METHOD FOR GENERATING A TOOL PATH AS WELL AS METHOD AND APPARATUS FOR ADDITIVE MANUFACTURING OF A WORKPIECE USING SUCH A TOOL PATH

Abstract

The present invention relates to a method for generating a tool path (20; 82) for an application tool (12) for additive manufacturing, in particular for additive manufacturing using buildup welding, of a substantially rotationally symmetric workpiece (28; 328), comprising the following steps: a) providing cross-sectional contour data describing at least a portion of a cross-sectional contour (42; 342; 442; 542) of the workpiece (28; 328); b) providing axis data describing a rotation axis (R) of the rotationally symmetric workpiece (28; 328); c) generating a continuous cross-sectional path (54; 354; 355; 454; 554), taking into account the cross-sectional contour data, the cross-sectional path (54; 354; 355; 454; 554) being inscribed in the portion of the cross-sectional contour (42; 342; 442; 542); d) generating the tool path (20; 82) with a helical or/and spiral course revolving around the rotation axis (R), wherein the tool path (20; 82) intersects the cross-sectional path (54; 354; 355; 454; 554), preferably with each revolution around the rotation axis (R).

Claims

1. A method for generating a tool path (20; 82) for an application tool (12) for additive manufacturing, in particular for additive manufacturing using buildup welding, of a substantially rotationally symmetric workpiece (28; 328), comprising the following steps: a) providing cross-sectional contour data describing at least a portion of a cross-sectional contour (42; 342; 442; 542) of the workpiece (28; 328); b) providing axis data describing a rotation axis (R) of the rotationally symmetric workpiece (28; 328); c) generating a continuous cross-sectional path (54; 354; 355; 454; 554), taking into account the cross-sectional contour data, the cross-sectional path (54; 354; 355; 454; 554) being inscribed in the portion of the cross-sectional contour (42; 342; 442; 542); d) generating the tool path (20; 82) with a helical or/and spiral course revolving around the rotation axis (R), wherein the tool path (20; 82) intersects the cross-sectional path (54; 354; 355; 454; 554), preferably with each revolution around the rotation axis (R).

2. The method of claim 1, characterized in that step d) comprises the sub-steps of: d1) determining tool path points (80; 81; 83; 94; 481; 483; 494; 581; 583) on the cross-sectional path (54; 354; 355; 454; 554), taking into account at least one manufacturing parameter; and d2) generating the tool path (20; 82) from tool path sections (84, 92, 96), wherein each tool path section (84, 92, 96) rotates completely about the rotation axis (R) and connects two adjacent tool path points (80; 81; 83; 94; 481; 483; 494; 581; 583) on the cross-sectional path (54; 354; 355; 454; 554) to one another.

3. The method of claim 2, characterized in that at least a width or/and a height of a one-time material application of the application tool (12) is/are provided as manufacturing parameter(s).

4. The method of one of the preceding claims, characterized in that at least one manufacturing parameter is taken into account when generating the continuous cross-sectional path (54; 354; 355; 454; 554), at least a width or/and a height of a one-time material application of the application tool (12) being provided as manufacturing parameter(s).

5. The method of claim 4, characterized in that the cross-sectional path (54; 354; 355; 454; 554) is inscribed in the portion of the cross-sectional contour (42; 342; 442; 542) in such a way that, as a result of a continuous material application along the tool path (20; 82), taking into account the at least one manufacturing parameter, the portion of the cross-sectional contour (42; 342; 442; 542) is substantially completely filled with material.

6. The method of any one of claim 4 or 5, in particular insofar as dependent on claim 2, characterized in that the cross-sectional path (54; 354; 355; 454; 554) is formed to be meandering or/and run parallel at least in sections, in particular if the width of the material applied is smaller than a width of the portion of the cross-sectional contour (42; 342; 442; 542).

7. The method of any one of the preceding claims, characterized in that the cross-sectional path (54; 354; 355; 454; 554) comprises a starting point (78; 378) and an end point (79; 379) each located at an outer or inner edge of the portion.

8. The method of claim 2 and any of the preceding claims, wherein during the determining of the tool path points (80; 81; 83; 94; 481; 483; 494; 581; 583) on the cross-sectional path (54; 354; 355; 454; 554) a course of the cross-sectional path (54; 354; 355; 454; 554) with respect to the rotation axis (R) is taken into account.

9. The method of claim 2 and any one of the preceding claims, wherein the tool path points (80; 81; 83; 94; 481; 483; 494; 581; 583) are determined with a substantially constant distance (L) from each other or with at least a first and a second distance (L1, L2) on the cross-sectional path (54; 354; 355; 454; 554).

10. The method of any one of claim 2, 8 or 9, characterized in that each tool path section (84, 92, 96) between adjacent tool path points (80; 81; 83; 94; 481; 483; 494; 581; 583) of the cross-sectional path (54; 354; 355; 454; 554) is determined according to a course of the cross-sectional path section lying between these adjacent tool path points (80; 81; 83; 94; 481; 483; 494; 581; 583).

11. The method of claim 10, characterized in that the tool path section (84, 92, 96) is generated between the adjacent tool path points (80; 81; 83; 94; 481; 483; 494; 581; 583) by taking into account at least one item of position information starting from a first of the adjacent tool path points (80; 81; 83; 94; 481; 483; 494; 581; 583) until the second of the adjacent tool path points (80; 81; 83; 94; 481; 483; 494; 581; 583) is reached.

12. The method of claim 11, characterized in that the position information comprises: a height coordinate (z) of a point (86; 511) on the cross-sectional path (54; 354; 355; 454; 554) or/and a distance coordinate (r) of a point (86; 511) on the cross-sectional path (54; 354; 355; 454; 554) relative to the rotation axis (R) or/and angle information (α) with respect to the first or/and the second tool path point (80; 81; 83; 94; 481; 483; 494; 581; 583).

13. The method of any one of the preceding claims, characterized by the step of providing alignment information for at least one point of the tool path (20; 82), preferably for at least one of the tool path points (80; 81; 83; 94; 481; 483; 494; 581; 583), said alignment information describing an alignment of a tool axis (W) of the application tool (12) in said point of the tool path (20; 82), specifically the tool path point (80; 81; 83; 94; 481; 483; 494; 581; 583).

14. The method of claim 13, characterized in that the alignment information for at least one further point of the tool path (20; 82), in particular another one of the tool path points (80; 81; 83; 94; 481; 483; 494; 581; 583), is determined, taking into account the alignment information for the at least one point of the tool path (20; 82), in particular the at least one of the tool path points (80; 81; 83; 94; 481; 483; 494; 581; 583).

15. The method of claim 14, wherein the alignment information is provided each for a first and a second point on the tool path (20; 82), preferably for a first and a second tool path point (80; 81; 83; 94; 481; 483; 494; 581; 583), and a continuous course is determined for points between the first and second point on the tool path (20; 82), preferably between the first and second tool path point (80; 81; 83; 94; 481; 483; 494; 581; 583), preferably using interpolation, particularly preferably using linear interpolation.

16. The method of any one of claims 1 to 15, characterized in that (i) a first item of alignment information is provided for at least one point (501; 503; 505; 507; 509) on the cross-sectional path (54; 354; 355; 454; 554) and (ii) based on the first item of alignment information, a second item of alignment information is provided for at least one point of the tool path (20; 82), preferably for at least one of the tool path points (80; 81; 83; 94; 481; 483; 494; 581; 583); wherein each item of alignment information describes an alignment of a tool axis (W) of the application tool (12) for the respective point.

17. The method of claim 16, wherein the first item of alignment information is determined for at least one further point (86; 511) on the cross-sectional path (54; 354; 355; 454; 554), taking into account the first item of alignment information.

18. The method of claim 17, wherein the first item of alignment information is provided in step (i) each for a first and a second point (501; 503; 505; 507; 509) on the cross-sectional path (54; 354; 355; 454; 554) and a continuous course is determined for points (86; 511) between the first and second point (501; 503; 505; 507; 509) on the cross-sectional path (54; 354; 355; 454; 554) preferably using interpolation, particularly preferably using linear interpolation.

19. The method of any one of claims 13 to 18, characterized in that the alignment information describes an angle between the tool axis (W) and the rotation axis (R) or a direction vector (87; 502, 504, 506, 508, 510, 512) of the tool axis (W).

20. The method of any one of claims 13 to 19, characterized in that the alignment information of a point on the tool path (20; 82), preferably of a tool path point (80; 81; 83; 94; 481; 483; 494; 581; 583), or of a point (86; 511) of the cross-sectional path (54; 354; 355; 454; 554) is determined according to a course of the cross-sectional contour (42; 342; 442; 542).

21. The method of any one of the preceding claims, characterized in that the cross-sectional contour data or/and the axis data are determined from: 3D model data of the workpiece (28; 328) or data of a preferably two-dimensional removal tool path for a removal tool of a cutting process for manufacturing the workpiece (28; 328), preferably of a machining process, particularly preferably of a turning or/and milling process.

22. A method for additive manufacturing of a workpiece (28; 328) using at least one tool path (20; 82) generated according to the method of any one of claims 1 to 21.

23. The method of claim 22, wherein at least one of the following manufacturing parameters is variable during additive manufacturing of the workpiece: Composition of the additive manufacturing material (24), Feed rate of the application tool (12), Power of the application tool (12), and Gas flow of the application tool (12).

24. The method of claim 23, wherein different parameter values are assigned to at least one of the manufacturing parameters at different points along the cross-sectional path or tool path (54; 354; 355; 454; 554).

25. The method of claim 24, wherein the parameter values of a particular manufacturing parameter in a section of the cross-sectional path or tool path between two successive points at which the manufacturing parameter has different parameter values is determined by interpolation, preferably linear interpolation.

26. The method of any one of claims 22 to 25, wherein moving along the tool path (20; 82) is performed at a substantially constant feed rate for the application tool (12).

27. The method of any one of claims 22 to 26, wherein moving along the tool path (20; 82) is performed at a variable feed rate for the application tool (12).

28. The method of claim 27, wherein at least during a final tool revolution, the tool feed rate is increased or reduced relative to a non-final tool revolution.

29. An apparatus (10) for additive manufacturing of a substantially rotationally symmetric workpiece (28; 328) using a tool path (20; 82) generated according to the method of any one of claims 1 to 18; wherein the apparatus (10) comprises an application tool (12) for additive manufacturing, in particular a buildup welding head; wherein the apparatus (10) generates a continuous cross-sectional path (54; 354; 355; 454; 554) in accordance with cross-sectional contour data describing at least a portion of a cross-sectional contour (42; 342; 442; 542) of the workpiece (28; 328) and in accordance with axis data describing a rotation axis (R) of the rotationally symmetric workpiece (28; 328), taking into account the cross-sectional contour data; wherein the cross-sectional path (54; 354; 355; 454; 554) is inscribed in the portion of the cross-sectional contour (42; 342; 442; 542); wherein the apparatus (10) generates the tool path (20; 82) with a helical or/and spiral course revolving around the rotation axis (R); wherein the tool path (20; 82) intersects the cross-sectional path (54; 354; 355; 454; 554), preferably with each revolution around the rotation axis (R); and wherein the apparatus (10) guides the application tool (12) along the tool path (20; 82), thereby applying material.

30. The apparatus (10) of claim 29, the apparatus (10) further comprising a method of any one of the claims 22 to 28.

Description

[0069] In the following, the present invention is described by way of example with reference to the accompanying figures. In the drawings:

[0070] FIG. 1 is a schematic side view of an application tool according to the invention;

[0071] FIG. 2 shows a rotationally symmetric workpiece to be manufactured;

[0072] FIG. 3 shows a model of a workpiece to be manufactured;

[0073] FIG. 4 shows a cross-sectional contour of a workpiece to be manufactured;

[0074] FIG. 5 shows a cross-sectional contour incl. continuous cross-sectional path;

[0075] FIG. 6 shows a section of the cross-sectional contour incl. tool path points;

[0076] FIG. 7 shows a cross-sectional contour with a continuous cross-sectional path incl. exemplary tool path;

[0077] FIG. 8 shows an exemplary tool path in connection with the continuous cross-sectional path;

[0078] FIG. 9 is an alternative view of the tool path in connection with the continuous cross-sectional path;

[0079] FIG. 10 is another alternative view of the tool path in connection with the continuous cross-sectional path;

[0080] FIG. 11 shows a section of the cross-sectional contour incl. continuous cross-sectional path;

[0081] FIG. 12 is a view of an extended tool path;

[0082] FIG. 13 is an alternative view of the extended tool path;

[0083] FIG. 14 is a view of an additionally extended tool path;

[0084] FIG. 15 shows an alternative workpiece to be manufactured;

[0085] FIG. 16 shows a cross-sectional contour of the alternative workpiece to be manufactured;

[0086] FIG. 17 shows a cross-sectional contour of the alternative workpiece to be manufactured incl. continuous cross-sectional path;

[0087] FIG. 18 shows a section of the cross-sectional contour with alternative tool path points;

[0088] FIG. 19 shows a section of the cross-sectional contour with a continuous cross-sectional path incl. alignment information;

[0089] FIG. 20 shows a section of the cross-sectional contour with a continuous cross-sectional path incl. determined alignment information;

[0090] FIG. 21 shows a section of the cross-sectional contour with a continuous cross-sectional path incl. determined alignment information for one point; and

[0091] FIG. 22 shows a cross-sectional contour with a continuous cross-sectional path incl. exemplary tool path.

[0092] FIG. 1 is a schematic side view of an apparatus 10 according to the invention for additive manufacturing of a substantially rotationally symmetric workpiece. The apparatus 10 comprises an application tool 12 including application tool head 14. The application tool 12 moves relative to a workpiece base (not shown in more detail) onto which a material path 16 is applied along a tool path 20 for additive manufacturing of a workpiece. A laser beam 22 comes out of the application tool head 14 along with powder substance 24. The powder substance 24 could be supplied to the laser beam 22 in other ways, such as laterally. Further, instead of powder substance 24, wire, for example, could be supplied to laser beam 22. The laser beam 22 is directed to a focal point 26 and heats the powder substance 24 or material at this focal point 26 to such an extent that the powder substance 24 melts. In this process, material already applied from another material path or a surrounding substance may be melted and bonded to the melted, former powder substance 24. Outside the focal point 26, cooling takes place and the material path 16 is formed.

[0093] FIG. 2 is a perspective side view of an example of a rotationally symmetric workpiece 28 to be manufactured. Due to rotational symmetry, the workpiece 28 has a symmetry axis A. The workpiece 28 is hollow on the inside and comprises a frustoconical lateral surface 30. The workpiece 28 further comprises a cylindrical lateral surface 32 that is connected to the frustoconical lateral surface 30 by a transitional lateral surface 34. An inner shoulder 36 is recognizable on the workpiece 28.

[0094] FIG. 3 shows an example of a model 38 in the form of a 3D model of the rotationally symmetric workpiece 28 to be manufactured. The model 38, too, is shown in a perspective side view. Like the workpiece 28, the model has the symmetry axis A. Furthermore, the frustoconical lateral surface 30, the cylindrical lateral surface 32 and the transitional lateral surface 34 are visible. In addition, the inner shoulder 36 is recognizable.

[0095] Compared to the workpiece 28 of FIG. 2, the model 38 is a transparent representation of the workpiece 28, in which inner surfaces of the workpiece 28 are recognizable. It can be seen, for example, that on the inside below the shoulder 36, an inner surface 40 is formed that is not parallel to the frustoconical lateral surface 30. Rather, a wall of the workpiece 28 is thicker in the area of the shoulder 36 than a wall in a lower area of the frustoconical lateral surface 30. Wall thickness is constant in the areas of the transitional lateral surface 34 and of the cylindrical lateral surface 32.

[0096] FIG. 4 shows a cross-sectional contour 42 of the workpiece 28 to be manufactured together with a rotation axis R, the cross-sectional contour 42 being a closed contour line. The rotation axis R corresponds to the symmetry axis A of FIGS. 1 to 3.

[0097] The cross-sectional contour 42 is based on the rotationally symmetric workpiece 28 or model 38. The cross-sectional contour 42 is two-dimensional. It can be generated by intersecting the workpiece 28 or the model 38 with a plane in which the symmetry axis A lies. When the workpiece 28 or the model 38 is intersected in this manner, two cross-sectional half contours are generated that are separated from each other by the symmetry axis A. The cross-sectional contour 42 is one of the two cross-sectional half contours. The cross-sectional contour 42 is spaced from the rotation axis R because the workpiece 28 or model 38 is hollow on the inside. The arrangement of the cross-sectional contour 42 relative to the rotation axis R is the result of the rotationally symmetric workpiece 28 or the model 38 and the previously explained generation of the cross-sectional contour 42.

[0098] The cross-sectional contour 42 has an oblique contour line 44 that is based on the frustoconical lateral surface 30. The cross-sectional contour further has a perpendicular contour line 46 that is based on the cylindrical lateral surface 32. The oblique contour line 44 and the perpendicular contour line 46 are connected by an arcuate contour line 48 that is based on the transitional lateral surface 34. The cross-sectional contour 42 further has an inner contour line 50 that is based on the inner surface 40. Further, a shoulder contour line 52 is formed based on the shoulder 36.

[0099] It can be seen that the cross-sectional contour 42 together with the rotation axis R describes the rotationally symmetric workpiece 28 or model 38. A contour of the rotationally symmetric workpiece 28 or the model 38 can be generated by rotating the cross-sectional contour 42 about the rotation axis R. In the process, the cross-sectional contour 42 performs a 360° rotation about the rotation axis R.

[0100] It can further be seen that the cross-sectional contour 42 represents different wall thicknesses of the workpiece 28 or model 38.

[0101] FIG. 5 shows the cross-sectional contour 42 of FIG. 4 including the rotation axis R. However, in contrast to FIG. 4, a continuous cross-sectional path 54 is inscribed in the cross-sectional contour 42. The continuous cross-sectional path 54 starts at a lower end 56 of the cross-sectional contour 42 and extends to an upper end 58 of the cross-sectional contour 42. In particular, at the lower end 56 and the upper end 58, the cross-sectional path 54 is configured such that it contacts the cross-sectional contour 42. In between, the cross-sectional path 54 is spaced from the cross-sectional contour 42.

[0102] In a first portion 60 that is disposed at the lower end 56 and in an area of the perpendicular contour line 46 and the arcuate contour line 48, the cross-sectional path 54 is substantially evenly spaced with respect to the perpendicular contour line 46 or the arcuate contour line 48 and the inner contour line 50. In the area of the perpendicular contour line 46, the cross-sectional path 54 is substantially straight. In the area of the arcuate contour line 48, however, the cross-sectional path 54 is arcuate, too.

[0103] A second portion 62 of the cross-sectional path 54 is disposed in the areas of the arcuate contour line 48 and of the oblique contour line 44. In the second portion 62, the cross-sectional path 54 is meandering. In particular, the cross-sectional path 54 is meandering between the arcuate contour line 48 or the oblique contour line 44 and the inner contour line 50.

[0104] A third portion 64 of the cross-sectional path 54 is disposed in the area of the oblique contour line 44. In the third portion 64, the cross-sectional path 54 runs in paths that are parallel to each other. By way of example, a first path 66 is discussed that is arranged parallel to a second path 68. The first path 66 is connected to the second path 68 by a first connecting path 70. A third path 72 is arranged parallel to the first path 66 and the second path 68 and is connected to the second path 68 by a second connecting path 74. The paths 66, 68, 72 are arranged perpendicular to the rotation axis R. The first connecting path 70 is disposed near the inner contour line 50 and substantially parallel to an adjacent course of the inner contour line 50. The second connecting path 74 is disposed near the oblique contour line 44 and substantially parallel to an adjacent course of the oblique contour line 44. Generally, connecting paths may be parallel to an adjacent course of the cross-sectional contour 42.

[0105] It can be seen that the parallel paths, as exemplified by the paths 66, 68, 72, depend on the wall thickness of the cross-sectional contour 42. The greater the wall thickness of the cross-sectional contour 42, the longer the parallel paths.

[0106] It can further be seen that the parallel paths are the biggest in the area of the shoulder contour line 52 where the wall thickness of the cross-sectional contour 42 is the greatest.

[0107] In a fourth portion 76 above the shoulder contour line 52 and in the area of the upper end 58, the parallel paths of the cross-sectional path 54 become smaller before the cross-sectional path 54 is substantially straight again. Further, the cross-sectional path 54 is configured to contact the cross-sectional contour 42 in the area of the upper end 58.

[0108] It should be noted that the cross-sectional path 54 is an example of how the cross-sectional path 54 may be disposed within the cross-sectional contour 42. However, it is essential that the cross-sectional path 54 has a defined starting point 78 and a defined end point 79 that are disposed on the outside of the cross-sectional contour 42 or the outside of a portion of the cross-sectional contour if the cross-sectional contour 42 is divided into several portions. The cross-sectional path 54 may be configured in different ways within the cross-sectional contour 42 between the defined starting point 78 and the defined end point 79.

[0109] Furthermore, the cross-sectional path 54 is inscribed in the cross-sectional contour 42 in such a way that material application along a tool path to be generated from the cross-sectional path 54 is sufficient. In this context, it may be an advantage to take manufacturing parameters into account already when generating the continuous cross-sectional path 54. The manufacturing parameters may include a width and a height of the material applied.

[0110] According to a simplified procedure, it can be assumed that material is applied along the cross-sectional path 54. The cross-sectional path 54 is to be inscribed in the cross-sectional contour 42 in such a way that the material applied fills the cross-sectional contour 42 completely.

[0111] In the present case, it can be seen that apart from the starting point 78 and the end point 79, the cross-sectional path 54 is spaced from the cross-sectional contour 42. This is due to the manufacturing parameters. For example, if the cross-sectional path 54 is substantially parallel to an adjacent portion of the cross-sectional contour 42, as is the case with the first portion 46 or the connecting paths 70, 74, the cross-sectional path 54 may be spaced from the cross-sectional contour 42 by half the width of the material applied in each case.

[0112] The parallel paths, too, are generated taking into account manufacturing parameters. As explained by way of example with reference to the first path 66 and the second path 68, they are spaced from one another by a predetermined distance. Preferably, such predetermined distance also results from the manufacturing parameters. For example, the predetermined distance corresponds to a height of the material applied.

[0113] FIG. 6 shows a section of the cross-sectional contour 42 of FIG. 5. In contrast to FIG. 5, however, tool path points 80 are formed on the cross-sectional path 54. At the tool path points 80, a tool path to be generated and not yet illustrated intersects the cross-sectional path 54. More precisely, a tool path section of the tool path not illustrated revolves around the rotation axis R between adjacent tool path points 80.

[0114] The tool path points 80 are distributed along the cross-sectional path 54. The tool path points 80 may be distributed evenly along the cross-sectional path 54 as illustrated. When determining tool path points 80 on the cross-sectional path 54, taking into account manufacturing parameters may be an advantage. Manufacturing parameters may also include the width and/or height of a material applied. In particular, the tool path points 80 may be distributed evenly along the cross-sectional path 54 if the width and height of the material applied are identical. In the present case, the tool path points 80 are arranged along the cross-sectional path 54 at a fixed distance L.

[0115] Starting from the starting point 78, this point may represent a first tool path point 80. Starting from the starting point 78, further tool path points 80 may be generated along the cross-sectional path 54 until the end point 79 is reached.

[0116] FIG. 7 shows the cross-sectional contour 42 with a continuous cross-sectional path 54 including an example of a tool path 82. A first tool path section 84 of the tool path 82 extends between two adjacent tool path points 80 of the cross-sectional path 54 and revolves around the rotation axis R.

[0117] It can be seen that the tool path 82 intersects the cross-sectional path 54 or the surface surrounded by the cross-sectional contour 42 at the tool path points 80. The tool path 82 may be the tool path 20 of FIG. 1.

[0118] FIG. 8 shows the tool path 82 in connection with the continuous cross-sectional path 54. FIG. 8 in particular shows how the tool path 82 or the tool path section 84 is generated using the cross-sectional path 54.

[0119] Starting from a first tool path point 81, in the present case the lower of the two tool path points, position information is continuously taken into account until an adjacent, second tool path point 83, in the present case the upper of the adjacent tool path points, is reached. More precisely, position information of individual points on the cross-sectional path 54 between the adjacent tool path points 81, 83 is continuously assigned to individual points of the tool path section 84. In other words, points on the tool path section 84 are generated based on points on the cross-sectional path 54. The position information includes a height coordinate z and a distance coordinate r. The position information further includes angle information α. The angle information α may be formed for a point on the tool path section 84 by determining how far away a point on the cross-sectional path 54 is from the first tool path point 81 on the cross-sectional path 54 and how close it is to the second tool path point 83. Proportionally, the angle information α is formed as a proportion of a complete revolution about the rotation axis R.

[0120] FIG. 8 shows an example of a point 86 on the cross-sectional path 54 in the cross-sectional contour 42. The point 86 is on a portion of the cross-sectional path or a cross-sectional path section. Based on the point 86 of the cross-sectional path 54, a point 88 of the tool path section 84 is generated. For this purpose, the point 88 of the tool path section 84 is assigned the height coordinate z and the distance coordinate r of the point 86 of the cross-sectional path 54. The distance coordinate r describes a perpendicular distance of the point 86 relative to the rotation axis R. The height coordinate z describes a height in the direction of the rotation axis R. Furthermore, it is determined for the point 86 on the cross-sectional path 54 how far away it is from the first tool path point 81 on the cross-sectional path 54. This distance is set in relation to the distance between the two adjacent tool path points 81, 83 on the cross-sectional path 54. Proportionally, the angle information α is determined as a proportion of a complete revolution about the rotation axis R. The angle information α, too, is assigned to the point 88 of the tool path section 84.

[0121] Based on the described procedure for generating the tool path 82, it can be seen that starting from the first tool path point 81, the tool path section 84 is initially configured to combine a spiral shape and a helical shape. This is due to the fact that the first tool path point is formed on a connecting path between parallel paths of the cross-sectional path 54 and that this connecting path is arranged at an angle relative to the rotation axis R. When a corner point 90 is reached on the cross-sectional path 54 between the connecting path and the parallel path, the tool path section 84 is configured to have a spiral shape until the second tool path point 83 is reached. This is due to the fact that the cross-sectional path 54 between the corner point 90 and the second tool path point 83 is configured perpendicularly relative to the rotation axis R. This means that the tool path section 84 has a kink in its pitch.

[0122] FIG. 9 is an alternative view to that of FIG. 8. More specifically, FIG. 9 is a slightly tilted view of the cross-sectional contour 42.

[0123] FIG. 9 also shows the tool path 82 in connection with the continuous cross-sectional path 54. It can be seen that the tool path section 84 intersects the cross-sectional path 54 and thus the surface surrounded by the cross-sectional contour 42 at the first tool path point 81. Further, the tool path section 84 revolves about the rotation axis R (not illustrated) and intersects the cross-sectional path 54 or the surface surrounded by the cross-sectional contour 42 at the second tool path point 83. Further, the point 86 is shown on the cross-sectional path 54, which is disposed between the first tool path point 81 and the second tool path point 83 on the cross-sectional path 54. In addition, the corresponding point 88 on the tool path section 84, which was generated based on the point 86 on the cross-sectional path 54, is illustrated.

[0124] The point 86 on the cross-sectional path 54 is assigned the height coordinate z, the distance coordinate r and the angle information 0. The point 88 of the tool path section 84 is assigned the height coordinate z, the distance coordinate r and the angle information α. It could be said that the two points 86, 88 correspond to each other but that the point 86 of the cross-sectional path 54 is rotated around the rotation axis R using the angle information α to generate the point 88 of the tool path section 84.

[0125] FIG. 10 is a further alternative view of the tool path 82 in connection with the continuous cross-sectional path 54. Compared to FIG. 9, however, the entire tool path section 84 is shown. It can be seen that the tool path section 84, starting from the first tool path point 81, rotates completely around the rotation axis R until the second tool path point 83 is reached. In addition, the cross-sectional contour 42 is shown at least in sections.

[0126] FIG. 11 shows a section of the cross-sectional contour 42 including a continuous cross-sectional path 54. Other than in the previous illustrations, neither the tool path 82 nor the tool path section 84 is shown. The first tool path point 81 and the second tool path point 83 are shown on the cross-sectional path 54. Between the two tool path points 81, 83, there is the point 86 on cross-sectional path 54. The point 86 on the cross-sectional path 54 is assigned the height coordinate z, the distance coordinate r and the angle information 0.

[0127] FIG. 12 is another view of the tool path 82. Compared to the previous illustrations of the tool path 82, the first tool path section 84 is shown together with a second tool path section 92. The second tool path section 92 adjoins the first tool path section 82 and is further connected to the latter by the second tool path point 83. Further, the second tool path section 92 intersects the cross-sectional path 54 at a third tool path point 94.

[0128] FIG. 12 also shows the rotation axis R about which the first tool path section 84 and the second tool path section 92 revolve. Furthermore, the cross-sectional contour 42 is shown almost completely.

[0129] FIG. 13 in an alternative view of the tool path 82 of FIG. 12. More specifically, FIG. 13 is a tilted view of the cross-sectional contour 42. The first tool path section 84, starting from the first tool path point 81, revolves around the rotation axis R (not illustrated) and intersects the cross-sectional path 54 at the second tool path point 83. Furthermore, the second tool path section 92 is connected to the first tool path section 84 by the second tool path point 83. The second tool path section 92, starting from the second tool path point 83, revolves around the rotation axis R (not illustrated) to the third tool path point 94.

[0130] The cross-sectional path 54 is disposed between the second tool path point 83 and the third tool path point 94 substantially perpendicularly relative to the rotation axis R. Accordingly, the second tool path section 92 has a spiral shape.

[0131] From FIGS. 12 and 13 it can be seen that tool path sections 84, 92 can be easily formed starting from the cross-sectional path 54 and the tool path points 81, 83, 94. The more tool path sections are formed for adjacent tool path points, the more completely the tool path 82 is described.

[0132] FIG. 14 is a view of an additionally extended tool path 82. Compared to the illustrations of the first tool path section 84 and the second tool path section 92 in FIGS. 12 and 13, another four tool path sections 96 are shown, each disposed between adjacent tool path points 80.

[0133] For reasons of clarity, only a selection of tool path sections 84, 92, 96 are shown. However, the tool path sections 84, 92, 96 may be formed for the entire cross-sectional path 54 so that a complete tool path 82 can be provided for the cross-sectional contour 42.

[0134] FIG. 15 is a perspective side view of an alternative workpiece 328 to be manufactured. The workpiece 328 is rotationally symmetric about the symmetry axis A. Upon close scrutiny, it can be seen that the alternative workpiece 328 is based on the workpiece 28 of FIG. 2. For example, the workpiece 328 is formed to be hollow on the inside and includes the inner shoulder 336. Further, an inner surface 340 (not shown in detail in the illustration) is formed below the shoulder 336.

[0135] In addition, the workpiece 328 includes a plate-shaped collar 397. The collar 397 is formed on the frustoconical lateral surface 330 that is connected to the cylindrical lateral surface 332 at a lower end of the workpiece 328 by the transitional lateral surface 334. Starting from the frustoconical lateral surface 330, the plate-shaped collar 397 is disposed substantially perpendicularly relative to the symmetry axis A, i.e. in a radial direction. The plate-shaped collar 397 further has an upper plate surface 398 and a lower plate surface 399 that are parallel to each other. The plate-shaped collar 397 thus has a constant collar thickness.

[0136] FIG. 16 shows an example of a cross-sectional contour 342 of the alternative workpiece 328 to be manufactured including the rotation axis R. The rotation axis R corresponds to the symmetry axis A of FIG. 15. Like the cross-sectional contour 42 of FIG. 4, the cross-sectional contour 342 of the alternative workpiece 328 to be manufactured is a closed contour line.

[0137] The cross-sectional contour 342 is based on the alternative rotationally symmetric workpiece 328 and is two-dimensional. The cross-sectional contour 342 may be generated in a manner that is analogous to the cross-sectional contour 42 of FIG. 4. In particular, the cross-sectional contour 342 may be generated by intersecting the workpiece 328 with a plane in which the symmetry axis A is. Intersecting the workpiece 328 in this manner creates two cross-sectional half contours that are separated by the workpiece axis A and the rotation axis R, respectively, with the cross-sectional contour 342 being one of the two cross-sectional half contours. The cross-sectional contour 342 is spaced apart from the rotation axis R, the arrangement of the cross-sectional contour 342 relative to the rotation axis R resulting from the rotationally symmetric workpiece 328 and the previously explained generation of the cross-sectional contour 342.

[0138] The cross-sectional contour 342 includes an upper oblique contour line 344 and a lower oblique contour line 345, with a plate contour 347 formed between the two that is based on the plate-shaped collar 397. The plate contour 347 includes an upper plate contour line 349 and a lower plate contour line 351 that are connected by a lateral plate contour line 353.

[0139] The cross-sectional contour 342 further includes a perpendicular contour line 346 based on the cylindrical lateral surface 332. The lower oblique contour line 345 and the perpendicular contour line 346 are connected by an arcuate contour line 348 based on the transitional lateral surface 334. The cross-sectional contour 342 further includes an inner contour line 350 based on the inner surface 340. In addition, a shoulder contour line 352 is formed based on the shoulder 336.

[0140] It can be seen that the cross-sectional contour 342 together with the rotation axis R describes the rotationally symmetric workpiece 328. A contour of the rotationally symmetric workpiece 328 may be generated by rotating the cross-sectional contour 342 about the rotation axis R. In the process, the cross-sectional contour 342 performs a 360° rotation about the rotation axis R.

[0141] Looking at the cross-sectional contour 342, varying wall thicknesses of the workpiece 328 can be seen. It can further be seen that the plate contour 347 is substantially perpendicular or extends in a radial direction relative to the rotation axis R.

[0142] FIG. 17 shows the cross-sectional contour 342 of the alternative workpiece 328 to be manufactured of FIG. 16, having a first continuous cross-sectional path 354 and a second continuous cross-sectional path 355. The first continuous cross-sectional path 354 is formed analogously to the continuous cross-sectional path 54 of FIG. 5 and is inscribed in a portion of the cross-sectional contour 342 based on the cross-sectional contour 42 of FIG. 5. With respect to forming the first continuous cross-sectional path 354 and with respect to general aspects of forming a continuous cross-sectional path, reference is made to the continuous cross-sectional path 54 of FIG. 5.

[0143] The second continuous cross-sectional path 355 is inscribed in a portion of the cross-sectional contour 342 based on the plate contour 347. Starting from a left end 357 of the plate contour 347, the second continuous cross-sectional path 355 extends to the lateral plate contour line 353. The second continuous cross-sectional path 355 is formed as parallel paths, wherein adjacent parallel paths are connected to each other by a connecting path.

[0144] It can be seen that the parallel paths depend on a wall thickness of the portion of the cross-sectional contour 342, the wall thickness resulting from a distance between the upper plate contour line 349 and the lower plate contour line 351. The greater the wall thickness of the portion of the cross-sectional contour 342, in the present case the plate contour 347, the longer the parallel paths. For example, the parallel paths are longer at the left end 357 where the wall thickness of the plate contour 347 is greater.

[0145] It should be noted that the second cross-sectional path 355 is an example of how the second cross-sectional path 355 may be disposed within the cross-sectional contour 42. However, it is essential that the second cross-sectional path 355 also has a defined starting point 378 and a defined end point 379 that are disposed on the outside of the cross-sectional contour 342 or the outside of a portion of the cross-sectional contour 342, such as the plate contour 347 in the present case, if the cross-sectional contour 342 is divided into several portions. The second cross-sectional path 355 may also be formed between the defined starting point 378 and the defined end point 379 in different ways.

[0146] Furthermore, the second cross-sectional path 355 is also inscribed in the cross-sectional contour 342 in such a way that material application along a tool path to be generated from the second cross-sectional path 355 is sufficient to fill the portion of the cross-sectional contour 342, in the present case the plate contour 347. In this context, it may be an advantage to take manufacturing parameters into account already when generating the second continuous cross-sectional path 355. The manufacturing parameters may include a width and a height of the material applied.

[0147] According to a simplified procedure, it can be assumed that material is applied along the second cross-sectional path 355. The second cross-sectional path 355 is to be inscribed in the portion of the cross-sectional contour 342 in such a way that the material applied completely fills the portion of the cross-sectional contour 342, i.e. the plate contour 347.

[0148] Dividing the cross-sectional contour 342 into portions is a particular advantage if the cross-sectional contour 342 is complex. As a result of a complex cross-sectional contour 342, manufacturing using a tool path may not be possible or may at least involve an increased effort. If, for example, the parallel paths of the first cross-sectional path 354 were to extend into the plate contour 347, at least the lowest parallel path would initially have no path below it to build upon unless the rotation axis is tilted. However, this would complicate the manufacturing process. Dividing into several portions may thus improve the application or manufacturing process. The application or manufacturing process may be customized for the individual portions. In particular, cross-sectional path shapes, width and/or height of the material applied, substance and/or alignment information may be selected individually for portions. Complex manufacturing processes can thus be avoided, for example, by appropriately selecting portions of the cross-sectional contour 342. In the present case, a second cross-sectional path 355 laterally adjoining the first cross-sectional path 354 or the first portion of the cross-sectional contour 342 and manufacturing the workpiece first using a tool path based on the first cross-sectional path 354 and then using a tool path based on the second cross-sectional path 355 may help to avoid complicated manufacturing. For the second cross-sectional path 355, alignment information is then to be selected, e.g. an alignment perpendicular to the rotation axis R.

[0149] FIG. 18 shows a section of a cross-sectional contour 442 similar to that of FIG. 6, but tool path points are determined differently. A first distance L1 and a second distance L2 are used to arrange tool path points on differently aligned parts of the cross-sectional path 454 or path sections of different pitch relative to the rotation axis R. In the present case, the first distance L1 is used to arrange tool path points along a first path section, i.e. a horizontal path section, on the cross-sectional path 454. The second distance L2 is used to arrange tool path points along a second path section, i.e. a connecting path. A combination of the two distances L1 and L2 is used to determine the tool path points at transitions in the cross-sectional path 454.

[0150] For example, a first tool path point 481 is spaced from a second tool path point 483 by distance L1. Both tool path points 481, 483 are arranged on a first path 466, wherein the first path 466 is one of the parallel paths and runs straight.

[0151] A third tool path point 494 is arranged on a first connecting path 470. Between the second tool path point 483 and the third tool path point 494 there is a transition with a corner point 490. Starting from the second tool path point 483, the first distance L1 is at least partially used for the first path 466 until it finally merges into the first connecting path 470. If only a percentage of the first distance L1 is used, a percentage of the second distance L2 is determined for the immediately following cross-sectional path 454 in proportion to the remaining percentage.

[0152] The respective distance L1, L2 may determine the extent to which the angle information α progresses. The distances L1, L2 may thus have an impact on the tool path points on the cross-sectional path 454 and the course of the tool path. In the present case, the chosen second distance L2 is smaller than the first distance L1. This means that the second distance L2 causes the angle information α to progress more strongly relative to the cross-sectional path. In other words, in the case of the smaller second distance L2, the tool path rotates about the rotation axis R within a smaller part of the cross-sectional path.

[0153] The distances L1 and L2 may be determined based on manufacturing parameters such as a height and width of a material applied. In the present case, the first distance L1 is based on a width of the material applied. In the present case, the second distance L2 is based on a height of the material applied or a combination of a height and width of the material applied.

[0154] In addition to the tool path points 481, 483, 494, other tool path points along the cross-sectional path may be determined in this manner. It should be noted that in addition to distance L or distances L1, L2, there may be any number of distances which are preferably provided for portions of the cross-sectional path 454 of different orientation.

[0155] FIG. 19 shows a section of a cross-sectional contour 542 having a continuous cross-sectional path 554, wherein alignment information is provided for some points on the cross-sectional path 554. The alignment information describes an alignment of a tool axis of the application tool 12. Preferably, the tool axis is the axis along which the laser 22 is directed. In the present case, the alignment information is a direction vector that is oriented in the direction of the application tool 12. However, the alignment information may also be an alignment angle indicating the angle of the tool axis relative to the rotation axis R.

[0156] The points on the cross-sectional path 554 may be any points. However, the points on the cross-sectional path may also be tool path points. Alternatively, the alignment information may also be provided for points on the tool path.

[0157] In the present case, a first direction vector 502 is provided at a first point 501 of the cross-sectional path 554. Further, a second direction vector 504 is provided at a second point 503 of the cross-sectional path 554, a third direction vector 506 is provided at a third point 505, a fourth direction vector 508 is provided at a fourth point 507, and a fifth direction vector 510 is provided at a fifth point 509.

[0158] It can be seen that the direction vectors 502, 504, 506, 508, 510 are not uniformly oriented. The first direction vector 502, third direction vector 506 and fifth direction vector 510 are oriented substantially the same in the upward direction, but they are slightly tilted. Depending on the cross-sectional contour 542 or the workpiece, the direction vectors 502, 506, 510 may also be oriented differently. The second direction vector 504 and the fourth direction vector 508, too, are oriented substantially the same, but they are substantially parallel to the inner contour line 550. Depending on the cross-sectional contour 542 or the workpiece, the direction vectors 504, 508 may also be oriented differently.

[0159] The alignment information may be derived from a local shape of the workpiece to be manufactured. The alignment information may further be used to align the tool axis of the application tool 12 in such a way that the material to be applied is applied to material that has already been applied. This is necessary because in additive manufacturing the material requires a substrate that supports the new material to be applied.

[0160] FIG. 20 shows the section of the cross-sectional contour 542 of FIG. 19, but the available alignment information has been expanded. More precisely, alignment information was determined for each exemplary point between the points having alignment information.

[0161] For example, the first direction vector 502 and the second direction vector 504 were used to determine direction vectors for points between the first point 501 and the second point 503 along the cross-sectional path 554. More specifically, the alignment information for these points is averaged based on the direction vectors 502, 504. For example, the farther such a point is located from the first point 501 toward the second point 503 along the cross-sectional path, the more similar the determined direction vector is to the second direction vector 504. Averaging may be performed on the basis of interpolation or linear interpolation.

[0162] FIG. 21 shows a section of the cross-sectional contour 542 of FIGS. 19 and 20. It is an example of how available alignment information is used to determine alignment information for a point 511 on the cross-sectional path 554.

[0163] Initially, the first direction vector 502 is present at the first point 501 and the second direction vector 504 is present at the second point 503. These direction vectors are shown in bold to stand out from determined direction vectors. A first tool path point 581 and a second tool path point 583 are located on the cross-sectional path 554 between the two points 501, 503. However, they are for illustrative purposes only and are not used for determining alignment information in this example. Nevertheless, alignment information could also be determined for them.

[0164] Between the two points 501, 503, the point 511 is disposed on the cross-sectional path 554. It is described by the height coordinate z and the distance coordinate r. Since the point 511 is disposed on the cross-sectional path 554, the angle information 0 (“zero”) is assigned to it. In this context, reference is made to FIG. 11. In this Figure, for example, point 511 is shown as point 86, but without alignment information. Depending on the distance of the point 511 to the first point 501 and the second point 503 on the cross-sectional path 554, the direction vectors 502, 504 are averaged, in particular linearly interpolated, in order to determine alignment information in the form of a direction vector 512 for the point 511.

[0165] FIG. 22 shows the cross-sectional contour 42 with a continuous cross-sectional path 54 including an exemplary first tool path section 84 of the tool path 82. FIG. 22 is based on FIG. 7 but provides a more comprehensive overview. It illustrates the rotation axis R about which the tool path section 84 rotates, for example. It also shows a point 85 on the tool path 82 that is rotated about the rotation axis R relative to the cross-sectional contour 42 by an angle α. Alignment information is provided for the point 85 on the tool path 82 in the form of a direction vector 87. The direction vector 87 is aligned along a tool axis W. The tool axis W intersects the rotation axis R at the axis intersection point 89. An application tool head 14 of the application tool 12 (not shown in more detail) is shown schematically at the point 85. This is to illustrate that the application tool 12 applies material along the tool path 82. Since the application tool head 14 is oriented along the tool axis W, the alignment information for point 85 is taken into account.

[0166] The tool path section 84 extends between the first tool path point 81 and the second tool path point 83. Individual points on the tool path section 84 were determined based on the cross-sectional path 54 between the first and second tool path points 81, 83. For example, as described previously, the distance coordinate r and the height coordinate z of a point on the cross-sectional path 54 between the tool path points 81, 83 were taken for the point 85. Furthermore, an angle information α was determined based on the position of the point on the cross-sectional path 54 with respect to the tool path points 81, 83 along the cross-sectional path 54. The alignment information for point 85 was either taken from the point on the cross-sectional path 54, provided alignment information was available for it. Alternatively, the alignment information was determined based on specified alignment information, as described above. In this case, it may be provided that the alignment information of the point on the cross-sectional path, in particular if it is available as a vector, is rotated about the rotation axis R to the point 85 of the tool path 84 using the angular information α. Again, alternatively, the alignment information for the point 85 was specified. For different points of the tool path 84, various of the previously explained procedures for determining the alignment information may be applied.

[0167] In analogy to the described procedure, starting from the cross-sectional path 54 in the cross-sectional contour 42 or the portion of the cross-sectional contour 42, arbitrary points of the tool path 82 may be generated to completely describe the tool path 82 and to enable additive manufacturing.

[0168] Preferably, the tool axis W intersects the rotation axis R. This is the case when the tool axis W is not aligned parallel to the rotation axis R.

[0169] In addition to the foregoing, according to further embodiments of the invention, it may be provided that at least one of the following manufacturing parameters is changed during additive manufacturing of the workpiece: [0170] Composition of the additive manufacturing material, [0171] Feed rate of the application tool, [0172] Power of the application tool, and [0173] Gas flow of the application tool.

[0174] For example, with reference to the illustration shown in FIG. 9, the powder composition may be changed at a particular point, for example at the point 81, in combination with the power of the application laser relative to the remaining path 84. The transitions may be abrupt or linearly interpolated.