Method for cutting workpiece by means of cutting beam

Abstract

The invention relates to a method for cutting a workpiece (1), in particular in the form of a plate, by means of a cutting beam, in which a workpiece part (2) to be cut off falls off or falls off from a surrounding residual workpiece (5) after the cutting off, in which the cutting beam is guided along a cutting contour for cutting the workpiece part (2), wherein in a first cutting region of the cutting profile, the cutting beam is moved at a first feed speed (13) and in a predetermined end section (E) of the cutting profile, the cutting beam is moved at a second feed speed (14), which is lower than the first feed speed (13).

Description

Technical Field

[0001] The present invention relates to a method for cutting, in particular, plate-shaped workpieces using a cutting beam. Background Technology

[0002] A method for cutting, particularly plate-shaped workpieces, using a cutting beam and cutting fluid is known from DE 10 2018 217 200 A1, in which the workpiece portion to be cut and separated is divided into at least two smaller sub-blocks and cut sequentially. After each sub-block is cut and separated, it descends from or detaches from the surrounding residual workpiece. For separating the first sub-block, the sub-block division and cutting plan are such that the cutting separation point of the first sub-block is located inside the outer contour of the workpiece portion to be cut and separated. Here, the workpiece portion to be cut and separated is divided by area into a larger first sub-block and a smaller second sub-block. The sub-block division and the cutting plan for separating the first sub-block are such that the cutting separation point of the first sub-block is located at the centroid of the workpiece portion to be cut and separated, at the centroid of the first sub-block, or in the region between these two centroids.

[0003] During 2D laser cutting, smaller circular inner contours (often called butzens) tend not to detach but instead become stuck in the retained portion. These butzens then have to be painstakingly knocked out of the part manually. Summary of the Invention

[0004] The purpose of this invention is to provide a solution that ensures reliable separation of the cut-out workpiece portion from the surrounding residual workpiece.

[0005] According to the present invention, this objective is achieved through the subject matter of the independent claims. Other possible embodiments of the invention are given in the dependent claims, the specification, and the drawings.

[0006] This invention relates to a method for cutting, particularly plate-shaped, workpieces using a cutting beam, especially a laser beam. This means that, within the scope of the method, a laser beam can be used to form a cut in the workpiece. The workpiece is, for example, a sheet of metal, particularly a sheet made of metallic material. In the method, a portion of the workpiece is cut and separated, and after the cutting separation is complete, it detaches or descends from the surrounding residual workpiece, wherein the cutting beam is guided along a cutting profile to cut the workpiece portion. In the initial cutting region of the cutting profile, the cutting beam moves at a first feed rate; while in a predetermined end section of the cutting profile, the cutting beam moves at a second feed rate reduced compared to the first feed rate. Due to the reduced feed rate of the cutting beam in the predetermined end section, a smaller riefennachlauf can be achieved in this end section compared to the initial cutting region of the cutting profile. The riefennachlauf describes the curvature of the cut produced when cutting the workpiece. Therefore, with the second feed rate in the end section, which is reduced compared to the first feed rate, a particularly straight cutting front edge and minimal riefennachlauf can be achieved within the kerf gap. Therefore, once the cutting beam reaches the cutting separation point of the workpiece portion, the workpiece portion will be completely separated from the remaining workpiece, thereby keeping the risk of the workpiece portion tipping over relative to the remaining workpiece at an extremely low level. In particular, by means of a reduced second feed rate, it is particularly effective to avoid the following situation: even if the cutting beam reaches the cutting separation point, due to the presence of the cut trail, the workpiece portion will still remain connected to the remaining workpiece in a small area on the side of the workpiece away from the cutting beam, and thus tip over before the workpiece portion can be completely separated from the remaining workpiece by means of the cutting beam. Therefore, the method enables reliable separation of the workpiece portion from the remaining workpiece.

[0007] The workpiece portion to be cut and separated is called a scrap block, which needs to be cut out from the remaining workpiece of the plate-shaped workpiece and then removed from the retained portion. Therefore, the method can cut out the area on the workpiece from the workpiece portion where an opening should be left.

[0008] In one possible improvement of the invention, the workpiece portion to be cut and separated from the workpiece is specified to be cut sequentially into at least two smaller sub-blocks, which, after each being cut and separated, detach or descend downwards from the surrounding residual workpiece. By dividing the workpiece portion to be cut and separated into at least two smaller sub-blocks (which detach from the residual workpiece sequentially after each being cut and separated), the risk of the sub-blocks getting stuck between each other or with the residual workpiece, and thus failing to reliably detach from the residual workpiece, can be kept at an extremely low level.

[0009] To cut the first workpiece, a cutting beam is guided along a sub-cutting contour of the cutting profile. Here, the cutting beam moves at a first feed rate within the initial cutting region of the sub-cutting contour, and at a second feed rate lower than the first feed rate in a predetermined end section belonging to the sub-cutting contour. This means that the feed rate of the cutting beam is reduced, particularly significantly, just before the cutting separation point of the first sub-block is reached, as the cutting separation of the first sub-block is about to end. Therefore, once the cutting beam reaches the cutting separation point of the first sub-block, the first sub-block will be completely separated from the remaining workpiece, thereby keeping the risk of the first sub-block tilting relative to the remaining workpiece extremely low. In particular, the reduced second feed rate effectively avoids the situation where, even if the cutting beam reaches the cutting separation point, the first sub-block remains connected to the remaining workpiece in a small area on the side of the workpiece away from the cutting beam due to the presence of the cut trail, thus preventing tipping before the cutting beam can completely separate the first sub-block from the remaining workpiece. Therefore, the method enables reliable separation of the first sub-block from the remaining workpiece. After the first sub-block is separated from the residual workpiece, the second sub-block of the workpiece portion to be cut and separated can be separated from the surrounding residual workpiece particularly easily. This is because, since the first sub-block has been removed from the residual workpiece, the second sub-block is at least partially adjacent to the opening on the residual workpiece formed by the removal of the first sub-block, thus making the risk of the second sub-block getting stuck in the residual workpiece extremely low.

[0010] In one possible improvement of the invention, the division of sub-blocks and the cutting plan for separating the first sub-block are specified such that the cutting separation point of the first sub-block is located inside the outer contour of the workpiece portion to be cut and separated. This means that the cutting separation point of the first sub-block is not located on the outer contour of the workpiece portion to be cut and separated. Here, the outer contour defines the workpiece portion within a plane stretched by the surface of the plate-like workpiece, wherein the cutting beam for cutting and separating the workpiece portion is aligned with this surface. In other words, the sub-cutting contour for the first sub-block terminates at the middle of the workpiece portion to be cut and separated, rather than at the edge of the workpiece portion to be cut and separated, thereby making the cutting separation point close to the center of gravity of the workpiece portion to be cut and separated and / or the first sub-block. Since the cutting separation point is close to the center of gravity of the workpiece portion to be cut and separated and / or the first sub-block, the first sub-block can reliably detach from the remaining workpiece once the cutting beam reaches the cutting separation point. Therefore, the risk of the first sub-block getting stuck or tipping over in the opening of the remaining workpiece can be kept at a very low level.

[0011] In another possible embodiment of the invention, the workpiece portion to be cut and separated is described as being cut using a cutting fluid. The cutting fluid is, in particular, a cutting gas. A suitable gas is selected as the cutting gas for the laser beam based on the material and chemical properties of the plate-shaped workpiece, for example, to suppress oxidation of the workpiece on the cutting surface. For example, nitrogen can be used as the cutting gas. Therefore, during the cutting process, the cutting fluid continuously flows over the plate-shaped workpiece. Specifically, for cutting, the cutting fluid and the cutting beam are at least approximately aligned with the same location on the workpiece surface. By using the cutting fluid to flow over the workpiece portion to be cut and separated, an impulse is applied to that portion, or in other words, the portion to be cut and separated is ejected by the cutting gas. In particular, the sub-block to be cut and separated is ejected from the remaining workpiece by the cutting gas. This allows the first sub-block, which has been cut and separated, to reliably detach and separate from the remaining workpiece.

[0012] In another possible design of the invention, it is specified that when the cutting separation point of the first sub-block is reached, the cutting beam is stopped, and the first sub-block is flushed with a cutting fluid flow for at least a preset time period. This means that once the first sub-block is completely cut out by the cutting beam, it will be pushed out by the cutting fluid from the opening formed by the residual workpiece. For this purpose, after the cutting beam stops, the first sub-block is flushed with a cutting fluid flow for a duration of up to two seconds, so that the first sub-block is reliably separated from the surrounding residual workpiece. Here, the cutting fluid can be directed at the cutting separation point, for example, during the preset time period. In particular, if the cutting separation point is arranged particularly close to the center of gravity of the first sub-block, the risk of the first sub-block tipping over and the resulting risk of the first sub-block getting stuck with the residual workpiece can be kept at a very low level. If the workpiece portion to be cut from the plate-shaped workpiece is cut out as a whole, and therefore not divided into at least two sub-blocks for cutting, the cutting beam can be stopped when the cutting separation point of the workpiece portion is reached, and the workpiece portion is flushed with a cutting fluid flow for at least a preset time period.

[0013] In one possible improvement of the invention, after the first sub-block is cut and separated, the cutting fluid is aligned with the center of gravity of the first sub-block to push it out of the opening formed in the remaining workpiece from which the first sub-block was cut. This means that the cutting beam and cutting fluid travel over the sub-cutting profile used to cut the first sub-block, and when the cutting separation point is reached, the cutting beam is stopped, and then the cutting fluid is redirected from alignment with the cutting separation point to alignment with the center of gravity of the first sub-block. By aligning the cutting fluid with the center of gravity of the first sub-block after it has been cut and separated, the first sub-block can be pushed out of the opening formed in the remaining workpiece with extremely high reliability, at least substantially straight and thus without tipping. If the workpiece portion to be cut from the plate-like workpiece is cut out as a whole, and therefore not divided into at least two sub-blocks for cutting, the cutting fluid can be aligned with the center of gravity of the workpiece portion after it has been cut and separated to push it out of the opening formed in the remaining workpiece from which it was cut.

[0014] In another possible design of the invention, the workpiece portion is cut out in a perfectly circular shape. This means that a so-called scrap block is cut out as a workpiece portion. For example, within the scope of the method, a perforated plate can be manufactured from which multiple perfectly circular workpiece portions are cut to obtain the perforated plate as a residual workpiece. On the one hand, the perfectly circularly cut workpiece portions can be cut out of the workpiece particularly easily; on the other hand, since the workpiece portions are designed to be perfectly circular, the risk of the cut-out workpiece portions getting stuck with the surrounding residual workpiece is extremely low. Therefore, the cut-out workpiece portions can be separated from the surrounding residual workpiece with extremely high reliability.

[0015] In this regard, it can be specifically stipulated that each sub-block is cut out with a sector-shaped base surface. In geometry, a sector is a portion of a circular surface bounded by a circular arc and two circular radii. A sector appears as a cake block viewed from above. Since each sub-block is cut out with a sector-shaped base surface, the cutting separation point of at least the first sub-block can be selected at the center of the circular base surface of the workpiece portion, and thus at the center of gravity of that workpiece portion. Here, in particular, the location of this cutting separation point is very close to the center of gravity of the first sub-block, thus keeping the risk of the first sub-block tipping over relative to the remaining workpiece at an extremely low level during the cutting separation.

[0016] In another possible design of the invention, the first sub-block occupies at least two-thirds, particularly three-quarters, of the circular base surface of the workpiece portion with its fan-shaped base. This means that the first sub-block of the workpiece portion is the largest sub-block in that workpiece portion. Therefore, once the first sub-block is separated from the surrounding residual workpiece, an opening is formed in the residual workpiece to which at least one other sub-block is connected. Since the at least one other sub-block is adjacent to the opening and is therefore at least partially surrounded by the opening, the risk of the at least one other sub-block tipping over and thus getting stuck with the wall of the limiting opening of the residual workpiece is extremely low. Therefore, the at least one other sub-block can detach or descend from the surrounding residual workpiece with extremely high reliability after being cut and separated.

[0017] In another possible design of the invention, the second feed rate is specified to be approximately one-tenth of the first feed rate. This means that, in order to adjust from the first feed rate to the second feed rate, the feed rate of the cutting beam is reduced by 90%. This significantly reduces cut trailing, thereby enabling the first sub-block or workpiece portion to be safely separated from the residual workpiece without the first sub-block or workpiece portion tipping over relative to the residual workpiece and thus becoming stuck with it.

[0018] In another possible design of the invention, the length of the end section of the cutting profile or sub-cutting profile is half the thickness of the plate-like workpiece. Here, the thickness direction of the workpiece extends along the direction in which the cutting beam is incident on the workpiece surface. To achieve cutting separation, each sub-block or workpiece portion needs to be reliably separated from the residual workpiece over the entire thickness of the workpiece by means of the cutting beam. Since the length of the end section of the cutting profile or sub-cutting profile is only half the thickness of the plate-like workpiece, this end section is designed to be particularly short, so that the majority of the cutting profile or sub-cutting profile can be cut at a faster first feed rate, and only this particularly short end section is cut at a slower second feed rate than the first feed rate. Therefore, the first sub-block or workpiece portion can be cut out quickly by means of the cutting beam, wherein the risk of the separated first sub-block or workpiece portion tipping over relative to the residual workpiece is kept at an extremely low level due to the reduced feed rate used when cutting along the end section.

[0019] In another possible embodiment of the invention, the feed rate decreases continuously and linearly from a first feed rate to a second feed rate over the length of the end section. Specifically, the cutting beam moves at the first feed rate at the beginning of the end section and at the second feed rate at the end of the end section. Thus, the feed rate decreases in a ramp-like manner over the length of the end section. The end section may terminate at a cutting separation point. Alternatively, the end section may terminate before the end section, wherein, in the transition region from the end of the end section to the cutting separation point, the cutting beam may continue to move at the second feed rate, or the feed rate may be further reduced, particularly until the feed rate is zero at the cutting separation point. Attached Figure Description

[0020] Other features of the present invention can be derived from the following description and the accompanying drawings. The features and combinations of features mentioned in the foregoing description, as well as the features and combinations of features shown individually in the following description and / or the accompanying drawings, may be used not only in their respective combinations, but also in other combinations or individually, without departing from the scope of protection of the present invention.

[0021] The attached diagram shows: Figure 1 This is a schematic top view of the part of the workpiece to be cut and separated from the plate-shaped workpiece; Figure 2 It is a schematic cross-sectional view of a plate-shaped workpiece from which the workpiece portion is to be cut and separated; and Figure 3 It is a graphical representation of the feed rate on the cutting contour when cutting and separating parts of a workpiece.

[0022] Components that are identical or have the same function are indicated by the same reference numerals in the accompanying drawings. Detailed Implementation

[0023] Figure 1 The image shows a workpiece 1 in a top view, currently designed as a plate. Workpiece 1 is currently a plate. A workpiece portion 2, currently a circular scrap block, needs to be cut from workpiece 1. The workpiece portion 2 to be cut is currently being cut into at least two smaller sub-blocks 3 and 4, which detach or descend from the surrounding residual workpiece 5 after their respective cutting and separation. The workpiece portion 2 is currently divided into a first sub-block 3 and a second sub-block 4, which are cut sequentially. Here, the first sub-block 3 and the second sub-block 4 each have a fan-shaped base surface. The first sub-block 3 has a fan-shaped base surface that occupies three-quarters of the circular base surface of workpiece portion 2. The second sub-block 4 has a fan-shaped base surface that occupies one-quarter of the circular base surface of workpiece portion 2.

[0024] Figure 1A sub-cutting profile 6 can also be seen, along which the laser beam is guided to cut out the first sub-block 3. Currently, the workpiece portion 2 is cut out using the cutting fluid with the help of the cutting beam. To separate the first sub-block 3, the workpiece portion 1 is inserted into the center at the insertion point A with the help of the cutting beam. Then, with the help of the cutting beam, it cuts from the insertion point A along line B to line C, which follows the outer contour of the workpiece portion 2. Then, it cuts along line C along the arc around the insertion point A at an angle of 270°. Then, with the help of the cutting beam, it cuts from the outer contour back to the insertion point A along line D. The insertion point A is also the cutting separation point of the first sub-block 3. Therefore, to separate the first sub-block 3, it cuts from the insertion point A along lines B, C, and D back to the insertion point A. Therefore, the sub-cutting profile extends from the insertion point A, through lines B, C, and D, back to the insertion point A. Once the first sub-block 3 is completed, the cutting beam can be stopped, and the cutting fluid can continue to flow over the first sub-block 3 for at least a preset time period.

[0025] After the cutting jet is stopped, the cutting fluid can be directed from the cutting separation point towards the center of gravity of the first sub-block 3 to push the first sub-block 3 out of the opening formed in the residual workpiece 5 by cutting and separating the first sub-block 3. By using the cutting fluid to push towards the center of gravity of the first sub-block 3, the first sub-block 3 can be pushed out of the residual workpiece at least substantially straight downwards. This effectively avoids the risk of the first sub-block 3 tipping over after cutting and separating and getting stuck on the wall of the opening formed by the boundary of the residual workpiece 5.

[0026] Figure 2 The workpiece 1 is shown in a schematic cross-sectional view. The first sub-block 3 has been cut and separated from the workpiece, wherein the center of gravity of the first sub-block 3 is impacted by the flow of cutting fluid 7, thereby applying a force 8 to the center of gravity of the first sub-block 3. With the help of this force, the first sub-block 3 can be pushed downward from the opening 9 formed by the cutting and separation of the remaining workpiece 5.

[0027] like Figure 1 As shown, the division of the workpiece portion 2 into sub-blocks 3 and 4 and the selection of the cutting plan for separating the first sub-block 3 ensure that the cutting separation point of the first sub-block 3 is located inside the circular outer contour of the workpiece portion 2. Currently, the cutting separation point of the first sub-block 3 is at least approximately located at the center point of the circular shape of the workpiece portion 2.

[0028] After the first sub-block 3 is cut from the workpiece 1, the cutting head configured to perform the method is moved, thereby aligning the cutting beam and cutting fluid with the outer contour of the workpiece portion 2. The cutting beam and cutting gas 7 are provided, in particular, by means of the nozzle 10 of the cutting head and aligned with the workpiece 1. Subsequently, the cutting beam moves along the line marked "F", which coincides with the outer contour of the workpiece portion 2. In this way, the second sub-block 4 is cut and separated, and can fall out of the remaining workpiece 5 through the opening formed in the remaining workpiece 5 by cutting and separating the sub-blocks 3 and 4, particularly downwards. Since the first sub-block 3 has been removed from the remaining workpiece 5 at the moment the second sub-block 4 is cut and separated, and the opening formed in the remaining workpiece 5 by cutting and separating the sub-blocks 3 and 4 is large enough, the risk of jamming (e.g., due to the second sub-block 4 tipping over) of the wall of the opening formed by the boundary between the second sub-block 4 and the remaining workpiece 5 is extremely low.

[0029] To keep the risk of tipping over during the cutting and separation of the first sub-block 3 at an extremely low level, this scheme specifies that the cutting beam cutting the first sub-block 3 moves at a first feed rate 13 within the initial cutting area of ​​the sub-cutting profile, and moves at a second feed rate 14, which is lower than the first feed rate 13, within a predetermined end section E of the sub-cutting profile. Specifically, the cutting beam may move at least along lines C and D at the first feed rate 13. Currently, the second feed rate 14 is one-tenth of the first feed rate 13. For example, the second feed rate 14 is in the range of 0.1 m / min to 1.5 m / min. Currently, the length of the end section E of the sub-cutting profile is half the thickness of the plate-shaped workpiece 1, or alternatively, 2 mm. Alternatively, the length of the end section E may use a different value and be determined experimentally.

[0030] Figure 3 The feed rate V along the cutting profile 11 is graphically represented, along which a portion of the workpiece is cut out as a single piece. The cutting profile 11... Figure 1 The image is drawn within the plane spanned by x and y. To cut out workpiece portion 2, a cutting beam is guided along the cutting contour 11. Here, within the initial cutting region 12 of the cutting contour 11, the cutting beam moves at a first feed rate 13; and in the predetermined end section E of the cutting contour 11, the feed rate V decreases continuously and linearly from the first feed rate to a second feed rate 14 lower than the first feed rate 13. Currently, the cutting beam moves at the first feed rate 13 at the starting point 15 of the end section E and at the second feed rate 14 at the ending point 16 of the end section E. From... Figure 3It can be clearly seen that the feed rate V of the cutting beam decreases continuously in the terminal section E, corresponding to a slope, which can therefore also be called the feed slope. This feed slope can be described by the deceleration section of the feed rate V and further by the length of the terminal section E and the feed rate V at the endpoint 16.

[0031] Therefore, this invention relates to a cutting strategy for scrap block removal. In machine schemes based on sheet metal movement, the reliable removal of the inner contour (particularly the scrap block) can be crucial to the overall process reliability of the system. Process reliability is ensured by inspecting each scrap block and subsequently performing supplementary cutting of the entire contour if necessary. However, in addition to the resulting additional and unpredictable time costs, the edge quality of the supplementally cut contour can also be negatively affected. Scrap block removal is facilitated by optimizing the cutting end in the form of a linear feed rate reduction along the path—i.e., by reducing the feed rate V of the cutting beam in the end section to a second feed rate 14. This cutting end strategy significantly reduces the risk of scrap block jamming, greatly reduces the risk of scrap block tipping into the still-active cutting beam, and significantly reduces the risk of localized fusion of the scrap block.

[0032] In 2D laser cutting, for workpieces thicker than 3 mm, circular outlines with diameters greater than 5 mm and less than 30 mm may become stuck in the remaining workpiece, requiring manual removal. This situation particularly occurs when the gas beam, and thus the cutting fluid, impacts the scrap block at the cutting point, causing it to tip over during its descent and become stuck in the opening created by the cutting process. To address this problem, the method described uses the cutting gas beam and thus the cutting fluid to center the scrap block and, consequently, the workpiece portion 2 to be cut (especially the first sub-block 3) downwards, preventing it from tipping over. Figure 1As shown, the cutting strategy for reliably detaching the scrap block includes: inserting the scrap block at insertion point A in the middle and moving along line B to a circular profile. Cutting the scrap block along line C to three-quarters of its length; at the end of this ¾ cut, cutting along line D towards insertion point A to the middle of the scrap block. During this cutting process, a feed ramp, specifically a 2 mm feed ramp, is implemented in the end section E of the sub-cut profile. Here, the feed rate V is reduced from a first feed rate 13 to a second feed rate 14, specifically 0.5 mm / m. At insertion point A, the scrap block is flushed with cutting fluid while the cutting beam stops for a waiting period of approximately 0.25 seconds until the ¾ scrap block detaches downwards. The first sub-block 3 is vertically pushed downwards by the central action of the cutting gas beam on the scrap block. Subsequently, the cutting beam remains active while the cutting fluid remains off during cutting head positioning. After the cutting head is repositioned, the cutting beam and cutting fluid are supplied again and aligned with the circular contour, thereby resuming cutting at this position. Using the activated cutting fluid and activated cutting beam, the last quarter of the scrap block is cut along the circular contour. At the cutting separation point of ¼ of the scrap block, the supply of the cutting beam and cutting fluid is stopped. As a specific example, nitrogen cutting can be used during the cutting process to cut a 10 mm diameter scrap block, which is part 2 of the workpiece, from a 6 mm thick sheet material, which is workpiece 1. Here, the laser power used can be, in particular, 12 kW, and the first feed rate 13 can be, in particular, selected as 14.4 m / min.

[0033] The cutting separation point is specifically chosen such that the distance between the cutting separation point of the first sub-block 3 and the center of gravity of the first sub-block 3 is as small as possible.

[0034] Currently, in this method, the waste block is inserted centrally, and most of the waste block (currently about 75%) is cut off as the first sub-block 3, while leaving the remaining small portion of the waste block (currently about 25%). The cut-off portion of the waste block is ejected with cutting fluid and / or compressed air after the cutting separation, thereby enabling the waste block (especially the large portion and subsequently after the small portion is cut off) to fall vertically and without jamming from the residual workpiece 5.

[0035] In summary, this invention reveals how to combine a cutting strategy with a feed ramp to achieve scrap block detachment.

[0036] List of reference numerals 1. Workpiece 2. Workpiece section 3 First sub-block 4 Second sub-block 5. Residual workpiece 6 Sub-cutting contours 7. Cutting fluid 8 Force 9 Opening 10 nozzles 11 Cutting the outline 12 First, cut the area 13 First feed rate 14 Second feed rate 15 Starting Point 16. Finish Line A. Penetration point Line B C line Line D E End Section F line V feed rate

Claims

1. A method for cutting a workpiece (1) by means of a cutting beam, said workpiece being particularly a plate-shaped workpiece, wherein, The workpiece portion (2) to be cut and separated falls or descends from the surrounding residual workpiece (5) after the cutting and separation, wherein the cutting beam is guided along the cutting profile (11) to cut the workpiece portion (2), wherein the cutting beam moves at a first feed speed (13) in the first cutting area (12) of the cutting profile (11), and in the predetermined end section (E) of the cutting profile (11), the cutting beam moves at a second feed speed (14) that is lower than the first feed speed (13).

2. The method according to claim 1, Its features are, The workpiece portion (2) to be cut and separated is cut in sequence into at least two smaller sub-blocks (3, 4), which fall or descend from the surrounding residual workpiece (5) after their respective cutting and separation. The cutting beam is guided along the sub-cutting profile (6) of the cutting profile to cut the first sub-block (3). The cutting beam moves at the first feed speed (13) in the first cutting area of ​​the sub-cutting profile (6), and moves at a second feed speed (14) that is lower than the first feed speed (13) in the predetermined end section (E) of the sub-cutting profile (6).

3. The method according to claim 2, Its features are, The division of the sub-blocks (3, 4) and the cutting plan for separating the first sub-block (3) are completed in the following manner: the cutting separation point of the first sub-block (3) is located inside the outer contour of the workpiece part (2) to be cut and separated.

4. The method according to any one of the preceding claims, Its features are, The workpiece part (2) to be cut and separated is cut out using the cutting fluid (7).

5. The method according to claim 2, 3 or claim 4 citing claim 2, Its features are, When the cutting separation point of the first sub-block (3) is reached, the cutting beam is stopped, and the first sub-block (3) is flushed with the cutting fluid (7) for at least a preset time period.

6. The method according to claim 5, Its features are, After the first sub-block (3) is cut and separated, the cutting fluid (7) is aligned with the center of gravity of the first sub-block (3) to push the first sub-block (3) out of the opening (9) formed in the residual workpiece (5).

7. The method according to any one of the preceding claims, Its features are, The workpiece portion (2) is cut out in a perfect circle.

8. The method according to claim 7 of claim 2, Its features are, Each of the sub-blocks (3, 4) is cut out with a fan-shaped base plane.

9. The method according to claim 8, Its features are, The first sub-block (3) occupies at least 2 / 3, particularly 3 / 4, of the circular base surface of the workpiece portion (2) with its fan-shaped base surface.

10. The method according to any one of the preceding claims, Its features are, The second feed rate (14) is approximately one-tenth of the first feed rate (13).

11. The method according to any one of the preceding claims, Its features are, The length of the end section (E) of the cutting profile and / or the sub-cutting profile (6) is half the thickness of the plate-shaped workpiece (2).

12. The method according to any one of the preceding claims, Its features are, Along the length of the end section (E), the feed rate (V) decreases continuously and linearly from the first feed rate (13) to the second feed rate (14).

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