Method for machining workpiece by means of laser device and laser device

Abstract

The invention relates to a method for machining a workpiece (10) by means of a laser device (12) having a nozzle (16) with a nozzle channel through which a laser beam (14) is emitted for machining the workpiece (10), and by means of which a cutting gas to be directed towards the workpiece (10) is guided during machining of the workpiece (10), in a machining step, in which the laser beam (14) is directed towards the workpiece (10). According to the invention, the workpiece (10) is machined by means of the laser device (12), whereby the nozzle (16) generates heat, and in a non-machining step following the machining step, the nozzle (16) is actively cooled by means of a cooling gas by conducting the cooling gas through the nozzle channel, in which machining of the workpiece (10) by means of the laser device (12) does not occur.

Description

Technical Field

[0001] The invention relates to a method for machining a workpiece by means of a laser device and to a laser device. Prior art

[0002] When using a 2D laser cutting machine for edge shaping, the laser beam can be strongly reflected on the rounded surface of the workpiece whose edge is being rounded. The reflected laser radiation hits the laser cutting nozzle of the laser cutting machine or the laser cutting head of the laser cutting machine with the laser cutting nozzle, thus causing these components to heat up rapidly. If this radiation acts on these components for too long, the laser cutting unit of the laser cutting machine can be damaged. Summary of the invention

[0003] The object of the present invention is to provide a solution by means of which damage to the laser device due to a significant heating up due to absorption of reflected laser radiation can be avoided.

[0004] This object is achieved by the subject matter of the independent claims. Other possible solutions of the invention are given in the dependent claims, the description and the drawings. The features, advantages and possible solutions stated for one of the subjects of the independent claims within the scope of the description can at least be regarded similarly as the features, advantages and possible solutions of the corresponding subjects of the other independent claims and any possible combination of the subjects of the independent claims (when necessary in combination with one or more dependent claims).

[0005] The invention relates to a method for processing a workpiece by means of a laser device. The workpiece is in particular a sheet metal / metal plate processed by means of a laser device. In particular, the workpiece is processed by means of a laser device in such a way that the laser device directs a laser beam at the workpiece, thereby causing the workpiece to be changed in its properties or in its contour due to contact with the laser beam.

[0006] DS16788P3640WO0-cn

[0007] The laser device has a nozzle with a nozzle channel. When processing a workpiece, a laser beam is radiated through the nozzle channel for processing the workpiece. In addition, when processing the workpiece, a cutting gas to be directed to the workpiece is guided by means of the nozzle channel. Therefore, the nozzle is configured to direct the laser beam and the cutting gas to the workpiece when processing the workpiece. Since part of the laser beam is reflected by the workpiece, the nozzle may become hot. If the nozzle rapidly heats up due to absorbing the reflected laser beam part, this may cause damage to the nozzle and the cutting unit.

[0008] In the method, it is proposed that the workpiece is processed by means of a laser device in the processing step. Therefore, the nozzle may heat up. In order to avoid damage to the nozzle due to the rapid heating of the nozzle, it is also proposed in the method that the nozzle is actively cooled by means of a cooling gas in a non-processing step following the processing step. In the non-processing step, the workpiece is not processed by means of a laser device. Since the workpiece is not processed by means of a laser device in the non-processing step, the laser beam is not reflected by the workpiece in the non-processing step in the direction of the nozzle, so that no further absorption of the laser radiation by means of the nozzle occurs in the non-processing step. Therefore, the nozzle does not heat up further in the non-processing step. Instead, in the non-processing step, the nozzle is actively cooled by means of a cooling gas by guiding the cooling gas through the nozzle channel. In particular, when the nozzle is actively cooled, the cooling gas is made to flow through the nozzle channel with a high volume flow rate, thereby cooling the nozzle channel particularly quickly and significantly. Therefore, during the non-processing step, the temperature of the nozzle can drop particularly quickly and significantly, thereby making the nozzle available for further processing steps again. In particular, damage to the nozzle due to excessive nozzle temperatures can be prevented by actively cooling the nozzle by means of cooling gas in a non-processing step between two corresponding processing steps.

[0009] The same gas used as cutting gas in the processing step can be used as cooling gas. Alternatively, different gases can also be used as cutting gas and cooling gas in the method. Although the cutting gas is guided through the nozzle channel when processing the workpiece, the cooling effect of the cutting gas is not sufficient to prevent the nozzle from heating up so much that the nozzle is damaged by the high temperature. In particular, during the non-processing step, the cooling gas flows through the nozzle at a higher pressure than the pressure at which the cutting gas flows through the nozzle channel in the processing step. Thus, a higher cooling effect can be achieved with the cooling gas than with the cutting gas.

[0010] In a possible improvement of the present invention, it is proposed that a processing head with a nozzle of the laser device is provided.

[0011] The nozzle is actively cooled by means of cooling gas during the movement. This means that the nozzle is actively cooled by means of cooling gas when the processing head moves from a first position to a second position different from the first position. Thus, the adjustment time used for changing the position of the processing head can be used to cool the nozzle by means of cooling gas. In particular, the processing head moves between two corresponding processing steps and thus changes the position of the processing head. Thus, the time required for the movement of the processing head can be particularly well utilized to reduce the temperature of the nozzle by active cooling. Thus, after the movement of the processing head of the laser device, the nozzle will be available again for further processing steps particularly quickly. Thus, it is possible to carry out a particularly large number of processing steps in succession with the help of the nozzle.

[0012] In a further possible embodiment of the invention, it is provided that during the processing step, a cutting gas with a pressure of less than 0.3 bar, in particular less than 0.05 bar, flows through the nozzle channel. In certain processing steps in which workpieces are processed by means of a laser device, it is advantageous for the processing result if a particularly low cutting gas pressure is used. If such a low cutting gas pressure is used within the scope of the processing step, it is particularly important to actively cool the nozzle with the aid of cooling gas in the non-processing step in order to avoid overheating of the nozzle. As a result, due to the low cutting gas pressure, particularly good workpiece processing results can be achieved after the processing step, wherein damage to the nozzle due to overheating can be prevented due to the active cooling of the nozzle with the aid of cooling gas in the non-processing step.

[0013] In a further possible embodiment of the invention, it is proposed that during the non-processing step, a cooling gas with a pressure of more than 10 bar, in particular with a pressure of more than 20 bar, flows through the nozzle channel. Due to the high cooling gas pressure, the cooling gas thus flows through the nozzle channel with a particularly high volume flow rate, whereby a particularly large amount of heat can be absorbed from the nozzle by means of the cooling gas when flowing through the nozzle channel. The nozzle can thus be cooled particularly quickly and particularly intensively by means of the cooling gas flowing through the nozzle channel. As a result, due to the particularly rapid and intensive cooling of the nozzle by means of the cooling gas, the risk of overheating of the nozzle in a further processing step following the non-processing step can be kept particularly low.

[0014] In another possible embodiment of the present invention, the cutting gas is directed to the workpiece by means of a chrome-plated nozzle. In other words, the nozzle of the laser device is provided with a chrome coating. This chrome coating of the nozzle enables the workpiece to be cut.

[0015] A particularly large part of the laser beam reflected by the workpiece in the direction of the nozzle is reflected again at the nozzle, and as a result: not at all or only a very small amount of the reflected laser radiation is absorbed by the nozzle. As a result, the heat development in the nozzle due to absorption of the laser beam can be kept particularly low. The chrome-plated design of the nozzle is understood to mean that the nozzle is provided with a chrome coating at least on its outer surface facing the workpiece surface during the machining of the workpiece. Therefore, the use of a chrome-plated nozzle for the machining step ensures that the nozzle only heats up very slightly during the machining step.

[0016] In another possible design of the present invention, it is proposed that in the processing step, the edge of the workpiece is rounded by means of a defocused laser beam. In the processing step, in particular, the edge of the workpiece that was previously cut by means of a laser device is rounded. In order to perform rounding, the defocused laser beam is directed to the edge of the workpiece to be rounded by means of a laser device. When using a 2D laser cutting machine for edge rounding, the laser beam is strongly reflected on the rounded surface of the workpiece, because edge rounding is a fusion welding process, in particular a heat conduction fusion welding process. In this process, the edge of the component to be rounded of the workpiece is melted by defocusing and thus rounded. In this case, up to 95 percent, for example about 70 percent, of the laser power is reflected by the workpiece, and only a small part (about 5 percent), preferably at most about 30 percent, is absorbed. The part of the laser power reflected by the workpiece is projected onto the nozzle again, and thus causes the nozzle to heat up due to absorption by the nozzle. The method makes it possible to round the edge of a workpiece within the scope of a processing step using a defocused laser beam and subsequently to significantly reduce the temperature of the nozzle by actively cooling the nozzle in a non-processing step so that further processing steps, in particular further edge rounding, can be carried out using the nozzle, wherein the risk of damage to the nozzle due to overheating is kept particularly low.

[0017] In this context, it can be proposed in particular that the following method steps a) to f) are performed within the scope of the method, wherein these steps are consecutive method steps and are therefore performed in the order mentioned. In the method, in a first method step a), a first cutting line can be cut into the workpiece by means of a laser beam in a cutting step. This cutting step is carried out in particular before the processing step and therefore before the edge rounding. Therefore, within the scope of the cutting step, the workpiece is cut by means of a laser device. In a subsequent second method step b), the processing head of the laser device is moved from the end point of the first cutting line back to the starting point of the first cutting line. This means that the position of the processing head of the laser device moves from the end point of the first cutting line back to the starting point of the first cutting line. Here, in particular, the processing head can move along the first cutting line from the end point back to the starting point. This DS16788P3640WO0-cn

[0018] This means that during the movement from the end point of the first cutting line to the starting point of the first cutting line, the processing head is always arranged above the first cutting line during the movement. As a result, the risk that the already completely cut workpiece section is tilted due to the blowing of the gas (whether cutting gas or cooling gas) flowing out of the nozzle can be kept particularly low. In addition, it is proposed in the method that a processing step is performed in the third method step c), in which the edge of the first cutting line of the workpiece generated during cutting is rounded. Therefore, in the processing step, the edge generated in the workpiece due to the cutting step is rounded. For this purpose, in the processing step, a defocused laser beam can be directed to the edge of the workpiece to be rounded.

[0019] In a fourth method step d) following the processing step, in a further cutting step, a second cutting line is cut into the workpiece by means of a laser beam. In particular, the starting point of the second cutting line coincides with the end point of the first cutting line. Thus, in the further cutting step, a further cut is made in the workpiece starting from the first cutting line. Subsequently, in a fifth method step e), the processing head of the laser device is moved back from the end point of the second cutting line to the starting point of the second cutting line, during which the nozzle is actively cooled by means of a cooling gas in this non-processing step. Thus, in the non-processing step during which the processing head is moved back from the end point of the second cutting line to the starting point of the second cutting line and following the processing step, the nozzle is actively cooled in order to reduce the temperature and to avoid damage to the nozzle due to excessive temperature development in the nozzle. In particular, it is proposed that the cutting gas pressure used in the respective cutting step is higher than the cutting gas pressure used in the respective processing step of rounding the respective edge of the workpiece. Thus, the nozzle heats up less during the respective cutting step than during the processing step. Thus, active cooling of the nozzle immediately after the respective cutting step is only necessary if a processing step has been additionally performed. If only cutting steps have been carried out and no processing steps have been carried out with a lower cutting gas pressure, active cooling of the nozzle by means of cooling gas can be omitted.

[0020] Furthermore, it is provided in the method that in a sixth method step f) a further processing step is performed in which the edges of the second cutting line of the workpiece generated during cutting are rounded. In particular, the further processing step can be performed using the same processing parameters as the processing step performed within the scope of the third method step c). Thus, the entire predetermined cutting contour is cut and rounded step by step.

[0021] DS16788P3640WO0-cn

[0022] A specific process example of the method will be explained below. For this process example, a two-millimeter-thick CrNi steel sheet can be processed as a workpiece using a laser device with a power of 8 kilowatts. In particular, a laser device with a chrome-plated nozzle can be used. As a result, the laser radiation reflected by the workpiece and directed toward the nozzle is reflected by the nozzle.

[0023] In the method, a portion of the contour is first cut with a laser, and in particular with a laser beam provided by a laser device, and in particular about 100 mm to 500 mm, in particular 200 mm to 400 mm, and preferably 300 mm. Then, the cutting head of the laser device, and in particular the processing head, is positioned back to the starting end of the cutting, and the rounding process is started when the gas pressure of the cutting gas is 0.02 bar. Here, the edge is rounded with a defocused laser beam. Here, the nozzle will heat up significantly. Then, cutting is performed again with the laser, in particular about 100 mm to 500 mm, in particular 200 mm to 400 mm, and preferably 300 mm. After cutting, the laser is turned off, which is understood to mean that no laser beam is provided, and the laser cutting head (i.e. the processing head) is positioned back to the starting end of the cutting. During the return stroke, the nozzle is cooled at the maximum gas pressure, in particular at a gas pressure greater than 20 bar. Next, the rounding process is started again. This process is repeated until all edges on the workpiece are rounded.

[0024] The cooling effect increases as the rounding path on the contour decreases. The optimal rounding length on the contour is about 100 mm to 500 mm, in particular 200 mm to 400 mm, preferably 300 mm. This means that the pre-cut is, for example, 300 mm long. Then, the laser cutting head is positioned back 300 mm with the maximum gas pressure, and the nozzle can be cooled. In the next step, these 300 mm are rounded, which is understood to be rounding the entire length of the edge generated in the pre-cut. Here, the nozzle becomes hot again. The cooling effect can be improved in the following way, that is, the pre-cut is shortened to half, in this case to 150 mm. As a result, the return stroke for cooling the nozzle is carried out in advance, or the number of intervals for cooling the nozzle is increased, and the length of the corresponding rounding path for the nozzle to become hot is shortened. Nozzle cooling is performed during the movement of the processing head from the pre-cutting position to the starting position of the rounding.

[0025] If the nozzle overheats, the rounding can be interrupted. During this rounding interruption, the nozzle can be cooled with a high gas pressure. This means that the nozzle is cooled by having a high gas pressure,

[0026] In particular, a cooling gas (for example nitrogen) flows into the nozzle channel at a pressure of more than 20 bar.

[0027] In another possible embodiment of the invention, it is proposed that nitrogen or nitrogen gas is guided through the nozzle channel as cutting gas and / or cooling gas. In particular, nitrogen gas can be used as both cutting gas and cooling gas. Alternatively, nitrogen gas can be used either as cutting gas or as cooling gas, while another gas other than nitrogen gas can be used for the corresponding other purpose. Nitrogen gas is a particularly inexpensive and particularly environmentally friendly gas. Instead of using nitrogen or in addition thereto, for example, argon gas or compressed air can also be used as cutting gas and / or cooling gas.

[0028] In a further possible embodiment of the invention, it is proposed that the nozzle is actively cooled by means of water during the processing step. This makes it possible to prevent damage to the nozzle due to a significant increase in temperature during the processing step. Therefore, in order to limit the increase in temperature of the nozzle during the rounding process, active cooling of the nozzle can be carried out with water during the rounding process. In this case, the water can be guided into a special cooling channel of the nozzle, in particular, which is different from the nozzle channel. The cooling channel can be a closed cooling channel with an inflow and a return flow. Instead of water cooling or in addition thereto, the nozzle can also be cooled by another gas cooling method, for example by means of compressed air.

[0029] The invention further relates to a laser device, which is configured for machining a workpiece in the method already described in conjunction with the method for machining a workpiece according to the invention. In particular, the laser device can be configured for rounding or chamfering a workpiece edge within the scope of a machining step. The laser device comprises a machining head, which is configured for directing a laser beam at a workpiece for machining the workpiece. The machining head of the laser device further comprises a nozzle, by means of which the laser beam can be directed at the workpiece, and the nozzle has a nozzle channel through which a cutting gas can flow. The cutting gas can be directed at the workpiece by means of the nozzle. In order to limit the heating of the nozzle due to laser beam absorption of the laser beam reflected by the workpiece, the nozzle can be designed to be chrome-plated.

[0030] Other features of the invention can be derived from the following description of the drawings and with the aid of the drawings. The above-mentioned features and feature combinations in the specification and the features and feature combinations shown separately in the following description of the drawings and / or in the drawings can be used not only in the respectively given combination, but also in other combinations or alone without departing from the scope of the invention.

[0031] out of the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In the attached picture:

[0033] Figure 1 A schematic perspective view of a workpiece processed by means of a laser device is shown. DETAILED DESCRIPTION

[0034] exist Figure 1 1 shows a workpiece 10 processed by a laser device 12 in a schematic perspective view. In the present invention, the laser device 12 is configured to cut the workpiece 10 and round the generated cut edge on the workpiece 10. In order to process the workpiece 10, the laser device 12 can provide a laser beam 14 and direct it to the workpiece 10. According to the set parameters of the laser beam 14 (such as power, focus position and focus diameter), the workpiece 10 is cut by the laser beam 14 or the edge of the workpiece 10 is rounded by the laser beam 14.

[0035] The laser device 12 includes a processing head 32 having a nozzle 16. The nozzle 16 includes Figure 1 A nozzle channel (not shown) is provided through which the laser beam 14 is radiated for machining the workpiece 10 and through which the cutting gas can be directed to the workpiece 10 during machining of the workpiece 10. In particular, the nozzle channel extends centrally through the nozzle 16. In the present invention, the nozzle 16 is a chrome-plated nozzle.

[0036] An example sequence of machining a workpiece 10 by means of a laser device 12 is described below. It is proposed that a cutting contour 18 is introduced into the workpiece 10 by means of the laser device 12, wherein the corresponding edges of the cutting contour 18 are to be rounded. In order to avoid a strong overheating of the nozzle 16 due to absorption of laser radiation, wherein the laser radiation is reflected by the workpiece 10, it is proposed that the cutting contour 18 is introduced into the workpiece 10 step by step and thus in sections. For this purpose, in a first cutting step, a first cutting line 20 is cut into the workpiece 10 by means of a laser beam 14. The first cutting line 20 extends from a first starting point 22 to a first end point 24. After the first cutting line 20 has been cut into the workpiece 10, a machining head 32 of the laser device 12, which provides the laser beam 14, is moved back to a first starting position so that the laser beam 14 can be directed again by the machining head 32 to the first starting point 22. A first machining step then follows, in which the edges generated during cutting along the first cutting line 20 are rounded. In this case, the edge is rounded by means of a defocused laser beam at a cutting gas pressure of less than 0.3 bar, in particular at a cutting gas pressure below 0.05 bar, in particular at a cutting gas pressure of 0.02 bar. DS16788P3640WO0-en

[0037] Subsequently, in a second cutting step, a second cutting line 26 is cut into the workpiece 10 by means of the laser beam 14. The second starting point 28 of the second cutting line 26 coincides with the first end point 24 of the first cutting line 20. This means that the second cutting line 26 is connected to the first cutting line 20. After the second cutting line 26 has been cut, the processing head 32 of the laser device 12 moves back to the second starting position, from which the second cutting line 26 has been cut by means of the processing head 32. This return movement of the processing head 32 to the second starting position after the second cutting line 26 has been cut is a non-processing step, in which no processing of the workpiece 10 by means of the laser device 12 occurs. During this non-processing step, the nozzle 16 is actively cooled by means of the cooling gas by guiding the cooling gas through the nozzle channel. In the present invention, the cooling gas flows into the nozzle channel at a pressure of more than 10 bar, in particular more than 20 bar. Therefore, the cooling gas flows through the nozzle channel at a particularly high volume flow rate, so that the nozzle 16 is cooled particularly quickly and particularly greatly by means of the cooling gas during the non-processing step. After the machining head 32 has been arranged at the second starting position, the edges generated when cutting the second cutting line 26 can be rounded in a second machining step by redirecting the laser beam 14 along the second cutting line 26. Following the second end point 30 of the second cutting line 26, further cutting lines can be cut. The cutting contour 18 is cut stepwise in the form of a plurality of interconnected cutting lines, and the edges generated when cutting are rounded in respective machining steps following the respective cutting steps. In the present invention, nitrogen is flowed through the nozzle channel of the nozzle 16 as cutting gas and cooling gas.

[0038] In order to limit or at least mitigate the heating of the nozzle 16 during the respective processing steps, the nozzle 16 can be actively cooled by water during the respective processing steps. In this case, water is guided through at least one cooling channel of the nozzle 16 that is different from the nozzle channel.

[0039] Since the cutting gas pressure used when cutting the workpiece 10 is higher than the cutting gas pressure when rounding the edge, the cooling of the nozzle 16 by the cutting gas flowing through the nozzle channel during cutting will be stronger than the cooling during rounding the edge. Therefore, the temperature rise of the nozzle 16 during cutting is lower than the temperature rise during rounding the edge.

[0040] In order to avoid collisions with components cut out of the workpiece 10 , it can be provided that the machining head 32 moves only over the cutting contour 18 when moving back into the respective starting position.

[0041] DS16788P3640WO0-cn

[0042] In summary, within the scope of the method for machining a workpiece 10, at least one machining step is performed, in which the workpiece 10 is machined by means of the laser device 12, as a result of which the nozzle 16 heats up. Within the scope of the machining step, the edge of the workpiece 10 can be rounded or chamfered. Furthermore, the method also provides for at least one non-machining step following the at least one machining step, in which no machining of the workpiece 10 takes place by means of the laser device 12, and in which the nozzle 16 is actively cooled by means of cooling gas by directing the cooling gas through the nozzle channel.

[0043] The method described is based on the recognition that the laser radiation reflected by the workpiece 10 strikes the laser cutting nozzle of the laser device 12 and thus the nozzle 16 as well as the laser cutting head and thus the processing head 32, so that these components heat up rapidly. In the case of too long an action time of the laser radiation on these components, the laser cutting unit and thus the laser device 12 may be damaged. To make matters worse, the gas pressure used for edge rounding is less than 0.3 bar, typically even 0.02 bar. As a result, there is no or only very little cooling of the nozzle by convection of the cutting gas. In order to protect the nozzle 16 from a large increase in temperature, a coating can be applied to the nozzle body of the nozzle 16. A chromium coating is particularly suitable for this. Another possible solution for reducing the temperature of the nozzle 16 is to use a cooling strategy during the processing process. In this cooling strategy, the nozzle 16 is cooled by a strong nitrogen pressure after a certain period of time. It is specifically carried out as follows: First, a section of about 300 mm in length in the cutting contour 18 is cut with the laser beam 14. Then, the laser cutting head is positioned back to the starting end of the cutting and the rounding process is started at a gas pressure of less than 0.3 bar, wherein the gas pressure is related to the cutting gas. Here, the 300 mm long edge is rounded. Here, the nozzle 16 becomes heated to a great extent. Then, about 300 mm long is cut again with the laser beam 14. After the cutting is completed, the laser device 12 is turned off, and therefore the laser beam 14 is no longer provided, and the laser cutting head is positioned back to the starting end of the cutting. During the return, the nozzle 16 is cooled with the maximum nitrogen pressure, in particular with a gas pressure of more than 20 bar. Next, the rounding process is started again. This process is repeated until all edges on the components to be cut out of the workpiece 10 are rounded. The described cooling strategy combined with the use of the chrome-plated nozzle 16 provides particularly good protection against the nozzle heating of the nozzle 16. In this method, the nozzle 16 is cooled with a high nitrogen pressure within a certain time interval after the rounding.

[0044] In summary, the present invention discloses how nozzle cooling can be achieved with edge rounding.

[0045] List of Reference Numerals

[0046] 10 Workpiece

[0047] 12 Laser device

[0048] 14 Laser Beam

[0049] 16 Nozzle

[0050] 18 Cutting contour

[0051] 20 First Cut Line

[0052] 22 First starting point

[0053] 24 First End

[0054] 26 Second cutting line

[0055] 28 Second starting point

[0056] 30 Second End

[0057] 32 Processing head

Claims

1. A method for machining a workpiece (10) by means of a laser device (12), the laser device having a nozzle (16) with a nozzle channel, through which a laser beam (14) is radiated for machining the workpiece (10), and during machining of the workpiece (10), a cutting gas is guided by means of the nozzle channel to be directed toward the workpiece (10), wherein - in a processing step, the workpiece (10) is processed by means of the laser device (12), whereby the nozzle (16) heats up, - in a non-processing step following the processing step, the nozzle (16) is actively cooled by means of the cooling gas by directing the cooling gas through the nozzle channel, in which non-processing step no processing of the workpiece (10) by means of the laser device (12) takes place.

2. The method according to claim 1, It is characterized in that During the movement of a processing head (32) of the laser device (12) having the nozzle (16), the nozzle (16) is actively cooled by means of the cooling gas.

3. The method according to claim 1 or 2, It is characterized in that During the machining step, a cutting gas with a pressure of less than 0.3 bar, in particular with a pressure below 0.05 bar, flows through the nozzle channel.

4. The method according to any one of the preceding claims, It is characterized in that During the non-processing step, a cooling gas having a pressure of more than 10 bar, in particular a pressure of more than 20 bar, flows through the nozzle channel.

5. The method according to any one of the preceding claims, It is characterized in that DS16788P3640WO0-cn The cutting gas is directed toward the workpiece (10) by means of a chrome-plated nozzle (16).

6. The method according to any one of the preceding claims, It is characterized in that In the processing step, the edge of the workpiece (10) is rounded by means of a defocused laser beam (14).

7. The method according to claim 6, It is characterized in that a) in a cutting step, cutting a first cutting line (20) into the workpiece (10) by means of the laser beam (14), b) moving the processing head (32) of the laser device (12) back to the starting point (22) of the first cutting line (20), c) in the processing step, rounding the edge of the first cutting line (20) of the workpiece (10) generated during cutting, d) in a further cutting step, cutting a second cutting line (26) into the workpiece (10) by means of the laser beam (14), e) moving the processing head (32) of the laser device (12) back to the starting point (28) of the second cutting line (26), while the nozzle (16) is actively cooled by means of cooling gas during this non-processing step, f) In a further processing step, the edges of the second cutting line (26) of the workpiece (10) produced during cutting are rounded.

8. The method according to any one of the preceding claims, It is characterized in that Nitrogen is conducted through the nozzle channel as cutting gas and / or cooling gas.

9. The method according to any one of the preceding claims, It is characterized in that The nozzle (16) is actively cooled by means of water during the processing step.

10. A laser device (12) configured for machining a workpiece (10) using a method according to any one of the preceding claims.

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