WO2012119731A1

WO2012119731A1 - Device and method for machining at least one workpiece

Info

Publication number: WO2012119731A1
Application number: PCT/EP2012/000922
Authority: WO
Inventors: Lars Richter; Hendrik Gebauer
Original assignee: Laser Zentrum Hannover E.V.
Priority date: 2011-03-04
Filing date: 2012-03-02
Publication date: 2012-09-13
Also published as: DE102011013210A1

Abstract

The invention relates to a device for machining at least one workpiece (12, 14), said device comprising a beam guiding device for guiding a laser beam (2) that is irradiated into the device. The beam guiding device comprises a first deflecting mirror (6) for deflecting the irradiated laser beam (2), said deflecting mirror being rotatably mounted about a rotational axis. The invention is characterized in that the beam guiding device comprises at least one first ring mirror (10) that is arranged such that a laser beam (2) that is deflected by the first deflecting mirror (6) strikes the at least one first ring mirror (10) and is reflected.

Description

title

Apparatus and method for processing at least one workpiece

description

The invention relates to a device for processing at least one workpiece, which comprises a beam guiding device for guiding a laser beam irradiated into the device, which comprises a first deflecting mirror for deflecting the irradiated laser beam, which is rotatably mounted about a rotation axis.

The invention also relates to a method for processing at least one workpiece, in which at least one laser beam is directed onto at least one region of the workpiece to be machined.

A generic device is for example from DE 10 2008

CONFIRMATION COPY 022 259 A1 known. The device described here for processing glass components is used, for example, to assemble two cylindrical glass elements to form a long cylindrical element. For this purpose, the two glass components are clamped horizontally and arranged together. The contact area is heated by means of a laser beam, so that it is plastically deformable.

The device described in the cited document is only suitable for joining hollow cylindrical workpieces. The laser beam is conducted by means of a radiation guide into an interior of the workpieces or the glass components and passed there by means of a deflecting mirror from the inside to be heated portions of the glass components. The Strahlungsleitvorrichtung, at which the deflection mirror is, is rotatable about the longitudinal axis, which coincides with the longitudinal axis of the cylindrical glass components, so that the deflection mirror rotates. The area in which the laser beam falls on the inner surface of the components to be joined, thus also rotates. Due to the high rotational speeds of, for example, 1000 revolutions per minute, there is an almost homogeneous heating of the joining region of the two components to be joined together.

The device described in the publication has, in addition to the exclusive usability for glass components which have a cavity, further disadvantages. While the laser heats the irradiated portions of the glass components to be processed up to 1,200 to 1,500 ° C, part of this heat is radiated from the glass components again. In the interior of the glass components in which the Strahlungsleitvorrichtung is with the deflection mirror, therefore, there is a strong increase in temperature. Since the interior is completely surrounded by glass, this heat is difficult to dissipate. In addition, the measurement of the temperature of the glass component in the radiated area difficult, so it is usually done from the outside. However, depending on the wall thickness of the hollow-cylindrical component, the measured temperature on the outside of the glass component may deviate significantly from the temperature on the inside. A precise control of the method due to the temperature of the glass components is thus difficult.

Another disadvantage is that the Strahlungsleitvorrichtung must be designed to be rotatable as a whole. As a result, relatively large masses must be set in rotation. In addition, the Strahlungsleitvorrichtung must be introduced into the interior of the glass components to be processed. As a result, the assembly process of the device shown in the cited document is time-consuming and error-prone.

In addition, the glass components to be joined together, in particular if they have a large diameter, must be set in rotation in order to prevent the heated soft glass components from collapsing inwards during the melting process.

From DE 100 52 072 B4 an apparatus and a method for processing a component made of quartz glass by means of a laser beam is known. In this case, a hollow cylindrical component is laser-worked on the inside. The laser beam is introduced from an end face into the hollow cylinder of the component, in which a displaceable deflecting mirror is arranged from the other side. The laser beam strikes the deflecting mirror, which besides the displaceability along the longitudinal direction is also rotatably mounted. The laser beam is thus deflected to the inside of the cylinder. Now, if the deflection mirror is set in rotation and simultaneously displaced along the longitudinal axis of the hollow cylinder, there is a spiral movement of the area which is irradiated by the laser. In this way, a surface finish, in particular a polishing of the inside of the hollow cylinder, possible. From US 2,648,166 a device is known, can be joined together with the two glass cylinder. Again, the two glass cylinders are clamped horizontally and set in rotation to prevent the resulting centrifugal forces, a flow of the heated glass portion due to gravity. The heating takes place in the device shown via a gas burner, which is arranged in the interior of the glass cylinder, which are to be connected to each other.

The invention is therefore based on the object to develop a generic device and a method so that the device is easily and quickly equippable, the process is easily controllable and other disadvantages of the prior art are mitigated or completely eliminated.

The invention achieves the stated object by a device for processing at least one workpiece, which comprises a beam guiding device for guiding a laser beam irradiated into the device, which comprises a first deflecting mirror for deflecting the incident laser beam, which is mounted rotatably about a rotation axis that extends therethrough characterized in that the Strahlleitvorrichtung comprises at least a first annular mirror, which is arranged such that a deflected from the first deflecting laser beam to the at least one first annular mirror and is reflected.

Preferably, the first annular mirror has a central axis and is designed and arranged such that it reflects the laser beam irradiated into the device in the direction of the central axis. When deflecting, the laser spot is distorted because the deflection takes place on a curved surface. However, especially in the case of ring mirrors that are planar in cross-section, the distortion takes place only in the circumferential direction, while the laser sport moves in a direction perpendicular to it Essentially not distorted. Since the spot rotates over the circumference of the workpiece, the heat input takes place almost independently of the shape of the spot in this direction.

If a workpiece which is to be processed is now introduced into the device, a laser beam is irradiated into the device. This is guided by the Strahlleitvorrichtung to the desired position. He first encounters the first deflecting mirror, which deflects the laser beam. In this case, the deflection mirror rotates, so that the direction in which the laser beam is deflected by the first deflection mirror, also rotates.

According to the invention, a second annular mirror is provided which is arranged such that a laser beam deflected by the first deflection mirror strikes the second annular mirror and is reflected onto the first annular mirror. This can ensure that the laser beam runs parallel between the two ring mirrors to the outer surface of the workpiece to be machined, whereby the device can be made compact. The ring mirrors may also have, for example, a spherical or parabolic shape in cross section, if this is desired for focusing reasons.

The laser beam deflected in this way now encounters an annular mirror which is arranged so that during the rotation of the first deflecting mirror the laser beam deflected by the latter and the second annular mirror always strikes the mirror surface of the first annular mirror. From there it can then be reflected, for example, directly onto the part of the at least one workpiece to be heated. If the laser beam, after it has been deflected by the deflecting mirror, reflected by the annular mirror in the direction of the central axis, it is ensured that it impinges on a part of the outer surface of the workpiece to be machined.

Preferably, the device comprises at least one holding device for holding the at least one workpiece. This is particularly advantageous for thin tubes or workpieces that can not be simply stacked, for example.

The device is particularly suitable for joining two workpieces, of which at least one has an area to be joined, which may consist of a glass. When joining the two workpieces they are arranged together and the contact area of both workpieces is heated by the irradiated laser beam. In the present case, the incident laser beam impinges from the outside on the workpieces to be joined by the deflection at the deflection mirror and the reflection at the first ring mirror. It has proven to be particularly advantageous when the laser beam strikes perpendicular or almost perpendicular to the outer surface of the workpieces to be joined. In this way, it is particularly well possible to irradiate the area to be heated and to ensure particularly good heat transfer. This can be achieved, for example, by deflecting the laser beam irradiated into the device at the deflecting mirror by less than 90 ° and, upon impinging on the first annular mirror, being reflected so that it impinges perpendicularly on the surface of the workpieces to be joined.

However, it is also possible with such a device, for example, to cut a workpiece or to adjust its geometry, for example, the circumference, exactly. This is especially possible for inner surfaces of a hollow workpiece. In addition, the workpieces to be machined may also consist of materials other than glass, for example of metal such as steel or of ceramic material. Also workpieces made of different materials can be connected together. It is conceivable, for example, the joining of a metal ring with a glass cylinder. The device ensures a nearly homogeneous circumferential heating of the workpiece to be machined. The ideal speed depends on how fast the material to be processed radiates the absorbed heat and locally cools down again. If necessary, already one revolution per second is sufficient. However, the higher the speed, the more homogeneous the workpiece will be heated over its circumference.

In a preferred embodiment, the first annular mirror and / or the second annular mirror are displaceably mounted in the direction of a longitudinal axis of the device. Thus, the area which is heated by the impact of the laser beam on the workpiece can be set very accurately. In non-planar cross-section ring mirrors, however, a displacement of the first annular mirror is bound to conditions that are to be maintained in order to ensure an optimal impact of the laser beam on the surface of the at least one workpiece. With ring mirrors that are planar in cross-section, a large area can easily be realized in which the ring mirrors can be displaced.

The laser beam is preferably radiated into the device, for example parallel to the longitudinal axis of the device, and deflected at a deflection direction in a direction perpendicular thereto. Here also every other deflection angle is conceivable. The beam direction, in which the laser beam is deflected at the deflection mirror, thereby rotates, as well as the deflection mirror is rotatably mounted and rotates during operation of the device. If, for example, a cylindrical or hollow-cylindrical workpiece is located in the device, the laser beam, after being deflected by the deflection mirror, for example, runs perpendicular to an axis of symmetry of the cylindrical workpiece. Here he meets the second ring mirror and is deflected at this down. At a certain distance, it then hits the first ring mirror, which redirects it to the outer surface of the workpiece to be reshaped or heated.

In order not to disturb or hinder the circulating laser beam, the holding device is preferably designed to be in an interior of the Workpiece to be arranged so that no contact of the holding device with an outer surface of the workpiece is necessary. Of course, this is only possible with workpieces that have an interior and, for example, are shaped like a hollow cylinder. In this way it can be ensured that the parallel to the outer surface extending laser beam is not disturbed by a holder of the workpiece, deflected or blocked. The holding device may in particular have a plurality of clamping elements, which are arranged for example concentrically on an axis. The clamping elements can be displaced outwards and can thus build on the inside of a hollow cylinder pressure, which ensures that the holding device or the clamping elements can not be moved relative to the hollow cylinder, but pinch in the interior of the hollow cylinder.

Alternatively, of course, a holding device is conceivable that engages an outer surface of the workpiece and holds it so. In this case, if necessary, parts of the holding device must be equipped with mirror arrangements or deflecting arrangements for the laser beam in order to prevent blocking or deflection of the laser beam by the holding device. The laser beam is then passed around the portions of the fixture.

Preferably, the holding device is designed such that the workpiece is non-rotating storable. In particular, if, for example, large cylindrical or hollow-cylindrical glass bodies are to be connected to one another, then they can be supported upright vertically or substantially vertically. As a result, the workpieces no longer have to be mounted in a rotating manner in order to counteract the influence of gravity on the heated and thus soft and easily moldable glass material. A flow of the material, as described in a horizontal storage in the prior art, is thus excluded and must can not be compensated by a rotation of the workpieces. In particular, for large and heavy workpieces on the one hand the handling is simplified because these workpieces now no longer need to be rotated, on the other hand, the device can be structurally smaller and more compact and ultimately produced more cost-effectively.

It has proven to be particularly advantageous if the first deflecting mirror is a semipermeable mirror. Preferably, a second deflection mirror is provided, which is arranged such that a portion of a laser beam not deflected by the first deflection mirror strikes the second deflection mirror. During operation of a device, this could, for example, achieve that part of the laser beam is deflected at the first deflecting mirror and fed to the at least one annular mirror. This part of the laser beam is directed to the outside or an outer surface of the workpiece to be heated. A second part of the laser beam is not redirected by the semitransparent deflection mirror. This meets at a certain distance on a second deflection mirror and is deflected by this. If, for example, a hollow cylindrical workpiece is located in the device, the second deflection mirror is advantageously located in the hollow space of this hollow cylindrical workpiece. This makes it possible to make the second part of the laser beam, which was not deflected by the first deflecting mirror, also strike a region of the inner surface of the hollow cylindrical workpiece. By means of a suitable choice of the distances, it is possible for the area of the outer surface and the area of the inner surface in which the two portions of the laser beam impinge to lie directly opposite one another, so that it extends beyond the wall thickness of the hollow cylindrical workpiece a nearly homogeneous heating can occur. Especially with workpieces with a large wall thickness, this procedure and this embodiment of the device makes sense.

The second deflecting mirror is also rotatable about the axis of rotation. so that also the area of the inner surface of the workpiece, on which the second part of the laser beam impinges, rotates. This ensures that an almost homogeneous heating of the component to be heated is achieved even over the circumference of the inner surface.

Preferably, the first deflecting mirror and the second deflecting mirror are connected to each other via a shaft. This makes it possible to ensure a particularly simple constructive manner that the rotational speed of the two deflecting mirrors is identical. On this shaft, for example, the clamping elements of the holding device can be arranged, which can attack from the inside to the workpiece and hold it so. The clamping elements may be arranged for example on a common bearing element, which is located on the shaft. The shaft is rotatably configured in this case relative to the bearing element, so that the bearing element itself can remain at rest relative to the rest of the device and also relative to a workpiece to be machined, so do not have to rotate with the shaft. This can be achieved that it comes to a clamping action of the clamping elements from the inside of the workpiece and yet the shaft can rotate with the second deflecting mirror located thereon so that the portion of the laser beam not deflected by the first deflecting mirror has a peripheral portion of the inner surface of the workpiece irradiated.

In one embodiment of the present invention, the device comprises a temperature sensor, for example a pyrometer, for determining a surface temperature of the workpiece, and the device additionally comprises a laser for irradiating a laser beam into the beam-guiding device and a control unit which is designed and set up, for example, electrically or electronically, to regulate a laser power emitted by the laser. The fact that the laser beam impinges on a region of the outer surface of the workpiece, the measurement of the temperature in this area directly from the outside to constructively very easy way possible. By comparing the measured temperature values with a previously predetermined temperature setpoint curve, the parked laser power of the laser beam which is radiated into the beam-guiding device can be regulated. A sensor can also be arranged as an alternative to the second deflecting mirror so that the beam portion not deflected by the first deflecting mirror strikes the sensor and can thus be used to monitor the process. Then it may be advantageous if the majority of the power of the laser beam, for example 90%, is deflected by the first deflection mirror.

In a preferred embodiment, a tilt angle of the first and / or second deflection mirror is adjustable. Thus, the angle is changed by which the laser beam is deflected at the respective mirror. Thus, the position can be changed, at which the laser beam impinges on the surface of the workpiece. The adjustment of the tilt angle can be done, for example, by a fine servomotor, possibly even continuously, so that the irradiated surface can be set very accurately. However, a change in the tilt angle leads to changes in the wide beam path. In that case, it may then no longer be ensured that the laser beam runs parallel to the outer surface of the at least one workpiece between the two annular mirrors or still impinges perpendicularly on the workpiece.

A method according to the invention for machining the at least one workpiece is characterized by the steps of a) deflecting the laser beam through a first deflection mirror rotating about a rotation axis and

b) redirecting the deflected laser beam through at least one annular mirror so that the laser beam strikes a portion of an outer surface of the at least one workpiece. According to the invention, the deflected laser beam is diverted through two annular mirrors.

It has proven to be advantageous that only a part of the laser beam is deflected by the first deflection mirror. The remaining part is then preferably deflected by a second deflection mirror such that it strikes a region of the inner surface of the at least one workpiece. Alternatively, the remaining part can also be directed to a sensor which, for example, measures the laser power irradiated into the beam guiding device, or the power of the remaining part. This information can be used to monitor the process. Preferably, the first deflecting mirror and the second deflecting mirror rotate at the same speed and in the same direction. This can, as already stated, particularly easy to implement by both mirrors are connected to each other via a common shaft.

The method is advantageously a method for joining a first workpiece and a second workpiece, wherein the at least one first workpiece has an area to be joined, which may consist of a glass, and the laser beam strikes the area to be joined of the workpieces. Such joining methods can be used, for example, in the production of glass tube elements for solar power plants. In this case, two short glass tube elements are initially provided with one metal ring at an outer end, on which later further components can be arranged. Subsequently, these two glass elements are placed on one end of a long glass tube, which may be four meters long, for example. This can be done for example with a joining method described here. The advantage here is that due to the relatively small diameter of these tubes, which may be 125 mm, for example, even with horizontal clamping or mounting of the glass workpieces to be joined, a rotation of the workpieces is not necessary, since the influence of gravity is not sufficient here to cause a deformation outside the tolerance ranges. Thanks to the very simple temperature monitoring on the outside of the glass tubes, the temperature can be measured very accurately, so that the process can be well controlled by balancing with a desired temperature and a corresponding control unit. In this way, there is a fast and energy-efficient connection of the various glass components. In addition, the fact that the laser beam impinges on the workpieces from the outside, no deflecting mirror, which is in particular rotatable, must be placed in the narrow interior of the workpiece. As a result, on the one hand reduces the placement times and on the other hand, the device structurally simple and less error-prone executable.

Alternatively, the method can also be used for connecting larger components, for example glass cylinders with a diameter of one meter. These can be stored vertically due to their stability, so that even here a rotation that would be very difficult to handle, especially in these heavy and large elements is avoided. Therefore, it is advantageous if the at least one workpiece can be stored vertically. Of course, the workpieces can also be stored horizontally or in any other orientation. This may make special demands on the respective holding device.

According to the invention, a glass tube for solar tube collectors comprises at least two glass partial tubes which have been joined by one of the above-mentioned methods. Characterized a chemical change of the components is effectively prevented compared to a use, for example, a gas burner for heating the components to be joined. If the components to be joined are heated with a burner, for example a gas burner, it can not be reliably ruled out that undesirable components are also contained which adhere to the components to be heated Adhere surfaces of the components and these change chemically. This is reflected in material stresses and possibly lower breaking strength. However, if the glass tubes are joined by a method described here, these disadvantages can be effectively prevented.

With reference to drawings, an embodiment of the present invention will be explained in more detail below. It shows

FIG. 1 shows a device according to a first exemplary embodiment of the present invention in a schematic 3-D view,

Figure 2 - the device shown in Figure 1 from another

Perspective,

FIG. 3 shows the device from FIGS. 1 and 2 in a schematic cross-sectional representation,

FIG. 4 shows a device according to a second exemplary embodiment of the present invention in a schematic 3D view,

Figure 5 - the device of Figure 4 from another perspective and

Figure 6 - the device according to Figures 4 and 5 in a schematic sectional view.

Figures 1 and 2 show a device according to a first embodiment of the present invention in schematic SD representations from different perspectives. A laser beam 2 is introduced from above into the device. He meets a first deflection mirror 6. This is in the illustrated embodiment at a 45 ° angle to the direction of incidence of the laser beam 2, so that the laser beam 2 is deflected by the first deflection mirror 6 by 90 °. The first deflecting mirror 6 is rotatably mounted about an axis of rotation which, in the exemplary embodiment shown in the figures, is combined with the direction of incidence of the laser beam 2. menfällt.

After the laser beam 2 has been deflected by the first deflecting mirror 6, it strikes the second annular mirror 8, from which it is deflected downwards in the figures. The second annular mirror 8 is designed so that the deflection of the laser beam 2 is again by 90 °.

If now the first deflecting mirror 6 is set in rotation, the reflected laser beam 2 also circulates in a circle. However, he always hits the second ring mirror 8 so that it is always reflected. Thereafter, in the embodiment shown, it strikes the first ring mirror 10, and is deflected from there again.

FIGS. 1 and 2 schematically show a first workpiece 12 and a second workpiece 14, which may be made of glass, for example, and which are to be joined together in the exemplary embodiment shown. For this they are arranged together. The contact region in which the first workpiece 12 comes into contact with the second workpiece 14 is now heated by the laser beam 2, which was deflected by the first annular mirror 10. Due to the fact that the first deflecting mirror 6 rotates, the point of impact at which the laser beam 2 strikes the connecting area between the first operative piece 12 and the second workpiece 14 also rotates, and runs around the circumference of the workpieces 12, 14. Due to the high speeds, there is a nearly homogeneous heating of the joining area.

When the laser beam 2 is deflected at the first ring mirror 10 and at the second ring mirror 8, the laser spot is distorted. Both ring mirrors 8, 10 have curved surfaces on which the laser is reflected. However, this is the case only in the circumferential direction of the ring mirrors 8, 10. In a direction perpendicular to this direction no distortion takes place. Around the joining area of the first workpiece 12 and the second workpiece 14 to heat as homogeneously as possible, the first deflecting mirror 6 is rotated at a relatively high speed of, for example, 1000 revolutions per minute. The heating thus takes place almost independently of the actual shape of the spot of the irradiated laser beam 2 in the circumferential direction. The distortion of the laser beam 2 in this direction caused by the first ring mirror 10 and the second ring mirror 8 consequently has no appreciable influence. The device is therefore particularly suitable for methods in which it depends on a homogeneous heating of the entire circumference of the workpiece to be machined.

Figure 3 shows the device already shown in a schematic sectional view. It can be seen the laser beam 2 entering from above into the device, which is deflected by the first deflection mirror 6. Subsequently, the laser beam strikes first on the second annular mirror 8 and then on the first annular mirror 10 before it impinges on the joining region between the first workpiece 12 and the second workpiece 14. It can be seen clearly in FIG. 3 that a change in the tilting angle of the first deflecting mirror 6 results in a displacement of the entire following beam path of the laser beam 2. If a change in the tilt angle takes place only to a very limited extent, the position of the laser beam 2 on the workpieces 12, 14 to be joined can thereby be set very precisely. If the tilt angle adjustment exceeds a critical value, the laser beam 2 no longer strikes the second annular mirror 8 or the first annular mirror 10 after deflecting onto the first deflecting mirror 6, so that heating of the first workpiece 12 and of the second Workpiece 14 is coming. If the region in which the laser beam strikes the workpieces 12, 14 to be joined is displaced by a greater amount, it makes sense to make the first annular mirror 10 displaceable. It can then in particular in a direction parallel to the axis of symmetry of the workpieces 12, 14 shown, in the figures 1 to 3 so up or down, be moved.

Figures 4 and 5 show a device according to a second embodiment of the present invention in a schematic SD view from different perspectives. It can be seen again the incident from the top of the device laser beam 2, which is at least partially deflected by the first deflection mirror 6. The portion of the laser beam 2 which is deflected by the first deflection mirror 6, as shown in Figures 1 to 3, first encounters the second annular mirror 8, from which it is reflected on the first annular mirror 10.

Again, a first workpiece 12 and a second workpiece 14 are provided, which are to be joined together and are arranged one above the other.

The part of the laser beam 2 which has been deflected by the first deflecting mirror 6 strikes the joining region between the first workpiece 12 and the second workpiece 14 after impinging on the first annular mirror 10 and heats the latter. As a result of the rotation of the first deflection mirror 6, the impact point runs over the circumference of the two workpieces 12, 14 and thus heats the peripheral region almost homogeneously.

Unlike in FIGS. 1 to 3, the first deflecting mirror 6 in FIGS. 4 and 5 is designed as a semitransparent mirror so that a partial beam 16 passes through the first deflecting mirror 6 without being deflected by it. Both the first workpiece 12 and the second workpiece 14 are formed as hollow cylindrical workpieces. The partial beam 16 now runs from above into the workpieces 12, 14 and meets there on a second deflection mirror 18. This is connected via a shaft 20 with the first deflection mirror 6 and thus rotatable together with this. The partial beam 16 is deflected by the second deflecting mirror 18 and now hits from the inside to the joining region between the first workpiece piece 12 and the second workpiece 14. This ensures even more homogeneous heating, in particular in the radial direction of the workpieces 12, 14. As an alternative to a second deflection mirror 18, a sensor could also be arranged at this point, for example, which determines, for example, the laser power striking it which can be used to monitor, control and / or regulate the method. For this purpose, it may be useful if the trained as a semitransparent mirror first deflecting mirror 6 only a small part, for example, 5% or 10% of the laser power impinging on it durchläset and deflects the vast majority remaining.

It can clearly be seen in FIGS. 4 and 5 that the first workpiece 12 and the second workpiece 14 do not rotate during the joining process. The arranged in the figures below second workpiece 14 may be arranged, for example, standing on a base plate 22. Additionally or alternatively, a holding device 24 is provided, which is covered by the first annular mirror 10 in FIG. In this special application, this holding device 24 is arranged on the shaft 20, on which both the first deflecting mirror 6 and the second deflecting mirror 18 are arranged, and which rotates during operation of the device. The holding device 24 is, however, arranged so that it is for example slidably mounted on the shaft 20, so that the holding device 24 does not rotate with the shaft 20. In the exemplary embodiment illustrated in the figures, the holding device 24 has three support elements 26, which extend from a ring 28 surrounding the shaft 20 to the respective workpiece 12, 14. The ring 28 is slidably mounted on the shaft 20 so that the shaft 20 can rotate relative to the ring 28. The support elements 26 can be pressed, for example, hydraulically from the inside to the inner surface of the respective workpiece 12, 14. As long as the frictional force generated thereby is greater than the frictional forces prevailing between the shaft 20 and the ring 28, the holding device 24 is not connected to the shaft 20. rotates. In this way it is guaranteed that the to be connected

Workpieces 12, 14 do not rotate relative to the location of the device and the rest of the structure of the device, so that here the handling of the system, especially for large and heavy workpieces, is significantly simplified and the system can be designed structurally smaller. The holding device 24 is designed such that the workpiece 12, 14 held by it is non-rotatably storable, although the shaft 20 rotates with the deflecting mirrors 6, 18 attached thereto relative to the workpieces 12, 14.

FIG. 6 shows the device from FIGS. 4 and 5 in a sectional view. It can again be seen that the incoming laser beam 2 is split by the first deflecting mirror 6 configured as a semitransparent mirror. The part of the laser beam 2 which is deflected meets the second annular mirror 8, the first annular mirror 10 and then the joint between the first workpiece 12 and the second workpiece 14. It is guided past the first workpiece 12 on the outside. The partial beam 16, which is not deflected by the first deflection mirror 6, however, enters into the interior of the workpiece 12 and there meets the second deflection mirror 18, which is coupled via the shaft 20 with the first deflection mirror 6. In Figure 6, only a holding device 24 is schematically indicated, which has a ring 28 which is slidably mounted on the shaft 20 and is connected via support members 26 with the first workpiece 12. This ensures that the

Workpieces 12, 14 do not move relative to the rest of the structure, in particular to the base plate 22.

In all the embodiments shown, a particularly simple structural embodiment is possible if the laser beam 2 is deflected at each mirror by exactly 90 degrees. Of course, other deflection angles are conceivable, depending on the structural design of the device and the workpieces to be machined and the respective processing _

- 21 -

Method can be useful and beneficial.

LIST OF REFERENCE NUMBERS

2 laser beam

6 first deflection mirror

8 second ring mirror

10 first ring mirror

12 first workpiece

14 second workpiece

16 partial beam

18 second deflecting mirror

20 wave

22 base plate

24 holding device

26 support element

28 ring

Fr / ad

Claims

claims

Anspruch [en] A device for processing at least one workpiece (12, 14), which comprises a beam guiding device for guiding a laser beam (2) irradiated into the device, comprising a first deflecting mirror (6) for deflecting the incident laser beam (2) Is mounted rotatably axis of rotation, characterized in that the Strahlleitvorrichtung comprises at least a first annular mirror (10) which is arranged such that one of the first deflecting mirror (6) deflected laser beam (2) on the at least one first annular mirror (10) meets and is reflected and that the device comprises a second annular mirror (8) which is arranged so that one of the first deflecting mirror (6) deflected laser beam (2) on the second annular mirror (8) and from there to the first annular mirror (10) is reflected.

2. Apparatus according to claim 1, characterized in that the first annular mirror (10) has a central axis and is designed and arranged such that it reflects the irradiated into the device laser beam (2) in the direction of the central axis.

3. Apparatus according to claim 1 or 2, characterized in that the device comprises at least one holding device (24) for holding the at least one workpiece (12, 14).

4. Device according to one of the preceding claims, characterized in that the first annular mirror (10) and / or the second annular mirror (8) is displaceably mounted in the direction of a longitudinal axis of the device.

5. Device according to one of the preceding claims, characterized in that the holding device (24) is adapted to in an interior of the workpiece (12, 14) to be arranged so that no contact of the holding device (24) with an outer surface of the workpiece (12, 14) is necessary. 6. Device according to one of the preceding claims, characterized in that the holding device (24) is designed such that the workpiece (12, 14) is non-rotatably storable.

Device according to one of the preceding claims, characterized in that the first deflecting mirror (6) is a semipermeable mirror.

8. The device according to claim 7, characterized in that a second deflection mirror (18) is provided, which is arranged such that from the first deflection mirror (6) not deflected portion of a laser beam (2) on the second deflection mirror (18).

9. Apparatus according to claim 7 or 8, characterized in that the second deflecting mirror (18) is rotatably mounted about the axis of rotation.

10. The device according to claim 9, characterized in that the first deflecting mirror (6) and the second deflecting mirror (18) via a shaft (20) are interconnected.

11. Device according to one of the preceding claims, characterized in that a temperature sensor for determining a surface temperature of the workpiece (12, 14), a laser for irradiating a laser beam (2) are provided in the Strahlleitvorrichtung and a ne control unit, which is established one of which

Laser radiated laser power to regulate.

12. Method for processing at least one workpiece (12, 14), in which at least one laser beam (2) is directed to at least one region of the workpiece (12, 14) to be machined,

characterized by the steps:

a) deflecting the laser beam (2) by a first deflecting mirror (6) rotating about an axis of rotation,

b) redirecting the deflected laser beam (2) through at least one annular mirror (10) so that the laser beam (2) strikes a region of the outer surface of the at least one workpiece (12, 14), the laser beam (2) passing through two annular mirror (8, 10) is deflected.

13. The method according to claim 12, characterized in that only a part of the laser beam (2) by the first deflection mirror (6) is deflected.

14. The method according to claim 13, characterized in that the part of the laser beam (2) which is not deflected by the first deflecting mirror (6) is deflected by a second deflecting mirror (18) such that it extends to an area of the inner

Surface of the at least one workpiece (12, 14) meets

15. The method according to claim 13 or 14, characterized in that the first deflecting mirror (6) and the second deflecting mirror (18) rotate at the same speed and in the same direction.

16. The method according to any one of claims 12 to 15, characterized in that a first workpiece (12) and a second workpiece (14) are joined together, wherein at least the first workpiece (12) has a portion to be joined, the glass can exist, and the laser beam (2) on the area to be joined of the workpieces (12, 14) meets.

17. The method according to any one of claims 12 to 16, characterized in that the at least one workpiece (12, 14) is mounted vertically while it is being processed.

Glass tube for solar tube collectors, comprising at least two glass sub-tubes, characterized in that the glass sub-tubes have been joined by a method according to one of claims 12 to 17.

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