ULTRASONIC WELDING DEVICE WITH A SONOTRODE CARRIER AND A SONOTRODE ATTACHED TO IT

Description

Field of the invention

[0001] The present invention relates to an ultrasonic welding device. Furthermore, the invention relates to a method for producing a sonotrode for such an ultrasonic welding device and a method for producing a sonotrode carrier for such an ultrasonic welding device. Background of the invention

[0002] Ultrasonic welding devices typically comprise a sonotrode carrier to which a replaceable sonotrode can be attached. The sonotrode carrier can be used to cause the sonotrode to vibrate ultrasonically, the energy of which can then be transferred via the sonotrode to a workpiece to be welded. Depending on the application, the sonotrode carrier can be combined with different types of sonotrodes, such as sonotrodes for spot or seam welding, or sonotrodes in the form of a flexible oscillator, which can also be used in hard-to-reach places (to name just a few examples).

[0003] The sonotrode can be screwed to the sonotrode carrier using one or more screws. Incorrect tightening torques of the screw(s), for example, due to the use of incorrect tools or dirty or faulty coupling surfaces, can significantly influence the vibration behavior of the sonotrode and thus the welding behavior of the ultrasonic welding device. Insufficient clamping force, for example, can cause the sonotrode to twist during welding and / or excessively deform in the area of ​​the coupling surfaces, which can negatively impact the welding result. In the worst case, this can lead to breakage of the sonotrode and / or the screw(s).

[0004] DE 103 30 431 B3 describes an ultrasonic welding device with several elements that are connected to one another via coupling surfaces.

[0005] US 2021 / 0154948 A1 describes an ultrasonic welding device with an interchangeable anvil. Summary of the invention and advantageous embodiments

[0006] There may therefore be a need for an ultrasonic welding device that enables improved attachment of a sonotrode to a sonotrode carrier.

[0007] Furthermore, there may be a need for a method for producing a correspondingly improved sonotrode.

[0008] Last but not least, there may be a need for a method for producing a correspondingly improved sonotrode carrier.

[0009] These needs can be met by the subject matter of the independent claims. Advantageous embodiments are set forth in the dependent claims, the following description, and the accompanying figures.

[0010] A first aspect of the invention relates to an ultrasonic welding device according to claim 1. The ultrasonic welding device comprises at least one sonotrode and a sonotrode carrier configured to cause the sonotrode to vibrate ultrasonically. The sonotrode and the sonotrode carrier each have a contact surface, also referred to above as a coupling surface. At least one of the contact surfaces is roughened, at least in sections. The sonotrode is replaceably attached to the sonotrode carrier in such a way that the contact surfaces are pressed against each other.

[0011] A second aspect of the invention relates to a method according to claim 8 for producing a sonotrode for an ultrasonic welding device, as described above and below. The method comprises at least one step of providing the sonotrode in a state to be machined and a step of machining the sonotrode to roughen the contact surface of the sonotrode at least in sections.

[0012] A third aspect of the invention relates to a method according to claim 9 for producing a sonotrode carrier for an ultrasonic welding device, as described above and below. The method comprises at least one step of providing the sonotrode carrier in a state to be machined and a step of machining the sonotrode carrier to roughen the contact surface of the sonotrode carrier at least in sections.

[0013] It should be noted that features of the ultrasonic welding device can also be understood as features of the methods described above and below and vice versa.

[0014] As mentioned at the beginning, the connection between the sonotrode and the sonotrode carrier is crucial for the quality of the welding result. The quality of this connection can depend on various factors, such as whether the specified tightening torque of the screw(s) is observed, how clean the contact surfaces are, or the production-specific surface finish of the contact surfaces.

[0015] The approach presented here makes it possible to make the connection between the sonotrode and the sonotrode carrier significantly more resistant to contamination, such as oil or grease, errors in the maintenance and assembly of the sonotrode, and variations in the manufacturing of the components in question, all without creating unwanted notches on the sonotrode and / or the sonotrode carrier. Such notches—even if relatively small—can potentially lead to damage given the heavy stress to which the sonotrode or the sonotrode carrier is exposed during welding.

[0016] This is achieved in principle by appropriately increasing the friction between the sonotrode and the sonotrode carrier by deliberately roughening one or both contact surfaces, or at least a section thereof. In other words, by appropriately roughening the sonotrode and / or the sonotrode carrier using a suitable machining process, one or more roughened sections can be created within one or both contact surfaces, which can interlock with the corresponding counterpart, for example, one or more unroughened sections and / or one or more similarly roughened sections of the counterpart, on a microscopic scale. Such micro-toothing ensures a secure connection between the sonotrode and the sonotrode carrier during welding, without the need to increase the clamping force with which the sonotrode and the sonotrode carrier are pressed against each other.

[0017] This advantageous effect was demonstrated in experiments in which a torsional force was measured that is required to twist a sonotrode in the form of a so-called flexural oscillator (see below) relative to the sonotrode carrier.

[0018] The following parameters were used for the tests: distance of the force application point for the torsional force from the center of the sonotrode: 78 mm; feed rate: 2 mm / min; tightening torque of the screws securing the sonotrode to the sonotrode carrier: 20 Nm. The force was applied perpendicular to the longitudinal axis of the sonotrode.

[0019] The torsional force was increased from approximately 550 N for a sonotrode with an unmachined, i.e., non-specially roughened, contact surface to approximately 800 N for a sonotrode with a laser-roughened contact surface, and even to 1150 N for a sonotrode with a contact surface roughened by irradiation with glass beads. Thus, the stability of the fastening was more than doubled while maintaining the same tightening torque. In terms of vibration, all tested sonotrodes exhibited no noticeable behavior.

[0020] The increase in torsional force can be explained by the fact that a defined structure within the contact surface on the sonotrode and / or on the sonotrode carrier creates a type of positive connection on a microscopic scale, i.e. micro-toothing. The structure can be designed in such a way that it penetrates minimally into the corresponding counterpart, i.e. that the sonotrode and the sonotrode carrier do not contact each other at the contact surface in a point-like or linear manner, but rather across a surface. The structure used for the micro-toothing and / or a surface of the counterpart pressed together with the structure can deform slightly elastically and / or plastically. Protruding edges or points of the structure created by roughening can penetrate slightly into material of the counterpart close to the surface and thus create the micro-toothing.The deformations can be only a few micrometers in size or even smaller, in particular significantly smaller than the structure created by roughening.

[0021] Some of the terms used above and below are explained in more detail below.

[0022] A contact surface can be understood, on the one hand, as a macroscopically flat surface section of the sonotrode where the sonotrode makes contact with the contact surface of the sonotrode carrier. On the other hand, it can be understood as a macroscopically flat surface section of the sonotrode carrier where the sonotrode carrier makes contact with the contact surface of the sonotrode. The two contact surfaces can be aligned by attaching the sonotrode to the sonotrode carrier and pressed against each other with a defined clamping force.

[0023] It is possible that the sonotrode and the sonotrode carrier only touch at their contact surfaces.

[0024] The contact surface may be roughened in sections, i.e., in one or more contiguous or separate sections. Alternatively, the entire contact surface may be roughened, i.e., the roughened section may extend over the entire contact surface.

[0025] In this context, a roughened section can be understood to mean a specially machined, for example flat, section of the contact surface, which as a result of the special processing has a significantly greater roughness than a section of the contact surface that has not been machined in this way or than any other surface of the sonotrode and / or the sonotrode carrier. For this purpose, the contact surface can have been machined, for example, using a mechanical, optical, electrical (e.g. erosion), electrochemical or chemical surface treatment process, or at least two of these processes in combination. In other words, a special friction-increasing structure can be formed in the region of the contact surface as a result of the processing, whereby the friction-increasing properties of the structure can be the same in all directions, i.e., non-directional or isotropic, or different in different directions, i.e., directional or anisotropic.

[0026] The roughness of a section of the contact surface roughened in this way can differ quantitatively and / or qualitatively from the roughness of a section of the contact surface not roughened in this way. The unroughened section can be essentially smooth, although any microscopic irregularities on the surface of this section can be caused by a manufacturing or machining process. For example, the unroughened section can have residual roughness resulting from machining of the component in question and / or from grinding, sanding, or polishing of the component in question. Such residual roughness is generally anisotropic, i.e. the section in question generally has a surface structure with a preferred direction, which can, for example, correspond to a machining direction during machining, grinding, sanding, or polishing.The roughness of the deliberately roughened section of the contact surface can be significantly greater than the non-roughened section, for example by a factor of 2, 5 or even 10. In addition, techniques that produce an isotropic rough surface structure, ie without a preferred direction, such as laser irradiation, particle blasting, in particular glass bead blasting or sandblasting, can be used to deliberately roughen the contact surface.

[0027] The sonotrode carrier can, for example, comprise a converter and / or a booster. Additionally, the sonotrode carrier can comprise a generator. The sonotrode can be attached to a free end of the (elongated) sonotrode carrier, for example, the booster or the converter, in particular such that an oscillation axis, along which the sonotrode carrier can be moved back and forth at frequencies in the ultrasonic range, is perpendicular to the contact surfaces.

[0028] In certain embodiments, the sonotrode carrier may additionally comprise an intermediate piece which may be attached to the booster or converter on the one hand and to which the sonotrode may be attached on the other hand.

[0029] A converter can be understood as an electromechanical component which is designed to convert a high-frequency electrical voltage provided by the generator into mechanical ultrasonic vibrations with a corresponding frequency in the ultrasonic range, for example between 20 kHz and 100 kHz, preferably between 20 kHz and 35 kHz.

[0030] The booster, also called a translation or amplitude transformation piece, can be designed to modify the amplitude of the ultrasonic vibrations provided by the converter, i.e., to reduce and / or increase the amplitude, and to transmit the thus modified ultrasonic vibrations to the sonotrode. Additionally, the booster can be designed to support the sonotrode carrier in the ultrasonic welding device.

[0031] A sonotrode can be understood as a tool that can be set into correspondingly high-frequency resonant vibrations by introducing ultrasonic vibrations and is designed to transmit these vibrations to one or more workpieces to be welded. For example, the sonotrode, especially if it is designed as a two-arm flexural oscillator (see below), can be shaped symmetrically with respect to its longitudinal and / or transverse axis. This prevents uneven stress on the sonotrode.

[0032] According to one embodiment, the sonotrode can be replaceably attached to the sonotrode carrier via at least one screw. The screw can press the contact surfaces together. This enables controlled compression of the contact surfaces. Furthermore, replacing the sonotrode can be simplified. The sonotrode can also be replaceably attached to the sonotrode carrier via two or more screws.

[0033] According to one embodiment, the screw can be inserted into a sonotrode opening in the sonotrode, and the sonotrode opening can be at least partially surrounded by the contact surface of the sonotrode. Additionally or alternatively, the screw can be inserted into a sonotrode carrier opening in the sonotrode carrier, and the sonotrode carrier opening can be at least partially surrounded by the contact surface of the sonotrode carrier. In other words, the screw can pass transversely, in particular vertically, through one or both contact surfaces. Thus, the frictional connection between the two contact surfaces can be improved.

[0034] According to one embodiment, the sonotrode opening can be surrounded by the contact surface of the sonotrode in a ring-shaped and / or ring-segment-shaped manner. Additionally or alternatively, the sonotrode carrier opening can be surrounded by the contact surface of the sonotrode carrier in a ring-shaped and / or ring-segment-shaped manner. This can simplify the alignment of the sonotrode relative to the sonotrode carrier, particularly if the sonotrode is attached to the sonotrode carrier with only one screw.

[0035] According to one embodiment, the sonotrode opening can be surrounded by at least one annular and / or ring-segment-shaped roughened section of the contact surface of the sonotrode. Additionally or alternatively, the sonotrode carrier opening can be surrounded by at least one annular and / or ring-segment-shaped roughened section of the contact surface of the sonotrode carrier. Thus, unwanted rotation of the sonotrode relative to the sonotrode carrier during welding can be effectively prevented, especially when the sonotrode is attached to the sonotrode carrier with only one screw.

[0036] According to one embodiment, at least one of the contact surfaces can comprise a striped pattern consisting of several striped, roughened sections. The striped sections can be oriented in the same direction or in different directions. It is expedient if the striped sections are distributed over the entire contact surface, in particular evenly distributed. The striped pattern can be created, for example, by laser machining the sonotrode or the sonotrode carrier. Particularly good results have been achieved in tests with this embodiment.

[0037] According to one embodiment, the roughened sections of the striped pattern can be arranged parallel to one another. The roughened sections of the same contact surface or of different contact surfaces can be arranged parallel to one another. Additionally, each roughened section of the striped pattern can run parallel to the longitudinal direction of the sonotrode. This embodiment has also achieved particularly good results in tests.

[0038] A roughened section of the contact surface which is at least partially roughened has a roughness which is characterized by an average roughness depth R z of the roughened section greater than 2.0 µm and / or a mean roughness value R a of the roughened section is greater than 0.3 µm. Such lower limits have proven particularly suitable for practical use in tests.

[0039] The average roughness depth R zis less than 14 µm. In addition or alternatively, the mean roughness R a less than 3.0 µm. Such upper limits have proven particularly suitable for practical use in experiments.

[0040] For example, the following roughness values ​​were measured in tests: for a section of the contact surface roughened by irradiation with glass beads: 0.53 µm for R a ; 3.29 µm for R z ; for a section of the contact surface roughened by laser treatment: 2.43 µm for R a ; 13.27 µm for R z ; for a non-roughened, i.e. untreated or merely ground section of the contact surface: 0.16 µm for R a ; 0.90 µm for R z .

[0041] The sonotrode is designed as a bending oscillator comprising a base body and at least one bending arm extending from the base body. The sonotrode can be exchangeably attached to the sonotrode carrier via the base body, and the base body can encompass the contact surface of the sonotrode. This has the effect of exciting the sonotrode to transverse oscillations, i.e., it is elastically deformed in a serpentine pattern when oscillating. The sonotrode can have several points, also called zero crossings, at which its deflection is zero or negligibly small relative to an imaginary zero line. This design makes it possible to weld even workpieces that are difficult to access.

[0042] It is possible for the base body to be the widest part of the sonotrode, while the bending arm can be significantly narrower and / or thinner than the base body, at least in sections. A sonotrode in the form of a rod-shaped flexural oscillator is also possible. For example, the cross-section of the bending arm can taper with increasing distance from the base body. This means that a free end of the bending arm can be moved closer to workpieces that are difficult to access without significantly compromising the strength of the bending arm. To ensure that the bending arm can oscillate freely, it should not touch the sonotrode carrier. In other words, it is possible for the sonotrode to contact the sonotrode carrier exclusively with its base body when oscillating, i.e. during welding. During welding, the bending arm can touch a workpiece to be welded with its free end.

[0043] For example, the flexural oscillator can comprise two bending arms that protrude from the base body in opposite directions.

[0044] According to one embodiment, the processing of the contact surface of the sonotrode and / or the sonotrode carrier can comprise laser treatment, mechanical processing by irradiation with a blasting agent, or a combination of both. This allows the processing of the sonotrode or the sonotrode carrier to be carried out with particular precision. For example, laser treatment can melt the contact surface in question at several locations using laser pulses. Depending on the selected laser parameters, microscopically small elevations can form at the relevant locations, which can have the effect of micro-toothing. For example, laser treatment can produce a precise stripe pattern consisting of several strip-shaped, roughened sections (see above).Ring-shaped and / or ring-segment-shaped patterns are also conceivable, for example, patterns consisting of several concentric rings and / or concentric ring segments. Suitable blasting media include glass beads or sand. Other blasting media are also possible.

[0045] It should be noted that possible features and advantages of embodiments of the invention are described above and below partly with reference to an ultrasonic welding device, partly with reference to a method for producing a correspondingly adapted sonotrode of the ultrasonic welding device, and partly with reference to a method for producing a correspondingly adapted sonotrode carrier of the ultrasonic welding device. A person skilled in the art will recognize that the features described for individual embodiments can be transferred, adapted, and / or exchanged in an analogous and suitable manner to other embodiments in order to achieve further embodiments of the invention and possibly synergistic effects. Short description of the drawings

[0046] Advantageous embodiments of the invention are further explained below with reference to the accompanying drawings. Fig. 1shows an ultrasonic welding device according to an embodiment of the invention. Fig. 2 shows a sonotrode carrier of an ultrasonic welding device according to an embodiment of the invention in plan view. Fig. 3 shows a side view of the sonotrode carrier. Fig. 4 shows a section of an easily screwable sonotrode of an ultrasonic welding device according to an embodiment of the invention. Fig. 5 shows a section of a double-screwable sonotrode of an ultrasonic welding device according to an embodiment of the invention. Fig. 6 shows a section of a double-screwable sonotrode of an ultrasonic welding device according to another embodiment of the invention.

[0047] The figures are merely schematic and not to scale. The same reference numerals designate the same or equivalent features in the various drawings. Description of advantageous embodiments

[0048] Fig. 1 shows an ultrasonic welding device 1 comprising a sonotrode carrier 2 and a sonotrode 3, which can be set into ultrasonic vibrations by means of the sonotrode carrier 2 (a vibration direction of the sonotrode carrier 2 is marked with a double arrow). The sonotrode 3 is replaceably attached to the sonotrode carrier 2, here via a screw 4 at a free end of the sonotrode carrier 2. The sonotrode 3 and the sonotrode carrier 2 each have a contact surface 5 at which they touch each other.

[0049] The two contact surfaces 5 can be pressed against each other with a defined clamping force using the screw 4.

[0050] At least one of the two contact surfaces 5 is roughened, at least in sections. This improves the frictional connection between the two contact surfaces 5.

[0051] The sonotrode carrier 2 can comprise a converter 6 for converting a high-frequency electrical voltage into mechanical ultrasonic vibrations and a booster 7 for transmitting the ultrasonic vibrations to the sonotrode 3. The booster 7 can be designed to suitably change the amplitude of the ultrasonic vibrations. The sonotrode 3 can accordingly be attached to a free end of the booster 7. Attaching the sonotrode 3 to the converter 6 is also possible. In this case, the booster 7 can be omitted. Additionally, the sonotrode carrier 2 can comprise a generator for providing the electrical voltage.

[0052] In this example, the sonotrode 3 is designed as a bending oscillator comprising a base body 8 and two bending arms 9 extending from the base body 8 in opposite directions. However, a sonotrode 3 with only one bending arm 9 is also possible. The sonotrode 3 is attached to the sonotrode carrier 2 via the base body 8 and contacts it exclusively at the base body 8. The contact surface 5 of the sonotrode 3 is thus provided by the base body 8.

[0053] Two plate-shaped workpieces 11, which partially overlap, are arranged between a free end of one of the bending arms 9 and an anvil 10. The two workpieces 11 can be welded together by the oscillating sonotrode 3.

[0054] Contrary to the Fig. 1 As shown, the anvil 10 can alternatively be formed at least partially by at least one of the workpieces 11 itself.

[0055] As in Fig. 2As can be seen, it is possible for the contact surface 5 of the sonotrode carrier 2 to have a central sonotrode carrier opening 12 into which the screw 4 can be screwed. The contact surface 5 of the sonotrode carrier 2 can, for example, surround the sonotrode carrier opening 12 in a ring shape.

[0056] Accordingly, the contact surface 5 of the sonotrode 3 can have a sonotrode opening 13 through which the screw 4 can be passed. The contact surface 5 of the sonotrode 3 can also surround the sonotrode opening 13 in a ring shape (see Fig. 4 ).

[0057] The contact surface 5 of the sonotrode carrier 2 can comprise a roughened section 14, the roughness of which is significantly greater than in the remaining contact surface 5.

[0058] For example, the roughened section 14 may have an average roughness depth R z between 2.0 µm and 14 µm.

[0059] Additionally or alternatively, the roughened section 14 may, for example, have a mean roughness value R a between 0.3 µm and 3.0 µm.

[0060] The roughened section 14 can surround the sonotrode carrier opening 12 in a ring-shaped manner, similar to the contact surface 5. However, an arrangement of one or more ring-segment-shaped roughened sections 14 is also possible, as in Fig. 4 shown using the example of the sonotrode 3. An arrangement of several concentric ring-shaped and / or ring-segment-shaped roughened sections 14 is also conceivable.

[0061] The roughened section 14 or the roughened sections 14 can be smaller in area than the respective contact surface 5 or the same size as the respective contact surface 5, ie the entire contact surface 5 can also be roughened.

[0062] It is possible that the contact surface 5 of the sonotrode carrier 2 is formed by a flat elevation 15 on the front side of the sonotrode carrier 2, as in Fig. 3 shown. This can prevent, for example, the bending arms 9 from being touched by the sonotrode carrier 2 in the oscillating state.

[0063] Contrary to the Fig. 4, Fig. 5 and Fig. 6 In the embodiments shown, the sonotrode 3, for example its base body 8, can alternatively or additionally be designed with such a flat elevation.

[0064] Alternatively or in addition to the sonotrode carrier 2, the contact surface 5 of the sonotrode 3 can be roughened in a corresponding manner, at least in sections. Fig. 4 shows an example of a sonotrode 3 with four ring-segment-shaped roughened sections 14 within the contact surface 5 of the sonotrode 3.

[0065] A striped pattern 16 with several striped roughened sections 14 is also possible, as in Fig. 5 The sections 14 of the stripe pattern 16 are, for example, aligned parallel to one another and distributed across the width of a rectangular contact surface 5 of the sonotrode 3. However, stripe patterns 16 are also possible whose sections 14 are oriented in different directions, for example, in mutually orthogonal directions.

[0066] Furthermore, in this example, the contact surface 5 has two sonotrode openings 13, each for receiving a screw 4 (correspondingly, the sonotrode carrier 2 can also have two sonotrode carrier openings 12). At least one of the sections 14 of the stripe pattern 16 can be located between the sonotrode openings 13 and / or at least one of the sonotrode openings 13 can be located between two sections 14 of the stripe pattern 16.

[0067] Alternatively, the entire contact surface 5 of the sonotrode 3 can be roughened (see Fig. 6 ).

[0068] It is pointed out that the examples of a roughened contact surface 5 described above with reference to the sonotrode 3 can apply correspondingly to the sonotrode carrier 2 and vice versa.

[0069] During assembly, the sonotrode 3 can be screwed to the sonotrode carrier 2 with a defined tightening torque so that the contact surfaces 5 touch completely and remain in contact during welding.

[0070] The contact surface 5 of the sonotrode 3 and / or the sonotrode carrier 2 can be produced, for example, by machining, preferably by grinding or milling.

[0071] If the sonotrode 3, as is often the case, is made of a harder material than the sonotrode carrier 2, a friction-enhancing structure comprising one or more roughened sections 14 should be created on the sonotrode 3. This simplifies the penetration of the structure into the (softer) sonotrode carrier 2. However, the reverse is also conceivable. By replacing the sonotrode 3, which is usually a wear part, the structure can be conveniently renewed at the same time.

[0072] If the sonotrode carrier 2 is similarly hard to the sonotrode 3, the structure can be created, for example, by laser treatment on the sonotrode 3, whereby the hardness of the sonotrode 3 is locally increased.

[0073] The structure should be designed in such a way that a uniform pressure pattern is produced on the contact surfaces 5. Furthermore, the structure should be designed in such a way that the sonotrode 3 remains sufficiently connected to the contact surface 5 of the sonotrode carrier 2 in the oscillating state. A structure suitable in this sense can be created, for example, by blasting, lasering, and / or eroding one or both contact surfaces 5. List of reference symbols

[0074] 1Ultrasonic welding device 2Sonotrode carrier 3Sonotrode 4Screw 5Contact surface 6Converter 7Booster 8Base body 9Bending arm 10Anvil 11Workpiece 12Sonotrode carrier opening 13Sonotrode opening 14Roughened section 15Flat elevation 16Stripe pattern

Claims

1. Ultrasound welding device (1), comprising: a sonotrode (3); and a sonotrode carrier (2) configured to set the sonotrode (3) in ultrasound oscillations; wherein the sonotrode (3) and the sonotrode carrier (2) each have a contact face (5) and at least one of the contact faces (5) is roughened at least in portions; wherein a roughened portion (14) of the contact face (5) roughened at least in portions has an mean roughness depth Rz of at least 2.0 um and / or an average roughness value Ra of at least 0.3 um; wherein the mean roughness depth Rz is at most 14 um and / or wherein the average roughness value Ra is at most 3.0 um; wherein the sonotrode (3) is fixed replaceably on the sonotrode carrier (2) in such a way that the contact faces (5) are pressed against one another, wherein the sonotrode (3) is configured as a flexural resonator, comprising a base body (8) and at least one bending arm (9) protruding from the base body (8); wherein the sonotrode (3) is fixed replaceably on the sonotrode carrier (2) via the base body (8), and the base body (8) comprises the contact face (5) of the sonotrode (3) .

2. Ultrasound welding device (1) according to claim 1, wherein the sonotrode (3) is fixed replaceably on the sonotrode carrier (2) via at least one screw (4).

3. Ultrasound welding device (1) according to claim 2, wherein the screw (4) is inserted into a sonotrode opening (13) in the sonotrode (3), and the sonotrode opening (13) is enclosed at least in part by the contact face (5) of the sonotrode (3); and / or wherein the screw (4) is inserted into a sonotrode carrier opening (12) in the sonotrode carrier (2), and the sonotrode carrier opening (12) is enclosed at least in part by the contact face (5) of the sonotrode carrier (2).

4. Ultrasound welding device (1) according to claim 3, wherein the sonotrode opening (13) is enclosed in a ring shape and / or in a ring segment shape by the contact face (5) of the sonotrode (3); and / or wherein the sonotrode carrier opening (12) is enclosed in a ring shape and / or in a ring segment shape by the contact face (5) of the sonotrode carrier (2).

5. Ultrasound welding device (1) according to either claim 3 or claim 4, wherein the sonotrode opening (13) is enclosed by at least one roughened portion (14), in a ring shape and / or in a ring segment shape, of the contact face (5) of the sonotrode (3); and / or wherein the sonotrode carrier opening (12) is enclosed by at least one roughened portion (14), in a ring shape and / or in a ring segment shape, of the contact face (5) of the sonotrode carrier (2).

6. Ultrasound welding device (1) according to one of the preceding claims, wherein at least one of the contact faces (5) comprises a strip pattern (16) consisting of a plurality of strip-shaped roughened portions (14).

7. Ultrasound welding device (1) according to claim 6, wherein the roughened portions (14) of the strip pattern (16) are arranged mutually parallel.

8. Method for producing a sonotrode (3) for an ultrasound welding device (1) according to one of the preceding claims, wherein the method comprises: providing the sonotrode (3) in a state for machining, the sonotrode (3) being configured as a flexural resonator, comprising a base body (8) and at least one bending arm (9) protruding from the base body (8), and the sonotrode (3) being intended to be fixed replaceably on a sonotrode carrier (2) via the base body (8), and the base body (8) comprising a contact face (5) of the sonotrode (3); and machining the sonotrode (3) to roughen the contact face (5) of the sonotrode (3) at least in portions, wherein a roughened portion (14) of the contact face (5) roughened at least in portions has an mean roughness depth Rz of at least 2.0 um and / or an average roughness value Ra of at least 0.3 um; and wherein the mean roughness depth Rz is at most 14 um and / or wherein the average roughness value Ra is at most 3.0 um.

9. Method for producing a sonotrode carrier (2) for an ultrasound welding device (1) according to one of claims 1 to 7, wherein the method comprises: providing the sonotrode carrier (2) in a state for machining, the sonotrode carrier (2) being configured to set a sonotrode (3) in ultrasound oscillations, the sonotrode (3) being configured as a flexural resonator, comprising a base body (8) and at least one bending arm (9) protruding from the base body (8), and the sonotrode (3) being intended to be fixed replaceably on the sonotrode carrier (2) via the base body (8), and the base body (8) comprising a contact face (5) of the sonotrode (3); and machining the sonotrode carrier (2) to roughen the contact face (5) of the sonotrode carrier (2) at least in portions, wherein a roughened portion (14) of the contact face (5) roughened at least in portions has an mean roughness depth Rz of at least 2.0 um and / or an average roughness value Ra of at least 0.3 um; and wherein the mean roughness depth Rz is at most 14 um and / or wherein the average roughness value Ra is at most 3.0 µm.

10. Method according to either claim 8 or claim 9, wherein the machining comprises laser treatment and / or mechanical machining by jetting using a jetting means.