US-12617037-B2 - Ultrasonic welding device comprising a sonotrode carrier and a sonotrode fastened thereto

US12617037B2US 12617037 B2US12617037 B2US 12617037B2US-12617037-B2

Abstract

An ultrasonic welding device comprises a sonotrode and a sonotrode carrier which is formed to cause ultrasonic vibrations of the sonotrode. The sonotrode and the sonotrode carrier have in each case a contact face, wherein at least one of the contact faces is roughened at least in sections. The sonotrode is fastened exchangeably to the sonotrode carrier in such a manner that the contact faces are pushed against one another.

Inventors

Stefan Müller
Valentin Muela

Assignees

SCHUNK SONOSYSTEMS GMBH

Dates

Publication Date: 20260505
Application Date: 20211216

Claims (11)

1 . An ultrasonic welding device, comprising: a sonotrode; and a sonotrode carrier which is formed to cause ultrasonic vibrations of the sonotrode; wherein the sonotrode and the sonotrode carrier have in each case a contact face and at least one of the contact faces is roughened at least in sections, and the sonotrode is fastened exchangeably to the sonotrode carrier in such a manner that the contact faces are pushed against one another; wherein a roughened section of the least one contact face roughened at least in sections has a mean roughness depth R z of at least 2.0 μm and/or an arithmetical mean roughness value R a of at least 0.3 μm; wherein the mean roughness depth R z is at most 14 μm and/or wherein the arithmetical mean roughness value R a is at most 3.0 μm; wherein the sonotrode is embodied as a flexural resonator which comprises a base body and at least one bending arm which projects from the base body; and wherein the sonotrode is fastened exchangeably to the sonotrode carrier via the base body and the base body comprises the contact face of the sonotrode.
2 . The ultrasonic welding device according to claim 1 , wherein the sonotrode is fastened exchangeably to the sonotrode carrier via at least one screw.
3 . The ultrasonic welding device according to claim 2 , wherein at least one of the following conditions applies: (i) the at least one screw is introduced into a sonotrode opening in the sonotrode and the sonotrode opening is surrounded at least partially by the contact face of the sonotrode; (ii) the at least one screw is introduced into a sonotrode carrier opening in the sonotrode carrier and the sonotrode carrier opening is surrounded at least partially by the contact face of the sonotrode carrier.
4 . The ultrasonic welding device according to claim 3 , wherein at least one of the following conditions applies: (i) the sonotrode opening is surrounded in a ring-shaped and/or ring segment-shaped manner by the contact face of the sonotrode; (ii) the sonotrode carrier opening is surrounded in a ring-shaped and/or ring segment-shaped manner by the contact face of the sonotrode carrier.
5 . The ultrasonic welding device according to claim 3 , wherein at least one of the following conditions applies: (i) the sonotrode opening is surrounded by at least one ring-shaped and/or ring segment-shaped roughened section of the contact face of the sonotrode; (ii) the sonotrode carrier opening is surrounded by at least one ring-shaped and/or ring segment-shaped roughened section of the contact face of the sonotrode carrier.
6 . The ultrasonic welding device according to claim 1 , wherein at least one of the contact faces comprises a striped pattern composed of several stripe-shaped roughened sections.
7 . The ultrasonic welding device according to claim 6 , wherein the roughened sections of the striped pattern are arranged parallel to one another.
8 . A method for producing the sonotrode for the ultrasonic welding device according to claim 1 , wherein the method comprises: providing the sonotrode in a state to be processed; and processing the sonotrode in order to roughen the contact face of the sonotrode at least in sections, wherein a roughened section of the contact face of the sonotrode roughened at least in sections has a mean roughness depth R z of at least 2.0 μm and/or an arithmetical mean roughness value R a of at least 0.3 μm; and wherein the mean roughness depth R z is at most 14 μm; and/or wherein the arithmetical mean roughness value R a is at most 3.0 μm.
9 . A method for producing the sonotrode carrier for the ultrasonic welding device according to claim 1 , wherein the method comprises: providing the sonotrode carrier in a state to be processed, wherein the sonotrode carrier is configured for generating ultrasonic vibrations in a sonotrode; and processing the sonotrode carrier in order to roughen the contact face of the sonotrode carrier at least in sections, wherein a roughened section of the contact face of the sonotrode carrier roughened at least in sections has a mean roughness depth R z of at least 2.0 μm and/or an arithmetical mean roughness value R a of at least 0.3 μm; and wherein the mean roughness depth R z is at most 14 μm; and/or wherein the arithmetical mean roughness value R a is at most 3.0 μm.
10 . The method according claim 8 , wherein the processing comprises laser treatment and/or mechanical processing by blasting with a blasting agent.
11 . The method according claim 9 , wherein the processing comprises laser treatment and/or mechanical processing by blasting with a blasting agent.

Description

FIELD The present invention relates to an ultrasonic welding device. The invention furthermore 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 Ultrasonic welding devices generally comprise a sonotrode carrier to which a sonotrode may be exchangeably fastened. Ultrasonic vibrations of the sonotrode may be brought about by means of the sonotrode carrier, the energy of which vibrations may then be transmitted via the sonotrode to a workpiece to be welded. Depending on the application, the sonotrode carrier may be combined with different types of sonotrodes, such as, for example, for spot or roll seam welding or sonotrodes in the form of a flexural resonator which may also be used at points which are difficult to access (only to mention a few examples). The sonotrode may be screwed to the sonotrode carrier, for example, via one or more screws. Deviating tightening torques of the screw(s), for example, as a result of the use of incorrect tools or as a result of dirty or defective coupling faces, may significantly influence the vibration properties of the sonotrode and thus the welding properties of the ultrasonic welding device. An insufficient clamping force may lead, for example, to the sonotrode rotating during welding operation and/or being excessively deformed in the region of the coupling faces, which may have a negative effect on the welding result. In a worst case, the sonotrode and/or the screw(s) may break. SUMMARY There may therefore be a need for an ultrasonic welding device which enables improved fastening of a sonotrode to a sonotrode carrier. There may furthermore be a need for a method for producing a correspondingly improved sonotrode. Not least, there may be a need for a method for producing a correspondingly improved sonotrode carrier. 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 which is formed to cause ultrasonic vibrations of the sonotrode. The sonotrode and the sonotrode carrier have in each case a contact face, also referred to below as a coupling face. At least one of the contact faces is roughened at least in sections. The sonotrode is fastened exchangeably to the sonotrode carrier in such a manner that the contact faces are pushed against one another. A second aspect of the invention relates to a method for producing a sonotrode for an ultrasonic welding device, as is described above and below. The method comprises at least one step of providing the sonotrode in a state to be processed and a step for processing the sonotrode in order to roughen the contact face of the sonotrode at least in sections. A third aspect of the invention relates to a method for producing a sonotrode carrier for an ultrasonic welding device, as is described above and below. The method comprises at least one step of providing the sonotrode carrier in a state to be processed and a step of processing the sonotrode carrier in order to roughen the contact face of the sonotrode carrier at least in sections. It should be pointed out that features of the ultrasonic welding device may also be understood as features of the methods described above and below and vice versa. Without restricting the scope of the invention in any manner, embodiments of the invention may be regarded as being based on the concepts and findings described below. As already mentioned, the connection between the sonotrode and the sonotrode carrier is decisive for the quality of the welding result. How good this connection is may depend on various influencing factors, for example, on whether the specified tightening torque of the screw(s) is adhered to, how clean the contact faces are, or on the production-specific surface properties of the contact faces. The approach presented here thus makes it possible to make the connection between the sonotrode and the sonotrode carrier significantly less sensitive to contamination, for example, by oil or grease, to errors in the maintenance and mounting of the sonotrode and to fluctuations in the production of the relevant components, and indeed without undesirable notches being generated on the sonotrode and/or the sonotrode carrier. Such notches may, even if they are relatively small, given the high level of strain to which the sonotrode or the sonotrode carrier is exposed during welding operation, potentially lead to damage. This is in principle achieved in that the friction between the sonotrode and the sonotrode carrier is increased by targeted roughening of one or both contact faces, or at least one section thereof, in a suitable manner. In other words, by corresponding roughening of the sonotrode and/or the sonotrode carrier using a suitable processing method, one or more roughened sections may be created within one or both contact faces