EP2934831A1

EP2934831A1 - Cutting head for an ultrasonic cutting device

Info

Publication number: EP2934831A1
Application number: EP13795272.7A
Authority: EP
Inventors: Marc-Christian HEILMEIER; Eva HONICKEL; Markus Huber
Original assignee: Bayerische Motoren Werke AG
Current assignee: Bayerische Motoren Werke AG
Priority date: 2012-12-19
Filing date: 2013-11-26
Publication date: 2015-10-28
Also published as: US20150266198A1; CN104736309A; DE102012223785A1; WO2014095260A1

Abstract

The present invention relates to a cutting head (10) for an ultrasonic cutting device (100), comprising an ultrasonic system (20) with a cutting blade (22) and a sonotrode (24), characterized in that the ultrasonic system (20) is mounted rotatably about an axis of rotation (R).

Description

description

Cutting head for an ultra-cutting device

The present invention relates to a cutting head for an ultrasonic cutting device and to an ultrasonic cutting device having such a cutting head.

Ultrasonic cutting devices are known in principle. They are e.g. used to cut semi-finished products for fiber composites. In particular, three-dimensionally complex geometries of fiber composite semi-finished products are cut to size at their edges. This trimming is often done by ultrasonic cutting devices, which have a robot mechanism. Such a robot mechanism, in particular a

Robotic arm, may e.g. be designed to be movable up to six axes. At the end of such a robotic arm, the cutting head is typically positioned to hold the

Carry out the trimming process.

A disadvantage of known ultrasonic cutting devices is that very complex movements of the cutting head must be performed by the ultrasonic cutting device. Is e.g. a robot arm provided, so in complex geometries very large and wide-abrasive cutting movements must be performed. This leads to an increased space requirement in the preparation of such

Ultrasonic cutter. Also disadvantageous in this case is that the expansive movement necessity of the ultrasonic cutting device is associated with a relatively high time requirement. When performing the cutting operation on a semifinished product, e.g. in the form of a fiber composite semifinished product, however, the time required for the tracking of the cutting head is crucial for the total time required. Thus, the increased need for movement and thus the increased time required for an extension of

Cycle times when performing the trimming. In addition, due to the increased movement requirement for the robot arm of the ultrasonic cutting device, increased stress on the individual joints as well as increased wear of a hose package for media supply along the robot arm are achieved.

It is an object of the present invention to at least partially overcome the disadvantages described above. In particular, it is the object of the present invention to provide a cutting head for an ultrasonic cutting apparatus and one such

To provide ultrasound cutting device, which in cost effective and simply allow a reduced footprint and / or a reduced processing time for the trimming of fiber composite semi-finished products.

The above object is achieved by a cutting head with the features of claim 1 and an ultrasonic cutting device with the features of claim 1. Further features and details of the invention will become apparent from the dependent claims, the description and the drawings. There are features and details that are in the

Are described in connection with the cutting head according to the invention,

of course, also in connection with the invention

Ultrasonic cutting device and in each case vice versa, so that with respect to the disclosure of the individual aspects of the invention always reciprocal reference is or can be.

An inventive cutting head for an ultrasonic cutting device has an ultrasonic system with a cutting blade and a sonotrode. One

Cutting head according to the invention is characterized in that the ultrasound system is rotatably mounted about a rotation axis

The ultrasonic cutting device is preferably designed in a known manner. The cutting head may e.g. be arranged at one end of a robot arm of the ultrasonic cutting device. In this case, the ultrasound system itself is also formed in a known manner. So it is provided with a cutting knife and a sonotrode, which perform the trimming together. The cutting blade itself has at least one cutting edge, which performs the trimming directly. To extend the durability of the cutting edge of the cutting blade while reducing the speed of the cutting blade

To improve cutting process, this cutting blade is firmly connected to the sonotrode. The sonotrode is designed to produce a high-frequency oscillation on the

Cutting blades and to produce themselves. In other words, that will

Cutting knife by the high-frequency vibration of the sonotrode also in

Oscillation. This cutting movements or sawing movements in the micrometer range are generated at the cutting edge of the cutting blade. Now moves such a cutting blade of an ultrasound system with the cutting head for the trimming of a fiber composite semi-finished along the edge, so can be performed with increased life and also at increased speed of the edge trimming.

In a cutting head according to the invention, however, in comparison to known

Cutting heads the ultrasound system rotatably mounted about a rotation axis. The means that a, in particular active, rotation of the ultrasound system and thus especially the cutting edge of the cutting blade can be done. By rotation of the cutting edge of the cutting blade tracking of even complex geometries can be carried out at least partially by the rotation of the ultrasound system. If the tracking is given at complex geometries at least partially by a rotation of the ultrasound system, correspondingly a reduced tracking by a robot arm of

Ultrasonic cutting device off.

It can be summarized that with a cutting head according to the invention at least part of the necessary movement during the edge trimming for the

Cutting knife can be provided by the rotation of the ultrasound system. Accordingly, this portion reduces the necessary movement requirement for the robot arm of the ultrasonic cutting device. The necessary movement of the cutting edge is thus divided into a movement by rotation of the ultrasound system and a movement by the ultrasonic cutting device or the robot arm.

Accordingly, the necessary movement of a robot arm of the ultrasonic cutting device is significantly reduced. Another advantage is the fact that the rotatability of the knife and the symmetrical shape of the cutting edge allow the knife to be rotated after each cut to ensure even cutting of the blades. This leads to a lifetime increase of the knife.

By the reduction of the movement necessity of a robot arm the

Ultrasonic cutting device also reduces the space required. As a result of the reduced movement, the processing time also decreases accordingly since the necessary movement by the robot arm can be carried out in a shorter time. It should be noted that a rotational movement of the ultrasound system itself due to the compact dimensions of the cutting head significantly faster and above all space-saving compared to a corresponding movement of the

Ultrasonic cutting device can be performed. Accordingly, a reduced cycle time and, in particular, at the same time a reduced necessary installation space for the ultrasonic cutting device is made possible by a cutting head according to the invention.

In the rotational storage of the ultrasound system in particular the rotational storage of the cutting blade and its cutting edge is important. However, since the cutting blade and sonotrode are often firmly connected together to transmit the high-frequency vibration from the sonotrode to the cutting blade, preferably the entire Ultrasonic system rotatable about the axis of rotation storable. This further reduces the complexity of one of the necessary movements of the robotic arm.

In this case, the cutting blade may have one or more cutting edges. It is preferred that at least one of the cutting edges is arranged at an acute angle to the axis of rotation in order to further enhance the effect of the rotational movement of the ultrasound system

Of course, the cutting head may be formed with a mechanical interface or a differently shaped interface to from the

Ultrasonic cutting device to be grasped or attached to this. Such an interface may e.g. be a standard mechanical interface, so that the

Cutting head can be gripped by a standard robot arm. The

Ultrasonic cutting device is preferably provided at least with a robot device or a robot arm.

In particular, frequencies in the range of approximately 20 kHz are provided as an excitation for the ultrasound system. The mounting of the ultrasound system is preferably arranged in a rotatable manner within a housing or a plate system of the cutting head. In this case, a wide variety of storage systems or storage means can be used, as will be explained later. The rotation around the rotation axis does not necessarily have to be arbitrary or free. Rather, it may be sufficient if a rotation is given by ± 180 ° or even less. However, a rotation around substantially full 360 * is conceivable. Especially with regard to the necessary

Media supply (especially the power supply) of the ultrasound system, can bring reduced rotation in a predefined range of rotation advantages. The axis of rotation or the axis of rotation of the ultrasound system thus forms an additional axis of rotation. If the ultrasound cutting device has a robot arm with usually up to six axes of rotation, the axis of rotation of the ultrasound system also forms, as it were, a seventh axis of rotation.

A cutting head according to the invention can be further developed such that the ultrasound system has a booster for the conversion of an electrical oscillation into a mechanical oscillation. Such a booster serves to convert an electrical oscillation, which is generated for example by a generator, into the necessary mechanical oscillation at the sonotrode. Thus, the booster is preferably also part of the ultrasound system, so that the booster together with the sonotrode and let the cutting blade move about the axis of rotation. The booster may have, for example, a piezo system which is able to convert incoming electrical oscillations into the desired mechanical vibrations. In this case, the generator is preferably formed separately from the cutting head. In particular, the generator can even be provided separately from the ultrasonic cutting device and, for example, be made available as a generator for a large number of different ultrasonic cutting devices. The vibrations, which are generated by the booster in a mechanical manner, are preferably in the range of the natural frequency of the sonotrode and / or the cutting blade. This further improves the resulting frequency amplitude, so that an improvement in the cutting process can be achieved in the desired manner with an increased service life of the cutting blade.

It may also be advantageous if, in a cutting head according to the invention, the cutting blade has at least two cutting edges, which at an acute angle to

Rotation axis are arranged. The provision of a cutting blade with at least two cutting edges doubles, so to speak, at least the number of cutting edges. These cutting edges are preferably aligned at different angles at an acute angle to the axis of rotation. Thus, the flexibility in the use of the cutting blade can be further increased. In particular, the necessary movement about the axis of rotation can be reduced so that e.g. a free rotation in the range of + 90 ° is sufficient. So, depending on the rotational position of the ultrasound system and more necessary today

Positioning of the cutting edge both one and the other of the two cutting edges are used. Of course, however, more than two, e.g. Three or more cutting conceivable in the context of the present invention.

It may also be advantageous if in a cutting head according to the invention according to the preceding paragraph, the cutting blade is formed in the shape of a triangle, in particular in the form of an isosceles triangle. This reduces the cost and complexity of manufacturing a cutting blade according to the invention. If the cutting blade is in the form of an isosceles triangle, preferably the two same legs together form the two cutting edges. The symmetrical design allows a particularly simple and above all substantially error-free insertion of the cutting blade on the sonotrode. This will be the

Error prone in the retrofitting or maintenance of an inventive

Cutting head reduced. A further advantage is achieved if, in the case of a cutting head according to the invention, the tip lies on or substantially on the axis of rotation between the two cutting edges. This is also a reduction of the complexity of an inventive

Cutting head achieved. In particular, a transfer of the mechanical vibration takes place on both cutting edges of the cutting head in the same way. In the regulation of

Cutting process must therefore no longer be distinguished, which of the two

Cutting is currently in cutting engagement. The two cutting edges are thus completely separated by the rotation axis. The intersection of the extension of the two cutting is thus on the axis of rotation.

It is also advantageous if, in the case of a cutting head according to the invention, at least one interface, in particular a mechanical interface for the connection to the ultrasonic cutting device and / or a media interface for the supply of the ultrasound system with media, is formed. Such an interface allows the connection in particular to existing ultrasonic cutting devices or to known robot arms. A mechanical interface is the attachment of the cutting head to the robot arm of an ultrasonic cutting device. This can e.g. be provided in a form-fitting manner. The media interface is preferably formed via plug devices. Under the media supply is to be understood in particular the connection to the supply of electricity or similar media, including the ultrasonic frequency.

It is a further advantage if, in the case of a cutting head according to the invention, at least one drive device is provided which is designed for the movement of the ultrasound system about the rotation axis. This drive device may e.g. an electric motor, in particular an electric stepper motor or a frequency converter. This is designed so small that it is part of the cutting head, it is arranged in particular within a housing of the cutting head. The supply of this drive device is preferably carried out via the media interface already described.

It is also advantageous if, in a cutting head according to the invention, the ultrasound system is mounted rotatably about the rotation axis via bearing means, in particular in the form of a roller bearing and / or a sliding bearing. Rolling and plain bearings are particularly cost-effective embodiments of such storage means. Of course, however, other storage means within the meaning of the present invention are conceivable. The storage is preferably carried out in a housing of the cutting head or a corresponding bearing plate of the cutting head. It may also be advantageous if, in the case of a cutting head according to the invention, at least one drag connection is provided around the rotatably mounted one

Supply the ultrasound system with media. This drag connection is provided at one end with the ultrasound system and at the other end with a plug connection, wherein the plug connection preferably forms the media interface. The towing connection thus allows a relative to the cutting head connection in the form of

Media interface and a relatively rotating connection to the ultrasound system. Thus, e.g. a cable channel chain are provided which the

Towing train trains. The mobility of the towing connection is preferably adapted to the maximum angle of rotation of the ultrasound system relative to its axis of rotation.

A further advantage is achieved if, in the case of a cutting head according to the invention, a parallel offset is formed between the axis of rotation and a connection axis to the ultrasonic cutting device, in particular a connection axis of the mechanical interface. This means that the axis of rotation and the connection axis are not coaxial. If the mechanical interface is implemented for connection to a robot arm, the spacing in parallel can offer greater freedom in performing the trimming. The connection axis is preferably also a rotation axis, e.g. the sixth axis of a robotic arm.

Likewise provided by the present invention is an ultrasonic cutting device, comprising a cutting arm and at least one cutting head, which on the

Cutting arm is attached. An ultrasonic cutting device according to the invention is characterized in that the cutting head is designed in accordance with the invention.

Accordingly, an ultrasonic cutting device according to the invention brings about the same advantages as have been explained in detail with reference to a cutting head according to the invention.

Further advantages, features and details of the invention will become apparent from the following description in which with reference to the drawings

Embodiments of the invention are described in detail. The features mentioned in the claims and in the description may each be essential to the invention individually or in any desired combination. They show schematically:

Fig. 1 shows an embodiment of a cutting head according to the invention and Fig. 2 shows an embodiment of an ultrasonic cutting device according to the invention.

In Fig. 1, a first embodiment of a cutting head 10 according to the invention is shown. This has an ultrasound system 20. The ultrasound system 20 is designed with a cutting blade 22 and a rod-shaped So notrode 24. In addition, a booster 26 is provided which is capable of generating an electrically generated or incoming vibration, e.g. in the form of a piezo system, to convert it into a mechanical oscillation for the sonotrode 24.

In this embodiment, the cutting blade 22 is substantially as

isosceles triangle formed. The two same thighs this

isosceles triangles are formed by two cutting edges 22a and 22b. In this case, the tip S of this isosceles triangle lies on the axis of rotation R, about this axis of rotation R, the entire ultrasound system 20 is rotatably mounted on the cutting head 10.

In order to be able to actively control and in particular also regulate the rotatability about the axis of rotation R, a drive device 40 is provided. This is e.g. in

formed electromotive manner and accordingly torque transmitting connected to the ultrasound system 20.

Moreover, the cutting head 10 of this embodiment has an interface 30 in the form of a mechanical interface. At this one can not be shown

Robot arm of an ultrasonic cutting device 100 attack. At the same time there is the possibility of rotation about this mechanical interface 30, so to a

As can be clearly seen in FIG. 1, there is a parallel offset between the axis of rotation R and the connection axis A. When rotated on the basis of this parallel offset, accordingly, a higher flexibility can be achieved in use for a clipping process.

FIG. 2 shows an embodiment of an ultrasonic cutting device 100 according to the invention. It is provided with a robot arm in the form of a cutting arm 110. At the end of this cutting arm 110, a cutting head 10 is arranged with a cutting blade 20. In this case, this cutting head is preferably formed, as shown in FIG. 1. The above explanation of the embodiments describes the present invention solely by way of example. Of course, individual features of the embodiments, if technically feasible, can be combined freely with one another, without departing from the scope of the present invention.

LIST OF REFERENCE NUMBERS

10 cutting head

20 ultrasound system

22 cutting blades

22a cutting edge

22b cutting edge

24 sonotrode

26 boosters

30 interface

40 drive device

100 U ultrasound cutting device

1 10 cutting arm

A connection axis

R rotation axis

S tip

Claims

claims

A cutting head (10) for an ultrasonic cutting device (100), comprising

Ultrasound system (20) with a cutting blade (22) and a sonotrode (24), characterized in that the ultrasound system (20) is rotatably mounted about a rotation axis (R).

2. Cutting head (10) according to claim 1, characterized in that the

Ultrasound system (20) has a booster (26) for the conversion of an electrical vibration into a mechanical vibration.

3. Cutting head (10) according to one of the preceding claims, characterized

characterized in that the cutting blade (22) has at least two cutting edges (22a, 22b) which are arranged at an acute angle to the axis of rotation (R).

4. Cutting head (10) according to claim 3, characterized in that the

Cutting knife (22) in the form of a triangle, in particular in the form of an isosceles triangle, is formed.

5. Cutting head (10) according to any one of claims 3 or 4, characterized in that the tip (S) between the two cutting edges (22a, 22b) on or substantially on the axis of rotation (R).

6. Cutting head (10) according to one of the preceding claims, characterized

in that at least one interface (30), in particular a mechanical interface for the connection to the ultrasonic cutting device (100) and / or a media interface for the supply of the ultrasound system (20) with media, is formed.

7. Cutting head (10) according to one of the preceding claims, characterized

characterized in that at least one drive device (40) is provided, which is designed for the movement of the Uitraschallsystems (20) about the rotation axis (R).

8. Cutting head (10) according to any one of the preceding claims, characterized in that the ultrasound system (20) via bearing means, in particular in the form of a rolling bearing and / or a plain bearing, is rotatably mounted about the rotation axis (R).

9. cutting head (10) according to one of the preceding claims, characterized

gekonnzeichnet that at least one drag connection is provided to supply the rotatably mounted ultrasound system (20) with media.

10. Cutting head (10) according to one of the preceding claims, characterized

in that a parallel offset is formed between the rotation axis (R) and a connection axis (A) to the ultrasonic cutting device (100), in particular an attachment axis (A) of the mechanical interface.

11. Ultrasonic cutting device (100), comprising a cutting arm (110) and

at least one cutting head (10) fixed to the cutting arm (10), characterized in that the cutting head (10) has the features of one of claims 1 to 10.