JOINING PROCESS AS WELL AS PROCESSING HEAD AND PRODUCTION MACHINE FOR CARRYING OUT THE PROCESS

Description

[0001] The invention relates to a joining method for connecting at least two thermoplastic workpieces. Furthermore, the invention relates to a machining head and a production machine for carrying out the method.

[0002] The application of laser technology for joining thermoplastic parts is well known and has been used on an industrial scale for some time, including induction welding, transmission laser welding, or in situ advanced fiber placement technology (AFPT). One example is known from DE 10 2015 110 193 A1. In addition to laser welding technology, a laser evaporation process is disclosed to provide scarf joints as a structurally efficient interface surface.

[0003] Transmission laser welding generally requires that at least one of the joining pieces be largely transparent, allowing the laser to penetrate the part down to the joining surfaces. Laser diffusion and overall heating of the joint are almost unavoidable and can significantly impact the controllability and speed of the joining process. In addition to the requirement for material transparency, this technology is also limited by the thickness of the joining pieces.

[0004] Induction welding, like transmission laser welding, results in overall heating with limitations for process control due to energy coupling into carbon fibers and / or copper braid for lightning protection.

[0005] WO 2004 / 106038 A1 discloses a joining method for pipes made of thermoplastic material.

[0006] US 10 046 511 B1 discloses a fiber laying device in which torques acting on the fiber strips are reduced.

[0007] WO 2015 / 164 954 A1 discloses a 3D printer that can process a first plastic material and a fiber-reinforced second plastic material.

[0008] WO 2014 / 029 969 A1 discloses a fiber laying device in which a flash lamp is used to connect the fiber layers.

[0009] JP 2011 / 0 179 289 A discloses a joining process in which matrix material is removed by laser radiation.

[0010] The invention is based on the object of proposing measures that enable an improved process flow when joining composite components.

[0011] The problem is solved by the subject matter of the independent claims. Preferred developments are the subject matter of the dependent claims.

[0012] The invention provides a joining method for connecting at least two thermoplastic workpieces, which in particular contain or are made of fiber-reinforced plastic, comprising the steps: a) scarfing an edge region on at least one of the workpieces to create at least one scarfing region, wherein the scarfing region is formed in steps by a plurality of workpiece layers of the workpiece, wherein the scarfing region is pretreated by exposing fibers of the workpiece and / or by coating the workpiece with a microstructured functional layer, b) positioning the workpieces relative to one another such that the scarfing region of one workpiece and the other workpiece delimit a seam region, wherein the workpieces are positioned such that a manufacturing gap is formed between the workpieces or the lowest workpiece layers of the workpieces, c) inserting a connecting body into the seam region and heating the part of the connecting body located in the seam region by means of local heat input to form a material-to-material connection between each workpiece and the connecting body,wherein, when inserting a first connecting body layer, the connecting body is pressed by means of a pressing device which grips the connecting body and a counter-pressing device which grips the workpiece, wherein the counter-pressing device extends below and between the workpieces.

[0013] It is preferred that in step a) the sheathing is carried out by appropriate fiber laying, material removal, laser ablation, machining and / or milling.

[0014] It is preferred that in step a) the scarfing area is pretreated by exposing fibers of the workpiece by means of laser surface treatment.

[0015] It is preferred that in step a) the scarfing area is pretreated by plasma-coating the workpiece with a microstructured functional layer.

[0016] It is preferred that in step b) the workpieces are positioned such that the width of the seam area increases or increases stepwise in the direction perpendicular to the workpiece layers.

[0017] It is preferred that in step b) the distance along the direction parallel to the workpiece layers between the workpieces increases or increases stepwise in the direction perpendicular to the workpiece layers.

[0018] It is preferred that in step b) the distance along the parallel direction to the workpiece layers between the lowest workpiece layers is the smallest distance between the workpieces.

[0019] It is preferred that in step b) the manufacturing gap is the smallest distance between the workpieces along the direction parallel to the workpiece layers.

[0020] It is preferred that in step c) the connecting body is pressed against the workpiece by means of a pressing device, in particular a pressing roller, wherein the pressing device preferably grips the connecting body on a connecting body broad side facing away from the workpiece.

[0021] It is preferred that in step c) the connecting body is heated on one, in particular a single, connecting body broad side.

[0022] It is preferred that in step c) a connecting body broad side faces the next lower workpiece layer.

[0023] It is preferred that in step c) the connecting body is heated on at least one, in particular both, narrow sides of the connecting body.

[0024] It is preferred that in step c) the connecting body narrow side faces the next workpiece layer narrow side in the transverse direction of the seam region.

[0025] It is preferred that in step c) a plurality of connecting bodies are inserted layer by layer and heated in order to produce a connecting body layer that is integrally connected to the respective workpiece layer.

[0026] It is preferred that in step c) when inserting a first connecting body layer, the connecting body is pressed by means of a counter-pressing device which grips a lowermost workpiece layer.

[0027] It is preferred that the counter-pressing device comprises a blade which is inserted between the workpieces when the pressing takes place.

[0028] It is preferred that the counter-pressing device has a counter-pressing roller which is arranged opposite the pressing device, in particular at an end region of the sword.

[0029] It is preferred that in step c) when inserting a second or further connecting body layer, the connecting body is pressed against the workpiece, in particular a workpiece layer corresponding to the connecting body layer, only by means of a pressing device which grips the connecting body.

[0030] It is preferred that in step c) the heating is carried out by scanning a laser beam over the seam area.

[0031] It is preferred that, in particular in step c), the manufacturing gap is filled with filler during insertion and heating of a first connecting body layer.

[0032] It is preferred that the connecting body is designed as a flexible connecting band.

[0033] It is preferred that the connecting body contains or is made of a fiber-reinforced plastic that is at most partially cured.

[0034] It is preferred that the connecting body contains or is made of a metal sheet.

[0035] It is preferred that the connecting body contains or is made of a fiber-metal layer.

[0036] It is preferred that the connecting body contains or is made of a multi-layer fiber-reinforced plastic.

[0037] It is preferred that the fiber-reinforced plastic is a carbon fiber-reinforced plastic and / or a glass fiber-reinforced plastic.

[0038] The invention provides a machining head for a manufacturing machine designed to manufacture a fuselage component for a fuselage segment of an aircraft or a fuselage segment for an aircraft, wherein the machining head is designed to join at least two workpieces that contain or are made of fiber-reinforced plastic and comprises a scarfing device designed to scarf an edge region on at least one of the workpieces to create at least one scarf region, an insertion device designed to insert a connecting body into a seam region between the workpieces, an activation device designed to heat the part of the connecting body located in the seam region by means of local heat input, and a pressing device designed to press the heated connecting body against the workpiece,to form a material-to-material connection between each workpiece and the connecting body, wherein the processing head comprises a pretreatment device, wherein the pretreatment device is designed such that a laser beam can be generated and guided to the seam area, wherein the laser beam is designed such that fibers of the workpiece can be exposed due to its irradiation with the laser beam; and / or wherein the pretreatment device is designed such that a microstructured functional layer can be generated on the workpiece, wherein the processing head comprises a counter-pressing device designed to grip the workpiece and press it towards the pressing device, wherein the counter-pressing device extends below and between the workpieces.

[0039] It is preferred that the counter-pressing device is designed to be removable in order to press the connecting body against the workpiece, in particular against a workpiece layer corresponding to the connecting body layer, only by means of the pressing device when inserting a second or further connecting body layer.

[0040] It is preferred that the activation device is designed to heat the connecting body on one, in particular a single, broad side of the connecting body.

[0041] It is preferred that the counter-pressing device is designed to grasp a lowermost workpiece layer and to press it in the direction of the pressing device.

[0042] It is preferred that the pressing device is arranged to grip the connecting body on a connecting body broad side facing away from the workpiece.

[0043] It is preferred that the counter-pressing device has a blade that can be inserted between the workpieces.

[0044] It is preferred that the counter-pressure device has a counter-pressure roller which is arranged opposite the pressure device, in particular at an end region of the sword

[0045] Preferably, the processing head comprises a filler supply device which is designed to supply filler to the seam area, in particular a production gap, so that the seam area can be partially filled with filler when a first connecting body layer is inserted and heated.

[0046] It is preferred that the activation device comprises a laser device which is designed to generate a laser beam for heating and to guide it to the seam area.

[0047] It is preferred that the laser device comprises a scanner module which is designed to scan the laser beam over the seam area.

[0048] The invention further provides a manufacturing machine which is designed to carry out a preferred method and which comprises a preferred machining head.

[0049] Preferably, the production machine comprises a workpiece positioning device which is designed to position workpieces in such a way that a production gap can be generated between the workpieces, in particular the lowest workpiece layers of the workpieces.

[0050] It is preferred that the scarfing device forms the scarfing area in such a way that, after positioning, the width of the seam area increases in the direction perpendicular to the workpiece layers, in particular stepwise and / or continuously.

[0051] It is preferred that the distance along the direction parallel to the workpiece layers between the workpieces increases in the direction perpendicular to the workpiece layers, in particular gradually and / or continuously.

[0052] It is preferred that the distance along the parallel direction to the workpiece layers between the lowest workpiece layers is the smallest distance between the workpieces.

[0053] It is preferred that the manufacturing gap is the smallest distance between the workpieces along the direction parallel to the workpiece layers.

[0054] The invention was made within the project "NEW2025 Multifunctional Fuselage" of the TP194 "Typical and Lower Center Fuselage." In addition to the nose and fuselage, the project focuses on future technologies for typical applications in fuselage components, including system integration and joining concepts.

[0055] The invention can also be used for any seam made of thermoplastic carbon fiber reinforced plastic (CFRP) or thermoplastic coated metal, as well as for fiber-metal laminate (FML) parts or panels. The most suitable application is likely to be the joining of fuselage skins and components, for example, longitudinal seams at the level of larger component production, such as fuselage segments, and circumferential seams at the level of final assembly, such as connecting fuselage segments.

[0056] In contrast to known methods, the invention takes the opportunity to heat the joining surfaces directly by raising one of the joining parts. Similar to the known AFPT process, the laser is directed into an opening gap to locally heat the surface to melting temperature. This prevents resin melting throughout the entire section by limiting the melting zone to the joining surfaces. While CFRP materials, on the other hand, are not amenable to transmission laser welding, the invention enables the application of laser welding processes to CFRP. In contrast to the AFPT process, which lays individual layers, the invention utilizes a set of layers that is sufficiently flexible to leave a gap for the laser.

[0057] The invention leverages the weldability of thermoplastic CFRP materials selected within the project. The invention eliminates CFRP dust during component manufacturing and final assembly, thus enabling cost-effective assembly of pre-equipped fuselage skins and sections. The invention combines existing technologies, such as laser welding and thermoplastic skirt joining, with industrialized automated applications derived from ongoing IWS and Airbus projects. The so-called MuVaX concept is being further developed for integrated seam preparation and joining of metallic structures using friction stir welding for final assembly, allowing only one side to be accessible.

[0058] The method proposed here is inherently robust in application due to the use of a laser for local heating of the weld line in combination with temperature control of the surfaces using thermal cameras during the joining process. In contrast, both transmission laser welding and induction welding rely on predefined process parameters to predict the actual melting temperature in the weld line. However, the melting temperature is a key process parameter for the quality of the joint. Induction welding is therefore less robust in application and cannot necessarily compensate for undetected process parameters, such as local changes in layer thickness. Furthermore, the invention can be used to join other material hull concepts, such as the metal waffle plate design, FML structures, or any other combination with a thermoplastic coating or matrix.

[0059] One important idea is the laser welding of longitudinal thermoplastic joints in component manufacturing. This allows for the joining / connecting of fuselage skins on an industrial scale. It is inherently robust and flexible in application, due, among other things, to the ability to control the surface temperature of the joining surface and the cooling process using thermal cameras. Since the shouldered geometry can accommodate tangential tolerances, the concept allows for the accumulation of geometric tolerances at the part level or during the positioning of the fuselage skin. Since the seam is not heated through its entire thickness, the likelihood of distortions or built-in stresses in the final seam can be reduced.

[0060] The technical setup is similar to AFPT, but uses strips of multilayer CFRP material with different material orientations. Pre-picking the strips on large rolls instead of individual strips can increase the speed of the process and allows the use of simple support and pressing tools to close the joint and control the formation process during the cooling process. The MuVaX system can be adapted to accommodate the laser and the strip material to weld the seam at the component assembly level. Thermal cameras are used to observe the laser heating and the surrounding material temperature to control the cooling process. The industrial setup is suitable for welding thermoplastic joints of hybrid structures, such as FML or waffle plate designs and could also be used outside the aviation industry.

[0061] Procedural steps include in particular: 1) Preparation of a sheared seam by customized fiber placement, laser ablation, or machining; 2) Surface structuring / activation by laser and / or plasma to increase the joint strength; 3) Fixing, edge preparation, and positioning using the MuVaX concept for final production; 4) Laser welding of the first layer with a pressure roller and supporting counterpressure roller, gap filling with thermoplastic filler wire using the laser strip welding unit of the MuVaX system; 5) Laser welding of the second to nth layers using laser welding

[0062] Examples of embodiments are explained in more detail using the attached schematic drawings. They show: Fig. 1 shows an embodiment of a production machine; Fig. 2 shows an embodiment of a machining head; Fig. 3 shows a detailed view of a part of the machining head from Fig. 3; Fig. 4 shows a cross-sectional view of a seam area; Fig. 5 shows a perspective view of a seam area; Fig. 6 shows a view of a pretreated scarf area; Fig. 7 shows an embodiment of a pretreatment device; and Fig. 8 shows an embodiment of a functional layer.

[0063] First, the Fig. 1 Reference is made to FIG. 1, which shows a partial view of a manufacturing machine 10. The manufacturing machine 10 extends along a longitudinal direction, which may also be referred to as the manufacturing direction.

[0064] The production machine 10 comprises a tool transport device 12 designed to transport different machining heads 14. The tool transport device 12 has two tool transport units 16 spaced apart along the production direction. The machining head 14 is arranged between the two tool transport units 16.

[0065] The tool transport units 16 move along the production direction by means of pneumatic or hydraulic cylinders 18. The tool transport units 16 move discontinuously, while the machining head 14 moves continuously. The tool transport units 16 have guide devices 20 spaced transversely to the production direction, which are guided by guide rollers 22 on guide rails 24. The guide rails 24 are only partially shown for the sake of clarity.

[0066] An embodiment of the machining head 14 is described in more detail in Fig. 2 and Fig. 3 The processing head 14 is designed to connect thermoplastic workpieces 26 to one another by means of a connecting body 28.

[0067] The machining head 14 comprises a machining head guide device 30 for guiding the machining head 14 along the production direction, which in Fig. 2runs from left to right.

[0068] The machining head 14 includes a support frame 32 that provides mounting areas for various components of the machining head 14. The support frame 32 has a pair of cylinder couplings 34 by means of which the machining head 14 can be connected to the cylinders 18.

[0069] The processing head 14 further comprises a pressing device 36 with at least one pressure roller 38, which can press the connecting body 28 against at least one of the workpieces 26 in order to connect them to one another in a materially bonded manner.

[0070] For joining, the processing head 14 can further comprise a laser device 40, which can direct a laser beam 42 onto the workpieces 26 and the connecting body 28 by means of a scanner module 44. The scanner module 44 comprises at least one actuator-movable scanner mirror 45.

[0071] The processing head 14 also has a filler supply device 46 which is designed to supply a filler 48, for example thermoplastic resin or thermoplastic material.

[0072] The machining head 14 can have a releasably mounted counter-pressure device 50. The counter-pressure device 50 preferably has a counter-pressure roller 52. The counter-pressure roller 52 can be smaller in diameter than the pressure roller 38.

[0073] Furthermore, the counter-pressing device 50 can comprise a sword 54 which extends between the workpieces 26 and at whose end region 56 the counter-pressing roller 52 is arranged.

[0074] At least one pair of blade guide rollers 58 may be arranged on the blade 54, which can improve the movement of the blade 54 through the workpieces 26.

[0075] The pressing device 36 and the counter-pressing device 50 define a gap between them for the workpieces 26 and the connecting body 28 so that they can be pressed.

[0076] The following refers to Fig. 4 and Fig. 5 Reference is made to FIGS. 1 and 2, which show a seam region 60. A first workpiece 62 and a second workpiece 64 comprise a plurality of workpiece layers 66.

[0077] The workpiece layers 66 are designed, for example already during manufacture or by material processing after manufacture, that each workpiece 62, 64 has a scarf area 68.

[0078] Each workpiece 62, 64 comprises a plurality of workpiece layers 70. The workpiece layers 70 are each placed on top of one another with a workpiece layer broad side 72, so that a workpiece layer narrow side 74 of one workpiece 62, 64 faces a workpiece layer narrow side 74 of the other workpiece 64, 62.

[0079] In this case, the lowest workpiece layers 76, which form the underside surface of the workpieces 62, 64, can form a production gap 78 for the blade 54 of the counter-pressure device 50. The production gap 78 is significantly narrower than the distance between the narrow sides 74 of the workpiece layers.

[0080] The lowest workpiece layer 76 can be followed by several workpiece intermediate layers 80, which in turn each lie on top of the other with their workpiece layer broad side 72.

[0081] Furthermore, uppermost workpiece layers 82 can be provided, which form the upper surface of the workpieces 62, 64.

[0082] In the present example, the bottom workpiece layers 76 and the workpiece intermediate layers 80 are made of fiber-reinforced plastic material, while the top workpiece layer 82 is made of a metal sheet 84. In this context, they are also referred to as fiber-metal laminates, or FML for short.

[0083] It should be noted that any combination is conceivable here and that this mainly depends on the desired area of ​​application.

[0084] The following procedure is now used to join the workpieces 62, 64. A band-shaped first connecting body 86, which can be supplied on rolls, for example, as a connecting band 88 and can also be made of fiber-reinforced plastic, is inserted into the seam region 60 defined by the respective scarf joint regions 68 and, if applicable, the production gap 78, after both the first connecting body 86 and both workpieces 62, 64 have been heated by the laser beam 42 in such a way that, with the aid of the pressing device 36 and the counter-pressing device 50, a material-to-material connection is subsequently created between the first connecting body 86 and the workpieces 62, 64. Within the same time frame, the filler 48 fed into the seam region 60 by the filler supply device 46 can completely close the production gap 78.In both processes, the laser beam 42 is scanned across the entire width of the seam area 60 by the scanner module 44, thus introducing heat locally. Only the surfaces of the workpieces 62, 64 and the first connecting body 86 are melted, thus preventing excessive heating of the other areas of these components.

[0085] In a further operation, the counter-pressing device 50 is first removed and then the process is repeated with further connecting bodies 90 until the entire seam area 60 is flush.

[0086] The following will be Fig. 6 to Fig. 8 Reference is made to the measures for improving the material connection by increasing the strength of the connection.

[0087] In Fig. 6An enlarged section of a scarfing area 92 is shown, which was pretreated by laser treatment. The laser beam parameters were selected such that the fibers of the scarfing area 92 were non-destructively exposed by ablation of the matrix material. This measure can create a reproducible, consistent surface structure 94. Furthermore, a local treatment of the scarfing area 92 is possible, so that this process can be easily integrated into the existing workflow. In addition, complex bath processes can be avoided. Tests by the applicants have shown that the strength of the material-to-material connection can be increased with this surface structuring.

[0088] In Fig. 7A plasma source 100 for plasma coating is shown. Plasma sources are known as such. The plasma source 100 is connected to a power supply 102, which supplies electrical energy to a cathode 104 and an anode 106 to form an arc 108 between them. The cylindrical arc chamber 110 has a plurality of cascade plates 112, each containing a plasma chamber 114. A plasma gas 116 is supplied via a plurality of plasma gas connections 118. Furthermore, an inert gas 120 is introduced into the arc chamber 110. A suitable outlet geometry creates a substantially rectangular, uniform plasma jet 122 for plasma coating a weld area.

[0089] In Fig. 8, top and bottom, a microstructured functional layer is shown at different magnifications, the result of the plasma coating. Due to the microstructured fractal geometry, the scarf area has a larger effective surface area than an untreated scarf area. Tests conducted by the applicants have also shown that this can increase the strength of the connection.

[0090] With the ideas described here, the application range of laser welding processes can be expanded to include complex systems made of fiber-reinforced plastic materials or workpieces without requiring transparent areas or exposing an excessively high portion of the component to heat. Overall, this allows for simpler and more robust joints between fiber-reinforced composite components. List of reference symbols:

[0091] 10 Manufacturing machine 12 Tool transport device 14 Machining head 16 Tool transport unit 18 Cylinder 20 Guide device 22 Guide roller 26 Workpiece 28 Connecting body 30 Machining head guide device 32 Support frame 34 Cylinder couplings 36 Pressure device 38 Pressure roller 40 Laser device 42 Laser beam 44 Scanner module 45 Scanner mirror 46 Filler feed device 48 Filler 50 Counter pressure device 52 Counter pressure roller 54 Blade 56 End area 58 Blade guide roller 60 Seam area 62 First workpiece 64 Second workpiece 66 Workpiece layer 68 Scarf area 70 Workpiece layer 72 Workpiece layer broad side 74 Workpiece layer narrow side 76 Bottommost workpiece layer 78 Manufacturing gap 80Workpiece intermediate layers 82Top workpiece layer 84Metal sheet 86First connecting body 88Connecting band 90Further connecting bodies 92Shaping area 94Surface structure 100Plasma source 102Power supply 104Cathode 106Anode 108Arc 110Arc chamber 112Cascade plate 114Plasma chamber116Plasmagas 118Plasmagasanschlüssen 120inertes Gas 122Plasmajet

Claims

1. Joining method for connecting at least two thermoplastic workpieces (26, 62, 64), with the steps of: a) splicing an edge region on at least one of the workpieces in order to produce at least one splice region (68, 92), wherein the splice region (68, 92) is formed in a stepped manner by a plurality of workpiece layers (66, 70, 76, 80, 82) of the workpiece (26, 62, 64), wherein the splice region (68, 92) is pretreated by fibres of the workpiece being exposed, and / or by the workpiece (26, 62, 64) being coated with a microstructured functional layer; b) positioning the workpieces (26, 62, 64) relative to one another in such a manner that the splice region (68, 92) of the one workpiece (26, 62, 64) and the other workpiece (26, 64, 62) bound a seam region (60), wherein the workpieces (26, 62, 64) are positioned in such a manner that a manufacturing gap (78) is formed between the workpieces (26, 62, 64) or the lowermost workpiece layers (76) of the workpieces (26, 62, 64); c) inserting a connecting body (28, 86, 90) into the seam region (60) and heating part of the connecting body (28, 86, 90) by means of local input of heat in order to form an integrally bonded connection between each workpiece (26, 62, 64) and the connecting body (28, 86, 90), wherein, when a first connecting body layer is inserted, the connecting body (86) is pressed by means of a pressing device (36) which detects the connecting body (86), and a counter pressing device (50) which detects the workpiece (26, 62, 64), wherein the counter pressing device (50) extends below and between the workpieces (26, 62, 64).

2. Joining method according to one of the preceding claims, characterized in that, in step a) - the splicing takes place by corresponding fibre placement, material abrasion, laser ablation, machining and / or milling; and / or - the splice region (68, 92) is pretreated by fibres of the workpiece (26, 62, 64) being exposed by means of laser surface treatment; and / or - the splice region (68, 92) is pretreated by the workpiece (26, 62, 64) being plasma-coated with a microstructured functional layer.

3. Joining method according to one of the preceding claims, characterized in that, in step b), the workpieces (26, 62, 64) are positioned in such a manner that the width of the seam region (60) increases or increases step by step in a direction perpendicular to the workpiece layers (66, 70, 76, 80, 82).

4. Joining method according to one of the preceding claims, characterized in that, in step c), the connecting body (28, 86, 90) is pressed against the workpiece (28, 86, 90) by means of a pressing device (36).

5. Joining method according to Claim 4, characterized in that the pressing device (36) detects the connecting body (28, 86, 90) on a connecting body wide side facing away from the workpiece (28, 86, 90).

6. Joining method according to one of the preceding claims, characterized in that, in step c), the connecting body (28, 86, 90) is heated on a connecting body wide side.

7. Joining method according to one of the preceding claims, characterized in that, in step c), a plurality of connecting bodies (28, 86, 90) are inserted and heated layer by layer in order to produce a connecting body layer which is connected in an integrally bonded manner to the respective workpiece layer (66, 70, 76, 80, 82).

8. Joining method according to one of the preceding claims, characterized in that, in step c), when a first connecting body layer is inserted, the connecting body (86) is pressed by means of the counter pressing device (50) which detects the lowermost workpiece layer (76).

9. Joining method according to Claim 8, characterized in that - the counter pressing device (50) has a blade (64) which is introduced between the workpieces (26, 62, 64) when the pressing takes place; and / or - the counter pressing device (50) has a counter pressing roller (52) which is arranged opposite the pressing device (36).

10. Joining method according to one of the preceding claims, characterized in that, in step c), when a second or further connecting body layer is inserted, the connecting body (90) is pressed against the workpiece (26, 62, 64) only by means of a pressing device (36) which detects the connecting body (90).

11. Joining method according to one of the preceding claims, characterized in that, in step c), the heating takes place by scanning a laser beam (42) over the seam region (60).

12. Joining method according to one of the preceding claims, characterized in that the manufacturing gap (78) is filled by means of filling material (48) during the insertion and heating of a first connecting body layer (90).

13. Joining method according to one of the preceding claims, characterized in that - the connecting body (28, 86, 90) is in the form of a flexible connecting strip; and / or - the connecting body (28, 86, 90) contains an at most partially cured fibre reinforced plastic or is manufactured therefrom; and / or - the connecting body (28, 86, 90) contains a metal sheet (84) or is manufactured therefrom; and / or - the connecting body (28, 86, 90) contains a fibre metal layer or is manufactured therefrom; and / or - the connecting body (28, 86, 90) contains a multilayered, fibre reinforced plastic or is manufactured therefrom; and / or - the fibre reinforced plastic is a carbon fibre reinforced plastic and / or a glass fibre reinforced plastic.

14. Machining head (14) for a manufacturing machine (10) which is designed for manufacturing a fuselage component for a fuselage segment of an aircraft or a fuselage segment for an aircraft, wherein the machining head (14) is designed for connecting at least two workpieces (26, 62, 64) which contain fibre reinforced plastic or are manufactured therefrom, and comprises an insertion device which is designed for inserting a connecting body (28, 86, 90) into a seam region (60) between the workpieces (26, 62, 64), an activation device which is designed for heating that part of the connecting body (28, 86, 90) which is located in the seam region (60) by means of local heat input, and a pressing device (36) which is designed for pressing the heated connecting body (28, 86, 90) onto the workpiece (26, 62, 64) in order to form an integrally bonded connection between each workpiece (26, 62, 64) and the connecting body (28, 86, 90), characterized in that the machining head (14) comprises a pretreatment device, wherein the pretreatment device is designed in such a manner that a laser beam (42) can be produced and can be conducted to the seam region (60), wherein the laser beam (42) is designed in such a manner that fibres of the workpiece (26, 62, 64) can be exposed because of the irradiation thereof with the laser beam (42); and / or wherein the pretreatment device is designed in such a manner that a microstructured functional layer can be produced on the workpiece, wherein the machining head (14) comprises a counter pressing device (50) which is designed to detect the workpiece (26, 62, 64) and to press it in the direction of the pressing device (36), wherein the counter pressing device (50) extends below and between the workpieces (26, 62, 64).

15. Manufacturing machine (10), which is designed to carry out a method according to one of Claims 1 to 13, characterized by a machining head (14) according to Claim 14.