Device for machining an elongated workpiece by means of a laser beam circulating around the workpiece

Abstract

Device (1) for machining an elongated workpiece (2) such as pipes or other metal semi-finished products by means of a laser beam (3) circulating around the workpiece (2), comprising a machine body (4), a holding element (5) rotatably mounted relative to the machine body (4), an opening (6) enclosed by the holding element (5) through which the workpiece (2) to be machined passes during machining of the workpiece (2), wherein the holding element (5) describes an enveloping surface (7) at least partially enclosing the workpiece (2) during its rotational movement, a laser beam source (8) for generating the laser beam (3), wherein the laser beam source (8) is held by the holding element (5), characterized by that the laser beam source (8) is arranged on the side of the holding element (5) facing away from the workpiece (2) during machining, i.e. on the outside of the described enveloping surface (7), and that the holding element (5) is rotatably mounted by the machine body (4) at at least two bearing points (20, 20a, 20b, 20c), the largest part of the holding element (5) running between the two bearing points (20, 20a, 20b, 20c) and a smaller part of the holding element (5) running beyond at least one of the two bearing points (20, 20a, 20b, 20c).

Description

[0001] The invention relates to a device for machining an elongated workpiece such as pipes or other metal semi-finished products by means of a laser beam circulating around the workpiece, with a machine body, with a holding element rotatably mounted relative to the machine body, with an opening enclosed by the holding element, through which the workpiece to be machined passes during machining of the workpiece, wherein the holding element describes an envelope surface at least partially enclosing the workpiece during its rotational movement, with a laser beam source for generating the laser beam, wherein the laser beam source is held by the holding element.

[0002] For decades, cutting semi-finished metal products to a desired length has been a standard task in industrial manufacturing. The semi-finished metal products are available in a certain fixed length prior to cutting or are supplied to the desired length through a continuous production process. Processing the semi-finished metal product can involve not only cutting to length, but also, for example, creating custom openings in the wall of a semi-finished product, such as a metal pipe, or a welding process for thermally bonding multiple workpieces.

[0003] Traditional machining processes used for a long time were associated with various problems due to unavoidable chip removal, such as contamination of the cut workpieces with chips at the cutting point or even the cutting device. Depending on the application, a complex and costly cleaning process was and still is required for the cut workpieces. Likewise, the fixtures used to machine the workpiece must be cleaned regularly to ensure reliable machining or machining of the desired quality.

[0004] Other prior art devices provide for the elongated workpiece to be machined without cutting by inserting a cutting tool – with or without a counterholder – for example, by shearing off a workpiece wall by the shearing edges of the machining device moving past each other. Problematic here, too, are the inevitable formation of burrs on the workpiece (which may then require reworking of the cutting edges) and possibly also the formation of chips.

[0005] With the introduction of laser technology, some of the aforementioned problems could be eliminated or at least mitigated, although the equipment and control technology required for production machines has increased significantly. Depending on the thickness of the material being processed, laser technology can produce very smooth cutting edges without burrs and without contamination of the workpieces at the processing point by chips.

[0006] In a device known from the prior art (EP 2 595 777 B1), a hollow-walled rotating body is provided as a holding element for the cutting means designed as a laser beam source, in whose hollow wall the laser beam source is arranged. This entails several disadvantages, such as a rather complex and heavy rotating hollow body, which protects the laser beam source but simultaneously complicates access to the cutting device.

[0007] From DE 10 2012 007 563 B3 a processing device with a rotating laser beam is known, wherein the laser beam source is aligned radially to the workpiece, radially penetrates the envelope surface defined by the rotational movement of the holding element and reaches the interior defined by the envelope surface in close relative proximity to the workpiece.

[0008] The object of the present invention is to further develop and specify a device of the generic type in which the disadvantages known from the prior art are at least reduced.

[0009] The previously derived and demonstrated object is achieved in the generic device for machining an elongated workpiece using a laser beam circulating around the workpiece by arranging the laser beam source on the side of the holding element facing away from the workpiece during machining, i.e., on the outside of the described enveloping surface. The inventive measure achieves various advantages, such as better accessibility of the laser beam source during maintenance or repair and a significantly simpler structure of the rotatably mounted holding element.

[0010] Due to the rotational movement of the holding element, the laser beam source also orbits the workpiece to be machined. During its rotational movement, the rotating (not necessarily rotating) holding element describes an imaginary envelope around the workpiece to be machined. The workpiece runs, at least partially, within the envelope defined in this way. Since the laser beam source is geometrically arranged on the outside of the described envelope, the interior space defined by the envelope, in which the workpiece is at least partially located, remains free of a rotating laser beam source. At the same time, the laser beam source is largely protected from what is happening inside the envelope.

[0011] An advantageous development of the invention is characterized in that a laser beam guide and / or laser beam optics and / or control electronics are arranged on the side of the holding element facing away from the workpiece during processing, i.e., on the outside of the described enveloping surface. Thus, all components required for laser cutting are fixedly mounted on the circumferential holding element and can be connected to one another accordingly. A particularly robust and fail-safe development is characterized in that the control electronics are connected to the laser beam source and / or laser beam guide and / or laser beam optics via a physical transmission medium.Cables of any design, including wire, fiber optics, and the like, can be considered as the physical transmission medium. Cable solutions are also suitable for the distribution and transmission of energy, not just low-power control signals. The arrangement of the control electronics on the rotating support element has the advantage that control signals required to control the entire laser beam arrangement (laser beam source, laser beam guide, laser beam optics) do not have to be transmitted from a stationary to a rotating machine part, thus eliminating a potential source of interference.

[0012] In an advantageous embodiment, the holding element is a hollow body with a substantially closed wall, which wall can have an opening for the passage of the laser beam. A simple example of such a hollow body is a tube, i.e. a cylinder, which can also be open at its end faces. One advantage here can be seen in the fact that the envelope surface is physically realized in its entirety - i.e., it does not only arise during an imaginary rotation of the holding element - so that the holding element has a protected interior in which the workpiece to be machined is at least partially located. A further advantage of the closed wall is the multitude of installation options for the various elements, i.e. the laser beam source, the laser beam guide and, if applicable, the laser beam optics and the control electronics.

[0013] In general, when selecting the installation locations for the various components on the outside of the support element, care is taken to ensure that there is a symmetrical mass distribution in order to avoid imbalances within the structure; if necessary, counterweights must be provided.

[0014] In an alternative embodiment of the device, the holding element is designed like a cage, i.e., has a wall that is essentially not closed. The cage-like holding element has, for example, longitudinal struts that run parallel to the axis of rotation of the holding element. For stabilization, the longitudinal struts can be supplemented by annular cross struts. When cabling the laser device arranged on the struts, if necessary, the struts are used as cable guides. An advantage of this design is the observability of the workpiece rotating around the cage-like holding element and the comparatively lightweight construction with only small rotating masses. As already explained for the holding element with a closed wall, the best possible mass balance must also be ensured with the cage-like design of the holding element.

[0015] A preferred embodiment of the device for machining an elongated workpiece using a circulating laser beam provides that the laser beam optics are arranged so as to be displaceable in the axial direction on the holding element. This measure not only makes it possible to machine the workpiece in the circumferential direction, but also allows a stationary workpiece to be machined in the axial direction thanks to the displaceability of the laser beam optics. It is also possible for a continuously fed workpiece, i.e. one that is fed at an axial feed rate through the opening enclosed by the holding element, to be moved along with the workpiece, so that the feed movement is balanced and machining can take place while stationary in the axial direction relative to the workpiece. For example, it is possible to cut continuously manufactured and fed pipes inline, so that the cutting plane runs perpendicular to the workpiece axis.In particular, it is then provided that an adjusting means for axially displacing the laser beam optics is arranged on the side of the holding element facing away from the workpiece during processing, i.e., on the outside of the described enveloping surface. It is then also particularly suitable to arrange an adjusting means control on the side of the holding element facing away from the workpiece during processing, i.e., on the outside of the described enveloping surface. With this solution, only very few masses need to be moved in the axial direction; in particular, entire machine parts, i.e., parts of the machine body, are not set in motion.

[0016] In an advantageous embodiment, it is provided that - alternatively or additionally - the machine body is arranged on a machine bed so that it can be displaced in the axial direction, whereby the axial direction again means the axis of rotation of the holding element, which generally corresponds to its longitudinal direction of the workpiece. For certain applications, it can be advantageous to implement both measures for axial displaceability simultaneously. For example, a movement that compensates for the feed of the workpiece could be achieved by displacing the machine body on the machine bed, while faster axial movements are achieved by mechanically displacing the laser beam optics. The adjustment path realized by the axial displacement of the laser beam optics would then only have to be as extensive as the stationary processing area on the workpiece.

[0017] In a further advantageous development of the processing device, an electrical transmission device is arranged between the machine body and the holding element, with which at least electrical energy is transmitted for operating the electrical consumers arranged on the holding element, i.e. in particular for operating the laser beam source, the laser beam guide, the laser beam optics, the associated control electronics, the actuating means for axially displacing the laser beam optics, and the actuating means. In particular, it is provided that the electrical transmission device is based on sliding contacts - for example in the form of slip rings and sliding contacts - or on inductive transformers. Restricting this to electrical power transmission makes sense because high-frequency interference in the supply voltage is either insignificant or easy to filter.

[0018] When transmitting control signals with a high bandwidth, high-frequency interference is not so easy to detect and filter through suitable measures. Furthermore, multi-pole sliding contacts are also a source of error that can be avoided. In a further embodiment of the invention, a radio data interface is arranged on the holding element, in particular whereby control data for operating the electrical loads arranged on the holding element are transmitted, i.e. in particular for operating the laser beam source, the laser beam guide, the laser beam optics, the associated control electronics of the actuating means for axially displacing the laser beam optics, and the actuating means control. The corresponding devices can thus be parameterized and controlled via a radio connection, with radio technologies that take latencies into account (e.g., IEEE 802.3af).11mc), so that a synchronous sequence of a control on the rotating holding element and a stationary control, which is located, for example, on the machine body, is ensured.

[0019] The machining device according to the invention is further characterized in that the holding element is rotatably mounted by the machine body at at least two bearing points. Compared to a one-sided bearing, this design has the advantage that vibrations about a one-sided bearing point are suppressed. In particular, it is provided that the largest part of the holding element runs between the two bearing points and a smaller part of the holding element runs beyond at least one of the two bearing points. This measure creates a bearing area for the holding element that is enclosed by the bearing points and has defined nodes at two locations for movement of the holding element extending between the bearing points.The area of ​​the holding element that projects beyond one of the two bearing points, i.e., which constitutes the smaller part of the holding element, initially has a lower tendency to vibrate than the area located between the bearing points. This is particularly true when the free end of the smaller part of the holding element is guided in a defined manner by another bearing point. For this reason, in an advantageous embodiment of the device, the smaller part of the holding element that extends beyond at least one of the two bearing points carries the laser optics, in particular wherein the larger part of the holding element carries one or more of the following electrical components, namely the laser beam source, the laser beam guide and / or the associated control electronics.This design has the advantage that the laser optics specifically responsible for the machining process exhibit only a low tendency to vibrate due to their bearings, allowing for particularly precise guidance. Preferably, however, an additional bearing point is also provided at the end, where the end of the smaller part of the holding element is additionally mounted.

[0020] In a preferred embodiment, the machine body additionally comprises a housing, wherein the housing is penetrated by the holding element in the axial direction of extension, and wherein the housing covers the region of the holding element on which the laser beam source is arranged. Preferably, the housing also covers the region of the holding element on which at least one of the following additional electrical components is arranged: namely, the laser beam guide, the laser beam optics, and the associated control electronics. Preferably, the aforementioned at least two bearing points are embedded in the housing walls of the housing.

[0021] In a preferred embodiment, the laser beam optics are arranged outside the housing on the holding element, i.e., on the smaller part of the holding element. This embodiment specifically ensures that the massive rotating or revolving machine parts are protected by the housing and that the laser beam optics, which may require regular maintenance and therefore regular access, are adequately accessible.

[0022] In detail, there are now various possibilities for designing and developing the device according to the invention. Reference is made to the claims subordinate to claim 1 as well as to the description of preferred embodiments in conjunction with the drawing. The drawing shows Fig. 1a, Fig. 1b schematically shows a device for pipe processing with a cage-like holding element, Fig. 2 schematically shows a device for pipe processing with a holding element designed as a hollow body with a substantially closed wall, Fig. 3 schematically shows a device for pipe processing with a machine bed, Fig. 4 schematically shows a device for pipe processing with housing and Fig. 5 schematically shows a detailed view of a device for pipe processing with an electrical transmission device between the machine body and the holding element of the device.

[0023] In Fig. Figure 1 shows a device 1 for machining an elongated workpiece 2, which in this case is a metal tube. The workpiece 2 is machined by a circulating laser beam 3. The device 1 has a machine body 4 with a holding element 5 rotatably mounted relative to the machine body 4. The holding element 5 encloses - at least indirectly - an opening 6, in particular an opening 6 in the machine body 4, through which the workpiece 2 to be machined passes during machining of the workpiece 2.

[0024] During its rotational movement, the holding element 5 describes an enveloping surface 7 ( Fig. 1b). A laser beam source 8 is arranged on the side of the holding element 5 facing away from the workpiece 2 during processing, i.e., on the outside of the described enveloping surface 7. In the present example, the opening 6 is provided in the center of rotation of the holding element 5. Due to the rotational movement of the holding element 5, the laser source 8 rotates synchronously with the holding element 5 during processing of the workpiece 2.

[0025] In Fig. 1a is related to Fig. 1b that the holding element 5 is realized merely by two longitudinal struts 13a, 13b, which run parallel to the axis A of the workpiece 2. The rotational movement of the holding element 5 makes it possible to machine the workpiece 2 over its entire circumference. It is now additionally provided that the laser beam source 8 is arranged on the side of the holding element 5 facing away from the workpiece 2 during machining of the workpiece 2, i.e. on the outside of the described enveloping surface 7. The enveloping surface 7 can be a purely imaginary enveloping surface 7, which a holding element 5 that does not physically surround the entire circumference causes during its rotational movement, but the enveloping surface 7 can also be a structurally actually realized surface, insofar as the holding element 5 has a wall that is essentially continuous along its circumference.

[0026] In the Fig. 1, a laser beam guide 9 and a laser beam optics 10 and a control electronics 11 are also arranged on the side of the holding element 5 facing away from the workpiece 2 during processing, i.e. on the outside of the described enveloping surface 7. The control electronics 11 is connected to the laser beam source 8 by a physical transmission medium 12, in this case by an optical fiber. Fig. In the device 1 shown in Figure 1, the holding element 5 is thus designed in a very simple cage-like manner. The cage essentially comprises two longitudinal struts 13a, 13b and a circumferential connecting ring 14. In this exemplary embodiment, the connecting ring 14 materially realizes the imaginary envelope surface 7, which would also result if only the longitudinal struts 13a, 13b were to rotate about the axis A of the workpiece 2, wherein the axis A of the workpiece is the same as the axis of rotation of the holding element 5. Of course, finer structures are also conceivable; however, it is essential that the wall of the holding element 5 is not completely closed.

[0027] In Fig. 2 shows a further embodiment of the processing device 1. At first glance, the device 1 is very similar to the one shown in Fig. 1a, however, the device according to Fig. 2 significant differences. A first difference is that the holding element 5 is not constructed in a cage-like manner, but is a hollow body with a substantially closed wall. The holding element 5 in Fig. 2 also has a significantly larger opening 15 than the one in Fig. 1a shown holding element 5. At the opening 15 in Fig. 2 is a slot through which the laser beam 3 can pass through the wall of the holding element 5 at various positions, shifted in the axial direction. Therefore, in addition to the embodiment of Fig. 1a, it is provided that the laser beam optics 10 is arranged displaceably in the axial direction on the holding element 5. In addition, the device 1 has an adjusting means 16, which serves to axially displace the laser beam optics 10 on the side of the holding element 5 facing away from the workpiece 2 during processing. In the illustrated embodiment, the adjusting means 16 is embedded in the wall of the holding element 5 next to the opening 15 and interacts with the laser beam optics 10 during axial displacement. An adjusting means control 17 is also provided and is also arranged on the side of the holding element 5 facing away from the workpiece 2 during processing, i.e. on the outside of the described envelope surface. In the present case, the control electronics 11 and the adjusting means control 17 are implemented in hardware on a common computer unit with corresponding IO interfaces.

[0028] Fig. 3 shows an embodiment of the device 1, in which the machine body 4 is arranged on a machine bed 18 so as to be displaceable in the axial direction. Fig. 3 shows that the device 1 is used in a continuous manufacturing process for the workpiece 2 in the form of a tube. The workpiece 2 is fed from right to left via a workpiece holder 19, and the processing of the tube 2 by the device 1 here consists in cutting the tube into pieces of a predetermined length. The workpiece 2 is fed continuously. During the cutting process, the machine body 4 is moved axially on the machine bed 18 so that the machine body 4 follows the feed movement of the workpiece 2, thus enabling inline cutting.

[0029] In all embodiments shown in the figures, the holding element is rotatably supported by the machine body at at least two bearing points 20, it being understood here that one bearing point differs from another bearing point if they are provided at different locations over the axial extent of the device 1.

[0030] In Fig. 3 shows that the two bearing points 20a, 20b of the holding element 5 are very solid, and that the largest part of the holding element 5 runs between the two bearing points 20a, 20b. A smaller part of the holding element 5 runs beyond the bearing point 20b. At the end, the smaller part of the holding element 5 is stored at another bearing point 20c. This is also where the separated pipe elements are removed, although this is not shown in detail.

[0031] The larger part of the holding element 5, which lies between the bearing points 20a, 20b, carries the laser beam source 8, the largest part of the laser beam guide 9 and the associated control electronics 11. The smaller part of the holding element 5, which extends between the two bearing points 20b, 20c, carries the laser beam optics 10. Due to this design, on the one hand, the tendency to vibrate at the location where the workpiece 2 is being machined is lower than, for example, the tendency to vibrate of the more massive, larger part of the holding element 5 between the bearing points 20a, 20b placed further apart from one another. On the other hand, the spatial separation of the laser beam optics 10 from the rest of the device makes it possible to take spatially separate measures, for example relating to machine and occupational safety.

[0032] In a design that Fig. 4, the machine body 4 additionally has a housing 21, wherein the housing 21 is penetrated by the holding element 5 in the axial direction of extension and wherein the housing 21 covers the area of ​​the holding element 5 on which the laser beam source 8 and the largest part of the laser beam guide 9 as well as the associated control electronics 11 are arranged. In this exemplary embodiment, the smaller part of the holding device 5, which carries the laser beam optics 10 (and a small part of the laser beam guide 9), remains freely accessible, whereby the laser beam optics 10 can be cleaned more easily when required, which may be necessary at shorter intervals.In another embodiment, which is not shown in detail here, the smaller part of the holding element 5, which carries the laser beam optics 10, is covered by a separate housing, so that when access to the laser beam optics 10 is required, only a small housing part has to be moved and the entire holding element 5 does not have to be exposed.

[0033] In Fig. 5 schematically shows that an electrical transmission device 22 is arranged between the machine body 4 and the holding element 5, with which electrical energy is transmitted for operating the electrical consumers arranged on the holding element 5, in this case for operating the laser beam source 8 and the laser beam guide 9 (if necessary at all) and the associated control electronics 11. The electrical transmission device 22 is realized here on the basis of sliding contacts.

[0034] For the transmission of control data, a radio data interface 23 is arranged on the holding element 5, via which control data for operating the electrical consumers arranged on the holding element 5 are transmitted. Reference symbol 1 device for machining an elongated workpiece 2 Workpiece 3 laser beam 4 machine bodies 5 Holding element 6 Opening 7 Envelope 8 Laser beam source 9 Laser beam guidance 10 Laser beam optics 11 Control electronics 12 physical transmission medium 13 Longitudinal strut 14 Connecting ring 15 Opening 16 setting agents 17 Actuator control 18 Machine bed 19 Workpiece holder 20 storage locations 21 housings 22 electrical transmission device 23 Radio data interface

Claims

[1] Device (1) for machining an elongated workpiece (2) such as pipes or other metal semi-finished products by means of a laser beam (3) circulating around the workpiece (2), with a machine body (4), with a holding element (5) rotatably mounted relative to the machine body (4), with an opening (6) enclosed by the holding element (5) through which the workpiece (2) to be machined passes during machining of the workpiece (2), wherein the holding element (5) describes an enveloping surface (7) at least partially enclosing the workpiece (2) during its rotational movement, with a laser beam source (8) for generating the laser beam (3), wherein the laser beam source (8) is held by the holding element (5), characterized by , that the laser beam source (8) is arranged on the side of the holding element (5) facing away from the workpiece (2) during machining, i.e. on the outside of the described enveloping surface (7), and that the holding element (5) is rotatably mounted by the machine body (4) at at least two bearing points (20, 20a, 20b, 20c), the largest part of the holding element (5) running between the two bearing points (20, 20a, 20b, 20c) and a smaller part of the holding element (5) running beyond at least one of the two bearing points (20, 20a, 20b, 20c). [2] Device according to claim 1, characterized by that a laser beam guide (9) and / or a laser beam optics (10) and / or a control electronics (11) is arranged on the side of the holding element (5) facing away from the workpiece (2) during machining, i.e. on the outside of the described enveloping surface (7). [3] Device (1) according to claim 2, characterized bythat the control electronics (11) is connected to the laser beam source (8) and / or the laser beam guide (9) and / or the laser beam optics (10) by a physical transmission medium (12). [4] Device (1) according to one of claims 1 to 3, characterized by that the holding element (5) is a hollow body with a substantially closed wall, which can have an opening (15) for the passage of the laser beam (3). [5] Device (1) according to claim 1 or 2, characterized by that the holding element (5) is designed like a cage. [6] Device according to one of claims 2 to 5, characterized by that the laser beam optics (10) is arranged displaceably in the axial direction on the holding element (5). [7] Device (1) according to one of claims 1 to 6, characterized by that the machine body (4) is arranged on a machine bed (18) so as to be displaceable in the axial direction. [8] Device (1) according to one of claims 1 to 7, characterized by that an electrical transmission device (22) is arranged between the machine body (4) and the holding element (5), with which at least electrical energy is transmitted for operating the electrical consumers arranged on the holding element (5). [9] Device (1) according to one of claims 1 to 8, characterized by that a radio data interface (23) is arranged on the holding element (5), wherein control data for operating the electrical consumers arranged on the holding element (5) are transmitted. [10] Device (1) according to one of claims 1 to 9, characterized by that the machine body (4) has a housing (21), wherein the housing (21) is penetrated by the holding element (5) in the axial direction of extension and wherein the housing (21) covers the area of ​​the holding element on which the laser beam source (8) is arranged. [11] Device (1) according to claim 10, characterized by that the housing (21) also covers the area of ​​the holding element (5) on which at least one of the following further electrical components is arranged: the laser beam guide (9), the laser beam optics (10), the associated control electronics (11). [12] Device (1) according to claim 11, characterized by that the laser beam optics (10) are arranged outside the housing (21) on the holding element (5). [13] Device (1) according to one of claims 1 to 12, characterized by that the smaller part of the holding element (5) extending beyond at least one of the two bearing points (20, 20a, 20b, 20c) carries the laser optics (10). [14] Device (1) according to one of claims 12 or 13 insofar as it is dependent on claim 10, characterized by that the walls of the housing (21) penetrated by the holding element (5) in the axial direction of extension form bearing points (20).

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