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

Abstract

The invention relates to a nozzle receptacle (6) for a laser processing nozzle (1) hav- ing a heat sink (23) which has a cooling channel (21) for receiving a coolant (24), and having a nozzle receptacle interface (20) for connecting the nozzle receptacle (6) to a laser processing head (1). The invention is characterised in that the nozzle recep- tacle interface (20) is designed as a separate sleeve element which is arranged in the heat sink (23) and which consists of a material having a material hardness or surface hardness of at least 214 HB (Brinell hardness).

Description

[0001] P3865PC00

[0002] 1

[0003] Bystronic Laser AG

[0004] Industriestr. 21

[0005] 3362 Niederonz

[0006] Switzerland

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

[0008] Description

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

[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 gasP3865PC00

[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 4201576 Al, 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 processingP3865PC00

[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 laser processing, 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 for higher cutting performances, 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.

[0024] WO 2024078067 Al discloses a liquid-cooled cooling device for a laser processing nozzle, which is placed separately on the nozzle receptacle by a fixing element. Due to the described structure, the heat sink is only in contact with the nozzle receptacle,P3865PC00

[0025] 4

[0026] not with the laser processing nozzle itself, which means that the potential cooling performance is limited.

[0027] The aforementioned cooling devices provide solutions for the coolant-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

[0028] (WO 2024078067 Al) or that the heat sink consisting of copper is attached by a complicated, multi-part structure (WO 2021051734 Al). Furthermore, the solution disclosed in WO 2021051734 Al has the disadvantage that the interface for receiving the laser processing nozzle is also ensured by the described copper ring. This is disadvantageous because a mechanical connection using, for example, a combination of an internal thread and an external thread is susceptible to wear due to the low surface hardness of the copper. This is particularly problematic for the nozzle receptacle, since, unlike the laser processing nozzle, it is not designed as a wear part.

[0029] CN 116 117352 B shows a nozzle receptacle for a laser processing nozzle where an insert made of stainless steel is located between a ceramic ring and a cooling ring.

[0030] DE 102006043693 B4 discloses a nozzle receptacle for a laser processing nozzle comprising an insert located in an isolation part having cooling channels for cooling gas. The insert is made of electric conducting material with a high melting point.

[0031] Document DE 102017215841 Al discloses a powder nozzle to be used in a machine for processing workpieces. The powder nozzle comprises a powder nozzle tip being made of a material which is more heat resistant and / or harder than the material of the remaining powder nozzle.

[0032] The object of the invention underlying the present application is that of providing an improved nozzle receptacle. Furthermore, it is an object of the invention to provide a corresponding laser processing head and a laser processing nozzle with high cooling performance.P3865PC00

[0033] 5

[0034] This object is achieved by the nozzle receptacle for a laser processing machine described in claim 1, and by the laser processing head described in claim 13 and by the laser processing nozzle claimed in claim 14.

[0035] In particular, the nozzle receptacle according to the invention fulfils the task that the laser processing nozzle can be sufficiently cooled even in the case when the processing focus position of the laser processing beam is close to or within the laser processing nozzle, which increases the flexibility of the possible laser processing methods. For example, it is possible to utilise the shutter function of the laser processing nozzle, which trims part of the laser beam and can thus contribute to increased cutting quality. This use of the laser processing nozzle as a shutter leads to an increased heat input into the laser processing nozzle, which is effectively dissipated by the nozzle receptacle according to the invention.

[0036] The nozzle receptacle according to the invention for a laser processing nozzle includes a heat sink having a cooling channel for receiving a coolant and has a nozzle receptacle interface for connecting the nozzle receptacle to a laser processing head. The nozzle receptacle is characterised in that the nozzle receptacle interface is designed as a separate sleeve element which is arranged in the heat sink and which consists of a material having a material hardness or surface hardness of at least 214 HB (Brinell hardness). This hardness corresponds to a Martens hardness of at least 1500 N / mm2In the case of a material hardness of at least 214 HB, the entire material of the sleeve element has this hardness. In the case of a surface hardness of at least 214 HB, at least the surface of the sleeve element has this hardness.

[0037] The advantage of the described invention over the known prior art is that the nozzle receptacle claimed here realises a very efficient cooling of the laser processing nozzle and additionally provides a wear-resistant nozzle receptacle interface. This makes it possible to cut even with high laser processing power, which ultimately increases process efficiency. Furthermore, the described type of laser cooling also allows laser cutting processes to be used in which the focus position of the laser processing beamP3865PC00

[0038] 6

[0039] is within the laser processing nozzle, which leads to a particularly high heat input into the laser processing nozzle.

[0040] Preferably, the wear-resistant sleeve element consists of a material from the group including stainless steel, manganese steel and Endura. The materials in this group are wear-resistant and yet easy to process.

[0041] In a preferred variant, the thermally conductive material of the heat sink of the nozzle receptacle has a thermal conductivity of at least 100 W / mK. This ensures effective heat removal from the laser processing nozzle towards the cooling liquid.

[0042] In particular, it is advantageous if the heat sink consists of a material from the group including aluminium, aluminium alloy, copper, brass, silver, silver alloy, gold, gold alloy and / or gold-coated metal. These materials are highly thermally conductive and comparatively resistant when used with a cooling liquid.

[0043] According to a preferred variant of the invention, the shape of the heat sink is designed such that at least one direct contact area is formed between the heat sink and the laser processing nozzle. This leads to an increase in heat dissipation from the laser processing nozzle towards the heat sink, since direct heat conduction via the contact area is possible.

[0044] Preferably, the nozzle receptacle according to the invention is designed such that the at least one contact area formed between the laser processing nozzle and the heat sink has a planar extension of at least 400 mm2in order to ensure effective heat transfer.

[0045] In a further variant of the nozzle receptacle according to the invention for a laser processing nozzle, the surface of the heat sink, which belongs to the at least one 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 heatP3865PC00

[0046] 7

[0047] 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.

[0048] In order to further increase the effective size of the contact area, according to a further variant of the nozzle receptacle according to the invention, depressions and / or elevations are formed in the surface of the heat sink, which belongs to the at least one contact area between the laser processing nozzle and the heat sink. These depressions and / or elevations correlate with corresponding elevations and / or depressions on the contact area of the laser processing nozzle and thereby increase the heat exchange potential between the laser processing nozzle and the nozzle receptacle.

[0049] A further embodiment of the nozzle receptacle is characterised in that at least one cooling rib is formed in the at least one cooling channel in the heat sink, the at least one cooling rib being preferably positioned on the inside of a wall or side of the heat sink facing the laser processing nozzle. This increases the heat exchange area between the cooling channel and the coolant and ensures improved heat dissipation.

[0050] A further embodiment of the nozzle receptacle is characterised in that the at least one cooling channel in the heat sink is open in the direction of the laser processing head and can be sealed by a counterpart in an interface of the laser processing head. This design has the advantage that the cooling channel can be manufactured using simple manufacturing methods without the need for an inner bore or similar. Furthermore, this type of design ensures that the cooling channel remains accessible later for maintenance or repair purposes.

[0051] According to a preferred embodiment, a flat surface and an elastic sealing element bearing against it are provided to seal the at least one cooling channel in the heat sink with respect to the interface of the laser processing head. This design contributes to efficient sealing and prevents unwanted cooling liquid leakage.P3865PC00

[0052] 8

[0053] According to a further embodiment of the invention, the lower part of the laser processing head, in particular the laser processing nozzle, is electrically insulated from the rest of the laser processing head. The additionally inserted insulation element, which is preferably made of PEEK plastic, can be combined with the heat sink. This variant of the invention has the advantage that a distance measurement between the laser processing nozzle and the workpiece works by measuring electrical capacitance. The advantage of using PEEK is that the material has an electrically thermally insulating effect and does not transfer heat to the components and electronics above it.

[0054] Particularly preferably, the insulation element made of PEEK plastic is inserted in such a way that it also seals the cooling channel from the direction of the laser processing head, which makes a space-saving design possible. Instead of PEEK, other suitable plastics with similar material properties to PEEK can be used.

[0055] For effective heat dissipation, in a preferred variant, a cooling liquid having a specific heat capacity of at least 1 kJ / kgK, preferably a cooling liquid having a specific heat capacity of at least 1 kJ / kgK, is used as the coolant for cooling the nozzle receptacle or the laser processing nozzle.

[0056] Particularly preferably, the cooling liquid used for the nozzle receptacle is water, and in particular deionised water, which has good availability and does not produce any undesirable reactions when in contact with the other materials used.

[0057] Furthermore, a laser processing head for a laser processing machine having an interface for connecting a nozzle receptacle to the laser processing head is claimed, which is designed to receive the nozzle receptacle according to the invention. This enables the laser processing head to carry out laser processing processes with high power and also processes with a focus position in the laser processing nozzle.

[0058] In a preferred variant of the laser processing head according to the invention, the laser processing head includes a sealing area at the interface to the nozzle receptacle,P3865PC00

[0059] 9

[0060] which sealing area seals the cooling channel formed in the nozzle receptacle in the direction of the laser processing head. This results in an effective sealing of the cooling channel filled with coolant without the need for a further separate sealing component.

[0061] Furthermore, a laser processing nozzle for a nozzle receptacle is provided, which can be inserted into the nozzle receptacle according to the invention via the nozzle receptacle interface. The laser processing nozzle has, in a surface which belongs to the at least one contact area between the laser processing nozzle and the heat sink, depressions and / or elevations, preferably ribs alternating with grooves. In addition to the depressions and / or elevations in the surface belonging to the at least one contact area, the laser processing nozzle has one of an external thread counterpart for engaging with an internal thread in the separate sleeve element or a plug-in element for engaging with a receiving element, particularly a receiving sleeve, of the separate sleeve element. 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). This design leads to an increase in the effective contact area between the laser processing nozzle and the heat sink of the nozzle receptacle, which results in improved heat transfer.

[0062] Examples of possible embodiments of the claimed invention are described in the figures appended below.

[0063] In the drawings:

[0064] Figure 1 schematically shows a representation of a laser processing head;

[0065] Figure 2 schematically shows the structure of an embodiment of the nozzle receptacle according to the invention with a connected laser processing nozzle;P3865PC00

[0066] 10

[0067] Figure 3 schematically shows the structure of an embodiment of the nozzle receptacle according to the invention with a connected laser processing nozzle having an inserted insulation block (PEEK);

[0068] Figure 4a and Figure 4b schematically show the structure of the cooling channel in various exemplary embodiments; and

[0069] Figure 4c shows a schematic representation of an embodiment, according to the invention, of elevations / depressions on the contact area.

[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 cooled 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 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,P3865PC00

[0073] 11

[0074] 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 20 and is designed such that a direct contact area 22 is formed between the laser processing nozzle 1 and the nozzle receptacle 6.

[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 receiving element 6. In Figure 2, a dashed rectangle also indicates a section IV which corresponds to Figures 4a to 4c 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 the schematic structure of a further embodiment of the nozzle receptacle 6 according to the invention having 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 receptacleP3865PC00

[0078] 12

[0079] interface 20 and is designed such that a direct contact area 22 is formed between the laser processing nozzle 1 and the nozzle receptacle 6.

[0080] Figure 3 further shows that a cooling channel 21 is formed in the heat sink 23, which cool 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 form of an insulation element 28 connected to the laser processing head 4. This insulation element is made of a thermally and electrically insulating material, in particular PEEK plastic, and ensures thermal and electrical insulation of the laser processing nozzle from the other components of the laser processing head, for example to enable capacitive distance measurement between the laser processing nozzle and the workpiece. Also shown is an elastic sealing element 26, which additionally seals the cooling channel 21 accordingly. In Figure 3, the nozzle receptacle interface 20 has an internal thread in the sleeve element, which engages 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.

[0081] Figure 4 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. A possible embodiment of the inside of the cooling channel 21 is also shown.

[0082] Figure 4a shows a flat design of the contact area 22, and in this embodiment it is preferably important that the surface quality of the surfaces forming the contact area 22 on the heat sink 23 and / or laser processing nozzle 1 have a surface roughness average roughness value Ra of less than 1.6 pm in order to create the largest possible direct contact area for the heat transfer without having unwanted air pockets between the said components, which have an insulating effect and reduce the effectiveness of heat transfer.P3865PC00

[0083] 13

[0084] Figure 4b shows an embodiment of the claimed invention in which the cooling channel 21 has at least one cooling rib 27 on the inner side located on the laser processing nozzle 1. This at least one cooling rib 27 increases the contact area between the coolant 24 and the cooling channel 21 and thus ensures improved heat transfer between the heat sink 23 and the coolant 24. The shape of the at least one cooling rib 27 can vary in design and is not limited to the embodiment shown.

[0085] Figure 4c shows an embodiment of the claimed invention in which the surfaces of the heat sink 23 and the laser processing nozzle 1, which form the contact area 22 be-tween said components, have elevations 25 and / or depressions 25 arranged to correlate with corresponding elevations 25 and / or depressions 25 in the counterpart. This arrangement results in a significant increase in the size of the heat exchange area, which is essential for efficient heat transfer, ultimately leading to improved heat transfer. It is important that the elevations / depressions 25 correlate with the corre-spending counterpart, since otherwise air pockets will form in the region of the contact area, which in turn have a negative influence on the heat transfer and must be minimised accordingly.P3865PC00

[0086] 14

[0087] List of reference signs

[0088] 1 Laser processing nozzle

[0089] 2 Laser processing beam

[0090] 3 Workpiece

[0091] 4 Laser processing head

[0092] 5 Focusing optical unit

[0093] 6 Nozzle receptacle

[0094] 7 Housing of the laser processing head

[0095] 20 Nozzle receptacle interface

[0096] 21 Cooling channel

[0097] 22 Contact area between laser processing nozzle and heat sink 23 Heat sink

[0098] 24 Coolant

[0099] 25 Depress! ons / elevations

[0100] 26 Elastic sealing element

[0101] 27 Cooling rib

[0102] 28 Insulation element

Claims

P3865PC0015Claims1. A nozzle receptacle (6) for a laser processing nozzle (1) having a heat sink (23) which has a cooling channel (21) for receiving a coolant (24), and having a nozzle receptacle interface (20) for connecting the nozzle receptacle (6) to a laser processing head (4),characterised in thatthe nozzle receptacle interface (20) is designed as a separate sleeve element which is arranged in the heat sink (23) and which consists of a material having a material hardness or surface hardness of at least 214 HB (Brinell hardness).

2. The nozzle receptacle (6) for a laser processing nozzle (1) according to claim 1, characterised in that the sleeve element consists of a material from the group including stainless steel, manganese steel and Endura.

3. The nozzle receptacle (6) for a laser processing nozzle (1) according to claim 1, characterised in that the material of the heat sink (23) has a thermal conductivity of at least 100 W / mK.

4. The nozzle receptacle (6) for a laser processing nozzle (1) according to claim 1 or 2 or 3, characterised in that the heat sink (23) consists of a material from the group including aluminium, aluminium alloy, copper, brass, silver, silver alloy, gold, gold alloy and / or gold-coated metal.

5. The nozzle receptacle (6) for a laser processing nozzle (1) according to any one of the preceding claims, characterised in that at least one direct contact area (22) is formed between the heat sink (23) and the laser processing nozzle (1).

6. The nozzle receptacle (6) for a laser processing nozzle (1) according to claim 5, characterised in that the at least one contact area (22) formed between the laser processing nozzle (1) and the heat sink (23) has a planar extension of at least 400 mm2.P3865PC00167. The nozzle receptacle (6) for a laser processing nozzle (1) according to any one of claims 5 to 6, characterised in that the surface of the heat sink (23), which belongs to the at least one contact area (22) between the laser processing nozzle (1) and the heat sink (23), 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.

8. The nozzle receptacle (6) for a laser processing nozzle (1) according to any one of claims 5 to 7, characterised in that depressions and / or elevations (25) are formed in the surface of the heat sink (23), which belongs to the at least one contact area (22) between the laser processing nozzle (1) and the heat sink (23).

9. The nozzle receptacle (6) for a laser processing nozzle (1) according to any one of the preceding claims, characterised in that the at least one cooling channel (21) in the heat sink (23) has at least one cooling rib (27), the at least one cooling rib (27) being preferably located on the inside of a wall of the heat sink (23) facing the laser processing nozzle (1).

10. The nozzle receptacle (6) for a laser processing nozzle (1) according to any one of the preceding claims, characterised in that the at least one cooling channel (21) in the heat sink (23) is open in the direction of the laser processing head (4) and can be sealed by a counterpart in an interface of the laser processing head (4).

11. The nozzle receptacle (6) for a laser processing nozzle (1) according to claim 10, characterised in that a flat surface and an elastic sealing element (25) bearing against it are provided for sealing the at least one cooling channel (21) in the heat sink (23) with respect to the interface of the laser processing head (4).

12. The nozzle receptacle (6) for a laser processing nozzle (1) according to any one of the preceding claims, characterised in that the coolant (24) for cooling the laser processing nozzle (1) is a cooling liquid having a specific heat capacity of at leastP3865PC00171 kJ / kgK, preferably a cooling liquid with a specific heat capacity of at least1 kJ / kgK.

13. A laser processing head (4) for a laser processing machine having an interface for connecting a nozzle receptacle (6) to the laser processing head (4), characterised in that the nozzle receptacle (6) is a nozzle receptacle (6) according to any one of the preceding claims.

14. A laser processing nozzle (1) for a nozzle receptacle (6) according to claim 8 or according to any one of claims 9 to 13 in combination with claim 8, characterised in that depressions (25) and / or elevations (25), preferably ribs alternating with grooves, are formed in a surface of the laser processing nozzle (1), which belongs to the at least one contact area (22) between the laser processing nozzle (1) and the heat sink (23), where in addition to the depressions and / or elevations in the surface be-longing to 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 in the separate sleeve element or a plug-in element for engaging with a receiving element of the separate sleeve element.

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