SONOTRODE HAVING COATED INLET PORTION

Abstract

A sonotrode or ultrasonic welding apparatus for ultrasonically processing a material, including a sealing surface adapted to contact the material to be processed, a rear surface opposite to the sealing surface, and a circumferential lateral surface connecting the sealing surface to the rear surface, the lateral surface having two side surfaces arranged substantially parallel to each other and two end surfaces arranged substantially parallel to each other. In order to provide a sonotrode or ultrasonic welding apparatus for processing a material, which at least reduces damage to the material and at the same time does not impair the production speed, it is proposed that the sealing surface has a convexly curved inlet section which adjoins the lateral surface, and wherein the sealing surface has a coating at least in a section.

Claims

1. A sonotrode for ultrasonic processing of a material, comprising: a sealing surface intended to come into contact with the material to be processed, a rear surface opposite the sealing surface, and a circumferential lateral surface connecting the sealing surface to the rear surface, wherein the lateral surface has two side surfaces arranged substantially parallel to one another and two end surfaces arranged substantially parallel to one another, and wherein the sealing surface has a convexly curved inlet section which adjoins the lateral surface, and wherein the sealing surface has a coating at least in a section.

2. The sonotrode according to claim 1, wherein the inlet section is curved with a radius of curvature R.sub.e, preferably the radius of curvature R.sub.e being at least 3 mm, preferably at least 5 mm and particularly preferably at least 7 mm.

3. The sonotrode according to claim 1, wherein the end surfaces are smaller than the side surfaces, the convexly curved inlet section adjoining one of the two side surfaces.

4. The sonotrode according to claim 3, wherein the sealing surface has a convexly curved outlet section which adjoins the other of the two side surfaces, wherein preferably the outlet section is curved with a radius of curvature R.sub.a, wherein particularly preferably the radius of curvature R.sub.a differs from the radius of curvature R.sub.e by not more than 50%, preferably by not more than 10%, wherein most preferably the radii of curvature R.sub.e and R.sub.a are equal.

5. The sonotrode (1) according to claim 1, wherein the sonotrode (1) has a thickness d at its sealing surface-side end (20), for which applies: 2R.sub.e?d?20R.sub.e, preferably ?10R.sub.e, particularly preferably ?5R.sub.e and especially preferably ?3R.sub.e.

6. The sonotrode according to claim 1, wherein the sonotrode has a recess extending at least in a section over the sealing surface, in which recess the coating is arranged, the coating preferably having a thickness which corresponds to a depth of the recess, so that a coated surface of the sonotrode is flush with an uncoated surface of the sonotrode.

7. The Sonotrode according to claim 6, wherein the recess has a section with continuously changing depth at its edges, so that the coating arranged in the recess has a thickness which decreases in the direction of the uncoated surface.

8. The sonotrode according to claim 6, wherein the recess extends into one side surface and preferably into both side surfaces.

9. The sonotrode according to claim 6, wherein the two end surfaces are spaced apart from one another by a distance A.sub.S, wherein for an extension A.sub.A of the recess in a direction extending from one of the end surfaces to the other end surface applies 0.5A.sub.S<A.sub.A?1A.sub.S.

10. The sonotrode according to claim 1, wherein the coating is convexly curved at least in a section.

11. The sonotrode according to claim 1, wherein the coating consists of hard metal and preferably of a non-oxide ceramic.

12. The sonotrode according to claim 1, wherein the sealing surface has at least one groove, preferably a plurality of grooves aligned parallel to one another, extending in the direction from one side surface to the other side surface.

13. The sonotrode according to claim 12, wherein the at least one groove is arranged exclusively in the coating.

14. An apparatus for ultrasonic processing of a material, comprising: the sonotrode according to claim 1, a counter tool having a sealing surface which is arranged opposite the sealing surface of the sonotrode in such a way that the material to be processed can be guided during processing through a gap formed by the two opposite sealing surfaces, and a material feed by means of which the material can be guided through the gap.

15. The apparatus according to claim 14, wherein the material feed is designed in such a way that the material is guided over the inlet section.

16. The sonotrode according to claim 2, wherein end surfaces are smaller than the side surfaces, the convexly curved inlet section adjoining one of the two side surfaces, wherein the sealing surface has a convexly curved outlet section which adjoins the other of the two side surfaces, wherein preferably the outlet section is curved with a radius of curvature R.sub.a, wherein particularly preferably the radius of curvature R.sub.a differs from the radius of curvature R.sub.e by not more than 50%, preferably by not more than 10%, wherein most preferably the radii of curvature R.sub.e and R.sub.a are equal, and wherein the sonotrode (1) has a thickness d at its sealing surface-side end (20), for which applies: 2R.sub.e?d?20R.sub.e, preferably ?10R.sub.e, particularly preferably ?5R.sub.e and especially preferably ?3R.sub.e.

17. The sonotrode according to claim 16, wherein the sonotrode has a recess extending at least in a section over the sealing surface, in which recess the coating is arranged, the coating preferably having a thickness which corresponds to a depth of the recess, so that a coated surface of the sonotrode is flush with an uncoated surface of the sonotrode, wherein the recess has a section with continuously changing depth at its edges, so that the coating arranged in the recess has a thickness which decreases in the direction of the uncoated surface, and wherein the recess extends into one side surface and preferably into both side surfaces.

18. The sonotrode according to claim 17, wherein the two end surfaces are spaced apart from one another by a distance A.sub.S, wherein for an extension A.sub.A of the recess in a direction extending from one of the end surfaces to the other end surface applies 0.5A.sub.S<A.sub.A?1A.sub.S, wherein the coating is convexly curved at least in a section, and wherein the coating consists of hard metal and preferably of a non-oxide ceramic.

19. The sonotrode according to claim 18, wherein the sealing surface has at least one groove, preferably a plurality of grooves aligned parallel to one another, extending in the direction from one side surface to the other side surface, and wherein the at least one groove is arranged exclusively in the coating.

20. An apparatus for ultrasonic processing of a material, comprising: the sonotrode according to claim 19, a counter tool having a sealing surface which is arranged opposite the sealing surface of the sonotrode in such a way that the material to be processed can be guided during processing through a gap formed by the two opposite sealing surfaces, and a material feed by means of which the material can be guided through the gap.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Further advantages, features and possible applications will become clear from the following description of two embodiments and the accompanying figures.

[0037] FIG. 1 shows a three-dimensional schematic representation of an embodiment of the sonotrode according to the invention.

[0038] FIG. 1a shows a sectional view of the embodiment of the sonotrode according to the invention shown in FIG. 1.

[0039] FIG. 1b shows a schematic enlargement of the sealing surface end of the sonotrode shown in FIG. 1.

[0040] FIG. 2 shows a sectional view of an embodiment of the sonotrode with coating according to the invention.

[0041] FIG. 3 shows a cross-sectional view of a section of a further embodiment of the sonotrode with coating according to the invention.

[0042] FIG. 4 shows a schematic representation of an embodiment of the ultrasonic processing device according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0043] According to FIGS. 1, 1a and 1b, the sonotrode 1 has a convexly curved inlet section 7 and a convexly curved outlet section 8 on its sealing surface 2. The convexly curved inlet section 7 adjoins the side surface 3 of the sonotrode 1, while the convexly curved outlet section 8 adjoins the other side 4 of the sonotrode 1. Both the convexly curved inlet section 7 and the convexly curved outlet section 8 are curved with a constant radius of curvature R.sub.e and R.sub.a of 7.5 mm, respectively. In an alternative embodiment, the inlet and outlet sections can also be curved with different radii of curvature.

[0044] The side surfaces 3, 4 connect the two end surfaces 5, 6 of the sonotrode 1 and together with these form the lateral surface of the sonotrode 1, which in turn connects a rear surface of the sonotrode 1 to the sealing surface 2 of the sonotrode 1. As shown in FIG. 1, the end surfaces 5,6 are also smaller than the side surfaces 3,4.

[0045] The sonotrode 1 has a thickness d at its sealing surface-side end 20 that corresponds to three times the radius of curvature R.sub.e of the inlet section 7.

[0046] The structure described above is also present in the embodiments of the sonotrode shown in FIGS. 2 and 3. FIGS. 2 and 3 therefore show only sections of the sonotrode.

[0047] In the embodiment of the sonotrode 1 according to the invention shown in FIG. 2, the sealing surface 2 has a recess 21 in which a coating 9 is arranged. The coating 9 has a thickness corresponding to a depth of the recess 21, so that the coated surface 22 of the sonotrode 1 is flush with the uncoated surface 23 of the sonotrode 1.

[0048] Further, the recess 21 has a portion of continuously changing depth at its edges so that the coating 9 disposed in the recess 21 has a thickness that decreases toward the uncoated surface 23. In addition, the coating 4 is also convexly curved and is made of a non-oxide ceramic.

[0049] In the embodiment shown in FIG. 3, however, the recess 21 extends into both side surfaces 3, 4 of the sonotrode 1.

[0050] In the schematic representation of an ultrasonic processing apparatus shown in FIG. 4, the sonotrode 1 according to the invention is shown together with a counter tool 11. The material system 10 to be processed is guided in the gap 15 formed between the sealing surface 2 of the sonotrode 1 and the sealing surface of the counter tool 11. In this case, the material system 10 to be processed consists of two material layers 12, 13 as well as a thread 14, which is arranged between the two material layers 12, 13. For guiding the thread 14, the sealing surface 2 of the sonotrode 1 has grooves which extend in the direction from one side surface 3 to the other side surface 4.

[0051] One of the material layers 12 is guided over the inlet section 7 of the sealing surface 2 of the sonotrode 1. The other material layer 13 is guided over the sealing surface of the counter tool 11, which is cylindrical. In this way, the material system to be processed is prevented from being damaged by the ultrasonic processing apparatus.

LIST OF REFERENCE SIGNS

[0052] 1 Sonotrode [0053] 2 Sealing surface of the sonotrode [0054] 3,4 Side surfaces [0055] 5,6 End surfaces [0056] 7 Inlet section [0057] 8 Outlet section [0058] 9 Coating [0059] 10 Material [0060] 11 Counter tool [0061] 12, 13 Material layers [0062] 14 Thread [0063] 15 Gap [0064] 20 Sealing end of the sonotrode [0065] 21 Recess [0066] 22 Coated surface [0067] 23 Uncoated surface