EP4326478A1

EP4326478A1 - Device and method with an optically transmissive tool

Info

Publication number: EP4326478A1
Application number: EP22726581.6A
Authority: EP
Inventors: Christian Wenzel; Thomas Gralla; Klaus SCHWEIZER
Original assignee: Innolite GmbH
Current assignee: Innolite GmbH
Priority date: 2021-04-22
Filing date: 2022-04-22
Publication date: 2024-02-28
Also published as: DE102021002115A1; WO2022223066A1

Abstract

The invention relates to a device with an optically transmissive tool for processing a surface, the device having an optically transmissive beam guiding element that is optically functionally coupled to the optically transmissive tool, such that radiation can pass from the beam guiding element into the tool. Furthermore, the invention relates to a method for processing a surface with an optically transmissive tool, wherein a laser beam is guided through the tool, and to a method for coupling a radiation guiding element to a tool.

Description

Apparatus and method using an optically transmissive tool

The invention relates to a device with an optically transparent tool for processing a surface, a method for processing a surface with an optically transparent tool in which a laser beam is guided through the tool, and a method for coupling a radiation guide element to a tool .

In particular, the invention relates to the production of high or ultra-precise surfaces, such as are required in optics or for haptic applications, by machining with geometrically defined cutting edges from monocrystalline natural or synthetic diamond. The diamond is preferably so sharp and easy to cut that subsequent polishing steps are no longer necessary. However, the materials that can be machined with monocrystalline diamond are limited. Traditionally, only non-ferrous metals, certain infrared materials and certain plastics can be processed.

[03] From a technical point of view, however, high-strength materials such as ceramics, hard metals and also glasses are of great importance in order to produce ultra-precise surfaces in or on them. For example, hard metal tools are used when pressing glass optics. The classic approach of machining with a geometrically defined cutting edge fails, and grinding and subsequent polishing of such materials are known from the prior art. The known processes are highly complex, tedious and error-prone.

[04] Alternatively, hybrid cutting with a geometrically defined cutting edge is possible. The material to be machined is locally heated and softened by a laser beam, so that a machining process is possible. Due to its high thermal conductivity, diamond is a suitable cutting material, but other cutting materials such as PCD or CBN (synthetic polycrystalline diamond, cubic boron nitride) are also known from the literature (dissertation by Dr. T. Bergs, WZL Aachen).

[05] A special property of monocrystalline diamond is its optical transparency. This enables the laser beam to be guided through the tool, so that the

confirmation copy Jet impinges directly in the cutting zone and softens. No material-specific heat conduction is required, the softening is almost ideal.

[06] A device with an optically transparent tool for processing a surface is known from EP 3484658. The optically permeable tool allows a laser beam to be guided into the area where the surface is being machined between the rake face and the flank face of the tool in order to machine the surface. Here, the laser beam is focused as a free beam on the back of the diamond blade body. In contrast to classic diamond tools, this back must be optically functionally polished so that as little scattered radiation as possible occurs when the beam is coupled in. Furthermore, the angle of the back of the tool must be selected in such a way that any back reflections on the back of the tool are not coupled back into the laser and destroy it.

[07] EP 3484658 describes possible angular constellations in order to focus the laser beam on the cutting edge between the flank face and the rake face, taking into account the refractive indices of air and diamond and the associated beam deflection.

[08] The device described in EP 3484658 has various disadvantages known from practice.

[09] Due to the large difference between the refractive index of air (nd=1) and that of diamond (nd= 2.4), total reflection quickly occurs inside the diamond, resulting in lossy scattered radiation. The diamond and tool holder, which are usually connected by a temperature-sensitive solder, can heat up as a result and the coupling of energy into the workpiece is less efficient. Since the diamond only has a flat, tilted, optically functional surface (back) as the coupling geometry, adjustment and compensation options are limited. The adjustment process is sensitive and can lead to non-ideal process conditions. Furthermore, it is dependent on the overall geometry of the diamond tool.

[10] The dimensions of a diamond tool are around 3 x 3 x 3 mm ³ . A mixture of cooling lubricant and compressed air is blown into the machining zone. During processing, the finest chips are created, which are caused by the compressed air and the process kinematics are whirled around. Depending on the component contour, the flow conditions and the process control, contamination can occur on the coupling surface of the diamond. The laser radiation burns chips or cooling lubricants, which can lead to a change in the beam coupling and, as a result, to a change in the process control.

[11] Furthermore, EP 3484658 does not provide for regulation of the laser power, but only describes the simplified beam guidance in the diamond with beam coupling on the planar surface. DE 10 2019 005 691 A1 describes the use of a pyrometer for controlling the laser, which is guided onto the workpiece surface in a free jet. Thus, using means from the prior art, a precise regulation can be set up, with which the laser power is controlled in such a way that the temperature in the machining zone or in the measurement vicinity of the machining zone can be kept constant continuously and independent of location. However, this regulation only works under ideal process conditions. If chips or cooling lubricant hit the laser beam, they burn up there immediately. The pyrometer detects a sudden increase in temperature and regulates the laser power down. The actual process is disrupted.

[12] DE 196 13 183 describes a device that has an optically transparent beam guidance element that guides a laser beam through a hole in the tool to an optically transparent window, so that radiation can enter the tool from the beam guidance element and through the window again can escape from the tool.

[13] The invention is based on the object of further developing such a device as described in EP3484658 and generic methods.

[14] This object is achieved with a device according to claim 1, a method according to claim 14 and a method according to claim 19. Advantageous developments are the subject of the subclaims.

[15] The basic invention is based on the use of a beam guiding element, which is optically functionally coupled to the diamond tool, which has an optically transparent cutting edge geometry. On the way to the cutting edge, the laser beam thus first passes through the beam guidance element and then through the tool body. in the In terms of process control during machining, the intensity profile of the laser radiation at the actively machining cutting edge should be adjustable as deterministically as possible. By using a beam guidance element, the device can be improved in different ways for this requirement.

[16] The beam guidance element extends the path of safe solid-state beam guidance in such a way that the problem of contamination in the machining zone is minimized or completely prevented. The solid-state element can be designed as an inherently rigid optical component with its own coupling geometry for a free laser beam. Alternatively, the beam guiding element can be designed as a flexible optical fiber that can be coupled directly to a laser far away from the machining zone while being completely protected from environmental pollution.

[17] For common laser wavelengths in the range of 1 pm or below (fiber laser, diode laser, NdYag laser), such beam guiding elements can be made of glass. The advantage of the glass version is the usual processability for the production of optical surfaces with non-planar geometry (lenses). For improved in-coupling with the possibility of beam shaping, for example, spherical or aspherical geometries can be produced on the in-coupling side of the beam-guiding element. Optically functional, non-planar surfaces or independent lenses can also be introduced in the area of the outcoupling of the beam guiding element and the incoupling towards the diamond. This degree of design freedom means that, depending on the geometry of the tool cutting edge, the laser radiation can be guided to the cutting edge significantly more precisely and flexibly without disturbing scattered radiation due to total reflection inside the tool. The laser beam intensity profile at the cutting edge can also be influenced in such a way that an intensity profile that is as homogeneous as possible or can be freely defined results over the cutting edge radius of the tool. The use of non-rotationally symmetrical lens geometries, such as those known from diode laser technology (FAC, Fast Axis Collimation), is advantageous here. The divergence of the laser beam is thus minimized in one direction (eg horizontal direction), whereas it is permitted with homogeneous distribution in the lateral direction (along the cutting edge of the tool). [18] In addition to applying a non-planar optical functional geometry to the end of the beam guidance element or inserting an independent micro-optics between the beam guidance element and the tool, such a functional surface can also be introduced into the tool itself. It is advantageous to process one side of the tool for coupling the beam with a laser through material removal or sublimation. This applies in particular to diamond, which is otherwise almost impossible to process. Targeted laser pulsing can be used to remove geometrically precise material from the diamond in order to produce lens geometries that are highly flexible and also non-rotationally symmetrical. Grinding and polishing of the diamond can thus be avoided. The surface roughness during laser ablation is usually not sufficient to keep scattered radiation at a sufficiently low level during coupling. By skilfully choosing a compensating adhesive or putty between the beam guidance element and the tool, however, surface roughness can be compensated for at least partially (cf. paragraph on optically functional joining).

[19] Beam guidance elements made of diamond are less flexible in terms of geometry, but when using CO2 laser radiation with wavelengths of 10.6 pm (not transparent for glass) they enable solid-state beam guidance to avoid contamination. Alternatively, hollow glass fibers can be used.

[20] The optically functional connection in the coupling zone can be designed in different ways, but it must prevent a gap between the beam guiding element and the cutting edge of the tool, into which gas, liquid or solid contamination can penetrate. In principle, this can be done by an additional mechanical element, which is attached to the tool itself or the tool holder and clamps the beam guidance element in place after alignment has taken place. Clamping of this type is particularly conceivable when using a rotationally symmetrical glass fiber. Beam guidance element and tool are mechanically fixed to each other in such a way that they either lie directly on top of each other or an air gap remains, which remains closed dirt-tight by the mechanical element.

[21] As an alternative and advantageous to mechanical clamping, an adhesive or an optical cement can be used for the optically functional coupling of the beam guidance element and the tool. The adhesive or the putty fulfills the tasks of mechanical fixation after hardening, sealing off from dirt and designing the refraction transition by so-called index matching. The adhesive with refractive index nd3 averages the transition of the beam from the beam guiding element with refractive index ndl to the diamond with refractive index nd2 with reduced losses. With a non-planar design of the transition between the beam guide and the tool, volume can thus be filled. Furthermore, such an adhesive or putty can level out residual surface roughness in order to prevent scattered radiation. The pre-machining of the back of the tool does not have to be carried out with the same precision as is the case with the direct coupling of a free jet.

[22] The most obvious way to couple the laser beam into a tool with a cutting edge between the flank face and the rake face is to use a beam guidance element on the side of the tool opposite the cutting edge. The laser beam is deflected or refracted according to Snell's law of refraction. The laser beam can be positioned by selecting the angle ratios at the transition zone between the tool and the beam guiding element.

[23] Alternatively, for reasons of accessibility or the specific tool geometry and the desirable decoupling area between the flank face and the rake face, it can be advantageous to deflect the laser beam inside the tool. It is conceivable here to couple the laser beam on one side with the beam guidance element and to reflect it on an opposite side. The laser beam can, for example, be coupled in at a top side of the tool and reflected at a bottom side of the tool. Alternatively, a slotted tool holder is conceivable, via which the beam guiding element is coupled to the underside of the tool and the deflection takes place on the upper side of the tool.

[24] In addition to the laser beam guidance in the beam guidance element and then in the tool, the invention also describes the coaxial or mutually offset guidance of the measuring beam of a temperature sensor. This temperature sensor is preferably a pyrometer.

[25] If the beam guidance element is designed as an inherently rigid solid, two separate beams (laser and pyrometer) can be coupled side by side into the coupling surface of the beam guidance element. The in-coupling surface can be designed as a continuous flat or optically functionally curved surface, or two or have more individual optics for the separate coupling of laser and pyrometer beam. By taking Snell's law of refraction into account, the position between the laser beam and the measuring beam can be influenced at the decoupling geometry in the tool. Alternatively, the laser beam and the measuring beam can be coaxially coupled before being coupled into the beam guidance element. This is preferably done using a deflection mirror that deflects one of the beams by 90°. A second, semi-transparent mirror deflects the previously deflected beam again by 90°, while the second beam shines through the semi-transparent mirror without restriction. This is possible due to the different wavelengths between the laser (approx. 1 pm) and the pyrometer (approx. 1.5 pm). The laser beam brought together coaxially in this way can now, as previously described for the pure laser, be coupled into the beam guiding element and forwarded into the tool. However, due to the different refractive indices and the different wavelengths, the laser and measuring beams do not exit the tool at the same point. If glass fibers are used as the beam guidance element, the laser and measuring beam can be guided separately to the tool and coupled in. For the separation zone between the beam guiding elements and the tool, optically functional curved surfaces can be placed either on the end of the beam guiding element, as micro-optics separately in between or directly in the tool for both coupling points, as already described, in order to control the divergence of the radiation.

[26] Especially with optical fibers (e.g. SMA fiber, 200 pm core) a typical NA is 0.22, i.e. a full divergence angle of the emitted radiation is 21°. This must be reduced by a focusing optical functional surface in order to expose the tool cutting edge sufficiently finely.

[27] Due to the dimensions of the parts to be joined (tool and beam guiding element), due to the sensitivity of the optical beam path in the solid bodies and at the transition zone as well as due to the design possibilities through the introduction of lens geometries, the adjustment of tool and beam guiding element is crucial.

[28] The invention proposes fully or partially automated assembly with an integrated joining process. The tool and tool holder are clamped in a device. A gripper holds the beam guidance element. The gripper's own kinematics or that of a higher-level movement system enables the beam guidance element to be positioned in five or six degrees of freedom. The kinematics are preferably motorized, but they can also be operated manually. Alternatively, the beam guiding element can be clamped and the tool actively guided. The positioning can be controlled passively or actively.

[29] In the passive variant, the adjustment is made by the gripper using geometric features. For example, two cameras with telecentric, distortion-free lenses detect geometric features of the tool and beam guiding element. With such a measurement setup, up to 5 degrees of freedom (3 x translational, 2 x rotational) can be determined. An adjustment is made on the basis of these geometric features. As an alternative to the cameras, other sensors can be used, for example chromatic confocal distance sensors that detect the positions of reference surfaces. With this approach, however, manufacturing tolerances prevent a statement about the actual beam and intensity characteristics at the cutting edge of the tool.

[30] Against this background, active adjustment is preferred. Here, a pilot beam or an attenuated direct laser beam is coupled into the beam guidance element and transferred to the tool. The process begins in a meaningful geometric starting point. A measuring setup is placed in front of the cutting edge of the tool or, more generally speaking, the process-relevant decoupling surface on the tool, which can directly measure the emitted radiation, for example in the form of power or intensity distribution. This can be, for example, a pinhole diaphragm with an integrating sphere located behind it or a direct camera with correspondingly attenuating laser filters. If the beam guidance element is moved relative to the tool while the beam is switched on, the signal that describes the beam characteristics at the decoupling point changes. Different relative positionings between the joining members are carried out until a desired state occurs. Search algorithms preferably support the systematics of the position change in order to bring about faster convergence. For example, so-called hill climb algorithms are known from laser assembly.

[31] A UV (ultraviolet) hardening adhesive should preferably be used for active adjustment. The adhesive is applied to the joint partners at the coupling point before the joining process. The adjustment is made while the low-viscosity adhesive fills the joining zone. is Once a suitable relative position has been found between the tool and the beam guidance element, a UV light source ensures that the adhesive hardens and fixes in place. Meanwhile, the gripper holds the movable joining partner.

[32] Depending on the design of the joint, the shrinkage or contraction of the adhesive must be taken into account during this process. This is usually significantly stronger than the rigidity of the gripper. Countering with force is not promising. With sufficient knowledge of the volume shrinkage, however, a corrective movement can be determined and made available before the UV light source is switched on, with which and with the shrinkage an optimal end position is set. As an alternative to UV-curing adhesive, thermally curing adhesive can also be used.

Several exemplary embodiments are shown in the drawing and are described in more detail below. It shows

Figure 1 shows a schematic of a device with a tool into which a laser beam is coupled directly without a beam guiding element,

Figure 2 shows a schematic side section through a tool with cutting edge, rake face and flank and coupled beam guidance element, with a laser beam radiating through the beam guidance element and tool,

FIG. 3 shows a schematic of a device as in FIG.

FIG. 4 shows a schematic of a device as in FIG. 3 with a laser beam and measuring beam, which, however, are coupled directly into the tool without a beam guiding element,

FIG. 5 shows a schematic of a device in which the laser beam and the measuring beam are coupled coaxially into the beam guidance element via an optically functional surface and then guided further into the tool via the optically functional joint, FIG. 6 shows schematically the same device as in FIG. 5 with a laser beam and measuring beam, which are brought together coaxially via mirrors, but are coupled directly into the tool with the cutting edge without a beam guiding element,

FIG. 7 shows a schematic of a device with tool and beam guidance element, between which independent optics or micro-optics are fixed by optically functional layers,

FIG. 8 shows a schematic of a device with a tool and beam guidance element, between which an optically functional, non-planar surface is arranged, which is introduced into the tool body,

FIG. 9 shows a schematic of a device with a tool into which the laser radiation is introduced via an optically functional coupling point through an optical fiber,

Figure 10 schematically shows a device with a tool in which the

Laser radiation is coupled in via an optical fiber with additional micro-optical collimation optics or a Grin fiber,

FIG. 11 schematically shows a device similar to that shown in FIG. 10, in which the micro-optical collimation optics are incorporated into the tool itself,

Figure 12 schematically shows a device with a tool in which the

Laser radiation is coupled in via a first optical fiber with an optically functional joint and measuring radiation is injected into the tool via a second optical fiber with an optically functional joint,

Figure 13 schematically shows a device with a tool in which the

Laser radiation is introduced via an optical fiber and an optically functional coupling point and a mirror element reflects the laser beam, FIG. 14 shows a device similar to that shown in FIG. 13, with the difference that the laser radiation is coupled directly into the surface of the tool without a beam guiding element,

FIG. 15 shows a device similar to that shown in FIG. 13, with the difference that the laser radiation is coupled in on the underside of the tool,

Figure 16 shows a process structure for passive adjustment between the tool and

Beam guidance element with subsequent fixation by an optically functional joint and

Figure 17 shows a process structure for the active adjustment between the tool and

Beam guidance element with subsequent fixation by an optically functional joint.

[33] FIG. 1 shows a tool 1 into which a laser beam 2 is coupled directly on the rear side opposite the cutting edge 3 without a beam guiding element. It corresponds to the prior art as described in EP 3484658, among others. The laser beam 2 exits at the cutting edge 3 with a horizontal intensity distribution 4 and a vertical intensity distribution 5 . The cutting edge 3 is delimited by the rake face 6 and the free face 7 of the tool.

[34] FIG. 2 shows a lateral section through a tool 1 with a cutting edge 3 , rake face 6 and free face 7 . The tool 1 is mounted on a tool holder 8 . The laser beam 2 is first coupled into the beam guidance element 10 through an optically functional surface 9 . The laser beam 2 is guided from the beam guidance element 10 into the tool 1 at the optically functional joint 11 in order to emerge again in the area of the cutting edge 3 .

[35] Figure 3 shows a lateral section through a tool 1 with cutting edge 3 and tool holder 8. In the beam guidance element 10, which is glued to the tool by the optically functional joint 11, a measuring beam 12 is placed next to the laser beam 2 via the optically functional area 9 coupled. Also this measuring beam 12 is passed into the tool 1 to be decoupled near the cutting edge 3.

[36] Figure 4 shows the same device as in Figure 3 with laser beam 2 and

Measuring beam 12, which, however, directly into the tool 1 without a beam guiding element

Cutting edge 3 are coupled.

[37] FIG. 5 shows a device in which the laser beam 2 and the measuring beam 12 are coupled coaxially into the beam guidance element 10 via the optically functional surface 9 and then are guided further into the tool 1 via the optically functional joint 11 . Both beams exit again near the cutting edge 3 . The measuring beam 12 is coupled to the laser beam 2 by means of a deflection mirror 13, which deflects the measuring beam 12 by 90°. A second semi-transparent mirror 14 deflects the measurement beam again by 90°, but lets the laser beam 2 through.

[38] Figure 6 shows the same device as in Figure 5 with laser beam 2 and

Measuring beam 12, which is brought together coaxially via the mirrors 13 and 14, but without

Beam guiding element are coupled directly into the tool 1 with cutting edge 3.

[39] FIG. 7 shows a device with a tool 1 and a beam guidance element 10, between which independent optics or micro-optics 15 are fixed by the optically functional layers 11 and 16. The optics 15 enable an adapted focusing of the laser radiation 2 after exiting the beam guidance element 10 in order to influence the intensity distribution of the laser radiation 2 in the area of the cutting edge 3 .

[40] Figure 8 shows a device with tool 1 and beam guiding element 10. Between the beam guiding element 10 and the tool 1 is an optically functional, non-planar surface 17, which is used to focus the beam and is introduced directly into the main body of the tool. The intensity distribution of the laser radiation 2 in the area of the cutting edge 3 can be influenced by the optics 17 .

[41] FIG. 9 shows a device with a tool 1 into which the laser radiation 2 is introduced via an optically functional coupling point 11 through an optical fiber 18 . The laser radiation 2 exits in the area of the cutting edge 3 . [42] FIG. 10 shows a device with a tool 1 into which the laser radiation 2 is coupled via an optical fiber 18 with additional micro-optical collimating optics 19 and an optically functional joint 11 and coupled out in the area of the cutting edge 3 .

[43] Figure 11 shows a device as shown in Figure 10, with the difference that the micro-optical collimation optics 20 is incorporated into the tool itself.

[44] FIG. 12 shows a device with a tool 1 into which the laser radiation 2 is coupled via an optical fiber 18 and an optically functional joint 11 . In addition, the measuring radiation 12 is coupled into the tool 1 via a separate optical fiber 21 and an optically functional joint 11 . Both radiations 2 and 12 leave the tool 1 in the area of the cutting edge 3.

[45] FIG. 13 shows a device with a tool 1 into which the laser radiation 2 is introduced via an optical fiber 12 and the optically functional coupling point 11 . Unlike in FIGS. 1-12, the coupling takes place on the surface 22 and not on the rear side 23 of the tool 1. A mirror element 24 reflects the laser beam 2 in order to couple it out in the area of the cutting edge 3. A different type of distribution of the laser beam decoupling between the flank 7 and the rake face 6 can be achieved with this structure.

[46] FIG. 14 is similar to FIG. 13 with the difference that the laser radiation 2 is coupled directly into the surface 22 of the tool 1 without a beam guiding element.

[47] FIG. 15 is similar to FIG. 13 with the difference that the coupling of the laser radiation 2 takes place on the lower surface 25 of the tool 1. The mirror element 24 is located on the surface 22 .

[48] Figure 16 shows the process structure for passive adjustment between tool 1 and beam guide element 10 with subsequent fixation by an optically functional joint 11. Two cameras 26 and 27 observe geometric features (e.g. edges) of tool 1 and beam guide element 10, using which the relative alignment takes place. Tool 1 and the tool holder are clamped in place. A gripper 28 grips the beam guidance element 10 to be adjusted. It can be adjusted by the kinematics 29 in> 5 degrees of freedom are positioned. The kinematics 29 are controlled via the control signal 30 which is generated by image processing by the cameras 26 and 27 .

[49] Figure 17 shows the process structure for the active adjustment between tool 1 and beam guiding element 10 with subsequent fixation by an optically functional joint 11. The laser beam 2 is coupled into the beam guiding element 10 at reduced power and into the tool 1 in the direction of the cutting edge 3 forwarded. A sensor system 31 detects the intensity distribution of the laser beam 2 at the cutting edge 3 of the tool 1. The tool 1 and the tool holder are clamped in place. A gripper 28 grips the beam guidance element 10 to be adjusted. It can be positioned in >5 degrees of freedom by the kinematics 29 . The kinematics 29 are controlled via the control signal 30 which is generated from the sensor 31 .

Claims

patent claims

1. Device with an optically transparent tool (1) for processing a surface, wherein the device has an optically transparent beam guiding element (10) which is optically functionally (11) coupled to the optically transparent tool (1) so that a radiation (2 ) from the beam guiding element (10) into the tool (1), characterized in that the tool has an optically transparent cutting edge (3) which is arranged between a cutting surface (6) and a free surface (7) for machining a surface is.

2. Device according to claim 1, characterized in that the tool (1) opposite the cutting edge (3) has a V-shaped rear side with surfaces arranged at an angle to one another.

3. Device according to claim 2, characterized in that the angle is an obtuse angle.

4. Device according to claim 2 or 3, characterized in that the

Beam guidance element (10) is coupled to the surfaces of the optically transparent tool (1) in such a way that the radiation can enter the tool as a measuring beam and/or as a laser beam.

5. Device according to one of the preceding claims, characterized in that the beam guidance element (10) is optically functionally (11) coupled in such a way that the radiation (2) is directed at a specific point in the area of the rake face (6), cutting edge (3) or Free surface (7) of the tool (1) reaches.

6. Device according to claim 5, characterized in that the

The beam guiding element (10) is optically functionally coupled (11) in such a way that the radiation (2) reaches the free surface (7) near the cutting edge (3).

7. Device according to one of the preceding claims, characterized in that the beam guiding element (10) has beam-forming properties.

8. Device according to one of the preceding claims, characterized in that the tool (1) has a diamond as the cutting edge.

9. Device according to one of the preceding claims, characterized in that the beam guiding element (10) has an optical fiber (18).

10. The device according to claim 9, characterized in that the beam guidance element has a gradient index optical fiber.

11. Device according to one of the preceding claims, characterized in that an optically functional adhesive is arranged in a transition area (11) between the tool (1) and the beam guidance element (10).

12. Device according to one of the preceding claims, characterized in that at least one lens (9) is arranged in the coupling-in region of the beam guidance element (10).

13. Device according to one of the preceding claims, characterized in that a curved surface such as in particular a lens (15) is arranged in the transition region (11) between the tool (1) and the beam guiding element (10).

14. Device according to one of the preceding claims, characterized in that it has a laser which is arranged in such a way that it couples laser radiation (2) into the beam guidance element (10).

15. Device according to one of the preceding claims, characterized in that it has a sensor which is arranged in such a way that it couples a measurement beam (12) into the beam guidance element (10).

16. The device according to claim 15, characterized in that the sensor is a temperature measuring sensor.

17. Device according to one of the preceding claims, characterized in that it has a coupling point (9, 23) for the simultaneous coupling of a measuring beam (12) and a laser beam (2).

18. Device with an optically transparent tool (1) according to any one of the preceding claims, which has a cutting edge (3) and a coupling point for a laser (2) and / or measuring beam (12), characterized in that the Coupling point is arranged on the cutting edge (3) opposite surface (23), so that the laser beam (2) is guided directly onto the cutting edge (3).

19. Device with an optically transparent tool (1) according to one of the preceding claims, which has a cutting edge (3) and a coupling point for a laser (2) and/or measuring beam (12), characterized in that it has a mirror element ( 24) which totally reflects the laser beam (2) coupled into one side of the tool on the opposite side to the coupling point.

20. A method for processing a surface with an optically transparent tool (1), in which a laser beam (2) through the tool (1) to a cutting edge (3) is guided, characterized in that in addition a measuring beam (12) through the tool (1) is guided.

21. The method according to claim 20, characterized in that the measuring beam (12) is guided through the tool (1) simultaneously with the laser beam (2).

22. The method according to claim 20 or 21, characterized in that the laser beam (2) and the measuring beam (12) are coupled coaxially.

23. The method according to claim 20 or 21, characterized in that the laser beam (2) and the measuring beam (12) are guided offset to one another.

24. The method according to any one of claims 20 to 23, characterized in that the measuring beam (12) is evaluated with a control unit and the power of the laser beam (2) is controlled.

25. Method for coupling a beam guiding element (10) to a tool (1), in particular for producing a device according to one of claims 1 to 19, characterized in that in a first step the beam guiding element (10) and the tool (1) are precisely aligned with one another aligned and joined or clamped without distortion in a second step.

26. The method according to claim 25, characterized in that the precise mutual alignment is carried out on the basis of external geometric features, preferably by edge detection with cameras (26, 27).

27. The method according to claim 25, characterized in that the precise mutual alignment is carried out on the basis of a reference beam (2) which is coupled into the beam guidance element (10) and connected to a sensor (31) at a coupling point of the tool (1) in its position and intensity distribution is evaluated.

28. The method according to any one of claims 25 to 27, characterized in that the beam guiding element (10) and the tool (1) are joined or clamped in the second step inside or outside the optical transition surface.

29. The method according to any one of claims 25 to 28, characterized in that the beam guiding element (10) and the tool (1) are joined with an adhesive and a defined offset between beam guiding element (10) and tool (1) is set before joining , in order to compensate for the shrinkage of the adhesive.