TRANSMISSION WELDING METHOD, TRANSMISSION WELDING DEVICE AND TRANSMISSION WELDING ARRANGEMENT

Abstract

To achieve universal welding of thermoplastic workpiece parts with simple equipment, an infrared light transmission welding method is disclosed in which simple polychromatic, incoherent infrared light is generated by a simple infrared light source and is directed through a first workpiece part to a weld point for the purposes of connection to a second workpiece part. In particular, the infrared light is directed through a transparent bracing element.

Claims

1. A transmission welding method for welding a first workpiece part, which is formed at least partially from thermoplastic material, to at least one second workpiece part at a weld point, comprising: directing polychromatic, incoherent infrared light radiation through the first workpiece part to the weld point.

2. The transmission welding method of claim 1, wherein at least one region of the first workpiece part or all of the first workpiece part is formed from a thermoplastic fiber composite material and wherein the infrared light radiation is directed through the fiber composite material to the weld point.

3. The transmission welding method of claim 1, comprising at least one or more steps of: generating the polychromatic, incoherent infrared light radiation by an infrared lamp; generating the infrared light radiation in a wavelength range from 1.0 to 3.0 μm; moving the infrared light radiation over the first workpiece part to weld the workpiece parts continuously along a welding region; moving an infrared light source generating the infrared light radiation over the first workpiece part around the workpiece parts along a welding region.

4. The transmission welding method of claim 1, comprising: a) bracing the first workpiece part and the second workpiece part by at least one bracing element which is at least partially transparent to the infrared light radiation; and b) directing the infrared light radiation through the bracing element to the first workpiece part.

5. The transmission welding method of claim 4, wherein step a) comprises at least one or more steps of: pressing the bracing element onto the first workpiece part; using a bracing element comprising a material selected from the group of materials consisting of a material transparent to the infrared light radiation, a flexible material, a rigid material, glass, transparent plastic, polyimide, vacuum packaging film and silicone, and also combinations of these materials; using a pressure plate or bracing jaw as bracing element; using a bracing element having at least one fluid medium cavity filled or fillable with a fluid medium; using a flexible bracing element and controlling contact pressure of the flexible bracing element by a pressure fluid; moving the bracing element over the first workpiece part; using a bracing element that is rotatable about an axis of rotation; using a bracing element which is roll-shaped, roller-shaped or spherical or in a form of a rolling body; rolling the bracing element over the first workpiece part; generating the infrared light radiation in an interior of the bracing element in a form of a rolling body; moving an infrared light source and the bracing element jointly over the first workpiece part; using a bracing element which has multiple rigid segments, which are flexibly articulated to one another, in order to replicate the topology of the first workpiece part.

6. The transmission welding method of claim 4, comprising: c) setting a temperature of the bracing element before, during and or after step b) to influence temperature of at least one region of the workpiece.

7. The transmission welding method of claim 4, wherein step a) and or step c) comprises at least one or more of steps of: using a bracing element with at least one channel and conducting a temperature-controlled fluid medium through the at least one channel; conducting a fluid medium that is transparent or transmissive to the infrared light radiation through the bracing element; preheating the bracing element and the workpiece to reduce heating time for the welding method; postheating or cooling the bracing element and the workpiece to improve workpiece quality or crystallization rate; controlling a pressure distribution by controlling pressure of the fluid medium.

8. The transmission welding method of claim 1, comprising one or more of steps of: welding the material parts, in each case selected from the group consisting of a fiber-reinforced plastics component, a component with a matrix comprising thermoplastic material, a component with a matrix comprising PPS, a component with a matrix comprising PEKK, a component with a matrix comprising PEEK, a component with a matrix comprising PA, a component with a matrix comprising PEI, a component with a matrix comprising LM PAEK, a component with a matrix comprising FBI, a component with a matrix comprising PE, a component with reinforcement fibers in a form of a woven fabric, a component with reinforcement fibers in a form of a scrim, a component with reinforcement fibers in a form of unidirectional fibers, a component with reinforcement fibers in a form of short fibers, a component with reinforcement fibers in a form of continuous fibers, a component with reinforcement fibers comprising carbon, a component with reinforcement fibers comprising glass, a component with reinforcement fibers comprising continuous carbon fibers, a component with reinforcement fibers comprising continuous glass fibers, a component with reinforcement fibers comprising short carbon or glass fibers, a component with reinforcement fibers comprising aramid fibers, a component with reinforcement fibers comprising silk, a component with reinforcement fibers comprising fibers from a biological source, and a component with reinforcement fibers comprising ceramic; welding the first workpiece part and the second workpiece part with an overlap or partial overlap; welding the first workpiece part and the second workpiece part with a butt joint; introducing an intermediate layer between the workpiece parts before the welding method.

9. A method of using the transmission welding method of claim 1 for: generating longitudinal and or circumferential connections on a vehicle or aircraft fuselage or vehicle or aircraft fuselage component or a vehicle or aircraft component; welding fastening elements, clips, brackets, clamps or clips to a fuselage structure or skin of a vehicle or aircraft welding a frame of a vehicle or aircraft; welding a skin to a frame on a vehicle or aircraft; welding stringers or formers to a skin of a vehicle or aircraft; welding structural components to form an enclosure for a door of a vehicle or aircraft; welding floor structures of a vehicle or aircraft; or welding coupling elements for coupling structural elements of a vehicle or aircraft.

10. A transmission welding apparatus for welding a first workpiece part, which is formed at least partially from thermoplastic material, to at least one second workpiece part at a weld point in order to form a workpiece, comprising: an infrared light source for generating a polychromatic, incoherent infrared light radiation; and a bracing element which is at least partially transparent to the infrared light radiation and which has a bracing surface for bracing the workpiece parts, wherein the infrared light source is on a side situated opposite the bracing surface and is configured to direct the infrared light radiation through the bracing element onto the workpiece.

11. The transmission welding apparatus of claim 10, wherein the infrared light source: has at least one infrared lamp; and or is configured to generate the infrared light radiation in a wavelength range of 1.0 to 3.0 μm; is configured to generate the infrared light radiation as IR-B radiation according to DIN5031; is movable by a movement device relative to a counterpart bracing element which is configured to exert an opposing bracing force when the workpiece is braced between the bracing element and the counterpart bracing element; and or is arranged in an interior of the bracing element in a form of a rolling body.

12. The transmission welding apparatus of claim 10, wherein the bracing element: has at least one fluid channel or fluid cavity for a fluid medium; and or is formed from a flexible or from a rigid material; and or is at least partially formed from glass, silicone or polyimide or a vacuum packaging film; and or is in a form of a bracing jaw or pressure plate; and or has at least one flexible skin region for bearing against the workpiece; and or is movable over the first workpiece part by a movement device while exerting a mechanical pressure; and or is rotatable about an axis of rotation; and or is in a form of, or has, a rolling body, roller, roll, tube or sphere; and or has multiple rigid segments with different thicknesses for replicating a topology of the first workpiece part, which rigid segments are flexibly articulated to one another.

13. A transmission welding arrangement, comprising a transmission welding apparatus of claim 10, a first workpiece part and a second workpiece part to be connected to the first workpiece part at a weld point by welding by the transmission welding apparatus, wherein the first workpiece part is formed from a thermoplastic material that is at least partially transparent to the infrared light radiation, and the first workpiece part is arranged such that the infrared light radiation can be directed through the first workpiece part to the weld point.

14. The transmission welding arrangement of claim 13, wherein: the first workpiece part is selected from the group consisting of a workpiece part comprising fiber composite material that is at least partially transparent to the infrared light radiation, a fiber-reinforced plastics component, a component with a matrix comprising thermoplastic material, a component with a matrix comprising PPS, a component with a matrix comprising PEKK, a component with a matrix comprising PEEK, a component with a matrix comprising PA, a component with a matrix comprising PEI, a component with a matrix comprising LM PAEK, a component with a matrix comprising FBI, a component with a matrix comprising PE, a component with reinforcement fibers in a form of a woven fabric, a component with reinforcement fibers in a form of a scrim, a component with reinforcement fibers in a form of unidirectional fibers, a component with reinforcement fibers in a form of short fibers, a component with reinforcement fibers in a form of continuous fibers, a component with reinforcement fibers comprising carbon, a component with reinforcement fibers comprising glass, a component with reinforcement fibers comprising continuous carbon fibers, a component with reinforcement fibers comprising continuous glass fibers; a component with reinforcement fibers comprising short carbon or glass fibers, a component with reinforcement fibers comprising aramid fibers, a component with reinforcement fibers comprising silk, a component with reinforcement fibers comprising fibers from a biological source, a component with reinforcement fibers comprising ceramic, a structural component for an aircraft, a skin part of an aircraft fuselage, a fastening element or reinforcing element to be fastened to a structure of an aircraft, a clamp, a clip, a cleat, a stringer, a former, a floor element of a floor of an aircraft, and a door frame element of an aircraft; and or the second workpiece part is selected from the group consisting of a fiber-reinforced plastics component, a component with a matrix comprising thermoplastic material, a component with a matrix comprising PPS, a component with a matrix comprising PEKK, a component with a matrix comprising PEEK, a component with a matrix comprising PA, a component with a matrix comprising PEI, a component with a matrix comprising LM PAEK, a component with a matrix comprising FBI, a component with a matrix comprising PE, a component with reinforcement fibers in a form of a woven fabric, a component with reinforcement fibers in a form of a scrim, a component with reinforcement fibers in a form of unidirectional fibers, a component with reinforcement fibers in a form of short fibers, a component with reinforcement fibers in a form of continuous fibers, a component with reinforcement fibers comprising carbon, a component with reinforcement fibers comprising glass, a component with reinforcement fibers comprising continuous carbon fibers, a component with reinforcement fibers comprising continuous glass fibers; a component with reinforcement fibers comprising short carbon or glass fibers, a component with reinforcement fibers comprising aramid fibers, a component with reinforcement fibers comprising silk, a component with reinforcement fibers comprising fibers from a biological source, a component with reinforcement fibers comprising ceramic, a structural component for an aircraft, a skin part of an aircraft fuselage, a fastening element or reinforcing element to be fastened to a structure of an aircraft, a clamp, a clip, a cleat, a stringer, a former, a floor element of a floor of an aircraft, and a door frame element of an aircraft.

15. An aircraft comprising: at least one workpiece produced by the transmission welding method of claim 1; and or a weld obtained by the transmission welding method.

16. An aircraft comprising: at least one workpiece produced by the transmission welding apparatus of claim 10; and or a weld obtained by the transmission welding apparatus.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0198] Example embodiments of the disclosure herein will be discussed in more detail below on the basis of the appended drawings, in which:

[0199] FIG. 1 is a schematic sectional illustration of a first embodiment of a transmission welding arrangement for carrying out a transmission welding method in which a first workpiece part and a second workpiece part are welded to form a workpiece;

[0200] FIG. 2 is a schematic sectional illustration similar to FIG. 1 of a second embodiment of the transmission welding arrangement;

[0201] FIG. 3 is a schematic sectional illustration similar to FIG. 1 of the transmission welding arrangement during the course of the transmission welding method, wherein thermoplastic material has been fused or plasticized at a weld point at which the first workpiece part is to be connected to the second workpiece part;

[0202] FIG. 4 is a schematic sectional illustration similar to FIG. 3 of a third embodiment of the transmission welding arrangement;

[0203] FIG. 5 is a schematic sectional illustration similar to FIG. 3 of a fourth embodiment of the transmission welding arrangement;

[0204] FIG. 6 is a schematic sectional illustration similar to FIG. 3 of a fifth embodiment of the transmission welding arrangement;

[0205] FIG. 7 is a schematic sectional illustration similar to FIG. 3 of a sixth embodiment of the transmission welding arrangement;

[0206] FIG. 8 is a schematic sectional illustration similar to FIG. 3 of a seventh embodiment of the transmission welding arrangement;

[0207] FIG. 9 shows a schematic sectional view through a first example embodiment of the workpiece, the workpiece parts of which are skin elements of an aircraft that are being welded to one another at a longitudinal seam;

[0208] FIG. 10 shows a further example embodiment for the workpiece, wherein a fastening element is being welded to a skin element of an aircraft;

[0209] FIG. 11 shows a further example embodiment for the workpiece, wherein a coupling element is to be welded on for the purposes of connecting two structural components of an aircraft;

[0210] FIG. 12 shows a further example embodiment for the workpiece, wherein a stiffening element is to be welded to a skin element of an aircraft;

[0211] FIG. 13 shows a highly schematic cross-sectional view through a fuselage component for an aircraft with different examples of welded connections that have been produced by the transmission welding method and the transmission welding arrangement according to the example embodiments of the disclosure herein; and

[0212] FIG. 14 shows a schematic view of a vehicle using the example of an aircraft, wherein different possible applications of the transmission welding method and of the transmission welding arrangement according to example embodiments of the disclosure herein are illustrated.

DETAILED DESCRIPTION

[0213] FIGS. 1 through 8 illustrate different embodiments of a transmission welding arrangement 10 for carrying out a transmission welding method. The transmission welding arrangement 10 has a first workpiece part 12 and a second workpiece part 14, which are to be connected to one another by the transmission welding method at a weld point 16 to form a workpiece 18, and a transmission welding apparatus 20 for performing the welding of the workpiece parts 12, 14 by infrared transmission welding.

[0214] At least the first workpiece part 12 or both workpiece parts 12, 14 are formed from a thermoplastic material at least in certain regions, in particular at the weld point 16.

[0215] Thermoplastic material is preferably a thermoplastic fiber composite material. In one refinement, at least one of the workpiece parts 12, 14, preferably both workpiece parts 12, 14, has continuous fibers (not illustrated) in a thermoplastic matrix.

[0216] The first workpiece part 12 is selected from a group comprising a fiber-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 FBI, a component with a matrix composed of PE, a component with reinforcement fibers in the form of a woven fabric, a component with reinforcement fibers in the form of a scrim, a component with reinforcement fibers in the form of unidirectional fibers, a component with reinforcement fibers in the form of short fibers, a component with reinforcement fibers in the form of continuous fibers, a component with reinforcement fibers composed of carbon, a component with reinforcement fibers composed of glass or glass materials, a component with reinforcement fibers composed of continuous carbon fibers, a component with reinforcement fibers composed of continuous glass fibers; a component with reinforcement fibers composed of short carbon or glass fibers, a component with reinforcement fibers composed of aramid fibers, a component with reinforcement fibers composed of silk, a component with reinforcement fibers composed of fibers from a biological source, a component with reinforcement fibers composed of ceramic, and a component composed of continuous fibers, and any combinations of these material specifications. Examples of fibers from a biological source would for example be silk or fibers from spiders.

[0217] The second workpiece part 14 is selected from a group comprising a fiber-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 FBI, a component with a matrix composed of PE, a component with reinforcement fibers in the form of a woven fabric, a component with reinforcement fibers in the form of a scrim, a component with reinforcement fibers in the form of unidirectional fibers, a component with reinforcement fibers in the form of short fibers, a component with reinforcement fibers in the form of continuous fibers, a component with reinforcement fibers composed of carbon, a component with reinforcement fibers composed of glass or glass materials, a component with reinforcement fibers composed of continuous carbon fibers, a component with reinforcement fibers composed of continuous glass fibers; a component with reinforcement fibers composed of short carbon or glass fibers, a component with reinforcement fibers composed of aramid fibers, a component with reinforcement fibers composed of silk, a component with reinforcement fibers composed of fibers from a biological source, a component with reinforcement fibers composed of ceramic, and a component composed of continuous fibers, and any combinations of these material specifications.

[0218] The transmission welding apparatus 20 has a bracing device 22 for bracing the first workpiece part 12 and the second workpiece part 14 and has an infrared light source 24 for generating simple infrared light radiation, that is to say not laser radiation but polychromatic and incoherent infrared light radiation.

[0219] The bracing device 22 has a bracing element 26, a counterpart bracing element 28 and a bracing force generating device 30 indicated by arrows, by which the bracing element 26 is movable relative to the counterpart bracing element 28 and by which a bracing pressure can be generated between the bracing element 26 and the counterpart bracing element 28.

[0220] The bracing element 26 is formed, at least in a region with which it engages on the first workpiece part 12, from a material that is transparent to the infrared light radiation 32. The bracing element 26 has a bracing surface 34 by which the first workpiece part 12 is engaged on, and a rear side 36 situated opposite the bracing surface 34. Between the bracing surface 34 and the rear side 36, the bracing element 26 is, at least in certain regions, transparent to the infrared light radiation 32.

[0221] The infrared light source 24 is arranged on the rear side 36 and is designed to direct the infrared light radiation 32 through the bracing element 26 onto the first workpiece part 12.

[0222] In some refinements, in particular as shown in FIGS. 1 through 5, the bracing element 26 is composed of a rigid material such as glass, in particular temperature-resistant glass, and may be in the form of a bracing jaw or pressure plate.

[0223] In other configurations, as shown in FIG. 6, the bracing element 26 is, at least in one region, in particular in a region that at least partially forms the bracing surface 34, composed of a flexible material such as silicone-containing material, and thus has, for example, a flexible skin region for bearing against the workpiece 18, in particular against the first workpiece part 12.

[0224] In an embodiment as illustrated in FIG. 4, the bracing 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, which fluid medium can be temperature-controlled by a temperature-control device having a heating device and/or a cooling device and can be placed under controlled fluid pressure by a pump or similar pressure generating device. In this embodiment according to FIG. 4, the bracing element 26 may be at least partially composed of flexible material instead of a rigid material.

[0225] In the embodiments illustrated in FIGS. 1 through 4, the bracing element 26 is in the form of a pressure plate or bracing jaw. In the embodiments illustrated in FIGS. 5 and 6, the bracing element 26 is in the form of a rolling body 90, for example in the form of a sphere, roller, roll or tube 92, which is rotatable about an axis of rotation. In these refinements, the bracing surface 34 is formed on the outer circumference of the rolling body 90, while the inside of the rolling body 90 forms the rear side 36. In these embodiments, the at least one infrared light source 24 is arranged in the interior of the rolling body 90. In the refinements according to FIGS. 7 and 8, the bracing element 26 has rigid components and flexible components.

[0226] In some refinements, the counterpart bracing element 28 is in the form of a fixed base or support, for example a bracing table or a smaller fixed support. The bracing force generating device 30 is designed to move the bracing element 26 with a defined force against the counterpart bracing element 28.

[0227] In a larger refinement, the counterpart bracing element 28 may be fixedly fastened to a machine table, whilst the bracing element 26 can be moved against the counterpart bracing element 28 by a hydraulic or pneumatic cylinder or some other actuator, for example an electric motor with a threaded rod. In another particularly simple and compact transmission welding apparatus 20, the bracing element 26 and the counterpart bracing element 28 may be in the form of jaws of a type of case.

[0228] In refinements of the transmission welding apparatus 20 that are particularly well suited for carrying out a continuous transmission welding method, the transmission welding apparatus 20 has a movement device 94 for moving the bracing element 26 relative to the counterpart bracing element 28 and thus for moving the bracing element 26 over the workpiece 18. Examples of these refinements are illustrated in FIGS. 5 to 8.

[0229] FIG. 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 one on top of the other and the infrared light radiation 32 is in a spectrum with wavelengths in a range to which the first workpiece part 12 is at least up to 2%, more preferably 10 to 20%, most preferably up to 30%, transparent. The remaining infrared light radiation 32 is absorbed in the first workpiece part 12 and converted into heat, which softens thermoplastic material of the first workpiece part 12. The welding energy passes to the weld point 16 partly by conduction. A proportion of the infrared light radiation 32 also passes to the weld point 16 by transmission, the weld point being formed here at those sides or surfaces of the workpiece parts 12, 14 which are braced together.

[0230] As illustrated in FIG. 3, this leads to a fusion of thermoplastic material at the weld point 16, such that welding can be carried out.

[0231] FIG. 2 shows a refinement of the transmission welding arrangement, where an additional layer 44 is also provided between the workpiece parts 12, 14. The additional layer 44 may be formed from thermoplastic material and thus provide additional fusion material for the welding process. Other additional layers 44 are also conceivable; for example, the additional layer 44 may have a material to be laminated or a functional layer.

[0232] In both embodiments according to FIGS. 1 and 2, the situation illustrated in FIG. 3 arises during welding, where either thermoplastic material of the workpiece parts 12, 14 or thermoplastic material of the workpiece parts 12, 14 and the additional layer 44 are fused at the weld point 16 by the infrared light radiation 32, which is directed partially by transmission and partially by conduction to the weld point 16.

[0233] FIG. 4 shows the refinement with the fluid cavities 38 in the form of channels 42.

[0234] Here, before the welding process is carried out, heated fluid medium 40 can be conducted through in order to preheat the transmission welding arrangement and in particular the workpiece parts 12, 14.

[0235] If the bracing element 26, as stated above, is at least partially formed from flexible material, the contact pressure of the bracing element 26 against different regions of the bracing surface 34 can be controlled through control of the pressure of the fluid medium 40.

[0236] After the welding process, the cooling and thus the consolidation of the material fused at the weld point 16 can be controlled through targeted temperature control of the fluid medium 40. For example, postheating may be performed here, or targeted cooling may be used.

[0237] In another approach, cooled fluid medium 40 serves to cool that side of the first workpiece part 12 which is situated opposite the weld point 16, such that the fusion of thermoplastic material occurs closer to the weld point 16.

[0238] Refinements of the embodiment shown in FIG. 4 thus have a fluid medium system (not illustrated) with a pressure generator, for example a pump or a pressurized medium reservoir, preferably automatically controllable valves, and a preferably automatically controllable temperature-control device—for example heating and/or cooling device. The fluid medium system may have 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.

[0239] Some refinements of the transmission welding apparatus 20 have a controller for controlling the infrared light source 24, the bracing force generating device 30 and, if applicable, the fluid medium system and/or the movement device 92.

[0240] In the fourth embodiment illustrated in FIG. 5, the bracing element 26 is in the form of a rolling body 90 in the form of a tube 92 composed of a rigid material, in particular glass, which is transparent to the infrared light radiation 32, and one or preferably more infrared light sources 24 are in the interior of the tube 92 over the length thereof. The tube 92 is rotatably mounted in a manner that is not illustrated, and is movable over the first workpiece 12 by the movement device 94.

[0241] The fifth embodiment shown in FIG. 6 substantially corresponds to the fourth embodiment with the difference that the tube 92 is formed at least in the region of the bracing surface 34 from a flexible material such as silicone or polyimide (for example Kapton® film) or vacuum packaging film. The interior of the tube 92 serves as a fluid cavity 38 into which fluid medium—in particular in the form of temperature-controlled air with a controlled pressure—can be introduced through a fluid medium system (not illustrated in any more detail) of the type discussed above.

[0242] In the embodiments of FIGS. 5 through 7, the bracing element 26 can be moved together with the at least one infrared light source 24 over the workpiece 18 in order to thus continuously weld a relatively large welding region 96. According to FIGS. 5 through 8, the welding region 96 has the weld point 16, with the material that has just been fused, and zones 96a and 96b, which are situated behind the weld point 16 in the direction of movement and which are already cooling.

[0243] In the refinements according to FIGS. 7 and 8, the bracing element 26 has rigid segments 98a, 98b, 98c, 98d of different thicknesses. The thickness of the segments 98a-98d is adapted to the topology of the first workpiece part 12. Unevennesses and varying heights on the surface of the first workpiece part 12 can thus be compensated for by the rigid segments 98a-98d, such that pressure surface regions 100a-100e are provided which are arranged approximately at the same height.

[0244] In the embodiment according to FIG. 7, the bracing element 26 also has the flexible tube 92, which lies, and exerts pressure, on these pressure surface regions 100a to 100e under the influence of internal pressure 102 in the tube 92—set for example by the fluid medium 40.

[0245] In the refinement according to FIG. 8, the bracing element 26 has a vacuum packaging film 104. The region between the vacuum packaging film 104 and the first workpiece part 12 can be evacuated by a pump (not illustrated) or the like, such that the pressing pressure 46 is exerted by the vacuum. At the same time, the flexible vacuum packaging film 104 connects the different rigid segments 98a-98d.

[0246] Furthermore, in the refinements of FIGS. 7 and 8, a separating film 106 is provided between the bracing element 26, in particular the rigid segments 98a-98d, and the surface of the first workpiece part 12, which separating film prevents an adhesion of the bracing element 26 or of the parts thereof, in particular of the segments 98a-98d, to the first workpiece part 12.

[0247] In the embodiments of FIGS. 7 and 8, the bracing element 26 thus has a combination of rigid and flexible elements. This is advantageous in particular for carrying out a welding process along a welding region 96, 96a, 96b with a varying topology of the workpiece 18. A separating film 106 (composed for example of Kapton® or silicone, . . . ) prevents adhesion.

[0248] Rigid segments 98a-98d with an adapted thickness are provided for transmitting the mechanical pressure 46 to the uneven surface of the workpiece 18.

[0249] In the refinement according to FIG. 7, the mechanical pressure 46 for applying a welding force is applied by the flexible tube 92 to the pressure surfaces 100a-100e and thus via the segments 98a-98d, or else in certain regions directly, to the workpiece 18.

[0250] FIG. 8 shows another possibility for the generation of the bracing force and of the mechanical pressure. Here, the mechanical pressure 46 is generated by vacuum. The bracing force generating device 30 thus has a pump (not illustrated) or the like. Instead of the flexible tube 92, the bracing element 26 has the vacuum packaging film 106, with which the bracing force generated by the vacuum is applied.

[0251] In all configurations of the transmission welding arrangement 10, simple, that is to say polychromatic and incoherent infrared light radiation is directed through the bracing element 26 and at least partially through the first workpiece part 12 to the weld point 16.

[0252] A refinement of the transmission welding method, as can be carried out with the embodiments of FIGS. 1 through 4, will be discussed in more detail below on the basis of the individual process steps.

[0253] Both parts to be connected—first workpiece part 12 and second workpiece part 14—are positioned relative to one another in the bracing device 22, which is designed for example as a clamping apparatus.

[0254] The upper part of the bracing device 22 illustrated at the top in each of the figures—the bracing element 26—should be designed to be transparent to the infrared light radiation and possibly flexible.

[0255] As illustrated in FIG. 2, it would be possible for at least one additional layer—additional layer 44—for example matrix layer—to be placed between the workpiece parts 12, 14 to be connected. An additional layer could also be integrated into one of the two workpiece parts 12, 14 before the welding process.

[0256] A mechanical pressure 46 is subsequently exerted by the bracing device 22 via the bracing element 26 and the counterpart bracing element 28. The bracing element 26 serves, for example, as a transparent part for the application of pressure. The counterpart bracing element 28 is, for example, a solid base or part of a clamping mechanism.

[0257] The infrared light source 24 is subsequently positioned over the transparent bracing element 26.

[0258] Infrared heating is applied as a transmission heating source through the transparent bracing element 26 to the outer surface of the first workpiece part 12.

[0259] The infrared light radiation heats the first workpiece part 12, partially in the form of surface heating and partially as penetrating heating energy because of transmission in the first workpiece part 12 to the connection region 48—that is to say the weld point 16—between the workpiece parts 12, 14.

[0260] The connection region 48 and thus the weld point 16 is heated over a large area.

[0261] The energy of the infrared light radiation 32—infrared heating—leads to the heating of the connection region 48—weld point 16—and to the fusion of the material of the workpiece parts 12, 14 or, if applicable, of the additional layer 44. The transmission welding arrangement 10 with correspondingly fused material at the weld point 16 at the connection region 48 is illustrated in FIG. 3.

[0262] FIG. 4 shows an optional possibility of infrared through welding with heating assistance from fluid medium 40.

[0263] One of the elements 26, 28 of the bracing device 22 by which the workpiece parts 12, 14 are clamped together—or both bracing elements 26, 28—could have one or more channels 42 as fluid cavities 38.

[0264] During the welding process, a fluid medium 40 could be provided in these channels 42 in order to improve the temperature and pressure distribution during the welding.

[0265] If—as illustrated in the refinement in FIG. 4—the bracing element 26, through which the infrared light radiation 32 of the infrared light source 24 is directed, is provided with channels 42 for the fluid medium 40, then it is advantageous if the fluid medium 40 is likewise at least partially or is at least largely transparent to the infrared light radiation 32.

[0266] In one embodiment, this is achieved by using high-temperature-resistant oil or water as the fluid medium 44.

[0267] The temperature of this fluid medium 44 is then controlled. This makes it possible to reduce the heating time by preheating the fluid medium 44, to reduce the welding time by additionally heating fluid medium 44 and/or to provide a better crystallization rate through postheating or through control of the cooling rate.

[0268] In one refinement of the embodiment of the transmission welding arrangement 10 illustrated in FIG. 4, the bracing element 26, 28 provided with the channels 42, in this case in particular the transparent bracing element 26, is formed from a flexible material at least in the region of the bracing surface 34. A suitable material that is also transparent to infrared light radiation 32 would be silicone or polyimide. In the case of the counterpart bracing element 28, it is also possible for other flexible materials to be provided for delimiting the channel 42 and for forming the counterpart bracing surface 34 if the channels 42 or a proportion of the channels 42 are provided in the counterpart bracing element 28.

[0269] In this refinement, the pressure of the fluid medium 40 within the channels 42 is controlled—in particular individually for each channel 42. This allows the possibility of controlling the pressure over the bracing surface 34 and thus over the entire welding region—connection region 48/weld point 16.

[0270] In addition, the pressure can be controlled over the chronological course of the welding process in order to thus improve the control of the welding process through control of the welding pressure by the fluid medium 40.

[0271] Preferred refinements of a continuous transmission welding method, as can be carried out with the embodiments of the transmission welding apparatus 20 of FIGS. 5 to 8, will be discussed in more detail below on the basis of the individual process steps.

[0272] Firstly, the first workpiece part 12 and the second workpiece part 14 are positioned relative to one another in the bracing device 22, for example are placed in a manner adapted to one another onto the counterpart bracing element 28 in the form of a support. As discussed above with regard to FIG. 3, it is also possible here for the additional layer 44 to optionally be introduced, even though it is not illustrated in FIGS. 5 to 8.

[0273] Subsequently, in the refinements of FIGS. 5 and 6, the tube 92 with the bracing force generating device 30 is pressed onto the first workpiece 12 in order to generate the mechanical pressure 46. The infrared light sources 24 are activated in order 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 with regard to the embodiments of the transmission welding method on the basis of FIGS. 1 through 4. The material at the weld point 16 is correspondingly fused.

[0274] By the movement device 94, the bracing element 26, which is in the form of a rolling body 90, is then moved over the surface of the first workpiece part 12. The rolling body 90 rolls on the surface and, by way of the bracing surface 34, continues to exert the mechanical pressure 46 on the workpiece 18 as welding pressure. The infrared light sources 24 arranged in the interior of the tube 92 are correspondingly moved conjointly. The welding region 96 is thus welded in continuous fashion.

[0275] In the embodiment illustrated in FIG. 6, because of the flexible material, the active region of the bracing surface 34 can be adjusted through adjustment of the bracing force and of the pressure in the interior of the tube 92. As shown by a comparison of FIGS. 5 and 6, a larger surface region of the workpiece 18 can thus be subjected to the mechanical pressure. A similar effect could also be achieved by a bracing element 26 supported in the manner of tank tracks.

[0276] In a method that can be carried out with the refinements according to FIGS. 7 and 8, the separating film 106 is firstly placed on. Differences in height are compensated for by rigid segments 98a-98d of corresponding thickness.

[0277] It is also the case in FIG. 7—as described above for FIG. 6—that the flexible tube 92 is subsequently moved together with the infrared light source 24 over the workpiece 18. The contact pressure is controlled by way of the internal pressure 102 in the flexible tube 92.

[0278] In the approach according to FIG. 8, the vacuum packaging film 104 is placed onto the rigid segments 98a-98d and the workpiece. The space between the vacuum packaging film 104 and the workpiece 18 is evacuated in order to thus exert the mechanical pressure 46. The infrared light source 24 is subsequently moved by the movement device 94 over the workpiece 18 in order to thus carry out the continuous welding.

[0279] Various experiments for carrying out the transmission welding method have been performed successfully.

[0280] For this purpose, transmission tests were firstly performed on various thermoplastic fiber composite materials. Specifically, a fiber composite material with unidirectional glass fibers with sample thicknesses of 0.7 mm, 1.2 mm, 2.6 mm and 2.9 mm was tested with infrared light radiation of different wavelengths. In the case of all of these samples, there was a significant increase in transmission above 1000 nm with a peak at approximately 1600 nm and, furthermore, also good transmissivity values at wavelengths in the range from 1650 nm to 2000 nm. Further different thermoplastic materials such as PEEK and PPS, also with carbon fiber or glass fiber reinforcement, were also tested. It was found with all of these that the transmission in the case of a standard laser wavelength of 940 nm for a standard diode laser is low. For such laser radiation, the major part of the radiation is very quickly absorbed in the first workpiece part 12. In the case of such laser radiation, it is only by conduction heat that the second workpiece part 14 is also fused. This often has the effect that the first workpiece part 12 is completely fused and a defined connection thus becomes difficult.

[0281] It is therefore desirable to perform welding with wavelengths in the range around 1600 nm, where thermoplastic materials have greater transparency.

[0282] The maximum transmittance of presently used thermoplastic materials lies in the range from 1000 nm to 1600 nm. However, there are no welding lasers on the market that would output radiation in this range, and very expensive special laser apparatuses would be necessary. According to DIN 5031, infrared radiation is categorized 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 a wavelength 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-wave range of the near infrared range (abbreviation: NIR). The 780 nm limit is because of the human sense of sight adapted to the solar spectrum. IR-B radiation represents the long-wave range of the NIR range. The boundary between IR-A and IR-B is based on the water absorption at 1450 nm.

[0283] Infrared radiation IR-C can be categorized into mid-infrared MIR from 3 to 50 μm and far-infrared FIR from 50 to 1000 μm. Mid-infrared is the range of thermal radiation at terrestrial temperatures. The atmosphere strongly absorbs far-infrared.

[0284] Based on the above considerations with regard to the transmittance of certain wavelengths in thermoplastic materials, an infrared light source 24 that emits IR-B and/or IR-C radiation is particularly preferably selected.

[0285] The short-wave infrared range (SWIR) IR-B extends from 1.4 to 3 μm. This range is relatively safe for the eyes because such light is absorbed in the eye before it can reach the retina.

[0286] An infrared lamp with a power of 400 W from an infrared heater of the Adler type (serial number 1803 with a total power of 2×400 W, at an operating voltage of 220 to 240 V and an operating current frequency of 50/60 Hz) was used for experiments.

[0287] Such an infrared lamp has a ceramic infrared source. The infrared source is in the form of a compact rod. The exact spectrum was not inspected; it is likely to be in the IR-B range, in particular between 1000 and 1600 nm.

[0288] Only one lamp of the two lamps in this radiant heater was used.

[0289] This lamp also has an upper reflector, such that the infrared light radiation emerges in a directed manner to one side.

[0290] The lamp emits radiation with a constant energy level.

[0291] As the bracing force generating device 30, use was made of bracing clamps that generate a clamping force by mechanical springs. The exact clamping force was not measured.

[0292] A glass plate with a thickness of approximately 1.5 mm was initially used as the transparent bracing element 26.

[0293] In a first example experiment, a piece of fiber composite material with unidirectional glass fibers in a PEKK matrix and a thickness of 1.2 mm was used as the first workpiece part 12.

[0294] A strip of fiber composite material with unidirectional carbon fibers in a PEKK matrix and a thickness of 1.8 mm was used as the second workpiece part 14.

[0295] Welding was subsequently performed, as illustrated in FIG. 1, with the following welding parameters: [0296] Welding energy: 400 W [0297] The entire length of the rod-shaped heating lamp was heated. [0298] The spectrum was not measured, it is assumed to be infrared B with a wavelength of 1000 nm to 1600 nm. [0299] Only a spring force was applied as mechanical pressure 46, and only locally. The exact clamping force was not measured. [0300] The welding was performed for 120 s.

[0301] The welding result was then inspected. It was found that the first workpiece part 12 and the second workpiece part 14 were firmly connected to one another. Local fusion of the first workpiece part 12 was identified.

[0302] A visual comparison with a corresponding sample welded by laser welding showed the same welding performance for the infrared transmission welding as for the laser transmission welding.

[0303] However, the infrared transmission welding was performed with significantly less expensive equipment—a simple infrared lamp—that does not require any specific protective measures, as is the case for example with a laser.

[0304] As a second test, a continuous welding process according to the embodiment of FIG. 5 was performed. The same workpiece parts 12, 14 were used as in the first test; as the bracing element 26, a cylindrical tube 92 composed of glass was used, through which the abovementioned rod-shaped infrared lamp as the infrared light source 24 was inserted through the tube 92. The welding was then performed with the following welding parameters:

[0305] An infrared lamp arranged in the tube 92 was used as the infrared light source 24. The infrared lamp had a power of 400 W and was heated over its entire length. As mentioned above, the exact spectrum is not known, but is assumed to be infrared B radiation (in the range from 1000 to 1600 nm). The tube 92 was composed of heat-resistant glass (lantern glass). The mechanical pressure was applied locally. The above-described clamping apparatus with mechanical clamps was used. The exact clamping pressure was not measured. The welding time was 120 s. This test also showed good welding quality.

[0306] As a further test, welding through a silicone layer was tested in order to test the performance of this material for use for the bracing element 26. The test was carried out under the same conditions as for the first test, wherein a strip of silicone was used in place of the glass plate. Here, too, the materials were welded together, but the results were poorer than with the glass plate. Accordingly, silicone materials should be selected in accordance with their transmittance for the infrared light radiation 32 used. It is also expedient to use silicone materials that are resistant to temperatures of higher than 400° C.

[0307] As a further test, the test was carried out with a Kapton® film instead of the glass plate of the first experiment. This yielded very good results that show that Kapton® or similar polyimides are highly suitable for forming a flexible bracing element. Other vacuum packaging films with correspondingly high temperature resistance may also be used.

[0308] Polyimide is suitable both as a material for the bracing element 26 or also as a non-stick coating for the bracing element 26, which is composed for example of glass. Polyimide showed efficient properties as a peel-off film (release film 106) and prevents adhesion of fused thermoplastic material to the surface of the bracing element 26.

[0309] In a further test, workpiece parts 12,14 composed of the high-performance thermoplastic PEKK, reinforced with continuous carbon fibers, were welded to one another under the same conditions as described above for the first test. Here, too, the welding performance was the same as for laser transmission welding.

[0310] In tests, it was found that the infrared transmission welding illustrated here using simple polychromatic, incoherent infrared light can be used for different materials. Welding of test materials with continuous carbon fibers, continuous glass fibers and short glass fibers as fiber reinforcement was performed successfully. Welding is also suitable for materials with short carbon fibers and various other fibers, such as aramid, silk or other biologically producible fibers, both in the form of long or continuous fibers or of short fibers, as fiber reinforcement. Welding of test materials with a PEKK matrix and with a PPS matrix was performed successfully. The method is also suitable for LM PAEK, PEEK, PEI, PBI, PA, PE, etc. as a matrix.

[0311] Different possible applications for the above-discussed refinements of the infrared transmission welding method and of the above-discussed transmission to form welding apparatuses 20 will be discussed in more detail below with reference to FIGS. 7 through 12.

[0312] FIG. 1 shows a first possible application scenario in which the first workpiece part 12 and the second workpiece part 14 are continuously welded to one another at a butt joint.

[0313] FIG. 9 shows an example embodiment for the 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 vehicle illustrated in FIGS. 13 and 14 in the form of an aircraft configured as an airplane 54. The welding indicated in FIG. 9 can be used both for longitudinal connections 58 and for circumferential connections 60 of skin elements 50, 52 or of other fuselage components 62 or of wing components 64 of the aircraft 54.

[0314] In FIG. 9, the connection region 48 is illustrated in dashed lines by an oval. Two workpiece parts 14, 49 in the form of skin elements 50, 52 are to be connected to one another at a butt joint. In the application example of FIG. 9, a reinforcement strip 66 composed of thermoplastic fiber composite material is provided as the first workpiece part 12, which covers the butt joint between the second workpiece part 14 formed as the first skin element 50 and a third workpiece part 49 formed as the second skin element 52. The skin elements 50, 52 are formed for example from thermoplastic carbon fiber reinforced composite material (CFRP/TP). The reinforcement strip 66 used as a doubler is formed for example from unidirectional glass fibers in a thermoplastic matrix or as a carbon fiber-reinforced strip with a likewise thermoplastic matrix.

[0315] The welding may for example be performed through the reinforcement strip 66 from the right as seen in FIG. 9. That is to say, a transparent bracing element 26 is placed onto the reinforcement strip 66, and the infrared light radiation 32 is directed through the bracing 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 here. At the same time, the skin elements 50, 52 are welded to the reinforcement strip 66.

[0316] FIG. 10 shows a further possible application example, wherein a fastening element 70 is used as the first workpiece part 12 and a skin element 50 or a frame element 72 of the aircraft 56 is used as the second workpiece part 14.

[0317] The fastening element 70 may for example be a clip element, a fastening plate, a cleat, a hook, a fastening eyelet or the like. The fastening element 70 is for example in the form of a thermoplastic glass fiber composite material. The glass fibers may be present as short fibers, as unidirectional fibers or as continuous fibers. Alternatively, the fastening element may be in the form of a thermoplastic carbon fiber composite material part. Here, too, the carbon fibers may be unidirectional, in the form of short fibers or in the form of continuous fibers.

[0318] As before, possible materials for the frame element 72 or the skin element 50 are carbon fiber composite materials with a thermoplastic matrix. The same principle as in FIG. 10 can also be used for the welded connection of brackets or attachments.

[0319] FIG. 11 shows a further application scenario in which a coupling part 74 as the first workpiece part 12 is being welded to a skin element 50 or a frame element 72 as the second workpiece part 14. The coupling part 74 may then serve for the coupling-on of a further frame element 76 or of a second skin element 52.

[0320] Possible materials for the coupling part 74 are thermoplastic materials with glass or carbon fibers. The fibers may be provided unidirectionally, as continuous fibers or in the form of woven fabrics or scrims.

[0321] The frame element 72 may for example be designed as a stiffening element, for example in the form of a stringer 80 or of a former (not illustrated). Preferred materials for this are again carbon fiber composite materials with a thermoplastic matrix. The same principle as in FIG. 11 can also be applied for the coupling-on of other components, such as floor struts, seat rails, bearings, door frame and window frame parts or the like.

[0322] FIG. 12 shows a further application scenario, wherein a stiffening element 78, for example a stringer 80—as an example for a frame element 72—as the first workpiece part 12 is being welded to a skin element 50 as the second workpiece part 14.

[0323] FIG. 13 shows a highly schematic cross section through a fuselage component 62 of the aircraft 54 with the stringer 80, with a floor element 86 and with a retaining bracket 88 as examples of workpiece parts 12 that are to be connected to a frame element 52 or a skin element 50 of the fuselage component 62 by the transmission welding method.

[0324] FIG. 14 shows the side view of the airplane 54 as an example of the aircraft 56 with different possible areas of application for connections to be produced using the transmission welding method. For example, parts 82 that form a structure around a door 84 can also be welded.

[0325] Above, arrangements, apparatuses and methods for infrared transmission welding have been proposed and described on the basis of example embodiments.

[0326] A new technology is thus proposed which combines the advantages of laser transmission welding, conduction welding and conventional infrared welding and which can be carried out using simple equipment.

[0327] The proposed technology can be applied to different connections. Examples of these are the integration of stiffening elements 78, such as stringers 80, connections and couplings, integration of frames and fastening elements 70, integration of brackets and holders 88.

[0328] The technology has been successfully tested using very simple equipment. The welding capability was thus demonstrated. It has been shown that the infrared energy can transmit through thermoplastic first workpiece part to the connection region 48.

[0329] It has been shown that even high-performance thermoplastic materials, such as PEKK, with fiber reinforcement and fusion temperatures around approximately 330° C. can be welded.

[0330] It has been shown that transmission welding through a transparent bracing element 26, such as a glass plate, is possible.

[0331] It has also been shown that clamping force can be applied by the bracing element 26 at the same time.

[0332] While at least one example embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the example embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a”, “an” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.

LIST OF REFERENCE DESIGNATIONS

[0333] 10 Transmission welding arrangement

[0334] 12 First workpiece part

[0335] 14 Second workpiece part

[0336] 16 Weld point

[0337] 18 Workpiece

[0338] 20 Transmission welding apparatus

[0339] 22 Bracing device

[0340] 24 Infrared light source

[0341] 26 Bracing element

[0342] 28 Counterpart bracing element

[0343] 30 Bracing force generating device

[0344] 32 Infrared light radiation

[0345] 34 Bracing surface

[0346] 36 Rear side

[0347] 38 Fluid cavity

[0348] 40 Fluid medium

[0349] 42 Channel

[0350] 44 Additional layer

[0351] 46 Mechanical pressure

[0352] 48 Connecting region

[0353] 49 Third workpiece part

[0354] 50 First skin element

[0355] 52 Second skin element

[0356] 54 Airplane

[0357] 56 Aircraft

[0358] 58 Longitudinal connection

[0359] 60 Circumferential connection

[0360] 62 Fuselage component

[0361] 64 Wing component

[0362] 66 Reinforcement strip

[0363] 68 Butt joint

[0364] 70 Fastening element

[0365] 72 Frame element

[0366] 74 Coupling part

[0367] 76 Further frame element

[0368] 78 Stiffening element

[0369] 80 Stringer

[0370] 82 Part of a surrounding structure for door

[0371] 84 Door

[0372] 86 Floor element

[0373] 88 Retaining bracket

[0374] 90 Rolling body

[0375] 92 Tube

[0376] 94 Movement device

[0377] 96 Welding region

[0378] 96a Relatively warm zone of the welding region

[0379] 96b Relatively cold zone of the welding region

[0380] 98a First rigid segment

[0381] 98b Second rigid segment

[0382] 98c Third rigid segment

[0383] 98d Fourth rigid segment

[0384] 100a First pressure surface region

[0385] 100b Second pressure surface region

[0386] 100c Third pressure surface region

[0387] 100d Fourth pressure surface region

[0388] 100e Fifth pressure surface region

[0389] 102 Internal pressure

[0390] 104 Vacuum packaging film

[0391] 106 Separating film