Method for improving the quality of good parts which are cut out of a plate-shaped workpiece using a laser and have at least one portion to be produced in an oblique cutting process

Abstract

The invention relates to a method for improving the quality of good parts (8) which are cut out of a plate-shaped workpiece (2), in particular a sheet metal panel, using a laser and which have at least one portion (10, 16) to be produced in an oblique cutting process, having the following steps: a. creating a CAD design (8a, 8b) for a good part (8) which is to be cut out of a plate-shaped workpiece (2) using a laser, b. determining whether the CAD design (8a, 8b) for the good part (8) has a portion (10, 16) which is to be produced in an oblique cutting process, c. determining whether the portion (10, 16) to be produced in an oblique cutting process is desgined as the crest side or the trough side in the present orientation of the CAD design (8a, 8b) for the good part (8), and d. carrying out a subsequent measure.

Description

[0001] Method for improving the quality of good parts cut from a plate-shaped workpiece using a laser, with at least one section to be produced in an oblique cut.

[0002] The invention relates to a method for improving the quality of good parts cut from a plate-shaped workpiece by means of a laser, which have at least one section to be produced in an oblique cut.

[0003] German patent application DE 10 2016 213 540 A1 discloses a method for creating recesses or protrusions on the cut edges of a plate-shaped workpiece, such as a sheet metal part, using laser cutting. The method involves tilting and moving the laser processing head during cutting so that the laser beam traces contours of different lengths on the two sides of the workpiece. This enables the creation of angled recesses or protrusions in the cut edge. The pivoting movements of the laser processing head can occur either inside or outside the processing head, with the point of impact of the laser beam either moving across the workpiece surface or the laser head being rotated around a fixed point in space.

[0004] During the cutting of the angled recess or projection, the tilt of the laser processing head can be changed to perform a cut of different lengths on the two sides of the workpiece. Therefore, the laser beam axis remains at a fixed point on the cutting edge or moves along it.

[0005] When creating a slanted recess or projection, a section is produced using a bevel cut. Bevel cuts always have a "mountain side" and a "valley side." A "mountain side" is characterized by the fact that the contour of the bottom edge (edge ​​on the underside of the workpiece) extends beyond the contour of the top edge (edge ​​on the top side of the workpiece). On a "valley side," the contour of the top edge extends beyond the contour of the bottom edge. A "mountain side" tends to produce less burr formation on the bottom edge than a "valley side." Therefore, it is desirable to produce the slanted sections of workpieces as "mountain sides" to minimize post-processing.

[0006] The object of the present invention is therefore to provide a method by which the quality of good parts cut from a plate-shaped workpiece by means of a laser can be improved.

[0007] According to the invention, this problem is solved by a method for improving the quality of good parts cut from a plate-shaped workpiece using a laser, which have at least one section to be produced by an oblique cut, comprising the following method steps: a. Creating a CAD design of a good part which is to be cut from a plate-shaped workpiece using a laser, b. Determining whether the CAD design of the good part has a section to be produced by an oblique cut, c. Determining whether the section to be produced by an oblique cut is executed as a mountain side or valley side in the present orientation of the CAD design of the good part, d. Carrying out a subsequent measure.

[0008] In particular, if it is determined that the component to be produced has only one sloping section, which is designed as the valley side, the CAD design of the component can be reoriented as a subsequent measure so that the sloping section is designed as the mountain side, provided there are no boundary conditions that prevent this reorientation. Alternatively, the orientation of the CAD design of the component can remain unchanged.

[0009] The inventive method makes it possible to produce as many good parts as possible in such a way that the sloping sections of the good part are formed as valley sides. This prevents or reduces burr formation on the good parts and thus reduces the need for post-processing. Good parts can therefore be produced with less process knowledge.

[0010] According to one variant of the process, the CAD design can be rotated 180° around a horizontal axis if step c. indicates that the section to be produced in a bevel cut will be executed as the valley side. This measure ensures that the section to be produced in a bevel cut is executed as the mountain side. This prevents or minimizes burr formation on the good part, thus reducing post-processing effort. This results in higher part quality and further reduces post-processing effort. The inventive method enables the production of high-quality good parts without requiring in-depth process knowledge.

[0011] Rotating the CAD design of the finished part can be done in a "scratch system" either manually by selecting the design or automatically. This "scratch system" can be a software application that plans where a corresponding finished part is produced on a sheet-like workpiece. A sctch system allows for optimal positioning of the finished parts on the workpiece, minimizing waste. Within this system, a CAD design to be reoriented, displayed on a screen, can be selected, for example, with a mouse, thereby initiating the rotation. Alternatively, the system can automatically rotate the finished part's CAD design when a section is detected as being produced on the downhill side, resulting in the finished part being produced with the uphill side facing up.Furthermore, it can be stipulated that rotation is only performed if no opposing boundary condition exists. Various boundary conditions are possible. For example, a finished part may have several sections to be produced in a bevel cut, with some of these sections being designed as the valley side and others as the mountain side. Rotation can, for instance, only be performed if the number or length of the sections designed as the valley side, given the current orientation, is greater than the number or length of the sections designed as the mountain side, given the current orientation. Another boundary condition could be that the top and bottom surfaces of the plate-shaped workpiece differ in material or quality, and the orientation in which the finished part is to be produced is determined by these materials or qualities.Furthermore, there are components that require coding, such as a TMC or QR code, meaning one side of the component is already predefined. In such cases, the component must not be reoriented.

[0012] Furthermore, it can be provided that a visual indicator is generated if, given the orientation of the CAD design of the component, a section is designed as a valley side. For example, the CAD design of the component displayed on a screen can be color-coded if a section of the component is designed as a valley side. This makes it easy to see which CAD designs of a component require reorientation.

[0013] Furthermore, it may be possible to mark the section that is designed as the valley side, given the current orientation. For example, such a section can be highlighted in color on a display device that shows the CAD design of the good part.

[0014] Alternatively or additionally, the section designed as the mountain side, given the current orientation, can be marked. Such a section could, for example, be marked in a different color than a section designed as the valley side. This makes it easy to see whether the number of sections designed as mountain sides or valley sides predominates. This information can then be taken into account when deciding whether to reorient the CAD design of the component.

[0015] Furthermore, it can be stipulated that an attribute be assigned to the CAD design of the good part, which is taken into account when deciding whether the CAD design should be rotated. An attribute could, for example, be a boundary condition, such as the requirement that the good part must be marked with a code. On a display device where the CAD designs of good parts are shown, such a CAD design could be marked with a special color or a symbol such as an exclamation mark, thus indicating that an attribute must be considered.

[0016] The invention also includes a computer program product which comprises code means adapted to carry out all steps of the inventive method when the program runs on a controller of a laser processing machine.

[0017] Further advantages and advantageous embodiments of the invention will become apparent from the description, the claims, and the drawings. Likewise, the features mentioned above and those listed further below can be used individually or in any combination. The embodiments shown and described are not to be understood as an exhaustive list, but rather serve as examples illustrating the invention.

[0018] They show:

[0019] Fig. 1 shows a movable and tiltable laser processing head for laser cutting of workpieces; Fig. 2 shows a schematic representation of the production of a good part with bevel cuts from a plate-shaped workpiece;

[0020] Fig. 3 is a picture of a mountainside;

[0021] Fig. 4 is a picture of a valley side,

[0022] Fig. 5 shows a schematic representation of a plate-shaped workpiece with the parts to be produced positioned on it.

[0023] The laser processing head 1 shown in Fig. 1 is used for laser cutting of plate-shaped workpieces 2, such as sheet metal, by means of a laser beam 3 emerging from the laser processing head 1. The laser beam 3 is generated in a laser beam source (not shown) and is transmitted to the laser processing head 1, for example by means of an optical fiber.

[0024] The laser processing head 1 is movable two-dimensionally in the X and Y directions parallel to the flat workpiece surface 4. Alternatively, the workpiece 2 can be moved in the X and Y directions and thus displaced relative to the laser processing head 1. It is also conceivable that both the laser processing head 1 and the workpiece 2 are movable in the X and Y directions. In any case, to cut out a good part 8, it is necessary that the laser processing head 1 and the workpiece 2 are movable relative to each other in the X and Y directions.

[0025] Furthermore, the laser processing head 1, with its longitudinal axis 5 or with the beam axis 6 of the emerging laser beam 3, can be inclined by an angle θ relative to the surface normal 7 of the workpiece 2 or relative to the perpendicular in the X and Y directions. The laser processing head 1 is moved in the X and / or Y direction along the desired cutting direction at a cutting speed to cut out a good part 8 from the workpiece 2. As can be seen from Figure 2, a section 10 of the good part 8, which is produced by a laser beam 3 inclined to the surface normal 7, has a top edge 12 and a bottom edge 14, with the contour of the bottom edge 14 projecting laterally beyond the contour of the top edge 12. Such a section 10 is referred to as the mountain side. If, on the other hand, a section 16 is generated by a laser beam 3 inclined to the surface normal 7, the contour of the upper edge 18 extends laterally beyond the contour of the lower edge 20.Section 16 is therefore referred to as the valley side. Sections 22 and 24 of workpiece 2 are offcuts or part of a residual grid.

[0026] It has been shown that a section 10 executed as a mountainside exhibits less ridge formation at its lower edge 14 than a section 16 executed as a valleyside at its lower edge 20. It is therefore desirable to avoid sections executed as valleysides whenever possible.

[0027] Figure 3 shows a section 10 designed as a mountainside, where the section 10 was created with a laser beam 3 that had an angle of 45° to the surface normal 7. No burr formation is visible in this representation.

[0028] Figure 4 shows a section 16, which was designed as a valley side. In this case as well, the laser beam 3 had an angle of 45° to the surface normal 7. Here it can be clearly seen that a significant ridge 30 was formed along the lower edge 20.

[0029] Figure 5 shows the representation of a workpiece 2 on a display device. To plan the cutting of good parts 8 from the workpiece 2, CAD designs 8a of the good parts 8 to be produced from the workpiece 2 are placed on the workpiece 2 or its representation. This is called nesting. This nesting can be done in a so-called nesting module. A nesting module is essentially a software application that allows the arrangement of CAD designs 8a of good parts. If a CAD design 8b of a good part is oriented such that at least one section is executed as a valley side in the given orientation, a visual indicator is generated indicating that it must be checked whether the orientation can be maintained or whether the CAD design 8b of the good part must be rotated 180° around a horizontal axis so that the section to be produced in a bevel cut is executed as a mountain side.The indication can be given, for example, by hatching or color-coding the CAD design 8b of the good part or its representation in the box animal.

[0030] Furthermore, it may be provided that section 40 is specially highlighted to indicate that a section 16 exists at this point, which would be executed as a valley side if the orientation of the CAD designation 8b of the good part were maintained. The highlighting can be done with color or section 40 can be highlighted graphically, e.g., by a specific line thickness.

[0031] The CAD designs 8a of the good parts can also be assigned an attribute that indicates, for example, that a reorientation of the CAD design 8b must be avoided, for instance, because the top surface of the good part is made of a special material. The presence of such an attribute can be indicated by a symbol 42, such as an exclamation mark.

[0032] The reorientation of a CAD design 8b of a good part can be automated or, for example, by selecting the CAD design 8b of the good part in the box, e.g. by clicking with a mouse.

Claims

Patent claims 1. A method for improving the quality of good parts (8) cut from a plate-shaped workpiece (2), in particular a sheet metal panel, by means of a laser, which have at least one section (10, 16) to be produced by an oblique cut, comprising the method steps: a. Creating a CAD design (8a, 8b) of a good part (8) which is to be cut from a plate-shaped workpiece (2) by means of a laser, b. Determining whether the CAD design (8a, 8b) of the good part (8) has a section (10, 16) to be produced by an oblique cut, c. Determining whether the section (10, 16) to be produced by an oblique cut is executed as a mountain side or valley side in the given orientation of the CAD design (8a, 8b) of the good part (8), d. Carrying out a subsequent measure.

2. Method according to claim 1, characterized in that the CAD design (8b) is rotated about a horizontal axis by 180° if step lc shows that the section (16) to be produced in an oblique cut is designed as a valley side.

3. Method according to claim 2, characterized in that the rotation in a jig is carried out by selecting the CAD design (8b) of the good part (8) or automatically.

4. Method according to claim 2 or 3, characterized in that the turning is only carried out if there is no opposing boundary condition.

5. Method according to one of the preceding claims, characterized in that a particularly visual indication is generated when at In the present orientation of the CAD design (8b) of the good part, one section is designed as the valley side.

6. Method according to one of the preceding claims, characterized in that the section (40) which is designed as the valley side in the present orientation is marked.

7. Method according to one of the preceding claims, characterized in that the section which is designed as the mountain side in the present orientation is marked.

8. Method according to one of the preceding claims, characterized in that an attribute is assigned to the CAD design (8a, 8b) of the good part (8) which is taken into account when deciding whether the CAD design (8a, 8b) of the good part is rotated.

9. Computer program product comprising code means adapted to perform all steps of the method according to any of the preceding claims when the program is run on a controller of a laser processing machine.

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