Laser processing nozzle, nozzle receptacle for a laser processing nozzle and laser processing head

Abstract

The invention relates to a laser processing nozzle (1) for a nozzle receptacle (6) having a nozzle receptacle interface (20) of a laser processing machine, wherein at least one contact area (22) is provided between the laser processing nozzle (1) and a heat sink (23) located on the nozzle receptacle (6), characterised in that depressions (25) and / or elevations (25) are introduced in the surface of the laser processing nozzle (1) forming the at least one contact area (22) towards the nozzle receptacle (6), where in addition to the depressions and / or elevations in the surface of the laser processing nozzle (1) forming the at least one contact area (22), the laser processing nozzle (1) has one of an external thread counterpart for engaging with an internal thread of the nozzle receptacle (6) or a plug-in element for engaging with a receiving element of the nozzle receptacle (6).

Description

[0001] P3871PC00

[0002] 1

[0003] Bystronic Laser AG

[0004] Industriestr. 21

[0005] 3362 Niederonz

[0006] Switzerland

[0007] Laser processing nozzle, nozzle receptacle for a laser processing nozzle and laser processing head

[0008] Description

[0009] The invention relates to a laser processing nozzle, a nozzle receptacle for a laser processing nozzle and a laser processing head for a laser processing machine.

[0010] In the laser processing of metallic workpieces, such as metal sheets, it is known to cut out workpiece parts with predetermined shapes and dimensions from a workpiece using a laser beam. The laser beam emerges from a laser processing head that is moved over the workpiece. The laser processing head usually has a laser processing nozzle through which the laser beam is guided to the location on the workpiece to be processed.

[0011] In laser processing machines designed as laser beam cutting machines, a cutting gas is typically used to cut parts from metallic workpieces, e.g. sheet metal panels, metal profiles or metal pipes. Such laser beam cutting machines have a laser power of at least 1 kW. The cutting gas primarily has the function of expelling the molten material of the workpiece from the cutting gap. Further functions of the cutting gasP3871PC00

[0012] 2

[0013] include cooling the material and providing a protective gas effect, in particular against oxidation.

[0014] There are various types of cutting gases used: In oxygen cutting, oxygen is used as a reactive gas. This typically results in low cutting speeds and good cutting quality, especially with larger sheet thicknesses. Oxygen or flame cutting is accompanied by oxidation, which is undesirable for certain materials. If oxidation is not critical, flame cutting is an extremely high-performance process. In fusion cutting, pure nitrogen can be used to expel the melt. In contrast to the use of oxygen as a cutting gas, higher cutting speeds are possible and a sufficiently good cutting quality is achieved. Furthermore, instead of pure nitrogen for cutting, compressed air can be used as a cutting gas or a mixed gas containing both oxygen and nitrogen and / or other gases.

[0015] According to EP 4201576A1, it has proven to be even more advantageous in the flame cutting process if the focus position of the processing laser is located significantly above the sheet metal. This setting is particularly advantageous for high laser power, in particular >10 kW, and for thicker metal sheets >20 mm. For certain fusion or mixed gas cutting processes, such as the creation of particularly wide cutting gaps, similar focus positions can also be advantageous. In this case, the cutting head optical unit is set such that the focal point of the laser beam is at a distance from the upper edge of the material. This distance is usually greater than the distance between the laser processing nozzle and the workpiece to be processed, which means that the focus is within the nozzle, i.e. above the nozzle opening. The primary advantage of this is that the nozzle opening also acts as an optical shutter for the laser beam and cuts off (or at least partially absorbs) laser edge radiation, which can lead to a particularly clean cut.

[0016] In general, laser processing of workpieces along the path of the laser beam generates heat, which heats the corresponding components of the laser processing machine, in particular the laser processing nozzle. With a focus position above the workpiece to be processed, as described above, the heating, in particular of the laser processingP3871PC00

[0017] 3

[0018] nozzle, can be more pronounced than with a focus position at the height of the workpiece or inside it.

[0019] Since heating of the components has a negative influence on the quality of laser processing or the service life of the components used, corresponding cooling of the affected components, in particular the laser processing nozzle, is advisable.

[0020] Various cooling methods are known from the prior art. The simplest version of temperature regulation is cooling the laser processing nozzle by air convection, in which heat is transferred to the surrounding air flowing past.

[0021] However, this type of cooling is not sufficient, in particular at higher processing powers, which is why coolant-cooled, in particular cooling liquid-cooled, laser processing nozzles are also known from the prior art.

[0022] Normally, the actual laser processing nozzle, usually made of a metallic material such as copper, is a wear part that is detachably connected to the laser processing head via an interface. In addition to the well-known plug-in and bayonet lock connections, screw connections consisting of an internal thread on the nozzle receptacle and an external thread on the laser processing nozzle have proven successful in practice.

[0023] WO 2021051734 Al discloses an arrangement for receiving a liquid-cooled laser processing nozzle with a multi -part structure consisting of a first and a second insulating block, a copper ring as a heat sink and a metal housing. The copper ring acts as a heat-conducting element and forms a liquid-filled cooling channel, which is sealed in the direction of the laser processing head by the insulating block located there. The laser processing nozzle has a planar contact with the inserted copper ring acting as a heat sink.

[0024] WO 2019021641 Al also discloses a laser processing nozzle, in which one surface has a planar contact with a heat sink, wherein a groove is integrated in the top side ofP3871PC00

[0025] 4

[0026] the laser processing nozzle, which simplifies the connection between the nozzle and the laser processing head since the contact area is reduced. The surface of the heat sink, which forms the contact area with the laser processing nozzle, is flat.

[0027] The aforementioned cooling devices provide solutions for the direct or indirect, cool-ant-based, in particular liquid-based, cooling of a laser processing nozzle or a nozzle receptacle for a laser processing nozzle. They have the disadvantage that either the heat sink of the cooling device has no direct contact with the laser processing nozzle or that the contact area between the laser processing nozzle and the heat sink is small, which results in limited heat transfer. Furthermore, the solution disclosed in WO 2019021641 Al has the disadvantage that the contact area between the laser processing nozzle and the heat sink is significantly reduced due to the one-sided groove within the surface of the laser processing nozzle, which also has a negative influence on the effectiveness of the heat transfer from the laser processing nozzle to the heat sink.

[0028] EP 4035 822 Al discloses a laser processing nozzle which is fixed to a nozzle carrier having a cooling channel by a threaded connection.

[0029] CN 116 117352 B shows a laser processing nozzle connected to a cooling ring of a nozzle receptacle.

[0030] DE 11 2020003451 T5 discloses a laser cutting head with a water cooling structure. A nozzle is disposed at the tip of the laser cutting head.

[0031] US 5 477026 A shows a laser powered metal cladding apparatus which includes a removable conical nozzle secured to a receptacle unit by a threaded connection.

[0032] The object of the invention underlying this application is that of providing a laser processing nozzle which enables improved heat exchange with the nozzle receptacle. Furthermore, it is an object of the invention to provide a corresponding laser processing head and an improved nozzle receptacle.P3871PC00

[0033] 5

[0034] This object is achieved by the laser processing nozzle, described in claim 1, for a laser processing machine and by the nozzle receptacle described in claim 8, in particular a cooled nozzle receptacle, and by the laser processing head described in claim 15.

[0035] In the laser processing nozzle according to the invention for a nozzle receptacle, in particular a cooled nozzle receptacle, having a nozzle receptacle interface of a laser processing machine, at least one contact area is provided between the laser processing nozzle and a heat sink located on the nozzle receptacle. In this case, depressions and / or elevations are introduced in the surface of the laser processing nozzle which forms the at least one contact area towards the nozzle receptacle. In addition to the depressions and / or elevations in the surface of the laser processing nozzle forming the at least one contact area, the laser processing nozzle has one of an external thread counterpart for engaging with an internal thread of the nozzle receptacle or a plug-in element for engaging with a receiving element, particularly a receiving sleeve, of the nozzle receptacle. Hence, the at least one contact area establishes a contact between the laser processing nozzle and the heat sink without providing a mechanical connection (i.e. without positive engagement or frictional connection).

[0036] The advantage of the described invention over the known prior art is that the laser processing nozzle claimed here, by means of the introduced depressions and / or elevations, correlates with corresponding depressions and / or elevations in the surface of the nozzle receptacle forming the contact area between the nozzle receptacle and the laser processing nozzle, and thereby the effective heat transfer area between the laser processing nozzle and the nozzle receptacle is increased, which achieves very efficient cooling of the laser processing nozzle. This makes it possible to cut even with high laser processing powers, which ultimately increases process efficiency. Furthermore, the type of cooling described also allows laser processing processes to be used in which the focus position of the laser processing beam is located within the laser processing nozzle, which leads to a particularly high heat input into the laser processing nozzle. In particular, the effective cooling also allows the shutter function ofP3871PC00

[0037] 6

[0038] the nozzle, in which part of the laser processing beam is cut in the edge region, to be used effectively at higher processing powers.

[0039] The depressions and / or elevations in the surfaces of the laser processing nozzle and the heat sink of the nozzle receptacle are each related to a reference height that corresponds to the height of the contact area between the laser processing nozzle and the heat sink of the nozzle receptacle without depressions and / or elevations.

[0040] Preferably, the elevations and / or depressions according to the invention are designed such that the elevations are arranged in the region of the surface of the laser processing nozzle forming the contact area, while the correlating depressions are located in the region of the surface of the heat sink of the nozzle receptacle forming the contact area. This has the advantage that heat transfer can be further increased if the laser processing nozzle is made of a material that is more thermally conductive than the heat sink.

[0041] One embodiment of the laser processing nozzle according to the invention is characterised in that the depressions and / or elevations in the at least one surface of the laser processing nozzle forming the contact area towards the nozzle receptacle are introduced in the form of regular geometric contours. The height of the introduced geometric contours is preferably in a range of 0.1 to 1 mm. This type of contours has the advantage that the regular shape of the contours makes it easier to design the elevations and / or depressions within the surface of the laser processing nozzle to correlate with those within the nozzle receptacle.

[0042] In a preferred variant, the depressions and / or elevations have the shape of triangular profiles in cross section which correlate with corresponding depressions and / or elevations in the form of triangular profiles in cross section which are introduced in the surface of the nozzle receptacle forming the contact area. The triangular profiles can be designed as an equilateral triangle, an isosceles triangle or a scalene triangle.P3871PC00

[0043] 7

[0044] In a further preferred variant, the depressions and / or elevations in cross section have the shape of quadrangular profiles, which correlate with corresponding depressions and / or elevations in cross section in the form of quadrangular profiles, which are introduced in the surface of the nozzle receptacle forming the contact area. This design further increases the effective heat transfer area relative to the previous embodiments. The quadrangular profiles can be rectangular, trapezoidal or in the shape of an irregular quadrangle, for example.

[0045] A further embodiment of the laser processing nozzle according to the invention is characterised in that the depressions and / or elevations in the at least one surface of the laser processing nozzle forming the contact area towards the nozzle receptacle are irregularly produced depressions and elevations. This design makes it possible to introduce the depressions and elevations in a production-optimised manner or to optimise their positioning with respect to heat transfer.

[0046] A preferred embodiment is characterised in that the depressions and elevations are designed as profiles that run concentrically with respect to a central nozzle axis, in particular in an annular manner. This design is particularly helpful for changing the nozzle with as little wear as possible, since the rotational axis of the laser processing nozzle is rotated around the same central nozzle axis when inserted into the nozzle receptacle, which requires less insertion force.

[0047] A further preferred embodiment is characterised in that the surface of the laser processing nozzle, which forms the contact area between the laser processing nozzle and the heat sink of the nozzle receptacle, has a surface average roughness value Ra of less than or equal to 1.6 pm and / or a contact area flatness of less than 10 pm. This design contributes to increased heat transfer between the nozzle receptacle and the laser processing nozzle, since it reduces the possibility of air pockets, which can have an insulating effect, in the region of the contact area.

[0048] The nozzle receptacle according to the invention has a nozzle receptacle interface and a heat sink and serves to receive a laser processing nozzle, according to theP3871PC00

[0049] 8

[0050] invention, of a laser processing machine. The nozzle receptacle is characterised in that depressions and / or elevations are formed in the surface of the heat sink that forms the at least one contact area, where in addition to the depressions and / or elevations in the surface of the heat sink forming the at least one contact area, the nozzle receptacle has one of an internal thread for engaging with an external thread counterpart of the laser processing nozzle or a receiving element, particularly a receiving sleeve, for engaging with a plug-in element of the laser processing nozzle. Hence, the at least one contact area establishes a contact between the laser processing nozzle and the heat sink without providing a mechanical connection (i.e. without positive engagement or frictional connection). These depressions and / or elevations correlate with the depressions and / or elevations in the surface of the laser processing nozzle, according to the invention, which forms the at least one contact area, which increases the effective heat transfer area between the laser processing nozzle and the nozzle receptacle and thus ensures better heat dissipation away from the laser processing nozzle.

[0051] According to a further preferred embodiment of the nozzle receptacle according to the invention, the depressions and / or elevations are introduced in the form of regular geometric contours into the surface of the nozzle receptacle forming the at least one contact area. This type of contour has the advantage that the regular shape of the contours makes it easier to design the elevations and / or depressions within the surface of the nozzle receptacle to correlate with those within the laser processing nozzle.

[0052] In a preferred variant, the depressions and / or elevations in the at least one surface of the nozzle receptacle forming the contact area towards the laser processing nozzle have the shape of triangular profiles in cross section which correlate with corresponding depressions and / or elevations in the form of triangular profiles in cross section which are introduced in the surface of the laser processing nozzle forming the contact area.

[0053] In a further preferred variant, the depressions and / or elevations in the at least one surface of the nozzle receptacle forming the contact area towards the laser processingP3871PC00

[0054] 9

[0055] nozzle have the shape of quadrangular profiles in cross section which correlate with corresponding depressions and / or elevations in the form of quadrangular profiles in cross section which are introduced in the surface of the laser processing nozzle forming the contact area. This design further increases the effective heat transfer area relative to the previous embodiments. The quadrangular profiles can be rectangular, trapezoidal or in the shape of an irregular quadrangle, for example.

[0056] A further embodiment of the nozzle receptacle according to the invention is characterised in that the depressions and / or elevations in the at least one surface of the nozzle receptacle forming the contact area towards the laser processing nozzle are irregularly produced depressions and elevations. This design makes it possible to introduce the depressions and elevations in a production-optimised manner or to optimise their positioning with respect to heat transfer.

[0057] A preferred embodiment is characterised in that the depressions and / or elevations in the at least one surface of the nozzle receptacle forming the contact area towards the laser processing nozzle are designed as profiles running concentrically with respect to a central nozzle axis. The central nozzle axis is the central axis of the laser processing nozzle inserted in the nozzle receptacle. This design is particularly helpful for changing the nozzle with as little wear as possible, since the rotational axis of the laser processing nozzle is rotated around the same central nozzle axis when inserted into the nozzle receptacle, which requires less insertion force.

[0058] In a further variant of the nozzle receptacle according to the invention for a laser processing nozzle, the surface of the nozzle receptacle, which forms the contact area between the heat sink and the laser processing nozzle, has a surface roughness average roughness value Ra of less than or equal to 1.6 pm and / or a contact area flatness of less than 10 pm. This offers the advantage that the effectiveness of heat transfer between the laser processing nozzle and the heat sink is further increased, since the quantity of insulating air pockets between the heat sink and the laser processing nozzle is minimised.P3871PC00

[0059] 10

[0060] For effective heat dissipation, a cooling liquid which has a specific heat capacity of at least 1 kJ / kgK is preferably used to cool the nozzle receptacle.

[0061] Water, and in particular deionised water, is particularly preferably used as the cooling liquid for the nozzle receptacle, since it is readily available and does not produce any undesirable reactions when in contact with the other materials used.

[0062] Furthermore, a laser processing head for a laser processing machine is claimed, which is characterised in that the contact areas on the laser processing nozzle and on the nozzle receptacle have mutually corresponding depressions and elevations, so that elevations on the at least one contact area of the laser processing nozzle engage in corresponding depressions on the at least one contact area of the nozzle receptacle and elevations on the at least one contact area of the nozzle receptacle engage in corresponding depressions on the at least one contact area of the laser processing nozzle when the laser processing nozzle is arranged on the nozzle receptacle. This laser processing head according to the invention has effective nozzle cooling and is capable of efficiently performing laser processing processes with high power. In particular, laser processing processes in which the shutter function of the laser processing nozzle is used to trim the laser processing beam can be used effectively without limiting the processing quality or the service life of the loaded components.

[0063] Examples of possible embodiments of the claimed invention are described in the figures appended below.

[0064] In the drawings:

[0065] Figure 1 schematically shows a representation of a laser processing head;

[0066] Figure 2 schematically shows the structure of an embodiment of the laser processing nozzle and the nozzle receptacle according to the invention;P3871PC00

[0067] 11

[0068] Figures 3 a and 3b schematically show a representation of an embodiment, according to the invention, of elevations / depressions on the contact area; and

[0069] Figure 4 schematically shows a plan view of the surface, forming the contact area, of an embodiment of a laser processing nozzle according to the invention with a concentric arrangement of the depressions / elevations.

[0070] Figure 1 shows the schematic structure of a laser processing head 4 for a laser processing machine during the processing of a workpiece 3 by the action of a laser processing beam 2. The laser processing head 4 contains the components of housing 7, focusing optical unit 5, nozzle receptacle 6 and laser processing nozzle 1. It can be seen that the beam path of the laser processing beam 2 is focused by the focusing optical unit 5. Figure 1 shows a laser processing method in which the focus region of the laser processing beam 2 is located within the laser processing nozzle 1, which leads to high heat input into the material of the laser processing nozzle 1, which must be removed by a cooling system if possible. Here, an application of the laser processing nozzle 1 according to the invention is shown.

[0071] In this case, the focusing optical unit 5 of the laser processing head 4 is set such that the focal point of the laser processing beam 2 is at a distance from the upper edge of the material. This distance is preferably greater than the distance between the laser processing nozzle 1 and the workpiece to be processed, which results in the focus being located within the laser processing nozzle 1, i.e. above the nozzle opening. The primary advantage of this is that the nozzle opening also acts as an optical shutter of the laser processing beam 1 and cuts off (or at least partially absorbs) laser edge radiation, which can lead to a particularly clean cut.

[0072] Figure 2 shows the schematic structure of an embodiment of the nozzle receptacle 6 according to the invention with a nozzle receptacle interface 20 and a heat sink 23, the nozzle receptacle interface 20 being designed as a separate sleeve element arranged in the heat sink 23. Furthermore, Figure 2 shows a laser processing nozzle 1 which is connected to the nozzle receptacle 6 via the nozzle receptacle interface 20P3871PC00

[0073] 12

[0074] and is designed such that a direct contact area 22 is formed between the laser processing nozzle 1 and the nozzle receptacle 6. This contact area is provided with correlating elevations 25 and / or depressions 25, according to the invention, in the laser processing nozzle 1 and the nozzle receptacle 6 in order to increase the effective heat transfer area between the components of nozzle receptacle 6 and laser processing nozzle 1.

[0075] Figure 2 further shows that a cooling channel 21 is formed in the heat sink 23, which cooling channel serves to receive a coolant 24. This cooling channel 21 is open in the direction of the laser processing head 4 and is sealed by a correspondingly shaped counterpart in the laser processing head 4. Also shown is an elastic sealing element 26, which additionally seals the cooling channel 21 accordingly. In Figure 2, the nozzle receptacle interface 20 has an internal thread in the sleeve element, the internal thread engaging with a corresponding external thread counterpart in the laser processing nozzle 1 in order to detachably connect the laser processing nozzle 1 to the nozzle receptacle 6. In Figure 2, a dashed rectangle also indicates a section III which corresponds to Figures 3a and 3b described below.

[0076] Instead of using an internal thread and an external thread counterpart as described above, the laser processing nozzle 1 may have a plug-in element for engaging with a receiving element of the nozzle receptacle interface 20 (i.e. the sleeve element) in order to detachably fix the laser processing nozzle 1 in the nozzle receptacle 6. In other words, the detachable connection may be a plug-in type connection instead of a threaded connection. Preferably, the plug-in type connection uses one or more pins or elevations which snap into one or more corresponding recesses or depressions in order to lock the laser processing nozzle 1 in the nozzle receptacle interface 20.

[0077] Figure 3 shows several design variants of the surfaces of the nozzle receptacle 6 and the laser processing nozzle 1 which are essential for cooling the laser processing nozzle 1 and which form the contact area 22 between the heat sink 23 located on the nozzle receptacle 6 and the laser processing nozzle 1.P3871PC00

[0078] 13

[0079] Figure 3 a shows a design of the elevations 25 and / or depressions 25 in the region of the contact area 22 in the form of quadrangular profiles in cross section, in particular in the form of trapezoidal profiles, wherein, in this embodiment, it is preferably important that the incorporated profiles in the laser processing nozzle 1 and the heat sink 23 of the nozzle receptacle 6 correlate with each other so that the laser processing nozzle 1 can be properly placed on the nozzle receptacle 6 and the largest possible heat transfer area is obtained in the region of the contact area 22 between the laser processing nozzle 1 and the nozzle receptacle 6. Furthermore, it is important that unwanted air pockets between the said components in the region of the contact area 22 are reduced, since these air pockets have an insulating effect and reduce the effectiveness of heat transfer.

[0080] Figure 3b shows a design of the elevations and / or depressions in the region of the contact area 22 in the form of triangular profiles in cross section, wherein, in this embodiment, it is also preferably important that the incorporated profiles in the laser processing nozzle 1 and the heat sink 23 of the nozzle receptacle 6 correlate with each other so that the laser processing nozzle 1 can be properly placed on the nozzle receptacle 6 and the largest possible heat transfer area is obtained in the region of the contact area 22 between the laser processing nozzle 1 and the nozzle receptacle 6. Furthermore, it is important that unwanted air pockets between the said components in the region of the contact area 22 are reduced, since these air pockets have an insulating effect and reduce the effectiveness of heat transfer.

[0081] Figure 4 shows a plan view of a variant of the laser processing nozzle 1 according to the invention. The representation shows that the elevations 25 and / or depressions 25 are arranged such that their course is arranged in concentric shapes around the central axis of the laser processing nozzle 1. This arrangement is particularly helpful for changing the nozzle with as little wear as possible, since the rotational axis of the laser processing nozzle 1 is rotated about the same central nozzle axis when inserted into the nozzle receptacle 6, which requires less insertion force.P3871PC00

[0082] 14

[0083] List of reference signs

[0084] 1 Laser processing nozzle

[0085] 2 Laser processing beam

[0086] 3 Workpiece

[0087] 4 Laser processing head

[0088] 5 Focusing optical unit

[0089] 6 Nozzle receptacle

[0090] 7 Housing of the laser processing head

[0091] 20 Nozzle receptacle interface

[0092] 21 Cooling channel

[0093] 22 Contact area between laser processing nozzle and heat sink 23 Heat sink

[0094] 24 Coolant

[0095] 25 Depress! ons / elevations

[0096] 26 Elastic sealing element

[0097] 27 Cooling rib

Claims

P3871PC0015Claims1. A laser processing nozzle (1) for a nozzle receptacle (6) having a nozzle receptacle interface (20) of a laser processing machine, wherein at least one contact area (22) is provided between the laser processing nozzle (1) and a heat sink (23) located on the nozzle receptacle (6), characterised in that depressions (25) and / or elevations (25) are introduced in the surface of the laser processing nozzle (1) forming the at least one contact area (22) towards the nozzle receptacle (6), where in addition to the depressions and / or elevations in the surface of the laser processing nozzle (1) forming the at least one contact area (22), the laser processing nozzle (1) has one of an external thread counterpart for engaging with an internal thread of the nozzle receptacle (6) or a plug-in element for engaging with a receiving element of the nozzle receptacle (6).

2. The laser processing nozzle (1) according to claim 1, characterised in that the depressions (25) and / or elevations (25) are introduced in the form of regular geometric contours into the surface of the laser processing nozzle (1) forming the at least one contact area (22) towards the nozzle receptacle.

3. The laser processing nozzle (1) according to claim 1 or 2, characterised in that the depressions (25) and / or elevations (25) have the shape of triangular profiles in cross section.

4. The laser processing nozzle (1) according to claim 1 or 2, characterised in that the depressions (25) and / or elevations (25) have the shape of quadrangular profiles in cross section.

5. The laser processing nozzle (1) according to claim 1, characterised in that the depressions (25) and / or elevations (25) are irregularly produced depressions (25) and / or elevations (25).P3871PC00166. The laser processing nozzle (1) according to claim 1, characterised in that the depressions (25) and / or elevations (25) are designed as profiles running concentrically with respect to a central nozzle axis.

7. The laser processing nozzle (1) according to any one of the preceding claims, characterised in that the surface of the laser processing nozzle (1), which forms the at least one contact area between the laser processing nozzle (1) and the heat sink (23) of the nozzle receptacle (6), has a surface average roughness value Ra of less than or equal to 1.6 pm and / or a contact area flatness of less than 10 pm.

8. A nozzle receptacle (6) for a laser processing machine for receiving a laser processing nozzle (1) according to any one of the preceding claims, wherein the nozzle receptacle (6) has a nozzle receptacle interface (20) and a heat sink (23), characterised in that depressions (25) and / or elevations (25) are formed in the surface of the heat sink (23) forming the at least one contact area (22), where in addition to the depressions and / or elevations in the surface of the heat sink (23) forming the at least one contact area (22), the nozzle receptacle (6) has one of an internal thread for engaging with an external thread counterpart of the laser processing nozzle (1) or a receiving element for engaging with a plug-in element of the laser processing nozzle (1).

9. The nozzle receptacle (6) according to claim 8, characterised in that the depressions (25) and / or elevations (25) in the form of regular geometric contours are introduced in the contact area (22).

10. The nozzle receptacle (6) according to claim 8 or 9, characterised in that the depressions (25) and / or elevations (25) have the shape of triangular profiles in cross section.P3871PC001711. The nozzle receptacle (6) according to claim 8 or 9, characterised in that the depressions (25) and / or elevations (25) have the shape of quadrangular profiles in cross section.

12. The nozzle receptacle (6) according to claim 8, characterised in that the depressions (25) and / or elevations (25) are irregularly produced depressions (25) and elevations (25).

13. The nozzle receptacle (6) according to claim 8, characterised in that the depressions (25) and elevations (25) are designed as profiles running concentrically with respect to a central nozzle axis.

14. The nozzle receptacle (6) according to any one of claims 8 to 13, characterised in that the surface of the nozzle receptacle (6), which forms the contact area (22) between the laser processing nozzle (1) and the heat sink (23) of the nozzle receptacle (6), has a surface average roughness value Ra of less than or equal to 1.6 pm and / or a contact area flatness of less than 10 pm.

15. A laser processing head (4) including a laser processing nozzle (1) according to any one of claims 1 to 7 and a nozzle receptacle (6) according to any one of claims 8 to 14, characterised in that the contact areas (22) on the laser processing nozzle (1) and on the nozzle receptacle (6) have mutually corresponding depressions (25) and / or elevations (25), so that elevations on the at least one contact area (22) of the laser processing nozzle (1) engage in corresponding depressions on the at least one contact area (22) of the nozzle receptacle (6) and elevations (25) on the at least one contact area (22) of the nozzle receptacle (6) engage in corresponding depressions (25) on the at least one contact area (22) of the laser processing nozzle (1) when the laser processing nozzle (1) is arranged on the nozzle receptacle (6).

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