Ultrasonic welding apparatus and method for welding processing of materials

Abstract

The present invention relates to an ultrasonic welding system (1), comprising: - an ultrasonic oscillation unit having an ultrasonic welding electrode (2) and a transducer (3), wherein the ultrasonic welding electrode (2) and the transducer (3) are arranged one after another along a longitudinal axis, an amplitude converter is optionally inserted therebetween, and the ultrasonic oscillation unit is enabled to resonate along the longitudinal axis by means of ultrasonic vibration having wavelength A; and - a mating tool (11); wherein the ultrasonic welding electrode (2) has sealing surfaces (12; 13) and the longitudinal axis travels parallel to the sealing surfaces (12, 13) or forms an angle of less than 90° with the sealing surfaces; the mating tool (11) includes a mating tool sealing surface (16) facing the sealing surfaces (12, 13) of the ultrasonic welding electrode (2); and the ultrasonic welding electrode (2) and the mating tool (11) are movable relative to each other in a processing direction perpendicular to the longitudinal axis, thereby adjusting the distance between the sealing surfaces (12, 13) of the ultrasonic welding electrode (2) and the mating tool sealing surface (16). According to the present invention, in order to describe in detail the ultrasonic welding system that at least reduces the described disadvantages, the ultrasonic oscillation unit or mating tool is held by a rotary retainer that can rotate about a rotation axis that travels perpendicular to the longitudinal axis, the rotation axis being arranged such that the distance between the sealing surfaces (12, 13) of the ultrasonic welding electrode (2) and the sealing surface (16) of the mating tool can be adjusted by means of the rotation of the rotary retainer.

Description

Technical Field

[0001] This invention relates to an ultrasonic welding apparatus having an ultrasonic oscillation unit and a mating tool. The ultrasonic oscillation unit includes an ultrasonic welding electrode and a transducer, wherein the ultrasonic welding electrode and the transducer are arranged sequentially along a longitudinal axis, and an amplitude converter is optionally inserted. The ultrasonic oscillation unit is designed such that it can resonate with ultrasonic oscillation at a wavelength λ along the longitudinal axis. Background Technology

[0002] The ultrasonic welding electrode includes a sealing surface arranged parallel to or forming an angle of less than 90° with the longitudinal axis. The mating tool includes a mating tool sealing surface arranged such that the material to be processed can be placed between the sealing surface of the ultrasonic welding electrode and the sealing surface of the mating tool for welding. The ultrasonic welding electrode and / or the mating tool can move along a processing direction perpendicular to the longitudinal axis, thereby adjusting the distance between the sealing surfaces of the ultrasonic welding electrode and the mating tool.

[0003] This ultrasonic welding equipment is known from WO 2020 / 126845.

[0004] The sealing surfaces of the ultrasonic welding electrode and the mating tool must be movable relative to each other. On the one hand, the two sealing surfaces need to move away from each other in order to position the material to be processed between the two sealing surfaces. On the other hand, during the welding process, i.e., when the ultrasonic welding electrode is set to ultrasonic vibration and its sealing surfaces are in contact with the material to be processed, a welding force needs to be applied to the material, causing the two sealing surfaces to move closer to each other for this purpose.

[0005] For this purpose, the prior art incorporates a linear guide that allows the two sealing surfaces to move linearly toward and away from each other. The ultrasonic oscillation unit is held on a fixed member, which in turn can move along the linear guide by means of a pneumatic cylinder.

[0006] To achieve optimal welding results, very precise control of the welding force—that is, the force exerted by the sealed surface of the ultrasonic welding electrode on the workpiece—is becoming increasingly important. Furthermore, sometimes a very low welding force is sufficient and even necessary. However, this is difficult to achieve with the aforementioned linear guide operated by a pneumatic cylinder. Firstly, friction within the guide and pneumatic cylinder has a negative impact. Secondly, hysteresis exists within the pneumatic cylinder, making it difficult to achieve good reproducibility of the welding force. Additionally, the pneumatic cylinder responds relatively slowly to small changes in welding force, negatively impacting cycle time. Summary of the Invention

[0007] Based on the described prior art, the object of the present invention is to provide an ultrasonic welding device that at least reduces the described disadvantages.

[0008] According to the present invention, this objective is achieved by holding the ultrasonic oscillation unit or mating tool by a rotary retainer that can rotate about a rotation axis extending perpendicular to the longitudinal axis, wherein the rotation axis is arranged such that the distance between the sealing surface of the ultrasonic welding electrode and the sealing surface of the mating tool can be adjusted by rotating the rotary retainer.

[0009] In this paper, the term "perpendicular to the longitudinal axis" is understood to mean any orientation of the axis of rotation located in a plane oriented perpendicular to the longitudinal axis. Therefore, the longitudinal axis and the axis of rotation do not necessarily intersect.

[0010] Adjusting the welding force by moving it away from the linear guide provides finer control over the welding force.

[0011] In a preferred embodiment, the sealing surface of the ultrasonic welding electrode has a depth of at least 0.25 cm. 2 Preferably at least 0.5cm 2 And most preferably at least 1cm 2 The size.

[0012] In another preferred embodiment, the mating tool has a mating tool sealing surface shaped to correspond to the sealing surface of the ultrasonic welding electrode, such that the distance between the sealing surfaces remains constant during processing.

[0013] In a preferred embodiment, the ultrasonic oscillation unit or mating tool is held by a linear mount connected to a linear guide, the linear mount being movable back and forth between two positions along the processing direction by means of the linear guide, wherein a first pneumatic actuator is preferably provided to move the linear mount between the two positions. Therefore, the ultrasonic welding apparatus includes both a rotary holder and a linear mount.

[0014] Using a linear guide, the ultrasonic welding electrode and mating tool can move away from each other, allowing the workpiece to be positioned between the sealing surface of the ultrasonic welding electrode and the surface of the mating tool. The ultrasonic welding electrode and mating tool can then move back towards each other using the linear guide. However, the welding force is adjusted by rotating the ultrasonic oscillation unit around its axis of rotation. In this way, most of the necessary movement can be provided by the linear guide, while the rotary retainer is only used to provide and change the welding force.

[0015] As is known in the prior art, a pneumatic actuator can be provided to move the linear mount between two positions.

[0016] In a preferred embodiment, the ultrasonic welding electrode or mating tool is held by both a rotary retainer and a linear mount, wherein preferably, the ultrasonic welding electrode is held by both a rotary retainer and a linear mount. Therefore, the functions of the linear mount and the rotary retainer can be achieved by a single linear rotary retainer, which preferably allows the ultrasonic welding electrode to move linearly relative to the mating tool and rotate about a rotation axis.

[0017] A second pneumatic actuator can be provided to move the rotary retainer about the axis of rotation. This second pneumatic actuator can engage points on the rotary retainer spaced apart from the axis of rotation. The term "second pneumatic actuator" is used herein to distinguish it from the optional first pneumatic actuator of the linear mount. Therefore, embodiments with only a first pneumatic actuator, only a second pneumatic actuator, and both a first and a second pneumatic actuator are possible.

[0018] In a particularly preferred embodiment, the actuator of the rotary retainer, such as a pneumatic cylinder, engages at a point on the rotary retainer that is farther from the axis of rotation than the ultrasonic welding electrode sealing surface is from the axis of rotation. This allows for very fine adjustment of the welding force.

[0019] A spring may also be provided for the movement of the rotary retainer, and its spring force is preferably adjustable. For example, a helical spring or a gas spring can be used as the spring. In a preferred embodiment, the spring is preloaded such that the rotary retainer presses the ultrasonic welding electrode and the mating tool against each other in a provided working position, in which material will be processed between the ultrasonic welding electrode and the mating tool. Thus, the spring applies a preferably adjustable welding force to the material.

[0020] In another preferred embodiment, a control device is provided that causes the acoustic oscillation unit or mating tool to rotate about a rotational axis during the welding process. Because of this rotation about the rotational axis during processing, i.e., when both the sealing surface and the mating tool sealing surface come into contact with the material to be processed, the distance between the sealing surface and the mating tool sealing surface is reduced. Preferably, the control device is configured such that during the welding process, the distance between the sealing surface of the ultrasonic welding electrode and the mating tool sealing surface is adjusted solely by rotation about the rotational axis. Therefore, the linear mount has no movement. In other words, the movement of the linear mount is provided only for positioning the sealing surface relative to the mating tool sealing surface, and then machining is performed solely by rotation about the rotational axis.

[0021] In another preferred embodiment, the mating tool is provided with a receiving element including a mating tool sealing surface, wherein the receiving element can be secured to the mating tool at at least two receiving element locations.

[0022] Depending on the additional force applied via the rotation axis or the angle through which the ultrasonic oscillation unit rotates about the rotation axis, the point where the sealing surface of the ultrasonic welding electrode contacts the sealing surface of the mating tool moves. Therefore, in a preferred embodiment, the sealing surface of the mating tool can be attached to the mating tool at at least two locations.

[0023] In a preferred embodiment, the rotary retainer includes a rotary bearing or solid joint that allows the ultrasonic oscillation unit to rotate about a rotation axis. In a preferred embodiment, the rotation axis does not intersect with the longitudinal axis.

[0024] Furthermore, the present invention relates to a method for welding materials such as metal braids or metal foils. According to the invention, a method overcoming the aforementioned drawbacks is achieved by using an ultrasonic welding apparatus as described above. Here, the material to be processed is arranged between a sealing surface of an ultrasonic welding electrode on one side and a sealing surface of a mating tool on the other side. By moving the sealing surface of the ultrasonic welding electrode along the direction of the mating tool's sealing surface using a rotary clamp, a welding force can then be applied to the material to be processed. If the ultrasonic oscillation unit is simultaneously vibrated, ultrasonic vibrations can be introduced into the material, thereby inducing welding.

[0025] Therefore, in a preferred embodiment, the ultrasonic oscillation unit first moves along a linear guide, reducing the distance between the sealing surface of the ultrasonic welding electrode and the sealing surface of the mating tool. Then, the ultrasonic oscillation unit rotates about a rotation axis, resulting in the application of the force required for welding to the metal material being processed. Therefore, this process is particularly suitable for welding metal foils or metal braids. Attached Figure Description

[0026] Other advantages, features, and possible applications of the invention will become apparent from the following description of preferred embodiments and the accompanying drawings. The drawings illustrate: Figure 1 This is a side view of the ultrasonic welding equipment in the working position according to the present invention. Figure 2 yes Figure 1 A side view of the ultrasonic welding equipment in its basic position. Figure 3 This is a partial cross-sectional view of the driver used to apply welding force, and Figure 4 This is an exploded view of the pairing tool adjustment device. Detailed Implementation

[0027] Figure 1The working position of an ultrasonic welding apparatus according to an embodiment of the present invention is shown. The ultrasonic welding apparatus 1 includes an ultrasonic oscillation unit. In the example shown, the ultrasonic oscillation unit consists of an ultrasonic welding electrode 2, a transducer 3, and an amplitude converter 4 disposed between the transducer 3 and the ultrasonic welding electrode 2. The transducer 3 receives a high-frequency electrical signal via a cable 14 and converts the high-frequency electrical signal into a mechanical longitudinal oscillation, the amplitude of which is transmitted to the ultrasonic welding electrode 2 in a modified form via the amplitude converter 4. The transducer 3, the amplitude converter 4, and the ultrasonic welding electrode 2 are tuned to each other such that resonant oscillation of the ultrasonic oscillation unit can be induced at a certain wavelength.

[0028] The ultrasonic oscillation unit is held by a retaining element 5 in the form of a sheathed element, which, in the example shown, encapsulates an amplitude converter in the form of a sheath. The retaining element 5 is connected to the amplitude converter 4 in a manner that minimizes its impact on the oscillation of the ultrasonic oscillation unit. If no amplitude converter is provided, the retaining element could, for example, hold a transducer 3. The retaining element 5 engages the vibrating node of a standing wave shaped along the longitudinal axis. The longitudinal axis A is in... Figure 1 The horizontal extension allows the ultrasonic welding electrode 2, amplitude converter 4, and converter 3 to be arranged one after another along the longitudinal axis.

[0029] The ultrasonic welding electrode 2 has multiple sealing surfaces 12, 13 at its end facing away from the amplitude converter 4, wherein one sealing surface 12 faces the mating tool 11, while another sealing surface 13 faces away from the mating tool 11. The ultrasonic oscillation unit, in the position shown, uses only the sealing surface 12 of the ultrasonic welding electrode 2. If the sealing surface 12 becomes worn during processing, the ultrasonic welding electrode 2 can be rotated about its longitudinal axis, for example, 180°, when the holding element 5 is temporarily released, such that another sealing surface 13 of the ultrasonic welding electrode is subsequently positioned opposite the mating tool 11. Only two sealing surfaces 12, 13 are visible in the figure. However, the ultrasonic welding electrode 2 can also have more than two sealing surfaces. For example, if the ultrasonic welding electrode has four sealing surfaces, these sealing surfaces can be used continuously if the ultrasonic welding electrode 2 is rotated 90° about its longitudinal axis in each case.

[0030] The illustrated embodiment is suitable for processing metals. Sealing surfaces 12 and 13 are oriented parallel to the longitudinal axis. Specifically, if no metal material is being processed, the sealing surfaces can also be arranged perpendicular to the longitudinal axis, such that the end face of the ultrasonic welding electrode away from the transducer acts as the sealing surface. In this case, the sealing surface of the mating tool should also be arranged orthogonally to the longitudinal axis of the ultrasonic oscillation unit.

[0031] The retaining element 5 is attached to the rod element 6, which is connected to the carriage element 17 via a rotary bearing 7. The carriage element 17 can move back and forth between two positions in a vertical direction, i.e., perpendicular to the longitudinal axis, via a linear guide 15. To achieve this, a pneumatic cylinder 9 is provided. When the pneumatic cylinder 9 is actuated, the carriage element 17 moves upward. Figure 2 The position is shown in the diagram. The rod element 6 has a rotary bearing 8 located away from the axis of rotation 7, which can be pulled downward in a vertical direction via a second pneumatic cylinder 10, causing the rod element 6, including the ultrasonic oscillation unit attached thereto, to rotate clockwise around the axis of rotation 7.

[0032] exist Figure 2 The diagram shows the basic position, in which pneumatic cylinder 9 has moved carriage element 17 to its upper position and second pneumatic cylinder 10 has moved rotary bearing 8 to its lower position, causing the ultrasonic system to tilt about the rotation axis 7.

[0033] exist Figure 2 In the position shown, the material to be processed, preferably a metallic material, can be positioned between the sealing surface 12 of the ultrasonic welding electrode and the sealing surface 16 of the mating tool.

[0034] If processing begins now, the carriage element 17 first moves downward above the linear guide 15 by means of the first pneumatic cylinder 9, which reduces the distance between the sealing surface 12 of the ultrasonic welding electrode 2 and the sealing surface 16 of the mating tool. During this time, the ultrasonic oscillation unit may have already been excited by ultrasonic oscillation. However, this can also be done at a later time immediately before the welding process.

[0035] For welding, only the second pneumatic cylinder 10 is now needed, which causes the rotary bearing 8 and thus the rod element 6 to rotate counterclockwise around the axis of rotation 7, and thus applies welding force to the material to be processed via the sealing surface 12 of the ultrasonic welding electrode 2.

[0036] For clarity, Figure 3 The diagram shows a detailed cross-sectional view of the rotary bearing 8 in the rod element 6. A second pneumatic cylinder 10 is connected to the carriage element 17. By moving the piston connected to the rotary bearing 8, the rotary bearing 8 can move in the direction of the carriage element 17 or away from the carriage element 17. Since the rotary bearing is rotatably connected to the rod element 6, this allows the rod element 6 to rotate a few degrees clockwise or counterclockwise about the axis 7, which also causes the sealing surface 12 of the ultrasonic welding electrode 2 to rotate about the axis of rotation 7.

[0037] Figure 4An exploded view of the mating tool 11 is shown. The mating tool 11 includes a lower mating tool support 26, an upper mating tool support 18, and a receiving element 19, which can be attached thereto and includes a sealing surface member 25 having a mating tool sealing surface 16. The upper mating tool support 18 can be height-adjusted relative to the lower mating tool support 26 to roughly adjust the distance between the mating tool 11 and the ultrasonic welding electrode 2. The upper mating tool support 18 includes a recessed groove 21 and a protruding groove stone 22. The receiving element 19 can thus be placed on the mating tool support 18 such that the groove stone 22 of the upper mating tool support 18 is located in a corresponding groove of the receiving element 19. In this position, the receiving element 19 can be displaced relative to the upper mating tool support 18 along the arrangement of the grooves. This displacement is achieved by means of a screw 20, which rests in a groove 23 and is supported thereon on the base of the groove. By rotating the screw 20, the receiving element 19 can be displaced relative to the upper mating tool support 18 along the direction of the recess 21. The receiving element 19 can be fastened to the upper mating tool support by means of the fastening screw 24.

[0038] The receiving element 19 includes a sealing surface member 25, which includes a mating tool sealing surface 16. Therefore, by rotating the screw 20, the mating tool sealing surface 16 can be moved.

[0039] Figure Labels

Claims

1. Ultrasonic welding apparatus (1) with an ultrasonic oscillation unit, which comprises an ultrasonic welding electrode (2) and a transducer (3), wherein The ultrasonic welding electrode (2) and the transducer (3) are arranged one after another along the longitudinal axis, and the ultrasonic oscillation unit is able to oscillate ultrasonically with wavelength λ along the direction of the longitudinal axis and resonate with the mating tool (11). The ultrasonic welding electrode (2) includes sealing surfaces (12; 13) and the longitudinal axis extends parallel to the sealing surfaces (12, 13) or forms an angle of less than 90° with the sealing surfaces. The mating tool (11) includes a mating tool sealing surface (16) facing the sealing surfaces (12, 13) of the ultrasonic welding electrode (2). The ultrasonic welding electrode (2) and the mating tool (11) are movable relative to each other in a processing direction perpendicular to the longitudinal axis, thereby allowing adjustment of the sealing surfaces (12, 13) of the ultrasonic welding electrode (2). 3) The distance between the ultrasonic oscillation unit and the mating tool sealing surface (16), wherein the ultrasonic oscillation unit or the mating tool is held by a rotary retainer that is rotatable about a rotation axis extending perpendicular to the longitudinal axis, wherein the rotation axis is arranged such that the distance between the sealing surface (12, 13) of the ultrasonic welding electrode (2) and the sealing surface (16) of the mating tool can be adjusted by rotating the rotary retainer, characterized in that the ultrasonic oscillation unit or the mating tool is held by a linear mounting member connected to a linear guide that is rotatable between two positions along the processing direction by means of the linear guide, wherein the ultrasonic welding electrode or the mating tool is held by both the rotary retainer and the linear mounting member.

2. Ultrasonic welding apparatus (1) according to claim 1, characterized in that A first pneumatic actuator is provided to move the linear mount between the two positions.

3. Ultrasonic welding apparatus (1) according to claim 1, characterized in that The ultrasonic welding electrode is held by both the rotating retainer and the linear mounting member.

4. The ultrasonic welding equipment (1) as described in any one of claims 1 to 3, characterized in that, A second pneumatic actuator is provided to rotate the ultrasonic oscillation unit about the rotation axis.

5. The ultrasonic welding equipment (1) as described in claim 4, characterized in that, The second pneumatic actuator engages a point of the rotary retainer that is spaced apart from the axis of rotation.

6. The ultrasonic welding equipment as described in any one of claims 1 to 3, characterized in that, A controller is provided that causes the ultrasonic oscillation unit or the mating tool to rotate about a rotation axis during the welding process.

7. The ultrasonic welding equipment as described in claim 6, characterized in that, The controller is configured such that during the welding process, the distance between the sealing surfaces (12, 13) of the ultrasonic welding electrode (2) and the sealing surface (16) of the mating tool is adjusted only by rotation about the axis of rotation.

8. The ultrasonic welding equipment (1) as described in any one of claims 1 to 3, characterized in that, The mating tool (11) provides a receiving element (19) including a sealing surface (16) of the mating tool, wherein the receiving element (19) is capable of being secured to the mating tool (11) at at least two receiving element locations.

9. The ultrasonic welding equipment (1) as described in any one of claims 1 to 3, characterized in that, The rotating retainer includes a rotating bearing or solid joint that enables the ultrasonic oscillation unit to rotate about the rotation axis.

10. The ultrasonic welding equipment (1) as described in any one of claims 1 to 3, characterized in that, An amplitude converter is inserted between the ultrasonic welding electrode (2) and the converter (3).

11. A method for welding materials, characterized in that, Using the ultrasonic welding apparatus (1) as described in any one of claims 1 to 10, while the ultrasonic oscillation unit is excited by ultrasonic vibration, the material to be processed is positioned between the sealing surface of the ultrasonic welding electrode and the sealing surface of the mating tool.

12. The method as described in claim 11, characterized in that, In order to apply welding force to the metal material disposed between the sealing surfaces (12, 13) of the ultrasonic welding electrode (2) and the sealing surface (16) of the mating tool, the ultrasonic oscillation unit rotates about its rotation axis.

13. The method as described in claim 12, characterized in that, The ultrasonic oscillation unit first moves along the linear guide, reducing the distance between the sealing surfaces (12, 13) of the ultrasonic welding electrode and the sealing surface (16) of the mating tool. Then, by rotating the ultrasonic oscillation unit around the rotation axis, the force necessary for welding is applied to the metal material to be processed.

14. The method as described in claim 11, characterized in that, The material is a metal woven fabric or a metal foil.

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