), comprises the step: controlling a pressure distribution by controlling the pressure of the fluid medium.

[0040] Preferably, the transmission welding process comprises the step of welding the material parts, each selected from the group consisting of a fiber-reinforced plastic component, a component with a thermoplastic matrix, a component with a PPS matrix, a component with a PEKK matrix, a component with a PEEK matrix, a component with a PA matrix, a component with a PEI matrix, a component with a LM PAEK matrix, a component with a PBI matrix, a component with a PE matrix, a component with reinforcing fibers in the form of a woven fabric, a component with reinforcing fibers in the form of a non-woven fabric, a component with reinforcing fibers in the form of unidirectional fibers, a component with reinforcing fibers in the form of short fibers, a component with reinforcing fibers in the form of continuous fibers, a component with reinforcing fibers made of carbon, a component with reinforcing fibers made of glass,a component with reinforcing fibers made of continuous carbon fibers, a component with reinforcing fibers made of continuous glass fibers; a component with reinforcing fibers made of short carbon or glass fibers, a component with reinforcing fibers made of aramid fibers, a component with reinforcing fibers made of silk, a component with reinforcing fibers made of fibers from a biological source, a component with reinforcing fibers made of ceramics, includes.

[0041] Preferably, the transmission welding process includes the step of welding the first workpiece part and the second workpiece part in overlap or partial overlap.

[0042] Preferably, the transmission welding process includes the step of welding the first workpiece part and the second workpiece part in a butt joint.

[0043] Preferably, the transmission welding process includes the step of inserting an intermediate layer between the workpiece parts before welding.

[0044] Preferably, the transmission welding process is used to create longitudinal and / or circumferential connections on a vehicle or aircraft fuselage or component.

[0045] Preferably, the transmission welding process is used for welding fasteners, clips, brackets, clamps or clamps to a hull structure or skin of a vehicle or aircraft.

[0046] Preferably, the transmission welding process is used for welding the frame of a vehicle or aircraft.

[0047] Preferably, the transmission welding process is used to weld a skin to a frame of a vehicle or aircraft.

[0048] Preferably, the transmission welding process is used for welding stringers or frames to the skin of a vehicle or aircraft.

[0049] Preferably, the transmission welding process is used for welding structural components to form a frame for a door of a vehicle or aircraft.

[0050] Preferably, the transmission welding process is used for welding floor structures of a vehicle or aircraft.

[0051] Preferably, the transmission welding process is used for welding coupling elements for connecting structural elements of a vehicle or aircraft.

[0052] Preferably, the transmission welding process is used to weld a window frame to the skin of a vehicle or aircraft.

[0053] Preferably, the transmission welding process is used to weld a reinforcement structure to a structural component of a vehicle or aircraft.

[0054] The invention or its embodiments could also be implemented or used in other structures, for example in land vehicles, ships, buildings, and technical constructions made of thermoplastic materials. The invention or its embodiments can also be used in aircraft, not only in airplanes, but also in helicopters, drones, flying cars, air taxis, as well as in rockets and satellites.

[0055] The invention relates to infrared transmission welding.

[0056] Prior art methods include infrared welding by irradiating the contact surfaces to be joined with infrared radiation and subsequent pressing together, laser welding and welding using conduction heat (local co-consolidation).

[0057] Preferred embodiments of the invention combine the advantages of these methods, but allow for simplified equipment and a wider range of applications. This makes it possible to perform welding joints even where they were previously not technically feasible or economically viable.

[0058] Studies have shown that even with a simpler infrared light source, without the use of a laser, transmission welding through a workpiece area made of thermoplastic material, in particular thermoplastic fiber composite material, is possible and high-quality welded joints can be achieved.

[0059] In particular, the invention relates to devices, methods and arrangements for infrared transmission welding of thermoplastic materials.

[0060] Compared to fastening methods previously used, particularly in the field of aircraft manufacturing, which involve drilled holes and overlap and butt joints with bolts or rivets, embodiments of the invention offer the advantages of a less complex process chain with fewer steps.

[0061] In the embodiments of the invention, no drilling is required, in particular no drilling within the fuselage of a vehicle, such as aircraft. This eliminates drilling operations that sometimes have to be carried out under difficult working conditions, and offers better possibilities for automation.

[0062] The elimination of machining operations prior to joining results in less dust generation, particularly a reduction in carbon dust.

[0063] In embodiments of the invention, a sealing connection is achieved, so that no additional seals are needed for a hermetic closure.

[0064] In embodiments of the invention, shorter lead times result – particularly compared to conventional joining techniques where parts are balanced via bolted connections with spacers or washers.

[0065] In embodiments of the invention, the cutting of fibers in fiber composite materials to be joined together is avoided and there is no risk of delamination.

[0066] Thermoplastic materials and thermoplastic technologies will be increasingly used in the future for the construction of lightweight structures, especially fiber composite structures, and more, particularly in vehicle and aircraft construction.

[0067] Thermoplastic materials and technologies offer the potential for significant changes in the manufacture and arrangement of aircraft structures. The thermoplastic materials, which can be welded together using the embodiments of the invention, enable the thermoplastic forming of elementary components. Main laminates can be stacked quickly. Consolidation cycles are very short, and no cleanrooms, freezing devices, or autoclaves are required.

[0068] The thermoplastic materials can be welded together, so that drilling work can be significantly reduced, expensive fasteners and bolts can be significantly reduced, and other auxiliary materials as well as scrap or waste can be significantly reduced.

[0069] According to this, thermoplastic materials and technologies offer a considerable opportunity for cost reduction in the manufacture and assembly of aircraft, especially airplanes and their structure.

[0070] It is particularly preferred that workpiece components made of thermoplastic fiber composite materials are welded together. The workpiece components are preferably reinforced with continuous fibers.

[0071] Welding thermoplastic materials reinforced with through-filament or continuous fibers is a particularly advantageous joining process. Preferably, the joining is carried out by welding using heat and pressure. In particular, the welding can be performed with or without the use of filler materials or auxiliary materials in the weld area.

[0072] Welding of thermoplastic materials is particularly preferred. Welding is defined in particular as a joining process in which two or more parts are joined to form a workpiece, whereby continuity in the properties of the workpiece material is created by applying heat or pressure, or both. This can be done with or without the use of filler material.

[0073] In contrast to previously known infrared welding processes, the embodiments of the invention involve guiding infrared radiation through a region of the workpiece formed by the parts to be joined. The infrared radiation passes through this region to the weld point. The workpiece parts can thus be pressed together before welding and then irradiated with infrared light. This allows an infrared light source to be positioned externally, and significantly more joints can be produced economically using this welding process than with previously known infrared welding technology.

[0074] In particular, local heating at the weld point can be achieved by applying pressure and subsequently passing infrared radiation through it, so that macromolecular interdiffusion up to complete diffusion of the macromolecules of the two welding partners can be achieved at the weld point.

[0075] Compared to laser welding processes, the advantage lies in the fact that infrared light sources with particularly preferred wavelength ranges, in which the thermoplastic materials to be welded exhibit especially good transmissivity, are readily and inexpensively available. The infrared light sources for generating the infrared radiation according to the invention are far less expensive than lasers and are easier to transport and handle.

[0076] In an advantageous embodiment of the infrared transmission welding process, the workpiece parts to be joined are positioned relative to each other in a clamping device. A first part of the clamping device – hereinafter referred to as the clamping element – ​​should be transparent to infrared light radiation. In some embodiments of the invention, this first part of the clamping device – the clamping element – ​​is flexible.

[0077] In some designs, an additional layer is inserted between the workpiece parts to be joined. This can be, for example, a matrix layer or a functional layer – e.g., a metal grid, a layer with conductive traces, a layer to improve fusion, etc. Such a layer could also already be integrated into one of the workpiece parts.

[0078] Preferably, mechanical pressure is exerted on the arrangement consisting of the first workpiece part and a second workpiece part via the clamping devices of the clamping device – in particular the clamping element and a counter-clamping element, such as a fixed support. This arrangement, as well as the product obtained by welding, is hereinafter also referred to as the workpiece.

[0079] Preferably, an infrared heating source is placed above the infrared-transparent clamping element. In another embodiment, particularly one in which the clamping element is designed as a rolling body, the infrared light source is integrated into the clamping element. For example, the clamping element surrounds the infrared light source and is rotatably mounted so that it can be moved by rolling it over the first workpiece.

[0080] Infrared heating is used as a through-heat source and passes through the transparent clamping element to the first workpiece part.

[0081] Infrared heating heats the first workpiece. This can be achieved partly through surface heating and partly through infrared light radiation penetrating the first workpiece via transmission. The heat is thus conducted to the weld point – the joining area – and into the second workpiece.

[0082] The energy from infrared heating leads to a heating of the joint area - weld point - up to the point of melting the first workpiece and possibly the joint area of ​​the second workpiece or the additional layer in this area.

[0083] In some designs, infrared transmission welding is performed with heating assistance provided by a fluid medium. Heating assistance from a fluid medium can be achieved, in particular, by having at least one of the parts of a clamping device have one or more channels for the fluid medium.

[0084] During the welding process, fluid medium can be introduced into these channels to improve temperature and pressure distribution. In some designs, a liquid medium is passed through at least one channel; in others, the fluid medium is a gas, e.g., compressed air, heating air, or cooling air.

[0085] If the transparent clamping element has such fluid channels, it is advantageous if the fluid medium is transparent and / or transmissive to infrared light. Suitable liquid fluid media for this purpose are, for example, high-temperature resistant oils or water.

[0086] Preferably, the temperature of the fluid medium is controlled. In particular, a cooling device and / or heating device for cooling and / or heating the fluid medium can be provided in an infrared transmission welding device according to one embodiment of the invention.

[0087] Controlling the temperature of this fluid medium allows, for example, the heating time to be reduced by preheating the fluid medium, or the welding time to be reduced by additionally heating the fluid medium, and / or better consolidation or crystallization to be achieved through subsequent temperature control, in particular post-heating or control of the cooling rate.

[0088] Especially when the clamping element is at least partially made of flexible material, such as silicone or polyimide like Kapton®, the pressure applied to the workpiece can be controlled by a fluid medium that is circulated through the clamping element at a controlled pressure. By controlling the pressure within multiple channels running through the clamping element, pressure can be applied in a targeted manner. For example, the pressure can be applied flexibly across the entire welding area. Controlling the pressure applied improves the control of the welding process. This can be achieved, in particular, by controlling the pressure of the fluid medium.

[0089] Some of the main advantages of the methods, devices and arrangements according to the invention or its advantageous embodiments are explained in more detail below.

[0090] Only simple and inexpensive equipment is required.

[0091] It is possible to use a continuous process.

[0092] For example, one or more infrared light sources could be arranged inside a transparent tube, and this tube can be moved over the workpiece.

[0093] A movement of at least one infrared light source, the clamping element, or a joint movement of at least one infrared light source and the clamping element, e.g. according to the preceding configuration, allows a simple way of applying a continuous welding process.

[0094] The tube could be rigid, e.g. made of glass or similar material. The tube could also be flexible (e.g. made of silicone or polyimide) or similar material.

[0095] Shapes other than a tube are also possible. Preferably, the clamping element is designed as a rolling body. The clamping element could also consist of a chain of rigid segments that are flexibly linked to one another (like tank tracks).

[0096] Pressure exerted on the clamping element, which is designed as a tube or similar rolling body, can be transferred as welding pressure to the workpiece parts to be joined during rolling or other movement.

[0097] The interior of the movable clamping element, designed, for example, as a rolling element or the like, could serve as a fluid medium channel or have one or more fluid medium channels. This would allow, for example, temperature control of the tube.

[0098] Particularly when using flexible material for the tube or other rolling element, the tube or similar component could be pressurized with fluid inside. This allows, in particular, the contact pressure to be controlled.

[0099] Advantageously, in embodiments of the invention, one or more infrared light sources are arranged inside a transparent, flexible tube. By moving such a tube, contact pressure can be applied over larger surfaces during continuous welding. The tube is preferably made, at least partially, of a flexible material such as silicone, polyimide, or another film material, such as that used for vacuum packaging films, which are also used in the production of fiber-reinforced composite components. Preferably, materials with a temperature resistance above the melting point of the thermoplastic material of the first workpiece are used. Alternatively, the tube can be cooled by a cooling fluid.

[0100] The pressure inside the tube is preferably set to a value of 1 to 10 bar, more preferably 4 to 8 bar. A welding force is applied to the tube and transferred to the workpiece parts to be joined.

[0101] It is also possible to use a semi-continuous process.

[0102] No elaborate protection is necessary – unlike, for example, with lasers.

[0103] No special tool with high-speed movements and pressure applications, as required in previously common infrared welding processes, is necessary.

[0104] Specifically for industrial applications, this technology allows welded joints to be used even where access is limited.

[0105] In addition, there are advantages that longitudinal connections, especially in fuselages or other components of aircraft, can be provided without drilling and without cutting frames or other structural elements.

[0106] The following explains the advantages of the method, the device and the arrangement according to the invention and / or its advantageous embodiments compared to previously known infrared welding methods.

[0107] In embodiments of the invention, one of the workpiece parts to be joined becomes flexible during the welding process – particularly due to the thermoplastic material. This allows workpiece parts with tolerances to be joined.

[0108] There is no need for rapid switching between steps of the procedure.

[0109] There is no need for intermediate cooling of workpiece parts.

[0110] There is no need for high-speed movement of parts.

[0111] No complex tools or devices are required for movement. Welding of complex parts is also possible with embodiments of the invention.

[0112] The following explains some advantages of the method, the device and the arrangement according to the inventive and / or advantageous embodiments compared to laser beam welding: The infrared light source for generating the infrared light radiation used here is more cost-effective and far simpler than a laser, such as is required for welding.

[0113] It is possible to use wavelengths in the range between 1000 and 2000 nm (especially wavelengths in the IR-B or IR-C range) with a higher energy penetration rate or energy penetration rate in the thermoplastic workpiece part to be joined.

[0114] No specific protective equipment against the radiation is necessary.

[0115] Simultaneous heating of the entire welding area is possible with simple equipment.

[0116] In comparison to conduction welding known from, for example, [3], the method, apparatus and arrangement of the invention and / or its advantageous embodiments have in particular the following advantages: The heating energy penetrates the workpiece parts internally not only by conduction, but at least partially also by means of light energy transmission.

[0117] A significant reduction in heating time is possible.

[0118] Welding is carried out with increased efficiency.

[0119] The infrared transmission welding technology shown here could be applied to various areas, such as: Longitudinal and circumferential connections; welding of clips, clamps, flanges, and fasteners to a vehicle body; welding of clips, clamps, flanges, and fasteners to a frame element; welding of frame elements; welding of a frame foot to a body element; welding of stringers or braces to a body element; welding of window frame structure components; welding of door surround structure components; welding of floor structures; welding of brackets, stirrups, and retaining elements; welding of coupling elements such as frame couplings, stringer couplings, etc.

[0120] Exemplary embodiments of the invention are explained in more detail below with reference to the accompanying drawings. These show: Fig. 1 a schematic sectional view of a first embodiment of a transmission welding arrangement for carrying out a transmission welding process in which a first workpiece part and a second workpiece part are welded together to form a workpiece; Fig. 2 a schematic sectional view comparable to the Fig. 1 a second embodiment of the transmission welding arrangement; Fig. 3 a schematic sectional view comparable to the Fig. 1 the transmission welding arrangement during the transmission welding process, wherein thermoplastic material is melted or plasticized at a welding point where the first workpiece part is to be joined to the second workpiece part; Fig. 4 a schematic sectional view comparable to the Fig. 3 a third embodiment of the transmission welding arrangement; Fig. 5 a schematic sectional view comparable to the Fig. 3 a fourth embodiment of the transmission welding arrangement; Fig. 6 a schematic sectional view comparable to the Fig. 3 a fifth embodiment of the radiographic welding arrangement; Fig. 7 a schematic sectional view comparable to the Fig. 3 a sixth embodiment of the transmission welding arrangement; Fig. 8 a schematic sectional view comparable to the Fig. 3 a seventh embodiment of the transmission welding arrangement; Fig. 9 a schematic sectional view through a first embodiment of the workpiece, the workpiece parts of which are skin elements of an aircraft that are welded together at a longitudinal seam; Fig. 10 another embodiment of the workpiece, wherein a fastening element is welded to a skin element of an aircraft; Fig. 11 another embodiment of the workpiece, wherein a coupling element is to be welded on to connect two structural components of an aircraft; Fig. 12 another embodiment of the workpiece, wherein a stiffening element is to be welded to a skin element of an aircraft; Fig. 13 a highly schematic cross-sectional view through a fuselage component for an aircraft with different examples of welded joints produced using the transmission welding process and the transmission welding arrangement according to the embodiments of the invention; and Fig. 14 a schematic view of a vehicle using an aircraft as an example, showing different possible applications of the transmission welding process and the transmission welding arrangement according to exemplary embodiments of the invention.

[0121] In the Fig. 1 bis 8 Different embodiments of a transmission welding arrangement 10 for carrying out a transmission welding process are shown. The transmission welding arrangement 10 comprises a first workpiece part 12 and a second workpiece part 14, which are to be joined together at a welding point 16 to form a workpiece 18 by means of the transmission welding process, and a transmission welding device 20 for carrying out the welding of the workpiece parts 12, 14 by means of infrared transmission welding.

[0122] At least the first workpiece part 12 or both workpiece parts 12, 14 are formed at least partially, in particular at the weld point 16, from a thermoplastic material.

[0123] The thermoplastic material is preferably a thermoplastic fiber composite material. In one embodiment, at least one of the workpiece parts 12, 14, preferably both workpiece parts 12, 14, has continuous fibers (not shown) in a thermoplastic matrix.

[0124] The first workpiece part 12 is selected from a group that includes a fiber-reinforced plastic component, a component with a thermoplastic matrix, a component with a PPS matrix, a component with a PEKK matrix, a component with a PEEK matrix, a component with a PA matrix, a component with a PEI matrix, a component with a LM PAEK matrix, a component with a PBI matrix, a component with a PE matrix, a component with reinforcing fibers in the form of a woven fabric, a component with reinforcing fibers in the form of a non-woven fabric, a component with reinforcing fibers in the form of unidirectional fibers, a component with reinforcing fibers in the form of short fibers, a component with reinforcing fibers in the form of continuous fibers, a component with reinforcing fibers made of carbon, a component with reinforcing fibers made of glass or glass materials, and a component with reinforcing fibers made of continuous carbon fibers.A component with reinforcing fibers made of continuous glass fibers; a component with reinforcing fibers made of carbon or glass short fibers; a component with reinforcing fibers made of aramid fibers; a component with reinforcing fibers made of silk; a component with reinforcing fibers made of fibers from a biological source; a component with reinforcing fibers made of ceramics; and a component made of continuous fibers, as well as any combinations of these material specifications. Examples of fibers from a biological source would be, for example, silk or spider fibers.

[0125] The second workpiece part 14 is selected from a group that includes a fiber-reinforced plastic component, a component with a thermoplastic matrix, a component with a PPS matrix, a component with a PEKK matrix, a component with a PEEK matrix, a component with a PA matrix, a component with a PEI matrix, a component with a LM PAEK matrix, a component with a PBI matrix, a component with a PE matrix, a component with reinforcing fibers in the form of a woven fabric, a component with reinforcing fibers in the form of a non-woven fabric, a component with reinforcing fibers in the form of unidirectional fibers, a component with reinforcing fibers in the form of short fibers, a component with reinforcing fibers in the form of continuous fibers, a component with reinforcing fibers made of carbon, a component with reinforcing fibers made of glass or glass materials, and a component with reinforcing fibers made of continuous carbon fibers.a component with reinforcing fibers made of continuous glass fibers; a component with reinforcing fibers made of carbon or glass short fibers, a component with reinforcing fibers made of aramid fibers, a component with reinforcing fibers made of silk, a component with reinforcing fibers made of fibers from a biological source, a component with reinforcing fibers made of ceramics, and a component made of continuous fibers, as well as any combinations of these material specifications.

[0126] The transmission welding device 20 has a clamping device 22 for clamping the first workpiece part 12 and the second workpiece part 14 and an infrared light source 24 for generating simple infrared light radiation, i.e. not laser radiation but polychromatic and incoherent infrared light radiation.

[0127] The clamping device 22 has a clamping element 26, a counter clamping element 28 and a clamping force generation device 30 indicated by arrows, by means of which the clamping element 26 can be moved relative to the counter clamping element 28 and by means of which a clamping pressure can be generated between the clamping element 26 and the counter clamping element 28.

[0128] The clamping element 26 is made of a material transparent to infrared light radiation 32, at least in the area where it grips the first workpiece part 12. The clamping element 26 has a clamping surface 34, by means of which it grips the first workpiece part 12, and a back surface 36 opposite the clamping surface 34. Between the clamping surface 34 and the back surface 36, the clamping element 26 is transparent to infrared light radiation 32, at least in certain areas.

[0129] The infrared light source 24 is arranged on the back 36 and is designed to direct the infrared light radiation 32 through the clamping element 26 onto the first workpiece part 12.

[0130] In some configurations, especially as they are in the Fig. 1 bis 5 As shown, the clamping element 26 is made of a rigid material, such as glass, in particular temperature-resistant glass, and can be designed as a clamping jaw or pressure plate.

[0131] In other configurations, such as in Fig. 6 As shown, the clamping element 26 is formed at least in one area, in particular in an area that at least partially forms the clamping surface 34, from a flexible material, such as a silicone-containing material, and thus has, for example, a flexible skin area for contact with the workpiece 18, in particular with the first workpiece part 12.

[0132] In a design such as that in Fig. 4 As shown, the clamping element has at least one fluid cavity 38 for a fluid medium 40. In particular, several channels 42 are formed through which fluid medium 40 flows. The fluid medium can be temperature-controlled by a temperature control device comprising a heating and / or cooling device and can be pressurized to a controlled fluid pressure by means of a pump or similar pressure-generating device. In this embodiment according to Fig. 4 The clamping element 26 can be made at least partially of flexible material instead of rigid material.

[0133] In the Fig. 1 bis 4 In the embodiments shown, the clamping element 26 is designed as a pressure plate or clamping jaw. In the embodiments shown in the Fig. 5 and 6In the illustrated embodiments, the clamping element 26 is designed as a rolling body 90, for example in the form of a ball, a cylinder, a roller, or a tube 92, which is rotatable about an axis of rotation. In these embodiments, the clamping surface 34 is formed on the outer circumference of the rolling body 90, while the inner side of the rolling body 90 forms the rear side 36. The at least one infrared light source 24 is arranged inside the rolling body 90 in these embodiments. In the embodiments according to the Fig. 7 and 8 The clamping element has 26 rigid components and flexible components.

[0134] In some embodiments, the counter-clamping element 28 is designed as a fixed base or support, for example as a clamping table or as a smaller fixed support. The clamping force generation device 30 is designed to move the clamping element 26 against the counter-clamping element 28 with a defined force.

[0135] In a larger embodiment, the counter-clamping element 28 can be fixedly attached to a machine table, while the clamping element 26 can be moved against the counter-clamping element 28 by means of a hydraulic or pneumatic cylinder or another actuator, for example, an electric motor with a threaded rod. In another, particularly simple and compact, transmission welding device 20, the clamping element 26 and the counter-clamping element 28 can be designed as jaws of a type of frame.

[0136] In embodiments of the transmission welding device 20 that are particularly well suited for carrying out a continuous transmission welding process, the transmission welding device 20 has a movement device 94 for moving the clamping element 26 relative to the counter clamping element 28 and thus for moving the clamping element 26 over the workpiece 18. Examples of these embodiments are described in the Fig. 5 bis 8 depicted.

[0137] Fig. 1 Figure 1 shows a first embodiment of the transmission welding arrangement 10, wherein the first workpiece part 12 and the second workpiece part 14 lie directly on top of each other, and the infrared light radiation 32 is emitted in a spectrum with wavelengths in a range for which the first workpiece part 12 is transparent at least up to 2%, more preferably 10 to 20%, and most preferably up to 30%. The remaining infrared light radiation 32 is absorbed in the first workpiece part 12 and converted into heat, which softens the thermoplastic material of the first workpiece part 12. The welding energy reaches the weld point 16 partly by conduction. Part of the infrared light radiation 32 also reaches the weld point 16 by transmission, which is formed here on the clamped sides or surfaces of the workpiece parts 12 and 14.

[0138] As in Fig. 3 As shown, this leads to a melting of the thermoplastic material at the weld point 16, so that welding is possible.

[0139] Fig. 2 Figure 1 shows an embodiment of the transmission welding arrangement where an additional layer 44 is provided between the workpiece parts 12 and 14. The additional layer 44 can be made of thermoplastic material and thus provide additional molten material for welding. Other additional layers 44 are also conceivable; for example, the additional layer 44 can consist of a material to be laminated or a functional layer.

[0140] In both embodiments according to Fig. 1 and 2 During welding, the process occurs in Fig. 3 The situation shown is one in which either the thermoplastic material of the workpiece parts 12, 14 or the thermoplastic material of the workpiece parts 12, 14 and the additional layer 44 at the weld point 16 has melted due to the infrared light radiation 32, which is partly transmissive and partly conducted to the weld point 16.

[0141] Fig. 4 The design with the fluid cavities 38 formed as channels 42 is shown.

[0142] Here, heated fluid medium 40 can be passed through before the welding process is carried out in order to preheat the transmission welding arrangement and in particular the workpiece parts 12, 14.

[0143] If the clamping element 26, as described above, is at least partially made of flexible material, the contact pressure of the clamping element 26 can be controlled at different areas of the clamping surface 34 by controlling the pressure of the fluid medium 40.

[0144] After welding, the cooling and thus the consolidation of the molten material at the weld point 16 can be controlled by targeted temperature regulation of the fluid medium 40. For example, reheating can be applied, or targeted cooling can be used.

[0145] In another procedure, cooled fluid medium 40 is used to cool the side of the first workpiece part 12 opposite the weld point 16, so that the melting of the thermoplastic material takes place closer to the weld point 16.

[0146] Features of the in Fig. 4 The illustrated embodiment thus comprises a fluid medium system (not shown) with a pressure generator, for example a pump or a pressurized medium reservoir, preferably automatically controlled valves, and a preferably automatically controlled temperature control device – e.g., a heating and / or cooling device. The fluid medium system can include a hydraulic circuit for oil or water or a compressed gas system, for example a compressed air source for supplying compressed air, cooling air, and / or heating air.

[0147] Some embodiments of the transmission welding device 20 have a control system for controlling the infrared light source 24, the clamping force generating device 30 and, if applicable, the fluid medium system and / or the motion device 92.

[0148] At the in Fig. 5 In the fourth embodiment shown, the clamping element 26 is designed as a rolling body 90 in the form of a tube 92 made of a rigid material, such as glass in particular, which is transparent to infrared light radiation 32, and one or preferably more infrared light sources 24 are arranged inside the tube 92 along its length. The tube 92 is rotatably mounted (not shown) and can be moved over the first workpiece 12 by means of the movement device 94.

[0149] The in Fig. 6 The fifth embodiment shown corresponds essentially to the fourth embodiment, with the differences that the tube 92, at least in the area of ​​the clamping surface 34, is formed from a flexible material such as silicone or polyimide (e.g., Kapton® film) or vacuum packaging film. The interior of the tube 92 serves as a fluid cavity 38, into which a fluid medium—in particular, temperature-controlled air at a controlled pressure—can be introduced by a fluid medium system of the type mentioned above (not shown in detail).

[0150] In the embodiments of the Fig. 5 bis 7 The clamping element 26, together with at least one infrared light source 24, can be moved over the workpiece 18 in order to continuously weld a larger welding area 96. The welding area 96 has, according to Fig. 5 bis 8 the weld point 16 with the material that has just melted and, in the direction of movement behind the weld point 16, zones 96a and 96b that are already cooling.

[0151] In the designs according to the Fig. 7 and 8 The clamping element has 26 rigid segments 98a, 98b, 98c, 98d of varying thicknesses. The thickness of segments 98a-98d is adapted to the topology of the first workpiece part 12. Unevenness and varying heights on the surface of the first workpiece part 12 can thus be compensated for by the rigid segments 98a-98d, resulting in pressure surface areas 100a-100e that are arranged at approximately the same height.

[0152] In the design according to Fig. 7 The clamping element 26 further comprises the flexible tube 92, which rests on these pressure surface areas 100a to 100e under the influence of internal pressure 102 in the tube 92 - e.g. set by means of the fluid medium 40 - and exerts pressure.

[0153] In the design according to Fig. 8 The clamping element 26 has a vacuum packaging film 104. The area between the vacuum packaging film 104 and the first workpiece part 12 can be evacuated by a pump (not shown) or the like, so that the clamping pressure 46 is exerted by the vacuum. At the same time, the flexible vacuum packaging film 104 connects the different rigid segments 98a-98d.

[0154] Furthermore, the design of the Fig. 7 and 8 A separating film 106 is provided between the clamping element 26, in particular between the rigid segments 98a-98d and the surface of the first workpiece part 12, which prevents the clamping element 26 or parts thereof, in particular the segments 98a-98d, from adhering to the first workpiece part 12.

[0155] In the embodiments of the Fig. 7 and 8The clamping element 26 thus comprises a combination of rigid and flexible elements. This is particularly advantageous for performing welding along a welding area 96, 96a, 96b with varying workpiece topology 18. A release film 106 (e.g., made of Kapton® or silicone, ...) prevents adhesion.

[0156] Rigid segments 98a-98d with adapted thickness are provided for the transmission of the mechanical pressure 46 to the uneven surface of the workpiece 18.

[0157] In the design according to Fig. 7 The mechanical pressure 46 is applied to the pressure surfaces 100a-100e via the flexible tube 92 to apply a welding force, and thus via the segments 98a-98d or also in certain areas directly onto the workpiece 18.

[0158] Fig. 8 Figure 1 shows another way of generating the clamping force and mechanical pressure. Here, the mechanical pressure 46 is generated by a vacuum. The clamping force generation device 30 therefore includes a pump (not shown) or the like. Instead of the flexible tube 92, the clamping element 26 has the vacuum packaging film 106, with which the clamping force generated by the vacuum is applied.

[0159] In all embodiments of the transmission welding arrangement 10, simple, i.e. polychromatic and incoherent infrared light radiation is directed through the clamping element 26 and at least partially through the first workpiece part 12 to the welding point 16.

[0160] The following describes a configuration of the transmission welding process, as it is used in the embodiments of the Fig. 1 bis 4 This is explained in more detail using the individual process steps.

[0161] Both parts to be joined - first workpiece part 12 and second workpiece part 14 - are positioned relative to each other in the clamping device 22, which is designed, for example, as a clamping device.

[0162] The upper part of the clamping device 22 shown at the top in the figures - the clamping element 26 - should be transparent to infrared light radiation and possibly flexible.

[0163] As in Fig. 2 As shown, at least one additional layer – an additional layer 44 – e.g., a matrix layer – could be placed between the workpiece parts 12 and 14 to be joined. An additional layer could also be integrated into one of the two workpiece parts 12 and 14 before welding.

[0164] Subsequently, a mechanical pressure 46 is exerted via the clamping device 22 through the clamping element 26 and the counter-clamping element 28. The clamping element 26 serves, for example, as a transparent part for applying the pressure. The counter-clamping element 28 is, for example, a fixed base or part of a clamping mechanism.

[0165] The infrared light source 24 is then positioned above the transparent clamping element 26.

[0166] Infrared heating is applied as a heat source through the transparent clamping element 26 to the outer surface of the first workpiece part 12.

[0167] The infrared light radiation heats the first workpiece part 12, partly in the form of surface heating and partly as penetrating heating energy due to transmission in the first workpiece part 12 up to the connection area 48 - i.e. the weld point 16 - between the workpiece parts 12, 14.

[0168] The connection area 48, and thus the welding point 16, is heated over a large area.

[0169] The energy of the infrared light radiation 32 – infrared heating – leads to the heating of the connection area 48 – weld point 16 – and to the melting of the material of the workpiece parts 12, 14 or, if applicable, the filler layer 44. The transmission welding arrangement 10 with correspondingly molten material at the weld point 16 on the connection area 48 is in Fig. 3 depicted.

[0170] Fig. 4 shows an optional possibility of infrared transmission welding with heating support by fluid medium 40.

[0171] One of the elements 26, 28 of the clamping device 22, by means of which the workpiece parts 12, 14 are clamped together, - or both clamping elements 26, 28 - could have one or more channels 42 as fluid cavities 38.

[0172] During the welding process, a fluid medium 40 could be provided in these channels 42 to improve the temperature and pressure distribution during welding.

[0173] If - as in the design in Fig. 4 If the clamping element 26, through which the infrared light radiation 32 of the infrared light source 24 is guided, is provided with channels 42 for the fluid medium 40, then it is advantageous if the fluid medium 40 is also at least partially or at least largely transparent to the infrared light radiation 32.

[0174] This is achieved in a design using high-temperature resistant oil or water as the fluid medium 44.

[0175] The temperature of this fluid medium 44 is then controlled. This allows the heating time to be reduced by preheating the fluid medium 44, the welding time to be reduced by additional heating of the fluid medium 44, and / or a better crystallinity rate to be achieved by post-heating or by controlling the cooling rate.

[0176] In a design of the in Fig. 4 In the illustrated embodiment of the transmission welding arrangement 10, the clamping element 26, 28, provided with the channels 42, and in particular the transparent clamping element 26, is formed from a flexible material, at least in the area of ​​the clamping surface 34. A suitable material that is also transparent to infrared light radiation 32 would be silicone or polyimide. Other flexible materials can also be provided for the counter clamping element 28 to define the channel 42 and to form the counter clamping surface 34, if the channels 42 or a portion thereof are provided in the counter clamping element 28.

[0177] In this configuration, the pressure of the fluid medium 40 within the channels 42 is controlled – in particular, individually for each channel 42. This allows the pressure to be controlled across the clamping surface 34 and thus across the entire welding area – connection area 48 / weld point 16.

[0178] Furthermore, the pressure can be controlled during the welding process in order to improve the control of the welding process by controlling the welding pressure using the fluid medium 40.

[0179] The following describes preferred embodiments of a continuous transmission welding process, as used in the embodiments of the transmission welding device 20 of the Fig. 5 bis 8 This is explained in more detail using the individual process steps.

[0180] First, the first workpiece part 12 and the second workpiece part 14 are positioned relative to each other in the clamping device 22, e.g., placed on top of each other on the counter-clamping element 28, which is designed as a support. As above. Fig. 3 As explained, the additional layer 44 can also be optionally inserted here, even if it is in Fig. 5 bis 8 not shown.

[0181] Subsequently, the design of the Fig. 5 and 6The tube 92 with the clamping force generating device 30 is pressed onto the first workpiece 12 to generate the mechanical pressure 46. The infrared light sources 24 are switched on to direct the infrared light radiation 32 through the tube 92 onto the first workpiece part 12. The effects are the same as described above for the embodiments of the transmission welding process based on the Fig. 1 bis 4 described. Accordingly, the material is melted at weld point 16.

[0182] The clamping element 26, designed as a rolling body 90, is then moved across the surface of the first workpiece part 12 by means of the movement device 94. The rolling body 90 rolls on the surface and, with its clamping surface 34, continues to exert the mechanical pressure 46 on the workpiece 18 as welding pressure. The infrared light sources 24 arranged inside the tube 92 are moved accordingly. Thus, the welding area 96 is welded continuously.

[0183] At the in Fig. 6 In the illustrated embodiment, the active area of ​​the clamping surface 34 can be adjusted by adjusting the clamping force and pressure inside the tube 92, due to the flexible material. As a comparison of the Fig. 5 and 6 This shows that a larger surface area of ​​the workpiece 18 can thus be subjected to mechanical pressure. A similar effect could also be achieved by a clamping element 26 supported in the manner of tank tracks.

[0184] In the case of one with the configurations according to Fig. 7 and 8 In the feasible procedure, the separating film 106 is first laid down. Height differences are compensated for by rigid segments 98a-98d of corresponding thickness.

[0185] Then, in Fig. 7 - as above Fig. 6 As described, the flexible tube 92, together with the infrared light source 24, is moved over the workpiece 18. The contact pressure is controlled by the internal pressure 102 in the flexible tube 92.

[0186] In the procedure according to Fig. 8 The vacuum packaging film 104 is placed on the rigid segments 98a-98d and the workpiece. The space between the vacuum packaging film 104 and the workpiece 18 is evacuated to exert the mechanical pressure 46. Subsequently, the infrared light source 24 is moved over the workpiece 18 by means of the motion device 94 to perform the continuous welding.

[0187] Various trials to perform the transmission welding process have been successfully conducted.

[0188] First, transmission tests were conducted on various thermoplastic fiber-reinforced composites. Specifically, a fiber-reinforced composite material with unidirectional glass fibers, with sample thicknesses of 0.7 mm, 1.2 mm, 2.6 mm, and 2.9 mm, was examined using infrared radiation of different wavelengths. All of these samples showed a significant increase in transmission above 1000 nm, with a peak at approximately 1600 nm, and also good transmissivity values ​​at wavelengths in the range of 1650 nm to 2000 nm. Other thermoplastic materials, such as PEEK and PPS, including those reinforced with carbon or glass fibers, were also investigated. For all of these, the transmission was found to be low at a standard laser wavelength of 940 nm for a standard diode laser. With this type of laser radiation, the majority of the radiation is absorbed very quickly in the first part of the workpiece.Only through conduction heat is the second workpiece part 14 melted by such laser radiation. This often leads to the first workpiece part 12 being completely melted, thus making a defined joining difficult.

[0189] It is therefore desirable to weld at wavelengths in the range around 1600 nm, where thermoplastic materials exhibit greater transparency.

[0190] The highest transmittance of currently used thermoplastic materials lies in the range of 1000 nm to 1600 nm. However, there are no welding lasers on the market that emit in this range, and very expensive specialized laser devices would be necessary. According to DIN 5031, infrared radiation is classified into IR-A with a wavelength of 0.78 to 1.4 µm, IR-B with a wavelength of 1.4 to 3.0 µm, and IR-C with wavelengths of 3 to 50 µm and 50 to 1000 µm. IR-A and IR-B represent the near-infrared range. IR-A is the short-wavelength part of the near-infrared range (abbreviation: NIR). The 780 nm limit is due to human vision being adapted to the solar spectrum. IR-B radiation represents the long-wavelength region of the NIR range. The boundary between IR-A and IR-B is due to water absorption at 1450 nm.

[0191] Infrared radiation (IR-C) can be divided into the mid-infrared (MIR) range of 3 to 50 µm and the far-infrared (FIR) range of 50 to 1000 µm. Mid-infrared radiation is the range of thermal radiation at terrestrial temperatures. Far-infrared radiation is strongly absorbed by the atmosphere.

[0192] Particularly preferred, based on the above considerations regarding the transmittance of certain wavelengths in thermoplastic materials, is an infrared light source 24 which emits IR-B and / or IR-C radiation.

[0193] The short-wave infrared (SWIR) range IR-B extends from 1.4 to 3 µm. This range is relatively safe for the eyes, as such light is absorbed in the eye before it can reach the retina.

[0194] For the tests, an infrared lamp with a power of 400 W from an Adler type infrared heater (serial number 1803 with a total power of 2x400 W, at an operating voltage of 220 to 240 V and an operating current frequency of 50 / 60 Hz) was used.

[0195] This type of infrared lamp has a ceramic infrared source. The infrared source is designed as a compact rod. The exact spectrum has not been investigated, but it is expected to be in the IR-B range, specifically between 1000 and 1600 nm.

[0196] Of the two lamps in this radiant heater, only one was used.

[0197] Furthermore, this lamp has an upper reflector, so that the infrared light radiation is directed to one side.

[0198] The lamp emits light at a constant energy level.

[0199] Clamping clamps were used as the clamping force generating device 30, which generates a clamping force by means of mechanical springs. The exact clamping force was not measured.

[0200] A glass plate with a thickness of approximately 1.5 mm was initially used as the transparent clamping element 26.

[0201] In a first example test, the first workpiece part 12 was a piece of fiber composite material with unidirectional glass fibers in a PEKK matrix and a thickness of 1.2 mm.

[0202] The second workpiece part 14 was a strip of fiber composite material with unidirectional carbon fibers in a PEKK matrix and a thickness of 1.8 mm.

[0203] Then a welding process was carried out, as in Fig. 1 shown, performed with the following welding parameters: Welding energy: 400 W. The entire length of the rod-shaped heating lamp was heated. The spectrum was not measured; it is assumed to be infrared B with a wavelength of 1000 nm to 1600 nm. Only a spring force was applied locally as mechanical pressure. The exact clamping force was not measured. Welding was carried out for 120 s.

[0204] The welding result was then examined. It was shown that the first workpiece part 12 and the second workpiece part 14 had been firmly joined together. Local melting of the first workpiece part 12 was observed.

[0205] A visual comparison with a corresponding sample welded by laser welding showed the same welding performance for infrared transmission welding as for laser transmission welding.

[0206] However, infrared transmission welding has been carried out with significantly more cost-effective equipment - a simple infrared lamp - which does not require specific protective measures, such as a laser.

[0207] As a second test, a continuous welding process according to the embodiment of Fig. 5 The test was carried out using the same workpiece parts 12 and 14 as in the first test. A cylindrical glass tube 92 served as the clamping element 26, through which the aforementioned rod-shaped infrared lamp was inserted as the infrared light source 24. Welding was then performed with the following parameters: The infrared light source 24 was an infrared lamp located inside the tube 92. The infrared lamp had a power output of 400 W and was heated along its entire length. As mentioned above, the exact spectrum is unknown, but it is assumed to be infrared-B radiation (in the range of 1000 to 1600 nm). The tube 92 was made of heat-resistant glass (lantern glass). Mechanical pressure was applied locally. The clamping device with mechanical clamps described above was used. The exact clamping pressure was not measured. The welding time was 120 s.This test also showed good weld quality.

[0208] As a further test, welding through a silicone layer was conducted to assess the material's suitability for use in the clamping element 26. This test was performed under the same conditions as the first test, but using a strip of silicone instead of the glass plate. Again, the materials were welded together, but the results were inferior to those obtained with the glass plate. Therefore, silicone materials should be selected according to their transmittance for the infrared light radiation 32 used. Furthermore, it is advantageous to use silicone materials that are resistant to temperatures exceeding 400°C.

[0209] As a further test, a Kapton® film was used instead of the glass plate from the first trial. This yielded very good results, demonstrating that Kapton® or comparable polyimides are well suited for forming a flexible clamping element. Other vacuum packaging films with correspondingly high temperature resistance can also be used.

[0210] Polyimide is suitable on the one hand as a material for the clamping element 26 or also as a non-stick coating for the clamping element 26, which is made of, for example, glass. Polyimide showed efficient properties as a release film (release film 106) and prevents adhesion of molten thermoplastic material to the surface of the clamping element 26.

[0211] In a further test, workpiece parts 12 and 14 made of the high-performance thermoplastic PEKK, reinforced with continuous carbon fibers, were welded together under the same conditions as described above for the first test. Here too, the same welding performance was achieved as with laser transmission welding.

[0212] Tests have shown that the infrared transmission welding process described here, using simple polychromatic, incoherent infrared light, is suitable for various materials. Welding of test materials with continuous carbon fibers, continuous glass fibers, and short glass fibers as fiber reinforcement was successfully carried out. The welding process is also suitable for materials with short carbon fibers and various other fibers, such as aramid, silk, or other bio-producible fibers, both as long or continuous fibers or as short fibers, as fiber reinforcement. Welding of test materials with PEKK and PPS matrices was also successfully performed. The process is also suitable for LM PAEK, PEEK, PEI, PBI, PA, PE, etc., as matrices.

[0213] The following will be based on the Fig. 7 bis 12 Different possible applications for the previously explained configurations of the infrared transmission welding process and the previously explained transmission to welding devices are explained in more detail 20.

[0214] Fig. 1 shows a first possible application scenario in which the first workpiece part 12 and the second workpiece part 14 are continuously welded together in a butt joint.

[0215] Fig. 9 Figure 1 shows an embodiment of workpiece 18, wherein the first workpiece part 12 and the second workpiece part 14 are, for example, a first skin element 50 and a second skin element 52 of a Fig. 13 und 14 The vehicle depicted is in the form of an aircraft trained as Aircraft 54. The in Fig. 9 Indicated welding can be used for longitudinal connections 58 as well as circumferential connections 60 of skin elements 50, 52 or of other fuselage components 62 or of wing components 64 of the aircraft 54.

[0216] In Fig. 9 The connection area 48 is shown as a dashed oval. Two workpiece parts 14, 49 in the form of skin elements 50, 52 are to be butt-jointed. In the application example of Fig. 9 The first workpiece part 12 is a reinforcing strip 66 made of thermoplastic fiber composite material, which covers the butt joint between the second workpiece part 14, designed as the first skin element 50, and a third workpiece part 49, designed as the second skin element 52. The skin elements 50 and 52 are, for example, made of thermoplastic carbon fiber reinforced polymer (CFRP / TP) composite material. The reinforcing strip 66, which acts as a doubler, is, for example, made of unidirectional glass fibers in a thermoplastic matrix or is a carbon fiber reinforced strip with a thermoplastic matrix.

[0217] Welding can be done, for example, from the right into Fig. 9 The process is carried out from the perspective of the person through the reinforcement strip 66. That is, a transparent clamping element 26 is placed on the reinforcement strip 66, and the infrared light radiation 32 is directed through the clamping element 26 and the reinforcement strip 66 into the butt joint 68 between the skin elements 50, 52 in order to weld the skin elements 50, 52 together. Simultaneously, the skin elements 50, 52 are welded to the reinforcement strip 66.

[0218] Fig. 10 Figure 1 shows another possible application example, where the first workpiece part 12 is a fastening element 70 and the second workpiece part 14 is a skin element 50 or a frame element 72 of the aircraft 56.

[0219] Fastening element 70 can be, for example, a clip, a mounting plate, a flange, a hook, a mounting eyelet, or the like. Fastening element 70 is, for example, made of thermoplastic glass fiber composite material. The glass fibers can be short fibers, unidirectional fibers, or continuous fibers. Alternatively, the fastening element can be made of thermoplastic carbon fiber composite material. Here, too, the carbon fibers can be unidirectional, short fibers, or continuous fibers.

[0220] Possible materials for the frame element 72 or the skin element 50 are, as before, carbon fiber composites with a thermoplastic matrix. The same principle as with Fig. 10 It can also be used for welding on brackets or attachments.

[0221] Fig. 11 Figure 1 shows another application scenario in which a coupling part 74 is welded to a skin element 50 or a frame element 72 as the second workpiece part 14. The coupling part 74 can then be used to couple a further frame element 76 or a second skin element 52.

[0222] Possible materials for the coupling part 74 are thermoplastic materials with glass or carbon fibers. The fibers can be unidirectional, continuous, or in the form of woven or non-woven fabrics.

[0223] The frame element 72 can, for example, be a stiffening element, such as a stringer 80 or a rib (not shown). Preferred materials for this are again carbon fiber composites with a thermoplastic matrix. The same principle as in Fig. 11 It can also be used for coupling other components, such as floor struts, seat rails, bearings, door frame and window frame parts, or the like.

[0224] Fig. 12 Figure 1 shows another application scenario, in which a stiffening element 78, for example a stringer 80 - example of a frame element 72 - is welded to a skin element 50 as the second workpiece part 14 as the first workpiece part 12.

[0225] Fig. 13 Figure 1 shows a highly schematic cross-section through a fuselage component 62 of the aircraft 54 ​​with the stringer 80, a bottom element 86 and a retaining bracket 88 as examples of workpiece parts 12 which are to be joined to a frame element 52 or a skin element 50 of the fuselage component 62 by means of the transmission welding process.

[0226] Fig. 14 Figure 54 shows a side view of aircraft 54 ​​as an example of aircraft 56 with different possible applications for connections produced by the transmission welding process. For example, parts 82 that form a structure around a door 84 can also be welded.

[0227] Above, arrangements, devices and methods for infrared transmission welding have been proposed and described using exemplary embodiments.

[0228] This proposes a new technology that combines the advantages of laser transmission welding, conduction welding and conventional infrared welding, and can be carried out with simple equipment.

[0229] The proposed technology can be applied to various connections. Examples include the integration of stiffening elements 78, such as stringers 80, joints and couplings, the integration of frames and fasteners 70, and the integration of brackets and supports 88.

[0230] The technology was successfully tested with very simple equipment, demonstrating its weldability. It was shown that infrared energy can transmit through the thermoplastic first workpiece component all the way to the connection area 48.

[0231] It has been shown that even high-performance thermoplastic materials, such as PEKK, with fiber reinforcement and melting temperatures around 330 °C can be welded.

[0232] It has been shown that transmission welding through a transparent clamping element 26, such as a glass plate, is possible.

[0233] It was also shown that clamping force can be applied simultaneously by the clamping element 26. Bezugszeichenliste:

[0234] 10 Transmission welding arrangement 12 First workpiece part 14 Second workpiece part 16 Weld point 18 Workpiece 20 Transmission welding device 22 Clamping device 24 Infrared light source 26 Clamping element 28 Counter clamping element 30 Clamping force generating device 32 Infrared light radiation 34 Clamping surface 36 Back side 38 Fluid cavity 40 Fluid medium 42 Channel 44 Filler layer 46 Mechanical pressure 48 Joint area 49 Third workpiece part 50 First skin element 52 Second skin element 54 Aircraft 56 Aircraft 58 Longitudinal joint 60 Circumferential joint 62 Fuselage component 64 Wing component 66 Reinforcing strip 68 Butt joint 70 Fastening element 72 Frame element 74 Coupling part 76 Further frame element 78 Stiffening element 80 Stringer 82 Part of a surrounding structure for door 84 Door 86 Floor element 88 Retaining bracket 90 Roller body 92 Tube 94 Movement device 96 Welding area 96a Warmer zone of the welding area 96b Colder zone of the welding area 98a First rigid segment 98b Second rigid segment 98c Third rigid segment98d fourth rigid segment 100a first printing area 100b second printing area 100c third printing area 100d fourth printing area 100f fifth printing area 102 inner print 104 vacuum packaging film 106 separating film

Claims

1. Transmission welding method for welding a first workpiece part (12), which is formed at least partially from thermoplastic material, to at least one second workpiece part (14) at a weld point (16), comprising: a) bracing the first workpiece part (12) and the second workpiece part (14) by means of at least one bracing element (26) which is at least partially transparent to the infrared light radiation (32); b) directing polychromatic, incoherent infrared light radiation (32) through the bracing element (26) to the first workpiece part (12), and through the first workpiece part (12) to the weld point (16), wherein at least one region of the first workpiece part (12) or the entire first workpiece part (12) is formed from a thermoplastic fibre composite material and the infrared light radiation (32) is directed through the fibre composite material to the weld point (16), characterized by c) setting a temperature of the bracing element (26) before, during and / or after step b) in order to influence the temperature of at least one region of the workpiece (18) .

2. Transmission welding method according to Claim 1, characterized by 2.1 generating the polychromatic, incoherent infrared light radiation (32) by an infrared lamp; and / or 2.2 generating the infrared light radiation (32) in a wavelength range from 1.0 to 3.0 µm.

3. Transmission welding method according to one of the preceding claims, characterized by: 3.1 moving the infrared light radiation (32) over the first workpiece part (12) in order to weld the workpiece parts (12, 14) continuously along a welding region; and / or 3.2 moving an infrared light source generating the infrared light radiation over the first workpiece part (12) around the workpiece parts (12, 14) along a welding region.

4. Transmission welding method according to one of the preceding claims, characterized in that step a) comprises: 4.1 pressing the bracing element (26) onto the first workpiece part (12); and / or 4.2 using a pressure plate or bracing jaw as bracing element (26).

5. Transmission welding method according to one of the preceding claims, characterized in that step a) comprises: using a bracing element (26) composed of a material selected from the group of materials which comprises a flexible material, a rigid material, glass, transparent plastic, polyimide, vacuum packaging film and silicone, and also combinations of these materials.

6. Transmission welding method according to one of the preceding claims, characterized in that step a) comprises: 6.1 using a bracing element (26) having at least one fluid medium cavity (38) filled or fillable with a fluid medium (40); 6.2 using a flexible bracing element (26) and controlling the contact pressure of the flexible bracing element (26) by means of a pressure fluid.

7. Transmission welding method according to Claim 6, characterized in that step a) and / or step c) comprises at least one or a plurality of the following steps: 7.1 using a bracing element (26) with at least one channel (42) and conducting a temperature-controlled fluid medium (40) through the at least one channel (42); and / or 7.2 conducting a fluid medium (40) that is transparent or transmissive to the infrared light radiation (32) through the bracing element (26); and / or 7.3 controlling a pressure distribution by controlling the pressure of the fluid medium (40).

8. Transmission welding method according to one of the preceding claims, characterized in that step a) comprises: 8.1 moving the bracing element (26) over the first workpiece part (12); and / or 8.2 using a bracing element (26) that is rotatable about an axis of rotation; and / or 8.3 using a bracing element (26) which is roll-shaped, roller-shaped or spherical or in the form of a rolling body (90); and / or 8.4 rolling the bracing element (26) over the first workpiece part (12).

9. Transmission welding method according to Claim 8, characterized in that step a) comprises: 9.1 generating the infrared light radiation (32) in the interior of the bracing element (26) in the form of a rolling body (90); and / or 9.2 moving an infrared light source (24) and the bracing element (26) conjointly over the first workpiece part (12) .

10. Transmission welding method according to one of the preceding claims, characterized by: using a bracing element (26) which has a plurality of rigid segments (98a-98d), which are preferably flexibly articulated to one another, in order to replicate the topology of the first workpiece part (12).

11. Transmission welding method according to any one of the preceding claims, characterized in that step a) and / or step c) comprises at least one or a plurality of the steps: 11.1 preheating the bracing element (26) and the workpiece (18) in order to reduce the heating time for the welding process; and / or 11.2 postheating or cooling the bracing element (26) and the workpiece (18) in order to improve the workpiece quality or the crystallization rate.

12. Transmission welding method according to one of the preceding claims, characterized by one or a plurality of the following steps: 12.1 welding the workpiece parts, in each case selected from the group comprising a fibre-reinforced plastics component, a component with a matrix composed of thermoplastic material, a component with a matrix composed of PPS, a component with a matrix composed of PEKK, a component with a matrix composed of PEEK, a component with a matrix composed of PA, a component with a matrix composed of PEI, a component with a matrix composed of LM PAEK, a component with a matrix composed of PBI, a component with a matrix composed of PE, a component with reinforcement fibres in the form of a woven fabric, a component with reinforcement fibres in the form of a scrim, a component with reinforcement fibres in the form of unidirectional fibres, a component with reinforcement fibres in the form of short fibres, a component with reinforcement fibres in the form of continuous fibres, a component with reinforcement fibres composed of carbon, a component with reinforcement fibres composed of glass, a component with reinforcement fibres composed of continuous carbon fibres, a component with reinforcement fibres composed of continuous glass fibres; a component with reinforcement fibres composed of short carbon or glass fibres, a component with reinforcement fibres composed of aramid fibres, a component with reinforcement fibres composed of silk, a component with reinforcement fibres composed of fibres from a biological source, a component with reinforcement fibres composed of ceramic; 12.2 welding the first workpiece part (12) and the second workpiece part (14) with an overlap or partial overlap; 12.3 welding the first workpiece part (12) and the second workpiece part (14) with a butt joint (68); 12.4 inserting an intermediate layer (44) between the workpiece parts (12, 14) before the welding process.

13. Use of a transmission welding method according to one of the preceding claims for 13.1 generating longitudinal (58) and / or circumferential connections (60) on a vehicle or aircraft fuselage or vehicle or aircraft fuselage component or a vehicle or aircraft component; or 13.2 welding fastening elements (70), brackets, clamps or clips to a fuselage structure or skin of a vehicle or aircraft (56); or 13.3 welding a frame of a vehicle or aircraft (56); or 13.4 welding a skin to a frame on a vehicle or aircraft (56); or 13.5 welding stringers (80) or formers to a skin of a vehicle or aircraft (56); or 13.6 welding structural components to form an enclosure for a door (84) of a vehicle or aircraft (56); or 13.7 welding floor structures of a vehicle or aircraft (56); or 13.8 welding coupling elements (74) for coupling structural elements of a vehicle or aircraft (56).