Matching tools, ultrasonic welding machines, and methods for producing sealing and decorative welds.

Abstract

The present invention relates to a mating tool for an ultrasonic welding machine having two sealing surfaces intended to contact the material to be treated, characterized in that the mating tool has two parts that are movable relative to each other, and each of the two parts has one of the sealing surfaces.

Description

[0001] The present invention relates to a mating tool for an ultrasonic welding machine, an ultrasonic welding machine having such a mating tool, and a method for producing sealing welds and decorative welds using an ultrasonic welding machine.

[0002] Packaging technology is constantly evolving. Recently, recyclable stand-up pouches, such as those made from polypropylene monomer materials, have been used more frequently. These pouches are used, for example, to package wet animal feed. In this case, two layers of roughly rectangular cut material are welded together to form the package.

[0003] To connect the material layers, a so-called sealing weld is created, designed to ensure a tight seal in the packaging. On the side of the sealing weld opposite to the product, there are end sections of material layers that are not part of the sealing weld. These non-welded material layer ends are undesirable for aesthetic and other reasons, so these parts not needed for the packaging seal are also welded together. Therefore, a so-called decorative weld is applied directly adjacent to the sealing weld and is primarily used to improve the appearance of the packaging and prevent debris, such as product residue, from accumulating in the unopened portion of the packaging.

[0004] This material typically comprises a support layer and a sealing layer. Specifically, in modern recyclable monomer materials used in stand-up pouches, the melting temperature difference between the support and sealing layers is very low, thus requiring very high process reliability when welding the material layers. Therefore, the lowest possible welding temperature is chosen to avoid thermal damage to the support layer. This prevents unnecessary shrinkage of the top edge of the bag due to excessive heat input. However, the risk of the weld reopening is significantly increased.

[0005] Typically, a heat-sealing jaw is used to introduce the weld into the material. Alternatively, welding can be performed in an ultrasonic welding machine. For this purpose, the material layer is positioned between the ultrasonic welding tool and the mating tool before the ultrasonic welding tool is placed under ultrasonic vibration and pressed against the material layer. The advantage of ultrasonic processing is that heat is generated only where the welding process actually requires it.

[0006] Typically, sealing and decorative welds are introduced into the material in two work steps at separate welding stations. Initial attempts to introduce both sealing and decorative welds into the package using an ultrasonic welding machine in a single welding station failed because reliable process control was impossible under these conditions. If insufficient force is applied during welding to press the ultrasonic welding tool and mating tool together, there is a risk of the decorative weld reopening after welding. To prevent this, the force required to press the ultrasonic welding tool and mating tool together during the welding process at the material layer must be increased, which can damage the sealing weld. In some cases, for optimal sealing welds, the force must be reduced, while for optimal decorative welds, the force must be increased, and vice versa. However, these two requirements cannot be met simultaneously.

[0007] Therefore, based on the described prior art, the object of the present invention is to provide an ultrasonic welding machine, a mating tool, and a method that allows for the reliable and simple generation of sealing welds and decorative welds.

[0008] This objective is achieved by a mating tool for an ultrasonic welding machine having two separate sealing surfaces configured to contact the material to be processed. One sealing surface is configured to produce a sealing weld, while the other sealing surface is configured to produce a decorative weld. According to the invention, the mating tool is formed in two parts, which are movable relative to each other, and each of the two parts includes one of the two sealing surfaces.

[0009] Due to the relative motion of the two parts, the force applied to the material to be processed by the mating tool can then be increased or decreased independently for the two individual sealing surfaces, which significantly improves the process reliability of the method. Furthermore, the welding processes for sealing welds and decorative welds can be separated in a timely manner, ensuring reliable process control, as the process parameters used to verify weld quality can then be evaluated during the two separate welding processes.

[0010] In a preferred embodiment, at least one of the two parts includes a driver by means of which the part can move relative to the other part. In a particularly preferred embodiment, only one of the two parts includes a driver by means of which the part can move relative to the other part, wherein the part is preferably attached to the other part.

[0011] In a preferred embodiment, the two parts of the mating tool are movable relative to each other such that in a first position, the first sealing surface protrudes beyond the second sealing surface, and in a second position, the second sealing surface protrudes beyond the first sealing surface.

[0012] This measure ensures that welding can be performed only through the first sealing surface or only through the second sealing surface.

[0013] Furthermore, the mating tool may include a deflecting element that pushes the package into a slot within the ultrasonic welding tool (sonotrode) designed for this purpose, thereby preventing the package from slipping during the welding process. This securing of the package may be necessary to ensure a reliable, tight, and repeatable ultrasonic welding process for sealing the weld. The deflecting element may be positioned between the two sealing surfaces. Alternatively, clamping of the package may also be performed directly above the sealing tool using an additional clamping device, thus eliminating the need for a deflecting element and slot within the ultrasonic welding tool (sonotrode). Since decorative welds do not require a tight seal, they can be welded without securing the package.

[0014] Furthermore, the first part of the mating tool may include a front surface with a protruding section, the front surface including a first sealing surface, wherein the second part of the mating tool is positioned on the front surface of the first part of the mating tool, rather than on the protruding section, and is movable relative to the front surface.

[0015] In another preferred embodiment, the first sealing surface of the mating tool is an elongated sealing profile with an unstructured surface, while the second sealing surface of the mating tool, configured to produce a decorative weld, has a sealing profile with a structured surface. The term "unstructured surface" is understood to mean a smooth surface. "Structured surface" is understood to mean a surface comprising multiple separate or interconnected structural elements that protrude from or embed into the surface to form recesses. The first sealing surface can be flat. However, it can also be convexly curved. For example, the first sealing surface can be in the form of a beaded rim with a radius between 1 and 5 mm.

[0016] Regarding the ultrasonic welding machine, the above objective is achieved by an ultrasonic welding machine having an ultrasonic welding tool that can be excited into an ultrasonic vibration state and includes the described mating tool.

[0017] In a preferred embodiment, the ultrasonic welding tool has a flat, optionally discontinuous, sealing surface comprising two sealing surface segments, each arranged opposite to the sealing surface of a mating tool. In this respect, the sealing surface segments are configured to interact with a first sealing surface of the mating tool to produce a sealing weld, while the other sealing surface segment is configured to interact with a second sealing surface of the mating tool to produce a decorative weld.

[0018] In another preferred embodiment, the separation of the sealing surface section in the ultrasonic welding tool can be omitted.

[0019] Regarding this method, the objective is achieved through the following steps to produce sealing welds and decorative welds:

[0020] A) Provides an ultrasonic welding machine according to any one of claims 6-7,

[0021] B) Arrange the multiple layers of material to be welded between the ultrasonic welding tool and the mating tool.

[0022] C) Arrange the two parts of the mating tool such that the first sealing surface of the mating tool is closer to the ultrasonic welding tool than the second sealing surface of the mating tool.

[0023] D) Move the ultrasonic welding tool and the mating tool toward each other, such that the multilayer material to be welded comes into contact with both the sealing surface of the ultrasonic welding tool and the first sealing surface of the mating tool, wherein, during and / or after step D), the ultrasonic welding tool is placed in an ultrasonic vibration state.

[0024] E) Move the second part of the mating tool relative to the first part of the mating tool such that the multilayer material to be welded comes into contact with both the sealing surface of the ultrasonic welding tool and the second sealing surface of the mating tool, wherein the ultrasonic welding tool is placed in an ultrasonic vibration state during and / or after step E).

[0025] In step E), movement can be performed such that the first sealing surface of the mating tool does not come into contact with the multilayer material to be welded.

[0026] The excitation of the ultrasonic welding tool may have already occurred during motion step D) or E). However, it is also possible that the ultrasonic excitation of the ultrasonic welding tool occurs only after motion step D) or E) has ended and the multilayer material has come into contact with the first or second part of the ultrasonic welding tool and the mating tool. Furthermore, a 20 ms rest phase may be provided after motion step D) or E), for example, before the ultrasonic welding tool is excited by ultrasonic vibration.

[0027] Furthermore, it may be advantageous that the multilayer material to be welded is held by means of a holding device during steps D) and / or E), thereby preventing relative movement of the individual layers of the multilayer material.

[0028] By separating the welding processes, the amplitude of the ultrasonic welding tool's vibration in the excited state after step D) can be selected to be different from the amplitude after step E). Although, according to the invention, both the sealing weld and the decorative weld can be produced in a single welding station, these two welds are produced sequentially, depending on the position of the second part of the mating tool. In an embodiment according to the invention, the force applied to the multilayer material via the first part of the mating tool to produce the sealing weld has no effect on the decorative weld because the second part of the mating tool is not in contact with the multilayer material at this time. Similarly, the force applied to the multilayer material via the second part of the mating tool to produce the decorative weld has no effect on the sealing weld because the first part of the mating tool is not in contact with the multilayer material at this time.

[0029] Other advantages, features, and possible applications of the present invention will become apparent from the following description of preferred embodiments and related drawings:

[0030] The attached diagram shows:

[0031] Figure 1 This is a schematic diagram according to the first embodiment of the present invention.

[0032] Figure 2 It is in the first position. Figure 1 Implementation examples,

[0033] Figure 3 It is in the second position. Figure 1 Implementation examples,

[0034] Figure 4 This is a side view of the second embodiment in the first position, and

[0035] Figure 5 This is a side view of the second embodiment in the second position.

[0036] Figure 1 A schematic diagram of a first embodiment of the present invention is shown. The ultrasonic welding tool 1 includes two sealing surface sections 8 and 9 located on a common sealing surface. The two sealing surface sections 8 and 9 are separated from each other by a recess 12. The ultrasonic welding tool 1 is arranged on one side of a material 5, which consists of at least two layers of material to be welded together. A mating tool 2 according to the invention is arranged opposite the material 5. The mating tool also includes two sealing surfaces, specifically sealing surface 6 and sealing surface 7. A deflecting element 10 is arranged between the two sealing surfaces, which, when the ultrasonic welding tool and the mating tool move together, enters the recess 12 of the ultrasonic welding tool and fixes the material 5 therein, preventing the individual layers of the multilayer material from sliding relative to each other.

[0037] The mating tool 2 consists of two parts, specifically a first part 3 and a second part 4. The first part 3 includes a first sealing surface 6. The second part 4 includes a second sealing surface 7, which is structured on its surface in the illustrated example. To perform the method according to the invention, the mating tool is first brought to... Figure 2 In the indicated position, the second part 4 of the mating tool 2 moves relative to the first part 3 of the mating tool 2 by means of mechanism 11, specifically such that the first sealing surface 6 protrudes toward the ultrasonic welding tool 1 compared to the second sealing surface 7. In this position of the mating tool, the ultrasonic welding tool and the mating tool then move toward each other, such that the material 5 is clamped between the sealing surface 8 of the ultrasonic welding tool and the sealing surface 6 of the first part 3 of the mating tool 2, thereby welding the material layers together. This produces a sealing weld.

[0038] In the next step, the mechanism 11 of the pairing tool is actuated to bring the pairing tool to... Figure 3 The position shown is such that, in this position, the second part 4 of the mating tool 2 protrudes towards the ultrasonic welding tool 1, compared to the first part 3 of the mating tool 2. Figure 2 and 3 As shown, the distances between the highest points of sealing surfaces 6 and 7 are b and a, respectively. In an embodiment according to the invention, a and b are each measured to be approximately 1 mm.

[0039] exist Figure 3 As shown, given the forward position of the second part 4 of the mating tool 2, a welding process is then performed between the sealing surface 7 of the mating tool 2 and the sealing surface 9 of the ultrasonic welding tool 1.

[0040] Alternatively, decorative welds can be generated first using the second part 4 of the mating tool 2, and then sealing welds can be generated using the first part 3 of the mating tool 2.

[0041] Pairing tools can also have different structures, such as Figure 4 and 5 As shown. In this case, the mating tool is also formed of two parts, the two parts being a first part 3', the first part having a stepped surface facing the ultrasonic welding tool 1, wherein in Figure 4 The indicated position pushes material 5 onto the sealing surface 6 of the ultrasonic welding tool 1 on the protruding part of the step. Figure 4 In the position shown, the second part 4' of the mating tool 2 is not in contact with the material. The second part 4' is arranged on the stepped surface of the first part of the mating tool such that it does not protrude beyond the stepped portion.

[0042] However, as Figure 5As can be seen, the second part 4' of the mating tool can move toward the ultrasonic welding tool 1, such that the second part 4' protrudes from the stepped portion of the first part 3', and only the second part 4' or its sealing surface with structural elements contacts the material 5 and presses it against the ultrasonic welding tool 1. (Comparison) Figure 4 and 5 The location shown is clearly in Figure 5 In the process, the first part 3' of the pairing tool has moved away from the ultrasonic welding tool 1, while the second part 4' has moved towards the ultrasonic welding tool.

[0043] In the illustrated embodiment, the second part 4' moves back and forth relative to the first part 3' of the mating tool 4 by means of a cylinder. To determine... Figure 5 The welding position shown for decorative welds can be equipped with a stop that interacts with the second part 4' or the cylinder to prevent the second part 4' from moving beyond the ultrasonic welding tool 1. Figure 5 The location shown.

[0044] With the aid of this invention, sealing welds and decorative welds can subsequently be produced at a single welding station. In this case, the two parts of the mating tool are able to press against the material with the desired welding force.

[0045] Figure Labels

[0046] 1. Ultrasonic welding tools

[0047] 2. Pairing tools

[0048] 3 Part 1

[0049] 3' Part 1

[0050] 4 Part Two

[0051] 4' Part 2

[0052] 5. Materials

[0053] 6 First sealing surface

[0054] 7 Second sealing surface

[0055] 8,9 Sealing surface section

[0056] 10 Deflection elements

[0057] 11 institutions

[0058] 12 recess

Claims

1. A mating tool for an ultrasonic welding machine, wherein, The mating tool includes two separate sealing surfaces designed to contact the material to be processed. The mating tool is characterized by having two parts, wherein the two parts are movable relative to each other, and each of the two parts includes one of the two sealing surfaces. The two parts of the mating tool are movable relative to each other such that in a first position, the first sealing surface protrudes beyond the second sealing surface, and in a second position, the second sealing surface protrudes beyond the first sealing surface, thereby enabling welding to be performed only via the first sealing surface or only via the second sealing surface, wherein the first sealing surface is configured to produce a sealing weld, and the second sealing surface is configured to produce a decorative weld.

2. The pairing tool as described in claim 1, characterized in that, The mating tool includes a deflection element disposed between the two sealing surfaces.

3. The pairing tool as described in any one of claims 1-2, characterized in that, The first portion of the mating tool includes a front surface having a protruding section and including a first sealing surface, wherein a second portion of the mating tool is positioned on the front surface of the first portion of the mating tool, rather than on the protruding section, and is movable relative to the front surface.

4. The pairing tool as described in any one of claims 1-2, characterized in that, One of the two sealing surfaces of the mating tool has an elongated sealing profile with an unstructured surface, while the other sealing surface of the mating tool has a sealing profile with a structured surface.

5. An ultrasonic welding machine, the ultrasonic welding machine having an ultrasonic welding tool capable of being excited into an ultrasonic vibration state and a mating tool as described in any one of claims 1-4.

6. The ultrasonic welding machine as described in claim 5, characterized in that, The ultrasonic welding tool includes a flat sealing surface comprising two sealing surface segments, each of which is arranged opposite to the sealing surface of the mating tool.

7. A method for producing sealing welds and decorative welds, comprising the following steps: A) Provides an ultrasonic welding machine as described in any one of claims 5-6, B) Arrange the multiple layers of material to be welded between the ultrasonic welding tool and the mating tool. C) Arrange the two parts of the mating tool such that the first sealing surface of the mating tool is closer to the ultrasonic welding tool than the second sealing surface of the mating tool. D) Move the ultrasonic welding tool and the mating tool toward each other such that the multilayer material to be welded comes into contact with both the sealing surface of the ultrasonic welding tool and the first sealing surface of the mating tool, wherein, during and / or after step D), the ultrasonic welding tool is placed in an ultrasonic vibration state to produce a sealing weld. E) Move the second portion of the mating tool relative to the first portion of the mating tool such that the multilayer material to be welded comes into contact with both the sealing surface of the ultrasonic welding tool and the second sealing surface of the mating tool, wherein, during and / or after step E), the ultrasonic welding tool is placed in an ultrasonic vibration state to produce a decorative weld. In step E), the movement is performed such that the first sealing surface of the mating tool does not come into contact with the multilayer material to be welded, thereby enabling welding to be performed only via the first sealing surface in step D) and only via the second sealing surface in step E).

8. The method as described in claim 7, characterized in that, The multilayer material to be welded is held by means of a holding device during steps D) and / or E) to prevent relative movement of the individual layers of the multilayer material.

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